UC3873B

LINEAR INTEGRATED CIRCUIT

UNISONICTECHNOLOGIESCO.,LTD

3 of 9

www.unisonic.com.tw

QW-R103-093.A



PARAMETER

SYMBOL

RATINGS

UNIT

Supply Voltage

30

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 ~ 24

V



PARAMETER

SYMBOL

TEST CONDITIONS

MIN

TYP

MAX

UNIT

SUPPLY SECTION

Start Up Current

2.5

20

μA

IC Operating current

0.8

1.8

mA

VCC Zener Clamp Voltage

31

33

35

V

UNDER-VOLTAGE LOCKOUT SECTION

Start Threshold Voltage

12

13

14

V

Min. Operating Voltage

6

7

8

V

CONTROL SECTION

5.4

V

PWM Input Gain

3

V/V

Burst-Mode Out FB Voltage

1.8

V

Reduce-Frequency end FB Voltage

2.9

V

Burst-Mode Enter FB Voltage

1.5

V

Normal

60

65

70

KHz

Switch Frequency

Power-Saving

Before enter burst mode

22

KHz

Duty Cycle

78

%

Frequency Hopping

-3

+3

%

Frequency VDD Stability

5

%

Frequency Temperature Stability

T=-20~100°C

1.5

5

%

PROTECTION SECTION

25

27

29

V

FB PIN Over Load Protection Threshold

4.2

V

Over Load Protection Delay-Time

80

88

96

mS

Soft start time

2.5

mS

CURRENT LIMITING SECTION

Peak Current Flat Threshold Voltage

0.85

0.95

1.05

V

Peak Current Valley Threshold Voltage

0.55

0.65

0.75

V

Lead Edge Blanking Time

350

ns

DRIVER OUTPUT SECTION

Output Voltage Low State

0.8

V

Output Voltage High State

11

V

Output Voltage Rise Time

170

ns

Output Voltage Fall Time

60

ns

RT SECTION

Output current of RT pin

100

105

110

uA

Threshold voltage for OTP

1.00

1.05

1.10

V