New and Updated Product Datasheets

UPDATED: LTC4266A/LTC4266C - Quad PoE/PoE+/LTPoE++ PSE Controller

Fri, 03 Feb 2012 10:45:24 -0800

The LTC®4266A is a quad power sourcing equipment (PSE) controller capable of delivering up to 90W of LTPoE++ power to a compatible LTPoE++ powered device (PD). A proprietary detection/classification scheme allows mutual identification between a LTPoE++ PSE and LTPoE++ PD while remaining compatible and interoperable with existing Type 1 (13W) and Type 2 (25.5W) PDs. The LTC4266A feature set is a superset of the popular LTC4266. These PSE controllers feature low RON external MOSFETs and 0.25Ω sense resistors which are especially important at the LTPoE++ current levels to maintain the lowest possible heat dissipation. The LTC4266C targets fully automatic PSE systems powering Type 1 (up to 13W) PDs. Advanced power management features include: 14-bit current monitoring ADCs, DAC-programmable current limit, and versatile quick shutdown of preselected ports. Advanced power management host software is available under a no-cost license. PD discovery uses a proprietary dual-mode 4-point detection mechanism ensuring excellent immunity from false PD detection. The LTC4266 includes an I2C serial interface operable up to 1MHz. The LTC4266 is available in multiple power grades allowing delivered PD power of 13W, 25W, 38.7W, 52.7W, 70W and 90W. These controllers are available in a 38-pin 5mm × 7mm QFN package.

NEW: LT3799-1 - Offline Isolated Flyback LED Controller with Active PFC

Fri, 03 Feb 2012 10:37:07 -0800

The LT®3799-1 is an isolated flyback controller with power factor correction specifically designed for driving LEDs. The controller operates using critical conduction mode allowing the use of a small transformer. Using a novel current sensing scheme, the controller is able to deliver a well regulated current to the secondary side without using an opto-coupler. A strong gate driver is included to drive an external high voltage MOSFET. Utilizing an onboard multiplier, the LT3799-1 typically achieves power factors of 0.97. The FAULT pin provides notification of open and short LED conditions. The LT3799-1 offers improved line regulation over the LT3799, but is not designed for use with a TRIAC dimmer. The LT3799-1 uses a micropower hysteretic start-up to efficiently operate at offline input voltages, with a third winding to provide power to the part. An internal LDO provides a well regulated supply for the part’s internal circuitry and gate driver.

UPDATED: LTC4155 - Dual Input Power Manager/ 3.5A Li-Ion Battery Charger with I2C Control and USB OTG

Fri, 03 Feb 2012 10:31:20 -0800

The LTC®4155 is a 15 watt I2C controlled power manager with PowerPath™ instant-on operation, high efficiency switching battery charging and USB compatibility. The LTC4155 seamlessly manages power distribution from two 5V sources, such as a USB port and a wall adapter, to a single-cell rechargeable Lithium-Ion/Polymer battery and a system load. The LTC4155’s switching battery charger automatically limits its input current for USB compatibility, or may draw up to 3A from a high power wall adapter. The high efficiency step-down switching charger is designed to provide maximum power to the application and reduced heat in high power density applications. I2C adjustability of input current, charge current, battery float voltage, charge termination, and many other parameters allows maximum flexibility. I2C status reporting of key system and charge parameters facilitates intelligent control decisions. USB On-The-Go support provides 5V power back to the USB port without any additional components. A dual-input, priority multiplexing, overvoltage protection circuit guards the LTC4155 from high voltage damage on the VBUS pin. The LTC4155 is available in the low profile 28-lead 4mm × 5mm × 0.75mm QFN surface mount package.

NEW: LTC4252B-1/LTC4252B-2 LTC4252C-1/LTC4252C-2 - Negative Voltage Hot Swap Controllers

Tue, 31 Jan 2012 11:01:46 -0800

The LTC®4252 negative voltage Hot SwapTM controller allows a board to be safely inserted and removed from a live backplane. Output current is controlled by three stages of current limiting: a timed circuit breaker, active current limiting and a fast feedforward path that limits peak current under worst-case catastrophic fault conditions. Adjustable undervoltage and overvoltage detectors disconnect the load whenever the input supply exceeds the desired operating range. The LTC4252’s supply input is shunt regulated, allowing safe operation with very high supply voltages. A multifunction timer delays initial startup and controls the circuit breaker’s response time. The circuit breaker’s response time is accelerated by sensing excessive MOSFET drain voltage, keeping the MOSFET within its safe operating area (SOA). An adjustable softstart circuit controls MOSFET inrush current at start-up. The LTC4252-2 provides automatic retry after a fault. The LTC4252C-1/LTC4252C-2 feature tight ±1% undervoltage/ overvoltage threshold accuracy. The LTC4252 is available in either an 8-pin or 10-pin MSOP. The LTC4252B and LTC4252C improve the ruggedness of the shunt regulator in the LTC4252 and LTC4252A.

NEW: LTC4253B - -48V Hot Swap Controller with Sequencer

Mon, 30 Jan 2012 10:13:40 -0800

The LTC®4253B negative voltage Hot Swap™ controller allows a board to be safely inserted and removed from a live backplane. Output current is controlled by three stages of current-limiting: a timed circuit breaker, active current limiting and a fast feedforward path that limits peak current under worst-case catastrophic fault conditions. The LTC4253B latches off after a circuit fault. Adjustable undervoltage and overvoltage detectors disconnect the load whenever the input supply exceeds the desired operating range. The LTC4253B’s supply input is shunt-regulated, allowing safe operation with very high supply voltages. A multifunction timer delays initial start-up and controls the circuit breaker’s response time. The circuit breaker’s response time can be accelerated by sensing excessive MOSFET drain voltage, keeping the MOSFET within its safe operating area (SOA). An adjustable softstart circuit controls MOSFET inrush current at start-up. Three power good outputs are sequenced by an adjustable timer and two ENABLE inputs to enable external power modules at start-up or disable them if the circuit breaker trips. The LTC4253B improves the ruggedness of the LTC4253 shunt regulator.

