SG6521 — PC Power Supply Supervisors
September 2008
SG6521 — PC Power Supply Supervisors
Features
Two 12V Sense Input Pins: VS12 and VS12B
Over-Voltage Protection (OVP) for 3.3V, 5V, and
two 12V
Over-Current Protection (OCP) for 3.3V, 5V, and
two 12V
Under-Voltage Protection (UVP) for 3.3V, 5V, and
two 12V
Open-Drain Output for PGO and FPO Pins
300ms Power-Good Delay
2.8ms PSON Control to FPO Turn-off Delay
48ms PSON Control Delay
No Lock-up During the Fast AC Power On/Off
Wide Supply Voltage Range: 4V to 15V
Over-Temperature Protection (OTP)
Additional Protection Input (Pext)
Description
The SG6521 is designed to provide the supply voltage,
current supervisor, remote on/off (PSON), power good
(PGO) indicator, and fault protection (FPO) functions for
switching power systems.
For supervisory functions, it provides the over-voltage
protection (OVP) for 3.3V, 5V, and two 12V; over-
current protection (OCP) for 3.3V, 5V, and two 12V;
under-voltage protection (UVP) for 3.3V, 5V, and two
12V. When 3.3V, 5V, or 12V voltage decreases to 2.3V,
3.5V, and 9V, respectively, the under-voltage protection
function is enabled. FPO is set HIGH to turn off the
PWM controller IC. The voltage difference across
external current shunt is used for OCP functions. An
external resistor can be used to adjust protection
threshold. An additional protection input pin provides
the flexibility for designing protection circuits.
The power supply is turned on after a 48ms delay when
PSON signal is set from HIGH to LOW. To turn off the
power supply, the PSON signal is set from LOW to
HIGH with a delay of 48ms. The PGI circuitry provides a
power-down warning signal for PGO. When PGI input is
lower than the internal 1.25V reference voltage, PGO
signal is pulled LOW.
Applications
Switch-Mode Power Supplies with Active PFC
Servo System Power Supplies
PC-ATX Power Supplies
Ordering Information
Part
Number
SG6521DZ
SG6521SZ
Operating Temperature
Range
-40°C to +85°C
-40°C to +85°C
Eco
Status
RoHS
RoHS
Package
16-pin Dual In-Line Package (DIP)
16-pin Small Outline Package (SOP)
Packing
Method
Rail
Tape & Reel
For Fairchild’s definition of “green” Eco Status, please visit:
http://www.fairchildsemi.com/company/green/rohs_green.html.
© 2007 Fairchild Semiconductor Corporation
SG6521 • Rev. 1.0.0
www.fairchildsemi.com
SG6521 — PC Power Supply Supervisors
Application Diagram
Figure 1.
Typical Application
© 2007 Fairchild Semiconductor Corporation
SG6521 • Rev. 1.0.0
www.fairchildsemi.com
2
SG6521 — PC Power Supply Supervisors
Block Diagram
Figure 2. Function Block Diagram
© 2007 Fairchild Semiconductor Corporation
SG6521 • Rev. 1.0.0
www.fairchildsemi.com
3
SG6521 — PC Power Supply Supervisors
Pin Configuration
Figure 3. Pin Configuration(Top View)
Pin Definitions
Pin #
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Name
PGI
GND
FPO
PSON
IS12
RI
IS12B
VS12B
Pext
IS5
IS33
VS12
VS33
VS5
VDD
PGO
Description
Power Good Input.
For ATX SMPS, it detects AC line voltage through the main transformer.
Ground.
Fault Protection Output.
Output signal to control the primary PWM IC through an opto-
coupler. When FPO is low, the PWM IC is enabled.
Remote On/Off Logic Input from CPU or Main Board.
The power supply is turned on/off
after a 48ms delay.
12V Over-Current Protection Sense Input.
For typical applications, this pin is connected to
the positive end of a current shunt through one resistor. When the voltage on IS12 is higher
than that of VS12 by 5mV, OCP is enabled.
Reference Setting.
One external resistor RI connected between the RI and GND pins
determines a reference current, I
REF
= 1.25/R
I
, for OCP programming.
12V Over-Current Protection Sense Input.
For typical application, this pin is connected to the
positive end of a current shunt through one resistor. When the voltage on IS12 is higher than
that of VS12 by 5mV, OCP is enabled.
Second 12V Over/Under-Voltage Control Sense Input.
External Protection Detects Input.
5V Over-Current Protection Sense Input.
3.3V Over-Current Protection Sense Input.
12V Over/Under-Voltage Control Sense Input.
3.3V Over/Under-Voltage Control Sense Input.
5V Over/Under-Voltage Control Sense Input.
Supply Voltage.
4.2V ~ 15V. For ATX SMPS, it is connected to 5V-standby and 12V through
diodes, respectively.
Power-Good Logic Output.
0 or 1 (open-drain). Power good=1 means that the power supply
is good for operation. The power good delay is 300ms.
© 2007 Fairchild Semiconductor Corporation
SG6521 • Rev. 1.0.0
www.fairchildsemi.com
4
SG6521 — PC Power Supply Supervisors
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.
Symbol
V
DD
V
IN
V
OUT
T
J
T
STG
T
L
ESD
DC Supply Voltage
Input Voltage
Output Voltage
Parameter
PSON, PGI, VS5, IS5, VS33, IS33, Pext
VS12, VS12B, IS12, IS12B
FPO, PGO
Min.
-0.3
-0.3
-0.3
-40
-55
Human Body Model:
JESD22-A114
Machine Model:
JESD22-A115
Max.
16
7.0
15.0
8.0
+125
+150
+260
3.0
200
Unit
V
V
V
V
°C
°C
°C
KV
V
Operating Junction Temperature
Storage Temperature Range
Lead Temperature (Soldering)
Electrostatic Discharge Capability
Recommended Operating Conditions
The Recommended Operating Conditions table defines the conditions for actual device operation. Recommended
operating conditions are specified to ensure optimal performance to the datasheet specifications. Fairchild does not
recommend exceeding them or designing to Absolute Maximum Ratings.
Symbol
T
A
Parameter
Operating Ambient Temperature
Min.
-40
Typ.
Max.
+85
Unit
°C
© 2007 Fairchild Semiconductor Corporation
SG6521 • Rev. 1.0.0
www.fairchildsemi.com
5
Analog electronics
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