CS8161 Cherry Semiconductor Corporation, CS8161 Datasheet - Page 6

• Manufacturer Part Number: CS8161
• Description: 12V/ 5V Low Dropout Dual Regulator with ENABLE
• Manufacturer: Cherry Semiconductor Corporation

The output compensation capacitor (Application diagram
C
linear regulator: start-up delay, load transient response
and loop stability.
Since both outputs are controlled by the same ENABLE,
the CS8161 is ideal for applications where a sleep mode is
required. Using the CS8161, a section of circuitry such as a
display and nonessential 5V circuits can be shut down
under microprocessor control to conserve energy.
The example in the Applications Diagram shows an auto-
motive radio application where the display is powered by
the 12V on V
on V
tion and the Radio On/Off switch are on.
Condition
2
ENABLE
NOTES:
* C1 required if regulator is located far from power supply filter.
** C2, C3 required for stability, value may be increased. Capacitor must operate at minimum temperature expected.
and C
System
V
V
OUT 2
OUT
OUT
V
IN
1
2
3
. Neither output is required unless both the igni-
) helps determine three main characteristics of a
2.0V
0.8V
14V
0V
0V
OUT 1
Turn
and the Tuner IC is powered by the 5V
On
Stability Considerations
12V
60V
Dump
Load
5V
31V
C
0.1 mF
1
*
12V
Low V
Typical Circuit Waveform
ENABLE
IN
Application Diagram
2.4V
2.4V
Application Notes
3V
CS8161
Line Noise, Etc.
V
Gnd
26V
6
IN
The capacitor value and type should be based on cost,
availability, size and temperature constraints. A tantalum
or aluminum electrolytic capacitor is best, since a film or
ceramic capacitor with almost zero ESR, can cause insta-
bility. The aluminum electrolytic capacitor is the least
expensive solution, but, if the circuit operates at low tem-
peratures (-25¡C to -40¡C), both the value and ESR of the
capacitor will vary considerably. The capacitor manufac-
turers data sheet usually provide this information.
The values for the output capacitors C
the Applications Circuit should work for most applica-
tions, however it is not necessarily the best solution.
To determine an acceptable value for C
ticular application, start with tantalum capacitors of the
recommended value on each output and work towards
less expensive alternative parts for each output in turn.
12V
5V
V
V
OUT
OUT
2
1
Circuit
V
Short
OUT 1
+
+
0V
Circuit
V
Short
C
22mF
C
22mF
OUT 2
2
3
**
**
0V
Display
Tuner
12V
Shutdown
Thermal
V
OUT 1
5V
14V
0V
2
2
and C
and C
12V
3
Turn
Off
3
shown in
for a par-
0V
0V