UPDATED: LT3799 - Offline Isolated Flyback LED Controller with Active PFC

Fri, 27 Jan 2012 16:06:23 -0800

The LT3799 is an isolated flyback controller with power factor correction specifically designed for driving LEDs. The controller operates using critical conduction mode allowing the use of a small transformer. Using a novel current sensing scheme, the controller is able to deliver a well regulated current to the secondary side without using an opto-coupler. A strong gate driver is included to drive an external high voltage MOSFET. Utilizing an onboard multiplier, the LT3799 typically achieves power factors of 0.97. The FAULT pin provides notification of open and short LED conditions. The LT3799 uses a micropower hysteretic start-up to efficiently operate at offline input voltages, with a third winding to provide power to the part. An internal LDO provides a well regulated supply for the part’s internal circuitry and gate driver.

UPDATED: LTC3589/LTC3589-1 - 8-Output Regulator with Sequencing and I2C

Fri, 27 Jan 2012 14:07:08 -0800

The LTC®3589/LTC3589-1 are complete power management solutions for ARM and ARM-based processors and advanced portable microprocessor systems. The device contains three step-down DC/DC converters for core, memory and SoC rails, a buck-boost regulator for I/O at 1.8V to 5V and three 250mA LDO regulators for low noise analog supplies. An I2C serial port is used to control enables, output voltage levels, dynamic voltage scaling, operating modes and status reporting. Differences between the LTC3589 and LTC3589-1 are summarized in Table 1. Regulator start-up is sequenced by connecting outputs to enable pins in the desired order or via the I2C port. System power-on, power-off, and reset functions are controlled by pushbutton interface, pin inputs, or I2C interface. The LTC3589/LTC3589-1 support i.MX53/51, PXA and OMAP processors with eight independent rails at appropriate power levels. Other features include interface signals such as the VSTB pin that simultaneously toggle up to four rails between programmed run and standby output voltages. The device is available in a low profile 40-pin 6mm × 6mm exposed pad QFN package. FeaturesLTC3589LTC3589-1 Power-On Inhibit Enable Dealy 1 second < 2ms Buck2 Current Output 1A 1.2A Buck3 Current Output 1A 1.2A PGOOD Fault Timeout Enabled by default, I2C disable Disabled by default, I2C enable PWR_ON to WAKE Delay 50ms 2ms LDO3 Vout 1.8V 2.8V LDO4 Vout 1.8V, 2.5V, 2.8V, 3.3V 1.2V, 1.8V, 2.5V, 3.2V Default LDO4 Enable LDO34_EN Pin I2C

UPDATED: LTC3115-1 - 40V, 2A Synchronous Buck-Boost DC/DC Converter

Thu, 26 Jan 2012 15:44:19 -0800

The LTC®3115-1 is a high voltage monolithic synchronous buck-boost DC/DC converter. Its wide 2.7V to 40V input and output voltage ranges make it well suited to a wide variety of automotive and industrial applications. A proprietary low noise switching algorithm optimizes efficiency with input voltages that are above, below or even equal to the output voltage and ensures seamless transitions between operational modes. Programmable frequency PWM mode operation provides low noise, high efficiency operation and the ability to synchronize switching to an external clock. Switching frequencies up to 2MHz are supported to allow use of small valued inductors for miniaturization of the application circuit. Pin selectable Burst Mode operation reduces standby current and improves light load efficiency which combined with a 3μA shutdown current make the LTC3115-1 ideally suited for battery-powered applications. Additional features include output disconnect in shutdown, short-circuit protection and internal soft-start. The LTC3115-1 is available in thermally enhanced 16-lead 4mm × 5mm × 0.75mm DFN and 20‑lead TSSOP packages.

UPDATED: LTC4274 - Single IEEE 802.3at Power Over Ethernet Controller

Thu, 26 Jan 2012 15:17:31 -0800

The LTC®4274 is a single power sourcing equipment controller designed for use in IEEE 802.3 Type 1 and Type 2 (high power) compliant Power over Ethernet systems. External power MOSFETs enhance system reliability and minimize channel resistance, cutting power dissipation and eliminating the need for heatsinks even at Type 2 power levels. External power components also allow use at very high power levels while remaining otherwise compatible with the IEEE standard. 80V-rated port pins provide robust protection against external faults. The LTC4274 includes advanced power management features, including current and voltage readback and programmable ICUT and ILIM thresholds. Available C libraries simplify software development; an optional AUTO pin mode provides fully IEEE-compliant standalone operation with no software required. Proprietary 4-point PD detection circuitry minimizes false PD detection while supporting legacy phone operation. Midspan operation is supported with built-in 2-event classification and backoff timing. Host communication is via a 1MHz I2C serial interface. The LTC4274 is available in a 5mm × 7mm QFN package that significantly reduces board space compared with competing solutions.

