LTC1437A Datasheet | Linear Technology

LTC1436A LTC1436A-PLL/LTC1437A High Efficiency Low Noise Synchronous Step-Down Switching Regulators DESCRIPTION The LTC®1436A/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 TM output stage selectively drives two N-channel MOSFETs at frequencies up to 400k Hz 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 parator is available for use as a lowbattery detector. A power-on reset timer (POR) is included which generates a signal delayed by 65536/f CLK (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). , LTC and LT are registered trademarks of Linear Technology Corporation. Adaptive Power is a trademark of Linear Technology Corporation. Features s s s s s s s s s s s s s s s s U APPLICATIONS s s s s s Maintains Constant Frequency at Low Output Currents Dual N-Channel MOSFET Synchronous Drive Programmable Fixed Frequency (PLL Lockable) Wide VIN Range: 3.5V to 36V Operation Low Minimum On-Time (≤ 300ns) for High Frequency, Low Duty Cycle Applications Very Low Dropout Operation: 99% Duty Cycle Low Dropout, 0.5A Linear Regulator for CPU I/O or Low Noise Audio Supplies Built-In Power-On Reset Timer Programmable Soft Start Low-Battery Detector Remote Output Voltage Sense Foldback Current Limiting (Optional) Pin Selectable Output Voltage Logic...