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UCC2808-1, UCC2808-2, UCC3808-1, UCC3808-2
SLUS168E – APR 1999 – REVISED AUGUST 2015
UCCx808-x Low Power Current Mode Push-Pull PWM
1 Features
•1 Dual Output Drive Stages in Push-Pull Configuration
• 130-μA Typical Starting Current • 1-mA Typical Run Current • Operation to 1-MHz • Internal Soft-Start • On-Chip Error Amplifier With 2-MHz Gain
Bandwidth Product • On-Chip VDD Clamping • Output Drive Stages Capable Of 500-mA Peak
Source Current, 1-A Peak Sink Current
2 Applications
• Server and Desktop Power Supplies • Telecom Power Supplies • DC-DC Converters • Switched-Mode Power Supplies
3 Description
The UCCx808-x is a family of BiCMOS push-pull, high-speed, low-power, pulse-width modulators. The UCCx808 contains all of the control and drive circuitry required for offline or DC-to-DC fixed frequency current-mode switching power supplies with minimal external parts count.
The UCCx808-x dual output drive stages are arranged in a push-pull configuration. Both outputs switch at half the oscillator frequency using a toggle flip-flop. The dead time between the two outputs is typically 60 ns to 200 ns depending on the values of the timing capacitor and resistors, thus limiting each output stage duty cycle to less than 50%.
Device Information(1)
PART NUMBER
PACKAGE
BODY SIZE (NOM)
UCC2808-1 UCC2808-2 UCC3808-1 UCC3808-2
SOIC (8) PDIP (8)
4.90 mm × 3.91 mm 9.81 mm × 6.35 mm
(1) For all available packages, see the orderable addendum at the end of the data sheet.
+ VIN 36 V TO 72 V
–
Simplified Schematic
ER28 32CTQ030 8:2
NP2 NS1 EF25 7µH
4700 µF
0.47 µF
51 kΩ 1/4 W
BYV 28–200 62 Ω 1000 pF
IRF640
62 Ω
BYV 28–200
1000 pF
IRF640
NP1 NS2 12
680 µF
0.01 µF LOOP B
VO 5 V 50 W
+
–
COMP
LOOP A
4700 pF 20 kΩ
200 Ω 19.1 kΩ
2.2 Ω
10 Ω 2.2 Ω 1 mH
DF02SGICT
10 µF
0.1 µF 2 kΩ
0.2 Ω
330 pF
20 kΩ VDD OUTA OUTB GND
8765
UCC3808D-1
PRIMARY GROUND
1234 COMP FB CS RC
RC
4.99 kΩ
2.80 kΩ
CURRENT 86.6 kΩ SENSE
2N2907
4.99 kΩ 20 kΩ
330 pF 432 Ω
0.1 µF
240 Ω
H11A1 4 U3 3
52
0.1 µF 6
1
0.01 µF 1 kV
470 pF
3 1 TL431 2
19.1 kΩ
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters and other important disclaimers. PRODUCTION DATA.
UCC2808-1, UCC2808-2, UCC3808-1, UCC3808-2
SLUS168E – APR 1999 – REVISED AUGUST 2015
www.ti.com
Table of Contents
1 Features .................................................................. 1 2 Applications ........................................................... 1 3 Description ............................................................. 1 4 Revision History..................................................... 2 5 Pin Configuration and Functions ......................... 3 6 Specifications......................................................... 4
6.1 Absolute Maximum Ratings ...................................... 4 6.2 ESD Ratings.............................................................. 4 6.3 Recommended Operating Conditions....................... 4 6.4 Electrical Characteristics........................................... 4 6.5 Typical Characteristics .............................................. 6 7 Detailed Description .............................................. 7 7.1 Overview ................................................................... 7 7.2 Functional Block Diagram ......................................... 7 7.3 Feature Description................................................... 8 7.4 Device Functional Modes.......................................... 9
8 Application and Implementation ........................ 10 8.1 Application Information............................................ 10 8.2 Typical Application ................................................. 10
9 Power Supply Recommendations...................... 11 10 Layout................................................................... 12
10.1 Layout Guidelines ................................................. 12 10.2 Layout Example .................................................... 12 11 Device and Documentation Support ................. 13 11.1 Related Links ........................................................ 13 11.2 Documentation Support ....................................... 13 11.3 Community Resources.......................................... 13 11.4 Trademarks ........................................................... 13 11.5 Electrostatic Discharge Caution ............................ 13 11.6 Glossary ................................................................ 13 12 Mechanical, Packaging, and Orderable Information ........................................................... 13
4 Revision History
NOTE: Page numbers for previous revisions may differ from page numbers in the c.