UCC3808D-1

RC

4.99 kΩ

4.99 kΩ

432 Ω

0.1 µF

10 µF

20 kΩ

330 pF

86.6 kΩ

0.01 µF

1 kV

NS1

NS2

NP1

NP2

680 µF

0.01 µF

470 pF

4700 pF 20 kΩ

19.1 kΩ

COMP

19.1 kΩ

200 Ω

LOOP B

LOOP A

2.2 Ω

0.2 Ω

2 kΩ

330 pF

1000 pF

62 Ω

62 Ω

1000 pF

2.2 Ω

51 kΩ

1/4 W

0.47 µF

4700 µF

VIN

36 V TO 72 V

+

–

BYV

28–200

BYV

28–200

32CTQ030

ER28

8:2

+

VO

5 V 50 W

5

6

7

8

4

3

2

1

H11A1

4

5

6

3

2

1

U3

CURRENT

SENSE

PRIMARY

GROUND

–

IRF640

IRF640

20 kΩ

2N2907

0.1 µF

240 Ω

0.1 µF

3

1 TL431

2

10 Ω

12

EF25 7µH

1 mH

DF02SGICT

2.80 kΩ

VDD

OUTA OUTB GND

RC

CS

FB

COMP

Product

Folder

Sample &

Buy

Technical

Documents

Tools &

Software

Support &

Community

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

3 Description

The UCCx808-x is a family of BiCMOS push-pull,

1

•

Dual Output Drive Stages in Push-Pull

high-speed, low-power, pulse-width modulators. The

Configuration

UCCx808 contains all of the control and drive circuitry

•

130-

μA Typical Starting Current

required for offline or DC-to-DC fixed frequency

•

1-mA Typical Run Current

current-mode switching power supplies with minimal

external parts count.

•

Operation to 1-MHz

•

Internal Soft-Start

The

UCCx808-x

dual

output

drive

stages

are

arranged in a push-pull configuration. Both outputs

•

On-Chip Error Amplifier With 2-MHz Gain

switch at half the oscillator frequency using a toggle

Bandwidth Product

flip-flop. The dead time between the two outputs is

•

On-Chip VDD Clamping

typically 60 ns to 200 ns depending on the values of

•

Output Drive Stages Capable Of 500-mA Peak

the timing capacitor and resistors, thus limiting each

output stage duty cycle to less than 50%.

Source Current, 1-A Peak Sink Current

Device Information(1)

2 Applications

PART NUMBER

PACKAGE

BODY SIZE (NOM)

•

Server and Desktop Power Supplies

UCC2808-1

SOIC (8)

4.90 mm × 3.91 mm

•

Telecom Power Supplies

UCC2808-2

UCC3808-1

PDIP (8)

9.81 mm × 6.35 mm

•

DC-DC Converters

UCC3808-2

•

Switched-Mode Power Supplies

(1) For all available packages, see the orderable addendum at

the end of the data sheet.

Simplified Schematic

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.