FAN7585
4
Pin Function
Pin Number Pin Name Pin Function Description
1V
CC
Supply voltage. Operating range is 15V~30V. Test condition : V
CC
=20V, Ta=25°C.
2COMP
Error amplifier output. It is connected to non-inverting input of pulse width modulator
comparator.
3 E/A(-) Error amplifier inverting input. Its reference voltage is always 1.25V.
4E/A(+)
Error amplifier non-inverting input feedback voltage. This pin may be used to sense
power supply output voltages.
5T
REM
Remote On/Off delay. Ton/Toff=8ms/24ms (Typ.) with C=0.1uF. Its High/Low threshold
voltages are 1.8V/0.6V.
6REM
Remote On/Off input. It is TTL operation and its threshold voltage is 1.4V. Voltage at
this pin can reach normal 4.6V, with absolute maximum voltage, 5.25V.
If REM = “Low”, PWM = “Low”, that means the main SMPS is operational.
when REM = “High”, then PWM = “High” and the main SMPS is turned-off.
7R
T
/C
T
Oscillation frequency setting R, C.(Test condition RT =10kΩ)
8RI
OCP current setting pin. You can fix the OCP reference current (Iref1) by using RI
resistor.
9 DET AC input under voltage detection pin. Its threshold voltage is 1.25V Typ.
10 T
PG
PG delay. Td =260ms (Typ.) with CTPG = 2.2uF. The High/Low threshold voltages are
1.8V/0.6V and the voltage of Pin10 is clamped to 2.9V for noise margin.
11 PG
Power Good output signal. PG = “High” means that the power is “Good” for operation
and PG = “Low” means “Power fail”.
12 Vref Precision voltage reference is trimmed to ±2% (Typical Value = 5V).
13 IS33
Current sense input for +3.3V output. This pin is connected to the current sensing
resistor or inductor. You can define OCP offset voltage for +3.3V by using RI resistor
externally. If you connect 62kΩ at pin 8 to ground, the reference current(Iref1) should be
20uA. After that , you can make a constant OCP offset voltage(V
offset
=R
offset
*5*20uA).
In case the voltage drop(I
O.33
*Rs) of the sense resistor or inductor is larger than offset
voltage, after OCP delay time the main SMPS is turned off. So the over current level is
determined by the following equation. I
O.33
=V
offset
/Rs.
14 V33 OVP, UVP input for +3.3V output (Typical Value = 4.1V/2.3V).
15 IS5
Current sense input for +5V output. You can make +5V OCP function as the previous
method in IS5(pin15).
16 V5 OVP, UVP input for +5V output (Typical Value = 6.4V/4.0V).
17 IS12
Current sense input for +12V output. You can make +12V OCP function as the previous
method in IS12(pin17).
18 V12 OVP, UVP input for 12V output (Typical Value = 14.2V/10V).
19 PT
This is prepared for an extra OVP input or another protection signal (Typical Value =
1.25V).
20 T
UVP
Timing delay pin for under voltage protection and over current protection. Its threshold
voltage is 1.8V and clamped to 2.9V after full charging. Target of delay time is 38ms and
it is realized through external capacitor (C
TUVP
= 0.47uF).
21 DTC
Deadtime control input. The deadtime control comparator has an effective 120mV input
offset which limits the minimum output dead time. Dead time may be imposed on the
output by setting the dead time control input to a fixed voltage, ranging from 0V to 3.3V.
22 C2 Output drive pin for push-pull operation.
23 GND Ground.
24 C1 Output drive pin for push-pull operation.
