Analog Devices

The LTC1422 is an 8-pin Hot Swap™controller that 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 a programmable rate. A high side switch driver controls the N-channel gate for supply voltages ranging from 2.7V to 12V.A programmable electronic circuit breaker protects against shorts. TheRESEToutput can be used to generate a system reset when the supply voltage falls below a programmable voltage. The ON pin can be used to cycle the board power or to generate a soft reset.The LTC1422 is available in 8-pin PDIP and SO packages.ApplicationsHot Board InsertionElectronic Circuit Breaker

The LTC1427-50 is a micropower, 10-Bit current output DAC with an output range of 0µA to 50µA. The DAC output is guaranteed monotonic and DNL is less than 0.9LSB under all operating conditions. Full-scale accuracy is ±2.5% over the commercial temperature range. The LTC1427-50 operates with power supply voltages from 2.7V to 5.5V and the DAC current source output can be biased from (VCC– 1.3V) to –15V.The LTC1427-50 communicates with external circuitry by using the SMBus serial interface. It acts as an SMBus slave device using one of four selectable SMBus addresses set by the two address pins AD0 and AD1.On power-up, the DAC output assumes midrange or zero scale, depending on the logic state of the two address pins. The LTC1427-50 can be shut down through theSHDNpin or by setting the SHDN bit = 1 in the SMBus command byte. Digital data for the DAC output is retained internally and the supply current drops to 10µA typically when in shutdown.The LTC1427-50 is available in an 8-pin SO package.ApplicationsLCD Contrast and Backlight Brightness ControlPower Supply Voltage AdjustmentBattery Charger Voltage/Current AdjustmentGaAs FET Bias AdjustmentTrimmer Pot Elimination

The LTC1430A is a high power, high efficiency switching regulator controller optimized for 5V to 1.xV-3.xV applications. It includes a precision internal reference and an internal feedback system that can provide output regulation of ±1% over temperature, load current and line voltage shifts. The LTC1430A uses a synchronous switching architecture with two N-channel output devices, eliminating the need for a high power, high cost P-channel device. Additionally, it senses output current across the drain-source resistance of the upper N-channel FET, providing an adjustable current limit without an external low value sense resistor.The LTC1430A includes a fixed frequency PWM oscillator for low output ripple under virtually all operating conditions. The 200kHz free-running clock frequency can be externally adjusted from 100kHz to above 500kHz. The LTC1430A’s maximum duty cycle is typically 93.5% compared to 88% for the LTC1430. This permits 3.3V to 2.xV conversion using a low power 5V supply. The LTC1430A features low 350µA quiescent current, allowing greater than 90% efficiency operation in converter designs from 1A to greater than 50A output current. Shutdown mode drops the LTC1430A supply current to 1µA.For new designs, refer to the LTC3830.ApplicationsPower Supply for Pentium®II and AMD-K6®MicroprocessorsHigh Power 5V to 3.xV RegulatorsLocal Regulation for Dual Voltage Logic BoardsLow Voltage, High Current Battery Regulation

The LTC1433/LTC1434 are monolithic pulse width modulated step-down DC/DC converters. By utilizing current mode switching techniques, they provide excellent AC and DC load and line regulation. Both devices operate at a fixed frequency with the LTC1434 phase-lockable to an external clock signal.Both devices incorporate two internal P-channel power MOSFETs with a parallel combined resistance of 0.6Ω (at a supply of 10V). The Adaptive Power output stage selectively drives one or both of the switches at frequencies up to 700kHz to reduce switching losses and maintain high efficiencies at low output currents.The LTC1433/LTC1434 are capable of supplying up to 450mA of output current and boasts a ±2.4% output voltage accuracy. An internal low-battery detector has the same level of accuracy as the output voltage. A power-on reset timer (POR) is included which generates a signal delayed by 65536/fCLK(300ms typ) after the output is within 5% of the regulated output voltage.Ideal for current sensitive applications, the devices draw only 470µA of quiescent current. In shutdown the devices draw a mere 15µA. To further maximize the life of the battery source, the internal P-channel MOSFET switch is turned on continuously in dropout.ApplicationsCellular TelephonesPortable InstrumentsWireless ModemsRF CommunicationsDistributed Power SystemsScannersBattery-Powered Equipment

