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IRUH33PA13A1M

Fig 2. Typical Application Circuit

Recommended input capacitance for a generic application is a 100

µF, 16V tantalum capacitor. However, the

input capacitance is not critical to the stability of the regulator and is therefore application dependant. In

designs with a clean bus voltage that is situated close to the input of the regulator, only a small ceramic

capacitor will be needed to decouple high frequency noise. On the other hand , in designs with a noisy bus,

a larger capacitor will be needed. Care should be taken to ensure that the input to the regulator is sufficiently

free of noise and disturbances.

Output Capacitance

Like most ultra low dropout voltage regulators, IRUH33PA13A1M requires the use of output capacitors as

part of the device frequency compensation. The device requires a minimum of 220

stability.

Many different types of capacitor are available and have widely varying characteristics. These capacitors

differ in capacitor tolerance, equivalent series resistance (ESR), equivalent series inductance and capacitance

temperature coefficient. The IRUH33PA13A1M frequency compensation optimizes frequency response with

low ESR capacitors. In general, use capacitors with an ESR of less than 50m

Ω for heavy load applications.

High quality bypass capacitors must be also be used to limit the high frequency noise generated by the load.

Multiple small ceramic capacitors are typically required to limit parasitic inductance (ESL) and ESR in the

capacitors to acceptable levels.

The upper limit of the capacitance is governed by the delayed over-current latch function of the regulator. The

regulator has a protection circuit that will latch the device off in the event of a short circuit. However, since it is

known that the regulator will draw a large in-rush current upon startup, the latch-off is delayed by about 10ms

to allow the outout capacitors to charge to a steady state without shutting down. During this period, the

regulator will have an output current at its maximum of around 5A typical. Therefore, the maximum output

capacitance can be as high as 20,000

Input Capacitance

IRUH33PA13A1M

Vout

Vin

SHDN

GND

100uF 16V

Tantalum

1.0uFX10

CeramicX7R

1000uF 6.3V

Low ESR Tantalum

Vin

Vout

Ground

R1

ADJUST

RESISTOR