AS1364
Datasheet - Detailed Description
8 Detailed Description
The AS1364 output voltage is factory-trimmed or is adjustable from +1.2V to +5V, and is guaranteed to supply 1A of output current. The device
consists of a +1.20V internal reference, error amplifier, MOSFET driver, P-channel pass transistor, internal feedback voltage-divider and a
comparator (see Figure 16).
Figure 16. AS1364 - Block Diagram
VIN
2.0V to 5.5V
4
IN
3
CIN
Thermal
Sensor
4.7µF
IN
5
MOSFET
Driver
OUT
6
w/ILIM
VOUT
1.2V to 5.0V
2
Shutdown
Logic
OUT
On
Off
COUT
4.7µF
EN
5k
1.20V
Reference
+
–
Error
Amplifier
R1
VOUT
Logic Supply Voltage
RPOK
100k
1
7
To Controller
POK
SET/BYP
+
–
+
–
R2
+
–
+
–
94%VREF
100mV
8
GND
AS1364
Figure 16 shows the block diagram of the AS1364. It identifies the basics of a series linear regulator employing a P-Channel MOSFET as the
control element. A stable voltage reference (1.2V REF in Figure 16) is compared with an attenuated sample of the output voltage. Any difference
between the two voltages (reference and sample) creates an output from the error amplifier that drives the series control element to reduce the
difference to a minimum. The error amplifier incorporates additional buffering to drive the relatively large gate capacitance of the series pass P-
channel MOSFET, when additional drive current is required under transient conditions. Input supply variations are absorbed by the series
element, and output voltage variations with loading are absorbed by the low output impedance of the regulator.
When in shutdown, a 5k discharge path is connected between the output terminal and ground.
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