UPDATED: LTC4218 - Hot Swap Controller

Thu, 26 Jan 2012 15:16:29 -0800

The LTC4218 is a Hot Swap controller that allows a board to be safely inserted and removed from a live backplane. An internal high side switch driver controls the gate of an external N-channel MOSFET for supply voltages from 2.9V to 26.5V. A dedicated 12V version (LTC4218-12) contains preset 12V specific thresholds, while the standard LTC4218 allows adjustable thresholds. The LTC4218 provides an accurate (5%) current limit with current foldback limiting. The current limit threshold can be adjusted dynamically using an external pin. Additional features include a current monitor output that amplifies the sense voltage for ground referenced current sensing. Overvoltage, undervoltage and power good monitoring are also provided.

UPDATED: LTC4274A/LTC4274C - Single PoE/PoE+/LTPoE++ PSE Controller

Thu, 26 Jan 2012 15:14:06 -0800

The LTC®4274A is a single Power Sourcing Equipment (PSE) controller capable of delivering up to 90W of LTPoE++ power to a compatible LTPoE++ Powered Device (PD). A proprietary detection/classification scheme allows mutual identification between a LTPoE++ PSE and LTPoE++ PD while remaining compatible and interoperable with existing Type 1 (13W) and Type 2 (25.5W) PDs. The LTC4274A feature set is a superset of the popular LTC4274. These PSE controllers feature low-RON external MOSFETs and 0.25Ω sense resistors which are especially important at the LTPoE++ current levels to maintain the lowest possible heat dissipation. The LTC4274C targets fully automatic PSE systems powering Type 1 (up to 13W) PDs. Advanced power management features include: a 14-bit current monitoring ADC, DAC-programmable current limit, and versatile quick port shutdown. PD Discovery uses a proprietary dual-mode 4-point detection mechanism ensuring excellent immunity from false PD detection. The LTC4274A/LTC4274C includes an I2C serial interface operable up to 1MHz. The LTC4274A/LTC4274C is available in multiple power grades, allowing delivered PD power of 13W, 25.5W, 38.7W, 52.7W, 70W and 90W. These controllers are available in a 38-pin 5mm × 7mm QFN package.

UPDATED: LTM2882 - Dual Isolated RS232 μModule Transceiver + Power

Thu, 26 Jan 2012 14:15:35 -0800

The LTM®2882 is a complete galvanically isolated dual RS232 μModule® transceiver. No external components are required. A single 3.3V or 5V supply powers both sides of the interface through an integrated, isolated DC/DC converter. A logic supply pin allows easy interfacing with different logic levels from 1.62V to 5.5V, independent of the main supply. Coupled inductors and an isolation power transformer provide 2500VRMS of isolation between the line transceiver and the logic interface. This device is ideal for systems with different grounds, allowing for large common mode voltages. Uninterrupted communication is guaranteed for common mode transients greater than 30kV/μs. This part is compatible with the TIA/EIA-232-F standard. Driver outputs are protected from overload and can be shorted to ground or up to ±15V without damage. An auxiliary isolated digital channel is available. This channel allows configuration for half-duplex operation by controlling the DE pin. Enhanced ESD protection allows this part to withstand up to ±10kV (human body model) on the transceiver interface pins to isolated supplies and across the isolation barrier to logic supplies without latchup or damage.

UPDATED: LTM2881 - Complete Isolated RS485/RS422 μModule Transceiver + Power

Thu, 26 Jan 2012 14:07:44 -0800

The LTM®2881 is a complete galvanically isolated fullduplex RS485/RS422 μModule® transceiver. No external components are required. A single supply powers both sides of the interface through an integrated, isolated, low noise, efficient 5V output DC/DC converter. Coupled inductors and an isolation power transformer provide 2500VRMS of isolation between the line transceiver and the logic interface. This device is ideal for systems where the ground loop is broken allowing for large common mode voltage variation. Uninterrupted communication is guaranteed for common mode transients greater than 30kV/μs. Maximum data rates are 20Mbps or 250kbps in slew limited mode. Transmit data, DI and receive data, RO, are implemented with event driven low jitter processing. The receiver has a one-eighth unit load supporting up to 256 nodes per bus. A logic supply pin allows easy interfacing with different logic levels from 1.62V to 5.5V, independent of the main supply. Enhanced ESD protection allows this part to withstand up to ±15kV (human body model) on the transceiver interface pins to isolated supplies and ±10kV through the isolation barrier to logic supplies without latch-up or damage.

NEW: LTC2974 - Quad Digital Power Supply Manager with EEPROM

Thu, 26 Jan 2012 11:36:29 -0800

The LTC®2974 is a quad, digital power-supply monitor, supervisor, sequencer, and margin controller. Supervisory functions include over and under threshold limits for current, voltage and temperature on four output channels as well as OV/UV threshold limits for a single input channel. Programmable fault response allows the power supplies to be disabled with optional retry after a fault has been detected. Serial bus telemetry allows four output voltages, four output currents, four output temperatures, internal die temperature and one input voltage to be monitored. Power supply sequencing, precision point-of-load voltage adjustment and margining are supported with PMBus commands. A programmable watchdog timer monitors microprocessor activity for a stalled condition and resets the micro if necessary. The 1-wire synchronization bus supports power supply sequencing across multiple LTC digital power devices. User programmable parameters can be stored in EEPROM. Voltage/current supervisor, voltage/current monitor and temperature faults can also be logged to EEPROM.

