STMicroelectronics UC2842A
The uoutput stage, suitable for driving N-Channel MOSdFETs, is low in the off-state. The UC3842A and UC3844A have UVLO thresholds of 16V (on) and 10V (off), ideally suited off-line applications The corresponding thresholds for the UC3843A and UC3845A are 8.5 V and 7.9V.FEATURES
Figure 1. Package● TRIMMED OSCILLATOR DISCHARGE CURRENT
● CURRENT MODE OPERATION TO 500kHz AUTOMATIC FEED FORWARD COMPENSATION DIP-8 SO-8
● LATCHING PWM FOR CYCLE-BY-CYCLE CURRENT LIMITING Table 1. Order Codes
● INTERNALLY TRIMMED REFERENCE WITH Part Number Package UNDERVOLTAGE LOCKOUT
● HIGH CURRENT TOTEM POLE OUTPUT t(s)UNDERVOLTAGE LOCKOUT WITH HYSTERESIS c● LOW START-UP CURRENT (< 0.5mA) uDOUBLE PULSE SUPPRESSION rod2
DESCRIPTION
PThe UC384xA family of control ICs provides the necessary features to implement off-line or DC to teDC fixed frequency current mode control schemes lewith a minimal external parts count. Internally imoplemented circuits include a trimmed oscillator for sprecise DUTY CYCLE CONTROL under voltage blockout featuring start-up current less than 0.5mA, Oa precision reference trimmed for accuracy at the -error amp input, logic to insure latched operation, )a PWM comparator which also provides current t(slimit control, and a totem pole output stage decsigned to source or sink high peak current.