The LTC1435 is a synchronous step-down switching regulator controller that drives external N-channel power MOSFETs using a fixed frequency architecture. Burst Mode™operation provides high efficiency at low load currents. A maximum duty cycle limit of 99% provides low dropout operation which extends operating time in battery-operated systems.The operating frequency is set by an external capacitor allowing maximum flexibility in optimizing efficiency. A secondary winding feedback control pin, SFB, guarantees regulation regardless of load on the main output by forcing continuous operation. Burst Mode operation is inhibited when the SFB pin is pulled low which reduces noise and RF interference.Soft start is provided by an external capacitor which can be used to properly sequence supplies. The operating current level is user-programmable via an external current sense resistor. Wide input supply range allows operation from 3.5V to 30V (36V maximum).For a guaranteed and test minimum on-time refer to the LTC1435A, the "A" version of the LTC1435. The minimum on-time of the LTC1435A is guaranteed to be ≤300ns. The only difference between these two parts is this guaranteed minimum on-time. Pricing is the same.ApplicationsNotebook and Palmtop Computers, PDAsCellular Telephones and Wireless ModemsPortable InstrumentsBattery-Operated DevicesDC Power Distribution Systems

The LTC1436A/LTC1437A are synchronous step-down switching regulator controllers that drive external N-channel power MOSFETs in a phase lockable, fixed frequency architecture. The Adaptive Power™output stage selectively drives two N-channel MOSFETs at frequencies up to 400kHz while reducing switching losses to maintain high efficiencies at low output currents.An auxiliary 0.5A linear regulator using an external PNP pass device provides a low noise, low dropout voltage source. A secondary winding feedback control pin (SFB) guarantees regulation regardless of the load on the main output by forcing continuous operation.An additional comparator is available for use as a lowbattery detector. A power-on reset timer (POR) is included which generates a signal delayed by 65536/fCLK(300ms typically) after the output is within 5% of the regulated output voltage. Internal resistive dividers provide pin selectable output voltages with remote sense capability.The operating current level is user-programmable via an external current sense resistor. Wide input supply range allows operation from 3.5V to 30V (36V maximum).ApplicationsNotebook and Palmtop Computers, PDAsCellular Telephones and Wireless ModemsPortable InstrumentsBattery-Operated DevicesDC Power Distribution Systems

The LTC1436A/LTC1437A are synchronous step-down switching regulator controllers that drive external N-channel power MOSFETs in a phase lockable, fixed frequency architecture. The Adaptive Power™output stage selectively drives two N-channel MOSFETs at frequencies up to 400kHz while reducing switching losses to maintain high efficiencies at low output currents.An auxiliary 0.5A linear regulator using an external PNP pass device provides a low noise, low dropout voltage source. A secondary winding feedback control pin (SFB) guarantees regulation regardless of the load on the main output by forcing continuous operation.An additional comparator is available for use as a lowbattery detector. A power-on reset timer (POR) is included which generates a signal delayed by 65536/fCLK(300ms typically) after the output is within 5% of the regulated output voltage. Internal resistive dividers provide pin selectable output voltages with remote sense capability.The operating current level is user-programmable via an external current sense resistor. Wide input supply range allows operation from 3.5V to 30V (36V maximum).ApplicationsNotebook and Palmtop Computers, PDAsCellular Telephones and Wireless ModemsPortable InstrumentsBattery-Operated DevicesDC Power Distribution Systems

The LTC1438/LTC1439 are dual, synchronous stepdown switching regulator controllers which drive external N-channel power MOSFETs in a phase-lockable fixed frequency architecture. The Adaptive Power™output stage selectively drives two N-channel MOSFETs at frequencies up to 400kHz while reducing switching losses to maintain high efficiencies at low output currents.An auxiliary 0.5A linear regulator using an external PNP pass device provides a low noise, low dropout voltage source. A secondary winding feedback control pin (SFB1) guarantees regulation regardless of load on the main output by forcing continuous operation.An additional comparator is available for use as a low battery detector. A power-on reset timer (POR) is included which generates a signal delayed by 65536/fCLK(typ 300ms) after the output is within 5% of the regulated output voltage. Internal resistive dividers provide pin selectable output voltages with remote sense capability on one of the two outputs.The operating current levels are user-programmable via external current sense resistors. Wide input supply range allows operation from 3.5V to 30V (36V maximum).ApplicationsNotebook and Palmtop Computers, PDAsPortable InstrumentsBattery-Operated DevicesDC Power Distribution Systems