CS5205−1, CS5205−3, CS5205−5

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6

The ESR of the output capacitor causes an immediate drop

in output voltage given by:

DV + DI

ESR

For microprocessor applications it is customary to use an

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

load transient conditions. The output capacitor network

should be as close as possible to the load for the best results.

Protection Diodes

When large external capacitors are used with a linear

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

CS5205−x family of linear regulators, 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 Figures 11 and 12 is recommended.

Figure 11. Protection Diode Scheme for Adjustable

Output Regulator

Adj

CS5205−1

IN4002 (optional)

Figure 12. Protection Diode Scheme for Fixed Output

Regulators

GND

CS5205−x

IN4002 (optional)

Output Voltage Sensing

Since the CS5205−x is a three terminal regulator, it is not

possible to provide true remote load sensing. Load

regulation is limited by the resistance of the conductors

connecting the regulator to the load. For best results the

fixed regulators should be connected as shown in Figure 13.

Figure 13. Conductor Parasitic Resistance can be

Minimized with the Above Grounding Scheme for

Fixed Output Regulators

GND

CS5205−x

Conductor Parasitic

Resistance

For the adjustable regulator, the best load regulation

occurs when R1 is connected directly to the output pin of the

regulator as shown in Figure 14. If R1 is connected to the

resistance between the regulator and the load becomes

RC

R1 ) R2

R1

Figure 14. Grounding Scheme for Adjustable Output

Regulator to Minimize Parasitics

Adj

CS5205−1

Conductor Parasitic

Resistance