ULTRA LOW CURRENT CONSUMPTION AND LOW DROPOUT CMOS VOLTAGE REGULATOR
S-1206 Series
Rev.1.1_00
Operation
1. Basic Operation
Figure 11 shows the block diagram of the S-1206 Series.
The error amplifier compares the reference voltage (Vref) with Vfb, which is the output voltage resistance-divided by
feedback resistors Rs and Rf. It supplies the output transistor with the gate voltage necessary to ensure a certain
output voltage free of any fluctuations of input voltage and temperature.
VIN
*1
Constant
current supply
Error amplifier
VOUT
−
+
Vref
Rf
Vfb
Reference voltage
circuit
Rs
VSS
*1. Parasitic diode
Figure 11
2. Output Transistor
The S-1206 Series uses a low-on-resistance P-channel MOS FET as the output transistor.
Be sure that VOUT does not exceed VIN + 0.3 V to prevent the IC from being damaged due to inverse current flowing
from the VOUT pin through a parasitic diode to the VIN pin.
12
Seiko Instruments Inc.
SII [ SEIKO INSTRUMENTS INC ]
