cs5203-1 ON Semiconductor, cs5203-1 Datasheet - Page 6

• Manufacturer Part Number: cs5203-1
• Description: Linear Voltage Regulators
• Manufacturer: ON Semiconductor

Stability Considerations
three main characteristics of a linear regulator: start−up
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
CS5203−1 the transient response and stability improve with
higher values of capacitor. 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
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
CS5203−1 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 14 is recommended.
The output or compensation capacitor helps determine
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
When large external capacitors are used with a linear
DV + DI
ESR
IN
drops. In the
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6
Output Voltage Sensing
possible to provide true remote load sensing. Load
regulation is limited by the resistance of the conductors
connecting the regulator to the load.
occurs when R1 is connected directly to the output pin of the
regulator as shown in Figure 15. If R1 is connected to the
load, R
resistance between the regulator and the load becomes.
where R
V
IN
Figure 15. Grounding Scheme for Adjustable Output
Since the CS5203−1 is a three terminal regulator, it is not
For the adjustable regulator, the best load regulation
Regulator to Minimize Parasitic Resistance Effects
V
Figure 14. Protection Diode Scheme for Large
IN
C
C
is multiplied by the divider ratio and the effective
= conductor parasitic resistance.
V
IN
C
CS5203−1
1
Adj
V
Output Capacitors
R C
IN
CS5203−1
IN4002 (Optional)
V
OUT
Adj
V
C
R1 ) R2
OUT
Adj
R1
R
R
1
2
R
C
Conductor Parasitic
R
R
1
2
Resistance
C
V
2
OUT
R
LOAD