UC3842TD

The  UC3842TD is a high performance current mode pwm controller.It provides  the necessary features to implement off-line or DC to DC fixed frequency current mode control schemes with a minimal external parts count. Internally imple- mented circuits include a trimmed oscillator for pre- cise DUTY CYCLE CONTROL under voltage lock- out featuring start-up current less than 0.5mA, a pre- cision reference trimmed for accuracy at the error amp input, logic to insure latched operation, a PWM comparator which also provides current limit control, and a totem pole output stage designed to source or sink high peak current. The output stage, suitable for driving N-Channel MOSFETs, is low in the off- state.

Features of the UC3842TD are:(1)trimmed oscillator for precise fre- quency control;(2)oscillator   frequency   guaranteed at 250khz;(3)current mode operation to 500khz;(4)automatic feed forward compensation;(5)latching   pwm   for   cycle-by-cycle current limiting;(6)internally  trimmed  reference  with undervoltage lockout;(7)high current totem pole output;(8)undervoltage lockout with hyster- esis;(9)low start-up and operating current.

The absolute maximum ratings of the UC3842TD can be summarized as:(1)Supply Voltage (low impedance source),V_I:30V;(2)Supply Voltage (Ii < 30mA),vi:Self Limiting;(3)Output Curren,I_O:±1A;(4)Output Energy (capacitive load),EO:5J;(5)Analog Inputs (pins 2, 3):-0.3V to 5.5V;(6)Error Amplifier Output Sink Current:10mA;(7)Power Dissipation at Tamb25 (Minidip):1.25W;(8)Power Dissipation at Tamb25 (SO8),P_tot:800mW;(9)Storage Temperature Range,T_stg:-65 to 150;(10)Lead Temperature (soldering 10s),T_L:300. All voltages are with respect to pin 5, all currents are positive into the specified terminal.

If you want to know more information such as the electrical characteristics about the UC3842TD, please download the datasheet in www.seekic.com or www.chinaicmart.com .