NEW: LTC3866 - Current Mode Synchronous Controller for Sub Milliohm DCR Sensing

Thu, 26 Jan 2012 09:44:42 -0800

The LTC®3866 is a single phase current mode synchronous step-down switching regulator controller that drives all N-channel power MOSFET switches. It employs a unique architecture which enhances the signal-to-noise ratio of the current sense signal, allowing the use of a very low DC resistance power inductor to maximize the efficiency in high current applications. This feature also reduces the switching jitter commonly found in low DCR applications. The LTC3866 also includes a high speed remote sense differential amplifier, a programmable current sense limit that can be selected to 10mV, 15mV, 20mV, 25mV or 30mV, and DCR temperature compensation to limit the maximum output current precisely over temperature. The LTC3866 also features a precise 0.6V reference with a guaranteed limit of ±0.5% that provides an accurate output voltage from 0.6V to 3.5V. A 4.5V to 38V input voltage range allows it to support a wide variety of bus voltages and various types of batteries. The LTC3866 is offered in a low profile 24-lead 4mm × 4mm QFN and 24-lead exposed pad FE packages.

NEW: LTC3861 - Dual, Multiphase Step-Down Voltage Mode DC/DC Controller with Accurate Current Sharing

Wed, 25 Jan 2012 16:10:58 -0800

The LTC®3861 is a dual PolyPhase® synchronous stepdown switching regulator controller for high current distributed power systems, digital signal processors, and other telecom and industrial DC/DC power supplies. It uses a constant-frequency voltage mode architecture combined with very low offset, high bandwidth error amplifiers and a remote output sense differential amplifier per channel for excellent transient response and output regulation. The controller incorporates lossless inductor DCR current sensing to maintain current balance between phases and to provide overcurrent protection. The chip operates from a VCC supply between 3V and 5.5V and is designed for stepdown conversion from VIN between 3V and 24V to output voltages between 0.6V and VCC – 0.5V. The TRACK/SS pins provide programmable soft-start or tracking functions. Inductor current reversal is disabled during soft-start to safely power prebiased loads. The constant operating frequency can be synchronized to an external clock or linearly programmed from 250kHz to 2.25MHz. Up to six LTC3861 controllers can operate in parallel for 1-, 2-, 3-, 4-, 6- or 12-phase operation. The LTC3861 is available in a 36-pin 5mm × 6mm QFN package.

UPDATED: LTC3780 - High Efficiency, Synchronous, 4-Switch Buck-Boost Controller

Wed, 25 Jan 2012 15:56:32 -0800

The LTC3780 is a high performance buck-boost switching regulator controller that operates from input voltages above, below or equal to the output voltage. The constant frequency current mode architecture allows a phase-lockable frequency of up to 400kHz. With a wide 4V to 30V (36V maximum) input and output range and seamless transfers between operating modes, the LTC3780 is ideal for automotive, telecom and battery-powered systems. The operating mode of the controller is determined through the FCB pin. For boost operation, the FCB mode pin can select among Burst Mode® operation, Discontinuous mode and Forced Continuous mode. During buck operation, the FCB mode pin can select among Skip-Cycle mode, Discontinuous mode and Forced Continuous mode. Burst Mode operation and Skip-Cycle mode provide high efficiency operation at light loads while forced continuous mode and discontinuous mode operate at a constant frequency. Fault protection is provided by an output overvoltage comparator and internal foldback current limiting. A Power Good output pin indicates when the output is within 7.5% of its designed set point. Protected by U.S. Patents, including 5481178, 6304066, 5929620, 5408150, 6580258, patent pending on current mode architecture and protection

UPDATED: LTC4266 - Quad IEEE 802.3at Power Over Ethernet Controller

Tue, 24 Jan 2012 16:51:47 -0800

The LTC4266 is a quad PSE controller designed for use in IEEE 802.3 Type 1 and Type 2 (high power) compliant Power over Ethernet systems. External power MOSFETs enhance system reliability and minimize channel resistance, cutting power dissipation and eliminating the need for heatsinks even at Type 2 power levels. External power components also allow use at very high power levels while remaining otherwise compatible with the IEEE standard. 80V-rated port pins provide robust protection against external faults. The LTC4266 includes advanced power management features, including current and voltage readback and programmable ICUT and ILIM thresholds. Available C libraries simplify power-management software development; an optional AUTO mode provides fully IEEE-compliant standalone operation with no software required. Proprietary 4-point PD detection circuitry minimizes false PD detection while supporting legacy phone operation. Midspan operation is supported with built-in 2-event classification and backoff timing. Host communication is via a 1MHz I2C serial interface. The LTC4266 is available in a 5mm × 7mm QFN package that significantly reduces board space compared with competing solutions. A legacy-compatible 36-pin SSOP package is also available.

NEW: LTC2368-16 - 16-Bit, 1Msps, Pseudo- Differential Unipolar SAR ADC with 94.7dB SNR

Tue, 24 Jan 2012 13:35:22 -0800

The LTC®2368-16 is a low noise, low power, high speed 16-bit successive approximation register (SAR) ADC. Operating from a 2.5V supply, the LTC2368-16 has a 0V to VREF pseudo-differential unipolar input range with VREF ranging from 2.5V to 5.1V. The LTC2368-16 consumes only 13.5mW and achieves ±0.75LSB INL maximum, no missing codes at 16 bits with 94.7dB SNR. The LTC2368-16 has a high speed SPI-compatible serial interface that supports 1.8V, 2.5V, 3.3V and 5V logic while also featuring a daisy-chain mode. The fast 2Msps throughput with no cycle latency makes the LTC2368-16 ideally suited for a wide variety of high speed applications. An internal oscillator sets the conversion time, easing external timing considerations. The LTC2368-16 automatically powers down between conversions, leading to reduced power dissipation that scales with the sampling rate.

