KA7553A

www.fairchildsemi.com KA7552A/KA7553A SMPS Controller Features Built-in drive circuits for direct connection power MOSFET (lO = ±1.5A) Wide operating frequency range (5kHz ~ 600kHz) Pulse by pulse over current limiting Over load protection On/off control by external trigger Internal UVLO Low standby current (typ. 90uA) Soft start circuit Description The KA7552A/KA7553A are switching power control IC for wide operating frequency range. The internal circuits include pulse by pulse current limiting, protection, on/off control by external trigger, low standby current, soft start, and high current totempole output for driving a POWER MOSFET. Maximum duty of the KA7552A is 70% and the KA7553A is 46%. When duty is maximum, the input threshold voltage of pin2 & pin8 are not same in KA7552A and KA7553A. 8-DIP 1 Internal Block Diagram CS + _ + 0.56 ~ 0.42V CT 7 RT 1 10uA VCC 6 8 OSC 7V UVLO BIAS (4V) OFF 3.6V 2.8V 4.3K + - 2.4V 1.9V + - 5 PWM OUTPUT 0.24V R _ + O.C.P Q S 2 FB 3 IS(+) 4 GND Rev. 1.0.2 ©2004 Fairchild Semiconductor Corporation KA7552A/KA7553A Absolute Maximum Ratings Parameter Supply voltage Output current Input voltage at overcurrent detection pin Input voltage at FB pin Input current at CS pin Total power dissipation (Ta = 25°C) Operating temperature Storage temperature range Junction temperature Symbol VCC IO VIN(IS) VIN(FB) IIN(CS) PD TOPR TSTG Tj Value 30 ±1.5 -0.3 to 4 4 2 800 -25 to 85 -65 to 150 +125 Unit V A V V mA mW °C °...