SG2525ADW

Product Summary

The SG1525A/1527A series of pulse width modulator integrated circuits aredesigned to offer improved performance and lower external parts count when usedto implement all types of switching power supplies. The on-chip +5.1 volt referenceis trimmed to ±1% initial accuracy and the input common-mode range of the erroramplifier includes the reference voltage, eliminating external potentiometers anddivider resistors. A Sync input to the oscillator allows multiple units to be slavedtogether, or a single unit to be synchronized to an external system clock. A singleresistor between the C T pin and the Discharge pin provides a wide range of deadtime adjustment.They also feature built-in soft-start circuitry with only a timingcapacitor required externally. A Shutdown pin controls both the soft-start circuitryand the output stages, providing instantaneous turn-off with soft-start recycle forslow turn-on. These functions are also controlled by an undervoltage lockout whichkeeps the outputs off and the soft-start capacitor discharged for input voltages lessthan that required for normal operation. Another unique feature of these PWMcircuits is a latch following the comparator. Once a PWM pulse has been terminatedfor any reason, the outputs will remain off for the duration of the period. The latchis reset with each clock pulse. The output stages are totem-pole designs capableof sourcing or sinking in excess of 200mA. The SG1525A output stage featuresNOR logic, giving a LOW output for an OFF state. The SG1527A utilizes OR logicwhich results in a HIGH output level when OFF.

Parametrics

ABSOLUTE MAXIMUM RATINGS (Note 1):
(1)Supply Voltage (+VIN):40V;
(2)Collector Supply Voltage (VC):40V;
(3)Logic Inputs:-0.3V to 5.5V;
(4)Analog Inputs:-0.3V to VIN;
(5)Output Current, Source or Sink:500mA;
(6)Reference Load Current:50mA;
(7)Oscillator Charging Current:5mA;
(8)Operating Junction Temperature Range,Plastic (N, DW Packages ):150℃;
(9)Storage Temperature Range:-65℃ to 150℃;
(10)Lead Temperature (Soldering, 10 seconds):300℃
Note 1. Values beyond which damage may occur.

Features

(1)8V to 35V operation;
(2)5.1V reference trimmed to ±1%;
(3)100Hz to 500KHz oscillator range;
(4)Separate oscillator sync terminal;
(5)Adjustable deadtime control;
(6)Internal soft-start;
(7)Input undervoltage lockout;
(8)Latching P.W.M. to prevent multiplepulses;
(9)Dual source/sink output drivers

Diagrams

<IMG border=0 src="http://www.seekic.com/uploadfile/ic-mfg/20127310147941.jpg">