©2004 Fairchild Semiconductor Corporation
www.fairchildsemi.com
Rev. 1.1.0
Features
• PC Power Supply Outputs Supervisory Circuitry
• Few External Components
• Over Voltage Protection for 3.3V, 5V and 12V Outputs
• Under Voltage Protection for 3.3V, 5V and 12V Outputs
• Over Current Protection for 3.3V, 5V and 12V Outputs
• Dual Over Current Portection for 12V Outputs
(FAN7687)
• Fault Protection Output With Open Drain Output
• Open Drain Power Good Output
• 300ms Power Good Delay
• 38ms PSON
On/Off Delay
• 73us Debounce
• 2.3ms PSON
to FPO Turn Off Delay
• Latch Function Controlled by PSON
Typical Application
• PC Switching Mode Power Supply
Description
The FAN7685/FAN7686/FAN7687 is a complete output
supervisory circuitry intended for use in the secondary side
of the switched mode power supply. It provides overvoltage
protection (OVP), undervoltage protection(UVP), overcur-
rent protection (OCP), and power good signal generator to
monitor and control the outputs of the switching power sup-
ply system. Remote on/off(PSON
) control and some preci-
sion protection features are also implemented.
It directly senses all the output rails for OVP, UVP, and OCP
without external divider resistors. As for output control,
power good output(PGO) and fault protection output(FPO
)
are included. The FAN7685/FAN7686/FAN7687 offers a
simple and cost effective solution with minimum number of
external components and greatly reduces PCB board space
for power supply.
FAN7685/FAN7686/FAN7687
PC Power Supply Output Monitoring IC
1
14SOP
1
14DIP