NEW: LTC2367-16 - 16-Bit, 500ksps, Pseudo- Differential Unipolar SAR ADC with 94.7dB SNR

Mon, 23 Jan 2012 14:32:54 -0800

The LTC®2367-16 is a low noise, low power, high speed 18-bit successive approximation register (SAR) ADC. Operating from a 2.5V supply, the LTC2367-16 has a 0V to VREF pseudo-differential unipolar input range with VREF ranging from 2.5V to 5.1V. The LTC2367-16 consumes only 6.8mW and achieves ±0.75LSB INL maximum, no missing codes at 16 bits with 94.7dB SNR. The LTC2367-16 has a high speed SPI-compatible serial interface that supports 1.8V, 2.5V, 3.3V and 5V logic while also featuring a daisy-chain mode. The fast 500ksps throughput with no cycle latency makes the LTC2367-16 ideally suited for a wide variety of high speed applications. An internal oscillator sets the conversion time, easing external timing considerations. The LTC2367-16 automatically powers down between conversions, leading to reduced power dissipation that scales with the sampling rate.

NEW: LTC2364-16 - 16-Bit, 250ksps, Pseudo- Differential Unipolar SAR ADC with 94.7dB SNR

Mon, 23 Jan 2012 14:25:19 -0800

The LTC®2364-16 is a low noise, low power, high speed 18-bit successive approximation register (SAR) ADC. Operating from a 2.5V supply, the LTC2364-16 has a 0V to VREF pseudo-differential unipolar input range with VREF ranging from 2.5V to 5.1V. The LTC2364-16 consumes only 3.4mW and achieves ±0.75LSB INL maximum, no missing codes at 16 bits with 94.7dB SNR. The LTC2364-16 has a high speed SPI-compatible serial interface that supports 1.8V, 2.5V, 3.3V and 5V logic while also featuring a daisy-chain mode. The fast 250ksps throughput with no cycle latency makes the LTC2364-16 ideally suited for a wide variety of high speed applications. An internal oscillator sets the conversion time, easing external timing considerations. The LTC2364-16 automatically powers down between conversions, leading to reduced power dissipation that scales with the sampling rate.

UPDATED: LTC3554/LTC3554-1/LTC3554-2 - Micropower USB Power Manager with Li-Ion Charger and Two Step-Down Regulators

Mon, 23 Jan 2012 12:02:19 -0800

The LTC®3554 family are micropower, highly integrated power management and battery charger ICs for single-cell Li-Ion/Polymer battery applications. They include a PowerPath™ manager with automatic load prioritization, a battery charger, an ideal diode and numerous internal protection features. Designed specifically for USB applications, the LTC3554 power managers automatically limit input current to a maximum of either 100mA or 500mA. Battery charge current is automatically reduced such that the sum of the load current and the charge current does not exceed the selected input current limit. The LTC3554 also includes two synchronous step-down switching regulators as well as a pushbutton controller. With all supplies enabled in standby mode, the quiescent current drawn from the battery is only 10μA. The LTC3554 family are available in a 3mm × 3mm × 0.75mm 20-pin QFN package. OptionsVfloat (V)Hard Reset Time (s) LTC3554 4.2V 5 seconds LTC3554-1 4.1V 5 seconds LTC3554-2 4.2V 14 seconds

UPDATED: LTC4260 - Positive High Voltage Hot Swap Controller with I2C Compatible Monitoring

Fri, 20 Jan 2012 13:32:17 -0800

The LTC4260 Hot Swap controller allows a board to be safely inserted and removed from a live backplane. Using an external N-channel pass transistor, the board supply voltage can be ramped up at an adjustable rate. An I2C interface and onboard ADC allow monitoring of board current, voltage and fault status. The device features adjustable analog foldback current limit with latch off or automatic restart after the LTC4260 remains in current limit beyond an adjustable time-out delay. The controller has additional features to interrupt the host when a fault has occurred, notify when output power is good, detect insertion of a load card and power-up in either the on or off state.

UPDATED: LTC3553 - Micropower USB Power Manager With Li-Ion Charger, LDO and Buck Regulator

Thu, 19 Jan 2012 15:07:28 -0800

The LTC®3553 is a micropower, highly integrated power management and battery charger IC for single-cell Li-Ion/Polymer battery applications. It includes a PowerPath manager with automatic load prioritization, a battery charger, an ideal diode and numerous internal protection features. Designed specifically for USB applications, the LTC3553 power manager automatically limits input current to a maximum of either 100mA or 500mA. Battery charge current is automatically reduced such that the sum of the load current and the charge current does not exceed the selected input current limit. The LTC3553 also includes a synchronous buck regulator, a low dropout linear regulator (LDO), and a pushbutton controller. With all supplies enabled in standby mode, the quiescent current drawn from the battery is only 12μA. The LTC3553 is available in a 3mm × 3mm × 0.75mm 20-pin QFN package. OptionsLDOPGOODHard Reset Time LTC3553 ON/OFF Control No 5 seconds LTC3553-2 Always On Yes 14 seconds

UPDATED: LTC3765 - Active Clamp Forward Controller and Gate Driver

Tue, 17 Jan 2012 13:01:39 -0800

The LTC®3765 is a start-up controller and gate driver for use in a self-starting secondary-side control forward converter. When combined with the LTC3766 secondaryside synchronous forward controller, a complete isolated power supply is created using a minimum of discrete parts. A proprietary scheme is used to multiplex gate drive signals and bias power across the isolation barrier through a small pulse transformer. The LTC3765 contains an on-chip bridge rectifier that extracts gate drive bias power from this pulse transformer, eliminating the need for a separate bias supply. A precision undervoltage lockout circuit and linear regulator controller ensure a quick and well-controlled start-up. The LTC3765 includes an active clamp output for driving an external PMOS, as well as an adjustable delay to optimize efficiency. The active clamp architecture reduces voltage stress on the main power switch, and provides the highest possible efficiency. Overcurrent protection and the Direct Flux Limit guarantee no transformer saturation without compromising transient response.

