Fairchild FSDM311A service manual

November 2007

TM

FSDM311A
Green Mode Fairchild Power Switch (FPS™)

FSDM311A — Green Mode Fairchild Power Switch (FPS

Features

 Internal Avalanche-Rugged SenseFET
 Precision Fixed Operating Frequency: 67KHz
 Consumes Under 0.2W at 265V

Advanced Burst-Mode Operation

& No Load with

AC

 Internal Start-up Circuit
 Pulse-by-Pulse Current Limiting
 Over-Voltage Protection (OVP)
 Overload Protection (OLP)
 Internal Thermal Shutdown Function (TSD)
 Auto-Restart Mode
 Under-Voltage Lockout (UVLO) with Hysteresis
 Built-in Soft-Start
 Secondary-Side Regulation

Applications

 Charger & Adapter for Mobile Phone, PDA, & MP3
 Auxiliary Power for White Goods, PC, C-TV, &

Monitors

Description

The FSDM311A consists of an integrated Pulse Width
Modulator (PWM) and SenseFET, and is specifically
designed for high-performance, off-line, Switch-Mode
Power Supplies (SMPS) with minimal external
components. This device is an integrated high-voltage
power switching regulator that combines a VDMOS
SenseFET with a voltage-mode PWM control block. The
integrated PWM controller features include a fixed
oscillator, Under-Voltage Lockout (UVLO) protection,
Leading-Edge Blanking (LEB), an optimized gate turn­on/turn-off driver, Thermal Shutdown (TSD) protection,
and temperature-compensated precision-current
sources for loop compensation and fault protection
circuitry. When compared to a discrete MOSFET and
controller or RCC switching converter solution, the
FSDM311A device reduces total component count and
design size and weight, while increasing efficiency,
productivity, and system reliability. This device provides
a basic platform that is well suited for the design of
cost-effective flyback converters.

Related Resources

AN-4134: Design Guidelines for Off-line Forward
Converters Using Fairchild Power Switch (FPS™)
AN-4137: Design Guidelines for Off-line Flyback
Converters Using Fairchild Power Switch (FPS™)
AN-4138: Design Considerations for Battery Charger
Using Green Mode Fairchild Power Switch (FPS™)
AN-4140: Transformer Design Consideration for Off­line Flyback Converters Using Fairchild Power Switch
(FPS™)
AN-4141: Troubleshooting and Design Tips for
Fairchild Power Switch (FPS™) Flyback Applications
AN-4147: Design Guidelines for RCD Snubber of
Flyback
AN-4148: Audible Noise Reduction Techniques for
FPS™ Applications

)

Ordering Information

Product Number Package Marking Code BV

FSDM311A

All packages are lead free per JEDEC: J-STD-020B standard.

FPS™ is a trademark of Fairchild Semiconductor Corporation.

© 2007 Fairchild Semiconductor Corporation www.fairchildsemi.com
FSDM311A • Rev.1.0.2

8DIP

DM311A

f

DSS

650V 67KHz

R

OSC

DS(ON)

14Ω

TM

Typical Application & Output Power Table

Figure 1. Typical Flyback Application

Internal Block Diagram

OUTPUT POWER TABLE

(1)

85~265V

AC

Product

230V

FSDM311A

Notes:

1. Maximum practical continuous power in an open­frame design with sufficient drain pattern as a heat
sinker, at 50°C ambient.

2. 230V

or 100/115VAC with doubler.

