MB39A104_06 Datasheet, PDF (13/38 Pages) Fujitsu Component Limited. – 2-ch DC/DC Converter IC with Overcurrent Protection

MB39A104
■ SETTING THE OUTPUT VOLTAGE
• Output Voltage Setting Circuit
VO
R1
(−INE2) 15
10
−INE1
R2
(CS2) 14
CS1
11
Error Amp
−
+
+
1.24 V
VO (V) =
1.24
(R1 + R2)
R2
■ SETTING THE TRIANGULAR OSCILLATION FREQUENCY
The triangular oscillation frequency is determined by the timing capacitor (CT) connected to the CT terminal (pin
13), and the timing resistor (RT) connected to the RT terminal (pin 12).
Moreover, it shifts more greatly than the calculated values according to the constant of timing resistor (RT) when
the triangular wave oscillation frequency exceeds 1 MHz. Therefore, set it referring to “Triangular Wave Oscillation
Frequency vs. Timing Resistor” and “Triangular Wave Oscillation Frequency vs. Timing Capacitor” in “■ TYPICAL
CHARACTERISTICS”.
Triangular oscillation frequency : fOSC
fOSC (kHz)
=:
1200000
CT (pF) × RT (kΩ)
13