UPDATED: LTM4615 - Triple Output, Low Voltage DC/DC μModule Regulator

Tue, 17 Jan 2012 12:58:15 -0800

The LTM4615 is a complete 4A dual output switching mode DC/DC power supply plus an additional 1.5A VLDO (very low dropout) linear regulator. Included in the package are the switching controllers, power FETs, inductors, a 1.5A regulator and all support components. The dual 4A DC/DC converters operate over an input voltage range of 2.375V to 5.5V, and the VLDO operates from a 1.14V to 3.5V input. The LTM4615 supports output voltages ranging from 0.8V to 5V for the DC/DC converters, and 0.4V to 2.6V for the VLDO. The three regulator output voltages are set by a single resistor for each output. Only bulk input and output capacitors are needed to complete the design. The low profile package (2.82mm) enables utilization of unused space on the bottom of PC boards for high density point of load regulation. High switching frequency and a current mode architecture enables a very fast transient response to line and load changes without sacrificing stability. The device supports output voltage tracking for supply rail sequencing. Additional features include overvoltage protection, foldback overcurrent protection, thermal shutdown and programmable soft-start. The power module is offered in a space saving and thermally enhanced 15mm × 15mm × 2.82mm LGA package. The LTM4615 is Pb-free and RoHS compliant.

NEW: LTC5585 - Wideband IQ Demodulator with IIP2 and DC Offset Control

Tue, 17 Jan 2012 12:53:00 -0800

The LTC®5585 is a direct conversion quadrature demodulator optimized for high linearity receiver applications in the 700MHz to 3GHz frequency range. It is also usable in the 400MHz to 700MHz and 3GHz to 4GHz ranges with reduced performance. It is suitable for communications receivers where an RF signal is directly converted into I and Q baseband signals with bandwidth of 530MHz or higher. The LTC5585 incorporates balanced I and Q mixers, LO buffer amplifiers and a precision, high frequency quadrature phase shifter. The integrated on-chip broadband transformer provides a single-ended interface at the RF input with simple off-chip L-C matching. In addition, the LTC5585 provides four analog control voltage interface pins for IIP2 and DC offset correction, greatly simplifying system calibration. The high linearity of the LTC5585 provides excellent spurfree dynamic range for the receiver. This direct conversion demodulator can eliminate the need for intermediate frequency (IF) signal processing, as well as the corresponding requirements for image filtering and IF filtering. These I/Q outputs can interface directly to channel-select filters (LPFs) or to baseband amplifiers.

NEW: LTC4251B/LTC4251B-1/ LTC4251B-2 - Negative Voltage Hot Swap Controllers in SOT-23

Mon, 16 Jan 2012 13:35:38 -0800

The LTC®4251B/LTC4251B-1/LTC4251B-2 negative voltage Hot Swap™ controllers allow a board to be safely inserted and removed from a live backplane. Output current is controlled by three stages of current limiting: a timed circuit breaker, active current limiting and a fast feedforward path that limits peak current under worst-case catastrophic fault conditions. Programmable undervoltage and overvoltage detectors disconnect the load whenever the input supply exceeds the desired operating range. The supply input is shunt regulated, allowing safe operation with very high supply voltages. A multifunction timer delays initial start-up and controls the circuit breaker’s response time. The LTC4251B UV/OV thresholds are designed to match the standard telecom operating range of – 43V to –75V. The LTC4251B-1 UV/OV thresholds extend the operating range to encompass –36V to –72V. The LTC4251B-2 implements a UV threshold of –43V only. The LTC4251B improves the ruggedness of the LTC4251 shunt regulator.

NEW: LTM8026 - 36VIN, 5A CVCC Step-Down μModule Regulator

Mon, 16 Jan 2012 12:56:37 -0800

The LTM®8026 is a 36VIN, 5A constant-voltage, constantcurrent (CVCC) step-down μModule® regulator. Included in the package are the switching controller, power switches, inductor and support components. Operating over an input voltage range of 6V to 36V, the LTM8026 supports an output voltage range of 1.2V to 24V. CVCC operation allows the LTM8026 to accurately regulate its output current up to 5A over the entire output range. The output current can be set by a control voltage, a single resistor or a thermistor. Only resistors to set the output voltage and frequency and the bulk input and output filter capacitors are needed to finish the design. The low profile package (2.82mm) enables utilization of unused space on the bottom of PC boards for high density point-of-load regulation. The LTM8026 is packaged in a thermally-enhanced, compact (11.25mm × 15mm) and low profile (2.82mm) overmolded land grid array (LGA) package suitable for automated assembly by standard surface mount equipment. The LTM8026 is RoHS compliant.

