FAN3506 Datasheet, PDF (2/16 Pages) Fairchild Semiconductor – PC SMPS Secondary Side Control IC

FAN3506
Pin Description
No Name I/O
Function
1
V33
I +3.3V Output Voltage of SMPS Secondary Side
2
V5
I +5V Output Voltage of SMPS Secondary Side
3
V12
I +12V Output Voltage of SMPS Secondary Side
4
VCC
I
Supply Voltage. +5Vsb(+5V Standby Supply) is Recommended for Vcc.
The Operating Range is 4.5V~15V. Vcc=5V, Ta=25°C at test.
Fault Protection Output(FPO) With Open Collector Structure. This Signal Controls the
5
FPO
O
Primary Switch(PWM IC) Through an Opto-coupler. Maximum Current Rating is 20mA.
When FPO = "Low", the Main SMPS is Operational and if FPO = "High", the Main SMPS
is Turned-off.
6
Rd
OFF Delay Resistor. This Block is Made up of a Buffer With Vout = 1.258V. A Resistor
-
Should be Connected to the Pin6 for Determination of Off Delay Current. The
Recommended Value of Rd Resistor is 28kΩ at Ctpson=0.22uF. The off Delay Time is
Gotten by Following Equation. Toff = [ Ctpson * (V8max-VthL) ] / (1.258V/Rrd)
7 PSON
Power Supply On/Off (Remote On/Off) Input. It is TTL Operation and its Threshold
I
Voltage is 1.4V. The Maximum Voltage of Pin7 is About 3.9V(Typ), With ABsolutely
Maximum Voltage, 5.25v. If Pson Is Low, Fpo Is Low, Too. That Means The main SMPS
is Operation(Active). When PSON is High, then FPO is High and the Main SMPS is off.
Power Supply On/Off Delay. Ton/Toff = 24ms/8ms(Typ) with Ctpson=0.22uF &
Rd=28kΩ. Its High/Low Threshold Voltages 1.8V/0.6V and the Maximum Voltage After
8 TPSON
-
Full Charging is About 2.2V. So Vcharge = VthH = 1.8V and Vdischg = V8max - VthL =
1.6V.
Each Delay Time is Decided by the Following Equations, Ton = (Ctpson*VthH) / Ion, Toff
= [Ctpson*(V8max-VthL)] / (Vrd/Rrd) .
9
PG
O
Power Good Signal Output with Open Collector. The Maximum Current Rating is 20mA.
PG High Means that the Power is Good for Operation and PG low Means Power Fail.
10 TPG
PG Delay. Td = 300ms(Typ) with Ctpg=2.2uF. The Threshold Voltage is 1.8V and the
- Delay Time is Decided by the Following Equation, Td = (Ctpg * Vth) / Ichg = 1.8Ctpg /
Ichg.
11 PGI
I
Power Good Signal Input. Its Threshold Voltage is 1.26V When the PGI Voltage Drops
From High to Low.
12 GND
- Ground
13 PT1
I Protection Input 1. This can be Used for an Adjustable OVP or Another Protection Input.
14 PT2
I Protection Input 2. This can be Used for an Adjustable OVP or Another Protection Input.
15
IK
I
Cathode of the Programmable Shunt Regulator. Absolute Min/Max Current Rating is
1mA/30mA.
16 VREF
I
Reference of Programmable Shunt Regulator. This Circuit is Prepared for Feedback of
Output Voltage as it Equals to KA431(LM431). It is Trimmed to ±2%.
2