CS52015-1
Typical Performance Characteristics
70.0
I
O
= 10mA
65.0
Adjust Pin Current (mA)
Ripple Rejection (dB)
85
75
65
55
45
35
60.0
55.0
50.0
T
CASE
= 25°C
I
OUT
= 1.5A
(V
IN
Ð V
OUT
) = 3V
V
RIPPLE
= 1.0V
PP
C
Adj
= 0.1mF
45.0
25
15
0
10
20
30
40
50
60
70
80
90 100 110 120 130
10
1
10
2
10
3
10
4
10
5
10
6
Temperature (°C)
Frequency (Hz)
40.0
Adjust Pin Current vs. Temperature
Ripple Rejection vs. Frequency
Voltage Deviation (mV)
3.5
200
100
0
3.3
3.1
2.9
2.7
I
SC
(A)
10
-100
-200
V
OUT
=3.3V
C
OUT
=C
IN
=22mF Tantalum
C
Adj
=0.1mF
2.5
2.3
2.1
1.9
Load Step (mA)
1500
750
1.7
0
0
1
2
3
4
5
Time
mS
6
7
8
9
1.5
1.0 1.5
2.0
2.5
3.0
3.5 4.0 4.5
V
IN
- V
OUT
(V)
5.0
5.5
6.0
6.5
7.0
Transient Response
Short Circuit Current vs V
IN
-V
OUT
Applications Information
The CS52015-1 linear regulator provides adjustable volt-
ages at currents up to 1.5A. The regulator is protected
against overcurrent conditions and includes thermal
shutdown.
The CS52015-1 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.
Adjustable Operation
50µA) also flows through R2 and adds a small error that
should be taken into account if precise adjustment of V
OUT
is necessary.
The output voltage is set according to the formula:
V
OUT
= V
REF
´
R1 + R2 + I
Adj
´
R2
R1
The term I
Adj
´
R2 represents the error added by the adjust
pin current.
R1 is chosen so that the minimum load current is at least
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.
(
)
The 52015-1 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
4
CHERRY [ CHERRY SEMICONDUCTOR CORPORATION ]