NEW: LTC2364-18 - 18-Bit, 250ksps, Pseudo- Differential Unipolar SAR ADC with 97dB SNR

Mon, 16 Jan 2012 12:49:28 -0800

The LTC®2364-18 is a low noise, low power, high speed 18-bit successive approximation register (SAR) ADC. Operating from a 2.5V supply, the LTC2364-18 has a 0V to VREF pseudo-differential unipolar input range with VREF ranging from 2.5V to 5.1V. The LTC2364-18 consumes only 3.4mW and achieves ±2.5LSB INL maximum, no missing codes at 18 bits with 97dB SNR. The LTC2364-18 has a high speed SPI-compatible serial interface that supports 1.8V, 2.5V, 3.3V and 5V logic while also featuring a daisy-chain mode. The fast 250ksps throughput with no cycle latency makes the LTC2364-18 ideally suited for a wide variety of high speed applications. An internal oscillator sets the conversion time, easing external timing considerations. The LTC2364-18 automatically powers down between conversions, leading to reduced power dissipation that scales with the sampling rate.

NEW: LTC2367-18 - 18-Bit, 500ksps, Pseudo- Differential Unipolar SAR ADC with 97dB SNR

Mon, 16 Jan 2012 12:41:33 -0800

The LTC®2367-18 is a low noise, low power, high speed 18-bit successive approximation register (SAR) ADC. Operating from a 2.5V supply, the LTC2367-18 has a 0V to VREF pseudo-differential unipolar input range with VREF ranging from 2.5V to 5.1V. The LTC2367-18 consumes only 6.8mW and achieves ±2.5LSB INL maximum, no missing codes at 18 bits with 97dB SNR. The LTC2367-18 has a high speed SPI-compatible serial interface that supports 1.8V, 2.5V, 3.3V and 5V logic while also featuring a daisy-chain mode. The fast 500ksps throughput with no cycle latency makes the LTC2367-18 ideally suited for a wide variety of high speed applications. An internal oscillator sets the conversion time, easing external timing considerations. The LTC2367-18 automatically powers down between conversions, leading to reduced power dissipation that scales with the sampling rate.

NEW: LTC2368-18 - 18-Bit, 1Msps, Pseudo- Differential Unipolar SAR ADC with 97dB SNR

Mon, 16 Jan 2012 12:33:25 -0800

The LTC®2368-18 is a low noise, low power, high speed 18-bit successive approximation register (SAR) ADC. Operating from a 2.5V supply, the LTC2368-18 has a 0V to VREF pseudo-differential unipolar input range with VREF ranging from 2.5V to 5.1V. The LTC2368-18 consumes only 13.5mW and achieves ±2.5LSB INL maximum, no missing codes at 18 bits with 97dB SNR. The LTC2368-18 has a high speed SPI-compatible serial interface that supports 1.8V, 2.5V, 3.3V and 5V logic while also featuring a daisy-chain mode. The fast 1Msps throughput with no cycle latency makes the LTC2368-18 ideally suited for a wide variety of high speed applications. An internal oscillator sets the conversion time, easing external timing considerations. The LTC2368-18 automatically powers down between conversions, leading to reduced power dissipation that scales with the sampling rate.

UPDATED: LT6011/LT6012 - Dual/Quad 135µA, 14nV/rtHz, Rail-to-Rail Output Precision Op Amp

Mon, 16 Jan 2012 12:24:37 -0800

The LT6011/LT6012 op amps combine low noise and high precision input performance with low power consumption and rail-to-rail output swing. Input offset voltage is trimmed to less than 60µV. The low drift and excellent long-term stability guarantee a high accuracy over temperature and time. The 300pA maximum input bias current and 120dB minimum voltage gain further maintain this precision over operating conditions. The LT6011/LT6012 work on any power supply voltage from 2.7V to 36V and draw only 135µA of supply current on a 5V supply. The output swings to within 40mV of either supply rail, making the amplifier a good choice for low voltage single supply applications. The LT6011/LT6012 are specified at 5V and ±15V supplies and from –40°C to 85°C. The LT6011 (dual) is available in SO-8 and space saving 3mm x 3mm DFN packages. The LT6012 (quad) is available in SO-14 and 16-pin SSOP packages.

UPDATED: LTC3891 - Low IQ, 60V Synchronous Step-Down Controller

Mon, 16 Jan 2012 10:39:01 -0800

The LTC3891 is a high performance step-down switching regulator DC/DC controller that drives an all N-channel synchronous power MOSFET stage. A constant frequency current mode architecture allows a phase-lockable frequency of up to 750kHz. The 50μA no-load quiescent current extends operating run time in battery-powered systems. OPTI-LOOP® compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values. The LTC3891 features a precision 0.8V reference and power good output indicator. A wide 4V to 60V input supply range encompasses a wide range of intermediate bus voltages and battery chemistries. The output voltage of the LTC3891 can be programmed between 0.8V to 24V. The TRACK/SS pin ramps the output voltages during start-up. Current foldback limits MOSFET heat dissipation during short-circuit conditions. The PLLIN/MODE pin selects among Burst Mode operation, pulse-skipping mode, or continuous conduction mode at light loads.

UPDATED: LTC6990 - TimerBlox: Voltage Controlled Silicon Oscillator

Thu, 12 Jan 2012 13:12:00 -0800

The LTC®6990 is a precision silicon oscillator with a programmable frequency range of 488Hz to 2MHz. It can be used as a fixed-frequency or voltage-controlled oscillator (VCO). The LTC6990 is part of the TimerBlox® family of versatile silicon timing devices. A single resistor, RSET, programs the LTC6990’s internal master oscillator frequency. The output frequency is determined by this master oscillator and an internal frequency divider, NDIV, programmable to eight settings from 1 to 128.

