Fairchild KA3S0680RB, KA3S0680RFB Service Manual

KA3S0680RB/KA3S0680RFB

Fairchild Power Switch(FPS)

www.fairchildsemi.com

Features

• Wide operatimg frequency range up to (150kHz)

• Pulse by pulse over current limiting

• Over load protection

• Over voltage protecton (Min. 23V)

• Internal thermal shutdown function

• Under voltage lockout

• Internal high voltage sense FET

• External sync terminal

• Auto Restart Mode

Description

The Fairchild Power Switch(FPS) product family is specially
designed for an off line SMPS with minimal extern al
components. The Fairchild Power Switch(FPS) consist of
high voltage power SenseFET and current mode PWM
controller IC. controller IC features a trimmed oscillator,
under voltage lock out, leading edge blanking, optimized
gate turn-on/turn-off driver, thermal shut down protection,
over voltage protection, temperature compensated precision
current sources for loop compensation and fault protection
circuit. compared to discrete MOSFET and controller or
R

switching converter solution, a Fairchild Power

CC

Switch(FPS) can reduce total component count, design size,
weight and at the same time increase & efficiency,
productivity, and system reliability. It has a basic platform
well suited for cost effective C-TV power supply.

TO-3P-5L

1

1.DRAIN 2.GND 3.V

TO-3PF-5L

1

4.FB 5.Sync

CC

Internal Block Diagram

#3 V

CC

32V

#5 Sync

5V

#4 FB

©2001 Fairchild Semiconductor Corporation

µ

2

7.5V

25V

A

1mA

−

+

6.4V

2.5R
1R

9V

+

−

+

−

Thermal S/D

OVER VOLTAGE S/D

OSC

−

+

5V

Vref

L.E.B

0.1V

Good

logic

S
R

Internal

bias

Q

S
R

Power on reset

#1 DRAIN

SFET

Q

#2 GND

Rev.1.0.2

KA3S0680RB/KA3S0680RFB

Absolute Maximum Ratings

Characteristic Symbol Value Unit

GS

(1)

=1MΩ)

Maximum Drain voltage
Drain Gate voltage (R
Gate source (GND) voltage
Drain current pulsed
Single pulsed avalanche energy
Continuous drain current (T

(2)

=25°C)

C

(3)

Continuous drain current (TC=100°C)
Maximum supply voltage
Input voltage range

Total power dissipation

Operating ambient temperature
Storage temperature

Note:

1. Tj=25°C to 150°C

2. Repetitive rating: Pulse width limited by maximum junction temperature

3. L=24mH, starting Tj=25 °C

V

D,MAX

V

DGR

V

I

DM

E

I
I

V

CC,MAX

V

(watt H/S)

P

D

Derating

T

T

STG

GS

AS

D
D

FB

A

800 V
800 V
±30 V

24.0 A

DC

455 mJ

6.0 A

4.0 A

DC
DC

30 V

−0.3 to V

SD

V

150 W

1.21 W/°C

−25 to +85 °C

−55 to +150 °C

2

KA3S0680RB/KA3S0680RFB

Electrical Characteristics (SFET part)

(Ta = 25°C unless otherwise specified)

Characteristic Symbol Test condition Min. Typ. Max. Unit

Drain source breakdown voltage BV

Zero gate voltage drain current I

Static drain source on resistance
Forward transconductance

(note)

(note)

DSS

DSS

R

DS(ON)

gfs V

Input capacitance Ciss

Reverse transfer capacitance Crss - 42 ­Turn on delay time t

d(on)

Rise time tr - 150 ­Turn off delay time t

d(off)

Fall time tf - 130 ­Total gate charge

(gate-source+gate-drain)

Qg

Gate source charge Qgs - 16 ­Gate drain (Miller) charge Qgd - 27 -

V

= 0V, ID = 50µA 800 - - V

GS

V

= Max., Rating,

DS

V

= 0V

GS

= 0.8Max., Rating,

V

DS

V

= 0V, TC = 125°C

GS

V

= 10V, ID = 4.0A - 1.6 2.0 W

GS

= 15V, ID = 4.0A 1.5 2.5 - S

DS

V

GS

= 0V, V

DS

= 25V,

--50µA

- - 200 mA

- 1600 -

f = 1MHz
VDD= 0.5BV

DSS

, ID= 6.0A

-60­(MOSFET switching
time are essentially
independent of

- 300 ­operating temperature)

=10V, ID = 6.0A,

V
V

GS
DS

= 0.5BV

(MOSFET

DSS

-70­switching time are

essentially independent of
operating temperature)

pFOutput capacitance Coss - 140 -

nS

nC

Note:

Pulse test: Pulse width ≤ 300µS, duty cycle ≤ 2%

1

S

--- -=

R

3

KA3S0680RB/KA3S0680RFB

Electrical Charcteristics (SFET par t) (Continued)

(Ta = 25°C unless otherwise specified)

Characteristic Symbol Test condition Min. Typ. Max. Unit

UVLO SECTION

Start threshold voltage V
Stop operating voltage V

START

STOP

OSCILLATOR SECTION

Initial accuracy F
Frequency change with temperature

(2)

Maximum duty cycle D

OSC

∆F/∆T −25°C ≤ Ta ≤ +85°C-±5 ±10 %

MAX

FEEDBACK SECTION

Feedback source current I
Shutdown Feedback voltage V
Shutdown delay current I

FB

SD

delay

SYNC. & SOFT START SECTION

Soft start voltage V
Soft start current I
Sync threshold voltage

(3)

V

SYTH

SS

SS

REFERENCE SECTION

Output voltage

(1)

Temperature Stability

(1)(2)

Vref Ta = 25°C 4.80 5.00 5.20 V

Vref/∆T −25°C ≤ Ta ≤ +85°C-0.30.6mV/°C

CURRENT LIMIT (SELF-PROTECTION) SECTION

Peak Current Limit I

OVER

PROTECTION SECTION

Thermal shutdown temperature (Tj)

(1)

Over voltage protection voltage V

T

SD

OVP

TOTAL DEVICE SECTION

Start Up current I
Operating supply current

(control part only)
V

zener voltage V

CC

START

I

OP

Z

After turn on 9 10 11 V

Ta = 25°C182022kHz

Ta = 25°C, Vfb = GND 0.7 0.9 1.1 mA

Ta = 25°C, 5V ≤ Vfb ≤V

V

= 2V 4.7 5.0 5.3 V

FB

Sync & S/S = GND 0.8 1.0 1.2 mA
Vfb = 5V 6.0 6.4 6.8 V

Max. inductor current 3.52 4.00 4.48 A

V

= 14V 0.1 0.3 0.55 mA

CC

Ta = 25°C 6 12 18 mA
I

= 20mA 30 32.5 35 V

CC

-141516V

-929598%

- 6.9 7.5 8.1 V

- 140 160 - °C

-232528V

SD

1.4 1.8 2.2 µA

Note:

1. These parameters, although guaranteed, are not 100% tested in production

2. These parameters, although guaranteed, are tested in EDS(water test) process

3.The amplitude of the sync. pulse is recommended to be between 2V and 3V for stable sync. function.

4