Description

The SG1525A/1527A series of pulse width modulator integrated circuits are designed to offer improved performance and lower external parts count when used to implement all types of switching power supplies. The on-chip +5.1 V reference is trimmed to ±1 initial accuracy and the input common-mode range of the error amplifier includes the reference voltage, eliminating external potentiometers and divider resistors. A Sync input to the oscillator allows multiple units to be slaved together, or a single unit to be synchronized to an external system clock. A single resistor between the CT pin and the Discharge pin provides a wide range of deadtime adjustment. These devices also feature built-in soft-start circuitry with only a timing capacitor required externally. A Shutdown pin controls both the soft-start circuitry and the output stages, providing instantaneous turn-off with soft-start recycle for slow turn-on. These functions are also controlled by an undervoltage lockout which keeps the outputs off and the soft-start capacitor discharged for input voltages less than that required for normal operation. Another unique feature of these PWM circuits is a latch following the comparator. Once a PWM pulse has been terminated for any reason, the outputs remain off for the duration of the period. The latch is reset with each clock pulse. The output stages are totempole designs capable of sourcing or sinking in excess of 200mA.

The SG1525A output stage features NOR logic, giving a LOW output for an OFF state. The SG1527A utilizes OR logic, which results in a HIGH output level when OFF.

Features

■ 8V to 35V Operation

■ 5.1V Reference Trimmed to 1

■ 100Hz to 500kHz Oscillator Range

■ Separate Oscillator Sync Terminal

■ Adjustable Deadtime Control

■ Internal Soft-start

■ Input Undervoltage Lockout

■ Latching P.W.M. to Prevent Multiple Pulses

■ Dual Source/Sink Output Drivers

High Reliability Features

Following are the high reliability features of SG1525A and SG1527A:

■ Available to MIL-STD-883, ¶ 1.2.1

■ MIL-M38510/12602BEA - JAN1525AJ

■ MIL-M38510/12604BEA - JAN1527AJ

■ MSC-AMS level “S” Processing Available

SG3525A属于集成电路（IC） > DC-DC 开关控制器。美高森美公司制造生产的SG3525ADC-DC 开关控制器PMIC（电源管理集成电路）DC 到 DC 开关式控制器是用于高效率电路的稳压 IC，其配置为生成高于（突升或步升）或低于（突降或步降）输入电源的输出电源电压。其他拓扑结构可能包括：降压-升压、反激、正激、Cuk、SEPIC、全桥、半桥和推挽式。这些器件不同于需要最小电压并“烧尽”多余电压的线性稳压器。