UPDATED: LTC4366-1/LTC4366-2 - High Voltage Surge Stopper

Thu, 12 Jan 2012 10:49:41 -0800

The LTC®4366 surge stopper protects loads from high voltage transients. By controlling the gate of an external N-channel MOSFET, the LTC4366 regulates the output during an overvoltage transient. The load may remain operational while the overvoltage is dropped across the MOSFET. Placing a resistor in the return line isolates the LTC4366 and allows it to float up with the supply; therefore, the upper limit on the output voltage depends only on the availability of high valued resistors and MOSFET ratings. An adjustable overvoltage timer prevents MOSFET damage during the surge while an additional 9 second timer provides for MOSFET cool down. A shutdown pin reduces the quiescent current to less than 20μA during shutdown. After a fault the LTC4366-1 latches off while the LTC4366-2 will auto-retry.

UPDATED: LTC3857-1 - Low IQ, Dual, 2-Phase Synchronous Step-Down Controller

Thu, 12 Jan 2012 10:48:32 -0800

The LTC3857-1 is a high performance dual step-down switching regulator controller that drives all N-channel synchronous power MOSFET stages. A constant frequency current mode architecture allows a phase-lockable frequency of up to 850kHz. Power loss and noise due to the ESR of the input capacitor ESR are minimized by operating the two controller output stages out of phase. The 50μA no-load quiescent current extends operating life in battery-powered systems. The LTC3857-1 features a precision 0.8V reference and a power good output indicator. wide 4V to 38V input supply range encompasses a wide range of intermediate bus voltages and battery chemistries. Independent TRACK/SS pins for each controller ramp the output voltages during start-up. Current foldback limits MOSFET heat dissipation during short-circuit conditions. The PLLIN/MODE pin selects among Burst Mode operation, pulse-skipping mode, or continuous inductor current mode at light loads. For a leadless 32-pin QFN package with the additional features of adjustable current limit, clock out, phase modulation and two PGOOD outputs, see the LTC3857 data sheet.

UPDATED: LTC3857 - Low IQ, Dual, 2-Phase Synchronous Step-Down Controller

Thu, 12 Jan 2012 10:47:37 -0800

The LTC3857 is a high performance dual step-down switching regulator controller that drives all N-channel synchronous power MOSFET stages. A constant frequency current mode architecture allows a phase-lockable frequency of up to 850kHz. Power loss and noise due to the ESR of the input capacitor ESR are minimized by operating the two controller output stages out of phase. The 50μA no-load quiescent current extends operating run time in battery-powered systems. The LTC3857 features a precision 0.8V reference and power good output indicators. A wide 4V to 38V input supply range encompasses a wide range of intermediate bus voltages and battery chemistries. Independent TRACK/SS pins for each controller ramp the output voltages during start-up. Current foldback limits MOSFET heat dissipation during short-circuit conditions. The PLLIN/MODE pin selects among Burst Mode operation, pulse-skipping mode, or continuous inductor current mode at light loads. For a leaded 28-lead SSOP package with a fixed current limit and one PGOOD output, without phase modulation or a clock output, see the LTC3857-1 data sheet.

NEW: LT8582 - Dual 3A Boost/Inverting/SEPIC DC/DC Converter with Fault Protection

Thu, 12 Jan 2012 10:44:47 -0800

The LT®8582 is a dual independent channel PWM DC/DC converter with a power good pin and built-in fault protection to help guard against input overvoltage and overtemperature conditions. Each channel consists of a 42V master switch and a 42V slave switch that can be tied together for a total current limit of 3A. The LT8582 is ideal for many local power supply designs. Each channel can be easily configured in boost, SEPIC, inverting, or flyback configurations. Together, the two channels can produce a 12V and a –12V output with 14.4W of combined output power from a 5V input. In addition, the LT8582’s slave switch allows the part to be configured in high voltage, high power charge pump topologies that are more efficient and require fewer components than traditional circuits. The LT8582 also features innovative SHDN pin circuitry that allows for slowly varying input signals and an adjustable undervoltage lockout function. Additional features such as output short protection, frequency foldback and soft-start are integrated. The LT8582 is available in a 24-pin 7mm × 4mm DFN package.

UPDATED: LT4356MP-1/LT4356MP-2 - Surge Stopper

Wed, 11 Jan 2012 12:00:04 -0800

The LT4356 surge stopper protects loads from high voltage transients. It regulates the output during an overvoltage event, such as load dump in automobiles, by controlling the gate of an external N-channel MOSFET. The output is limited to a safe value thereby allowing the loads to continue functioning. The LT4356MP also monitors the voltage drop between the VCC and SNS pins to protect against overcurrent faults. An internal amplifier limits the current sense voltage to 50mV. In either fault condition, a timer is started inversely proportional to MOSFET stress. If the timer expires, the FLT pin pulls low to warn of an impending power-down. If the condition persists, the MOSFET is turned off. After a cooldown period, the GATE pin pulls up turning on the MOSFET again. The auxiliary amplifier may be used as a voltage detection comparator or as a linear regulator controller driving an external PNP pass transistor. Back-to-back FETs can be used in lieu of a Schottky diode for reverse input protection, reducing voltage drop and power loss. A shutdown pin reduces the quiescent current to less than 7μA for the LT4356-1 during shutdown. The LT4356-2 differs from the LT4356-1 during shutdown by reducing the quiescent current to 60μA and keeping alive the auxiliary amplifier for uses such as an undervoltage lockout or always-on regulator.