SA57031-18UK PHILIPS [NXP Semiconductors], SA57031-18UK Datasheet - Page 8

• Manufacturer Part Number: SA57031-18UK
• Description: Micropower 150 mA, low-noise, low dropout linear regulator with on/off
• Manufacturer: PHILIPS [NXP Semiconductors]

Philips Semiconductors
TECHNICAL DISCUSSION
As illustrated in Figure 16, the SA57031 consists of a band-gap
voltage reference, an error amplifier, P-channel pass transistor,
current limit circuit and an internal feedback voltage divider. The
output voltage is fed back through an internal resistor voltage divider
connected to the V
The reference is connected to the error amplifier’s inverting input.
The error amplifier compares the reference with the feedback
2003 Jun 23
Micropower 150 mA, low-noise, low dropout linear
regulator with on/off
O
pin.
ON/OFF
SA57031-XX
V
I
4
3
Figure 16. Block diagram (bottom view).
V
REF
8
voltage and amplifies the difference. If the feedback voltage is lower
than the reference voltage, the pass transistor’s gate is pulled lower,
which allows more current to pass to the output and increase the
output voltage. If the feedback voltage is too high, the pass
transistor gate is pulled up, allowing less current to pass to the
output, resulting in a decrease in output voltage.
CURRENT
LIMITER
2
1
V
O
GND
SA57031-XX
SA00634
Product data