特点
Synchronizable/Programmable Fixed Frequency
OPTI-LOOP? Compensation Minimizes C
OUT
±1% Output Voltage Accuracy
Dual N-Channel MOSFET Synchronous Drive
Wide V
IN
Range: 4V to 36V Operation
V
OUT
Range: 0.8V to 6V
Internal Current Foldback
Output Overvoltage Crowbar Protection
Latched Short-Circuit Shutdown Timer with Defeat Option
Very Low Dropout Operation: 99% Duty Cycle
Forced Continuous Control Pin
Optional Programmable Soft-Start
Remote Output Voltage Sense
Power Good Output (LTC1735F Only)
Logic Controlled Micropower Shutdown: I
Q
< 25μA
LTC1435 Pin Compatible with Minor Component Changes
Available in 16-Lead Narrow SSOP, SO Packages and 20-Lead TSSOP Package (LTC1735F Only)
典型应用
描述
The LTC?1735 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. The precision 0.8V reference is compatible with future generation microprocessors. OPTI-LOOP compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values.
The operating frequency (synchronizable up to 500kHz) is set by an external capacitor allowing maximum flexibility in optimizing efficiency. A forced continuous control pin reduces noise and RF interference and can assist secondary winding regulation by disabling Burst Mode operation when the main output is lightly loaded.
Protection features include internal foldback current limiting, output overvoltage crowbar and optional shortcircuit shutdown. Soft-start is provided by an external capacitor that 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 4V to 30V (36V maximum).