CS5201-1GDP3 Cherry Semiconductor Corporation, CS5201-1GDP3 Datasheet - Page 4

• Manufacturer Part Number: CS5201-1GDP3
• Description: 1A Adjustable Linear Regulator
• Manufacturer: Cherry Semiconductor Corporation

Transient Response
Adjust Pin Current vs. Temperature
The CS5201-1 linear regulator provides adjustable volt-
ages at currents up to 1A. The regulator is protected
against overcurrent conditions and includes thermal
shutdown.
The CS5201-1 has a composite PNP-NPN output transistor
and requires an output capacitor for stability. A detailed
procedure for selecting this capacitor is included in the
Stability Considerations section.
The CS5201-1 has an output voltage range of 1.25V to 5.5V.
An external resistor divider sets the output voltage as
shown in Figure 1. The regulator maintains a fixed 1.25V
(typical) reference between the output pin and the adjust
pin.
A resistor divider network R1 and R2 causes a fixed cur-
rent to flow to ground. This current creates a voltage
across R2 that adds to the 1.25V across R1 and sets the
overall output voltage. The adjust pin current (typically
1000
-100
-200
200
100
500
70.0
65.0
60.0
55.0
50.0
45.0
40.0
0
0
0
0
10
1
20
2
I
Adjustable Operation
O
30
= 10mA
3
40
50
4
Temperature (°C)
Time mS
60
V
C
C
5
OUT
OUT=
Adj =
70
= 3.3V
0.1mF
C
Typical Performance Characteristics: continued
6
IN
80
= 22mF Tantalum
90 100
7
8
Applications Information
110 120 130
9
10
4
Ripple Rejection vs. Frequency
Short Circuit Current vs. V
50µA) also flows through R2 and adds a small error that
should be taken into account if precise adjustment of V
is necessary.
The output voltage is set according to the formula:
The term I
pin current.
R
2mA. R1 and R2 should be the same type, e.g. metal film
for best tracking over temperature. While not required, a
bypass capacitor from the adjust pin to ground will
improve ripple rejection and transient response. A 0.1µF
tantalum capacitor is recommended for Òfirst cutÓ design.
Type and value may be varied to obtain optimum perfor-
mance vs. price.
1
is chosen so that the minimum load current is at least
3.5
3.3
3.1
2.9
2.7
2.5
2.3
2.1
1.9
1.7
1.5
85
75
65
55
45
35
25
15
V
1.0
10
OUT
Adj
1
´ R2 represents the error added by the adjust
= V
1.5
T
I
(V
V
C
OUT
CASE
RIPPLE
Adj
IN
10
REF
Ð V
= 0.1mF
= 1A
2
= 25°C
OUT
´
= 1.0V
IN
(
2.0
) = 3V
- V
R1 + R2
PP
Frequency (Hz)
OUT
10
V
R1
IN
3
- V
2.5
OUT
)
(V)
+ I
10
4
Adj
3.0
´ R2
10
5
3.5
10
OUT
4.0
6