UC3837

Preliminary

LINEAR INTEGRATED CIRCUIT

UNISONICTECHNOLOGIESCO.,LTD

4 of 10

www.unisonic.com.tw

QW-R103-069.B



PARAMETER

SYMBOL

RATINGS

UNIT

Supply Voltage

23

V

Input Voltage to FB Pin

-0.3 ~ 7

V

Input Voltage to CS Pin

-0.3 ~ 7

V

Junction Temperature

+150

C

Operating Temperature

-40 ~ +125

°C

Storage Temperature

-50 ~ +150

C

Note: Absolute maximum ratings are those values beyond which the device could be permanently damaged.

Absolute maximum ratings are stress ratings only and functional device operation is not implied.



OPERATING RANGE

PARAMETER

SYMBOL

RATINGS

UNIT

Supply Voltage

10 ~ 22

V



PARAMETER

SYMBOL

TEST CONDITIONS

MIN

TYP

MAX

UNIT

SUPPLY SECTION

Start Up Current

5

20

μA

IC Operating current

3.2

5

mA

VDD Zener Clamp Voltage

23

24.6

26

mA

UNDER-VOLTAGE LOCKOUT SECTION

Start Threshold Voltage

13

14.5

15.5

V

Min. Operating Voltage

7.5

8.5

9.5

V

Hysteresis

5.4

V

CONTROL SECTION

5

V

PWM Input Gain

3

V/V

Burst-Mode Out FB Voltage

1.1

V

Reduce-Frequency end FB Voltage

1.8

V

Burst-Mode Enter FB Voltage

0.9

V

Normal

55

65

75

KHz

Switch Frequency

Power-Saving

Before enter burst mode

20

22

25

KHz

Duty Cycle

75

%

Frequency Hopping

-4

+4

%

Frequency VDD Stability

5

%

Frequency Temperature Stability

T=-20~100°C

1.5

5

%

Feedback Resistor

11

KΩ

PROTECTION SECTION

VCC Over Voltage Protection Threshold

26

V

FB PIN Over Load Protection Threshold

4.4

4.7

5.0

V

Over Load Protection Delay-Time

55

mS

Soft start time

4

mS

CURRENT LIMITING SECTION

Peak Current Threshold Voltage

0.6

0.65

0.7

V

Lead Edge Blanking Time

400

ns

DRIVER OUTPUT SECTION

Output Voltage Low State

0.8

V

Output Voltage High State

10

V

Output Voltage Rise Time

100

ns

Output Voltage Fall Time

60

ns

BNO SECTION

Threshold voltage for BNO

0.95

1.0

1.05

V