AC

±15%

AC

13W 8W

(2)

Open Frame

FSDM311A — Green Mode Fairchild Power Switch (FPS

V

Vfb

NC

Vstr

2

CC

OSC

PWM

TSD

Internal

Bias

9/7V

Vck

SRQ

SRQ

A/R

/

V

15mS

SD

Voltage

Ref

S/S

BURST

OLP

UVLO

I

I

DELAY

FB

400 A

5 A

3

V

BURL

V

BURH

4

Reset

Min.20V

OVP

L

H

LEB

I

LIM

5

DRIVER

Vth

Rsense

Drain

6,7,8

SFET

1

GND

)

Figure 2. Functional Block Diagram

© 2007 Fairchild Semiconductor Corporation www.fairchildsemi.com
FSDM311A • Rev.1.0.2 2

TM

Pin Configuration

Pin Definitions

Pin # Name Description

FSDM311A — Green Mode Fairchild Power Switch (FPS

Figure 3. 8-Lead DIP Pin Assignments (Top View)

1 GND

2 Vcc

3 Vfb

4 NC

5 Vstr

6,7,8 Drain

Ground. SenseFET source terminal on primary side and internal control ground.
Positive supply voltage input. Although connected to an auxiliary transformer winding,

current is supplied from pin 5 (Vstr) via an internal switch during start-up (see the Internal Block
Diagram in Figure 2). It is not until V

start-up switch opens and device power is supplied via the auxiliary transformer winding.

Feedback. Inverting input to the PWM comparator with its normal input level lies between 0.5V

and 2.5V. It has a 0.4mA current source connected internally, while a capacitor and opto­coupler are typically connected externally. A feedback voltage of 4.5V triggers overload
protection (OLP). There is a time delay while charging external capacitor C
using an internal 5µA current source. This time delay prevents false triggering under transient
conditions, but allows the protection mechanism to operate under true overload conditions.

No Connection.
Start-up. This pin connects directly to the rectified AC line voltage source. At start-up, the

internal switch supplies internal bias and charges an external storage capacitor placed
between the Vcc pin and ground. Once the VCC reaches 9V, the internal switch stops charging
the capacitor.

SenseFET Drain. The drain pins are designed to connect directly to the primary lead of the

transformer and are capable of switching a maximum of 650V. Minimize the length of the trace
connecting these pins to the transformer to decrease leakage inductance.

reaches the UVLO upper threshold (9V) that the internal

CC

from 3V to 4.5V

FB

)

© 2007 Fairchild Semiconductor Corporation www.fairchildsemi.com
FSDM311A • Rev.1.0.2 3

TM

FSDM311A — Green Mode Fairchild Power Switch (FPS

Absolute Maximum Ratings

Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be
operable above the recommended operating conditions and stressing the parts to these levels is not recommended.
In addition, extended exposure to stresses above the recommended operating conditions may affect device
reliability. The absolute maximum ratings are stress ratings only. T

Symbol Parameter Value Unit

V

Drain Pin Voltage 650 V

DRAIN

V

Vstr Pin Voltage 650 V

STR

VDG Drain-Gate Voltage 650 V

VGS Gate-Source Voltage

IDM Drain Current Pulsed

ID Continuous Drain Current (TC=25°C) 0.5 A

ID Continuous Drain Current (TC=100°C) 0.32 A

EAS Single Pulsed Avalanche Energy

VCC Supply Voltage 20 V

VFB Feedback Voltage Range -0.3 to V

PD Total Power Dissipation 1.40 W

TJ Operating Junction Temperature Internally limited °C

TA Operating Ambient Temperature -25 to +85 °C

T

Storage Temperature -55 to +150 °C

STG

Notes:

3. Repetitive rating: Pulse width is limited by maximum junction temperature.

4. L = 24mH, starting T

= 25°C

J

(3)

1.5 A

(4)

10 mJ

=25°C, unless otherwise specified.

A

±20

V

STOP

V

)

Thermal Impedance

TA=25°C, unless otherwise specified.

Symbol Parameter Value Unit

8DIP

θJA Junction-to-Ambient Thermal Impedance

θJC Junction-to-Case Thermal Impedance

Notes:

5. Free standing with no heatsink; without copper clad. (Measurement Condition – just before junction temperature
T

enters into OTP).

J

6. Measured on the DRAIN pin close to plastic interface.

7. All items are tested with the standards JESD 51-2 and 51-10 (DIP).

(5)

88.84 °C/W

(6)

13.94 °C/W

© 2007 Fairchild Semiconductor Corporation www.fairchildsemi.com
FSDM311A • Rev.1.0.2 4