cs5201-3 ON Semiconductor, cs5201-3 Datasheet - Page 4

• Manufacturer Part Number: cs5201-3
• Description: 1.0 A, 3.3 V Fixed Linear Regulator
• Manufacturer: ON Semiconductor

output voltage at currents up to 1.0 A. The regulator is
protected against overcurrent conditions and includes
thermal shutdown.
transistor and requires an output capacitor for stability. A
detailed procedure for selecting this capacitor is included in
the Stability Considerations section.
Stability Considerations
main characteristics of a linear regulator: startup delay, load
transient response, and loop stability.
size and temperature constraints. A tantalum or aluminum
electrolytic capacitor is best, since a film or ceramic
capacitor with almost zero ESR can cause instability. The
aluminum electrolytic capacitor is the least expensive
solution. However, when the circuit operates at low
temperatures, both the value and ESR of the capacitor will
vary considerably. The capacitor manufacturer’s data sheet
provides this information.
applications, but with high current regulators such as the
CS5201−3 the transient response and stability improve with
higher values of capacitance. The majority of applications
for this regulator involve large changes in load current so the
output capacitor must supply the instantaneous load current.
The ESR of the output capacitor causes an immediate drop
in output voltage given by:
output capacitor network consisting of several tantalum and
The CS5201−3 linear regulator provides a fixed 3.3 V
The CS5201−3 has a composite PNP−NPN output
The output compensation capacitor helps determine three
The capacitor value and type is based on cost, availability,
A 22 mF tantalum capacitor will work for most
For microprocessor applications it is customary to use an
−100
−200
1000
300
200
100
500
0
0
0
1
Figure 7. Transient Response
2
C
OUT
DV + DI
3
= C
4
IN
Time (mS)
= 22 mF Tantalum
5
ESR
6
7
APPLICATIONS INFORMATION
8
http://onsemi.com
9
10
4
ceramic capacitors in parallel. This reduces the overall ESR
and reduces the instantaneous output voltage drop under
transient load conditions. The output capacitor network
should be as close to the load as possible for the best results.
Protection Diodes
regulator it is sometimes necessary to add protection diodes.
If the input voltage of the regulator gets shorted, the output
capacitor will discharge into the output of the regulator. The
discharge current depends on the value of the capacitor, the
output voltage and the rate at which V
CS5201−3 linear regulator, the discharge path is through a
large junction and protection diodes are not usually needed.
If the regulator is used with large values of output
capacitance and the input voltage is instantaneously shorted
to ground, damage can occur. In this case, a diode connected
as shown in Figure 9 is recommended.
When large external capacitors are used with a linear
3.5
3.3
3.1
2.9
2.7
2.5
2.3
2.1
1.9
1.7
1.5
Figure 9. Protection Diode Scheme for Large
1.0
V
IN
Figure 8. Short Circuit Current vs.
1.5
C
1
Output Capacitors
IN4002 (Optional)
V
IN
CS5201−3
2.0
GND
V
V
IN
IN
V
− V
OUT
− V
2.5
OUT
OUT
(V)
3.0
IN
drops. In the
C
V
3.5
2
OUT
4.0