Document
UCC28083, UCC28084, UCC28085, UCC28086 UCC38083, UCC38084, UCC38085, UCC38086
SLUS488E − SEPTEMBER 2002 − REVISED JULY 2009
8ĆPIN CURRENT MODE PUSHĆPULL PWM CONTROLLERS WITH PROGRAMMABLE SLOPE COMPENSATION
FEATURES
D Programmable Slope Compensation D Internal Soft-Start on the UCC38083/4 D Cycle-by-Cycle Current Limiting D Low Start-Up Current of 120 µA and 1.5 mA
Typical Run Current
D Single External Component Oscillator
Programmable from 50 kHz to 1 MHz
D High-Current Totem-Pole Dual Output Stage
Drives Push-Pull Configuration with 1-A Sink and 0.5-A Source Capability
D Current Sense Discharge Transistor to
Improve Dynamic Response
D Internally Trimmed Bandgap Reference D Undervoltage Lockout with Hysteresis
BASIC APPLICATION
V IN
VDD UCC3808x
CTRL OUTA
RT
OUTB
ISET
CS
RT R SET
GND
POWER TRANSFORMER
RF
CF
RS
FEEDBACK
APPLICATIONS
D High-Efficiency Switch-Mode Power Supplies D Telecom dc-to-dc Converters D Point-of-Load or Point-of-Use Power Modules D Low-Cost Push-Pull and Half-Bridge
Applications
DESCRIPTION
The UCC38083/4/5/6 is a family of BiCMOS 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 UCC3808A
architecture. 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 resistor
is monitored internally to set the magnitude of the slope
VOUT
compensation function. This device internal discharge transistor from the
also includes an 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 a
typical soft-start interval time of 3.5 ms while the UCC38085 and the UCC38086 has less than 100 µs 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/off thresholds of 4.3 V / 4.1 V. Each device is offered in 8-pin TSSOP (PW), 8-pin SOIC (D) and 8-pin PDIP (P) packages.
UDG−01080
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.
PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters.
www.ti.com
Copyright 2002−2009, Texas Instruments Incorporated 1
UCC28083, UCC28084, UCC28085, UCC28086 UCC38083, UCC38084, UCC38085, UCC38086
SLUS488E − SEPTEMBER 2002 − REVISED JULY 2009
ORDERING INFORMATION
THERMAL RESISTANCE TABLE
PACKAGE SOIC−8 (D)
θjc(°C/W) 42
θja(°C/W) 84 to 160(1)
PDIP−8 (P)
50
110(1)
TSSOP−8 (PW)
32(2)
232 to 257(2)
NOTES: (1) Specified θja (junction to ambient) is for devices mounted to 5-inch2 FR4 PC board with one ounce copper where noted. When resistance range is given, lower values are for 5 inch2 aluminum PC board. Test PWB was 0.062 inch thick and typically used 0.635-mm trace widths for power packages and 1.3-mm trace widths for non-power packages with a 100-mil x 100-mil probe land area at the end of each trace.
(2). Modeled data. If value range given for θja, lower value is for 3x3 inch. 1 oz internal copper ground plane, higher value is for 1x1-inch. ground plane. All model data assumes only one trace for each non-fused lead.
AVAILABLE OPTIONS
TA
INTERNAL SOFT START
UVLO
ON
OFF
SOIC-8 (D)
PACKAGES PDIP-8 (P)
TSSOP-8 (PW)
−40°C to 85°C
3.5 ms 75 µs
12.5 V 4.3 V 12.5 V 4.3 V
8.3 V 4.1 V 8.3 V 4.1 V
UCC28083D UCC28084D UCC28085D UCC28086D
UCC28083P UCC28084P UCC28085P UCC28086P
UCC28083PW UCC28084PW UCC28085PW UCC28086PW
0°C to 70°C
3.5 ms 75 µs
12.5 V 4.3 V 12.5 V 4.3 V
8.3 V 4.1 V 8.3 V 4.1 V
UCC38083D UCC38084D UCC38085D UCC38086D
UCC38083P UCC38084P UCC38085P UCC38086P
UCC38083PW UCC38084PW UCC38085PW UCC38086PW
† The D and PW packages are available taped and reeled. Add R suffix to device type, e.g. UCC28083DR (2500 devices per reel) or UCC38083PWR (2000 devices per reel).
D OR P PACKAGE (TOP VIEW)
PW PACKAGE (TOP VIEW)
CTRL 1 ISET 2
CS 3 RT 4
8 VDD 7 OUTA 6 OUTB 5 GND
OUTA
1
VDD
2
CTRL
3
ISET
4
8
OUTB
7
GND
6
RT
5
CS
2
www.ti.com
UCC28083, UCC28084, UCC28085.