Texas Instruments UCC38083PW

Current Mode Push-Pull PWM With Programmable Slope Compensation 8-TSSOP 0 to 70

Pulse Width Modulation (PWM) Controller IC; Frequency:1000kHz; Power Dissipation, Pd:400mW; No. of Pins:8; Operating Temperature Range:0°C to +70°C; Control Mode:Current; Number of PWM Outputs:2; Output Current:1A ;RoHS Compliant: Yes

The UCC38083/4/5/6 is a family of Bi CMOS pulse width modulation (PWM) controllers for dc-to-dc or off-line fixed-frequency current-mode switching power supplies. The dual output stages are configured for the push-pull topology. Both outputs switch at half the oscillator frequency using a toggle flip-flop. The dead time between the two outputs is typically 110 ns, limiting each output's duty cycle to less than 50%. The new UCC3808x family is based on the UCC3808Aarchitecture. The major differences include the addition of a programmable slope compensation ramp to the Cs signal and the removal of the error amplifier. The current flowing out of the ISET pin through an external resistoris monitored internally to set the magnitude of the slope compensation function. This device also includes an internal discharge transistor from the CS pin to ground, which is activated at each clock cycle after the pulse is terminated. This discharges any filter capacitance on the CS pin during each cycle and helps minimize filter capacitor values and current sense delay. The UCC38083 and the UCC38084 devices have atypical soft-start interval time of 3.5 ms while the UCC38085 and the UCC38086 has less than 100 t,s for applications where internal soft-start is not desired. The UCC38083 and the UCC38085 devices have the turn-on/off thresholds of 12.5 V / 8.3 V, while the UCC38084 and the UCC38086 has the turn-on/offthresholds of 4.3 V / 4.1 V. Each device is offered in 8-pin TS SOP (PW), 8-pin SOIC (D) and 8-pin PDIP (P)packages. fiffl'^\Delta \Theta jfl'ffi ^aejae o/AEOEO/!"#$o/O/AE o/% &'!!(AE$ #% O/OE )'*+o/&#$o/O/AE ,#$(- fi!O/,'&$% &O/AEOEO/!" $O/ %)(&o/OEo/&#$o/O/AE% )(! $.( $(!"% O/OE j(/#% flAE%$!'"(AE$% %$#AE,#!, 0#!!#AE$1- fi!O/,'&$o/O/AE )!O/&(%%o/AE2 ,O/(% AEO/$ AE(&(%%#!o/+1 o/AE&+',( $(%$o/AE2 O/OE #++ )#!#"($(!%- Copyright (C) 2002-2003, Texas Instruments Incorporated Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.