MB3817_03 Datasheet, PDF (13/28 Pages) Fujitsu Component Limited. – Switching Regulator Controller

s SETTING OUTPUT VOLTAGE
• Output voltage VO is plus
VO⁺
R1
−IN
4
+IN
R2
3
Error Amp.
−
+
VREF
MB3817
VO⁺ = ^VREF (R1 + R2)
R2
• Output voltage VO is minus
VREF
R2 R
−IN
4
+IN
3
R1 R
VO^−
Error Amp.
−
+
VO^− =
−
VREF
2 × R2
(R1 + R2) +
VREF
s OSCILATOR FREQUENCY SETTING
The oscillator frequency can be set by connecting a timing capacitor (CT) to the CT terminal (pin1) and a timing
resistor (RT) to the RT terminal (pin2) .
Oscillator frequency : fOSC
1023000
fOSC (kHz) =: _{CT (pF) •RT (kΩ)}
13