2

UC2855A/B

UC3855A/B

ABSOLUTE MAXIMUM RATINGS

Supply Voltage VCC.......................... Internally Limited

VCC Supply Clamp Current ....................... 20mA

PFC Gate Driver Current (continuous) ..............± 0.5A

PFC Gate Driver Current (peak) ...................± 1.5A

ZVT Drive Current (continuous) ...................± 0.25A

ZVT Drive Current (peak)........................± 0.75A

I

nput Current (IAC, RT, RVA) .......................5mA

Analog Inputs (except Peak Limit) ..............

−0.3 to 10V

Peak Limit Input ...........................

−0.3 to 6.5V

Softstart Sinking Current ......................... 1.5mA

Storage Temperature ...................

−65°C to +150°C

Junction Temperature ...................

−55°C to +150°C

Lead Temperature (Soldering, 10 sec.) ............. +300

°C

Currents are positive into, negative out of the specified termi-

nal. Consult Packaging Section of Databook for thermal limita-

tions and considerations of packages. All voltages are

referenced to GND.

CONNECTION DIAGRAMS

PLCC-20 & LCC-20 (Top View)

Q or L Package

DIL–20 (Top View)

J or N Package

SOIC-20 (Top View)

DW Package

ELECTRICAL CHARACTERISTICS:Unless otherwise specified: VCC = 18V, RVS = 23k, CT = 470pF, CI = 150pF, VRMS

= 1.5V, IAC = 100

µA, ISENSE = 0V, CAO = 4V, VAOUT= 3.5V, VSENSE = 3V. –40°C to 85°C (UC2855A/B), 0°Cto70°C

(UC3855A/B).

PARAMETER

TEST CONDITIONS

MIN

TYP

MAX

UNITS

Overall

Supply Current, OFF

CAO, VAOUT = 0V, VCC = UVLO

−0.3V

150

500

µA

Supply Current, OPERATING

17

25

mA

VCC Turn-On Threshold

UC3855A

15.5

17.5

V

VCCTurn-Off Threshold

UC3855A,B

9

10

V

VCC Turn-On Threshold

UC3855B

10.5

10.8

V

VCC Clamp

I(VCC) = ICC(on) + 5mA

18

20

22

V

Voltage Amplifier

Input Voltage

2.9

3.1

V

VSENSE Bias Current

−500

25

500

nA

Open Loop Gain

VOUT =2to5V

65

80

dB

VOUT High

ILOAD = –300µA

5.75

6

6.25

V

VOUT Low

ILOAD = 300µA

0.3

0.5

V

Output Short Circuit Current

VOUT = 0V

0.6

3

mA