SI-3033ZF

High-Current,

Low-Dropout,

3.3 V Regulator

www.allegromicro.com

Linear

Regulators

5

APPLICATIONS INFORMATION

Input Capacitor (C

necessary either when the input line includes inductance or

when the wiring is long.

Output Capacitor (C

designed for a use with a very low ESR output capacitor

such as a ceramic capacitor. Output oscillation may occur

with that kind of capacitor.

Determination of DC Input Voltage. The minimum

input voltage V

fixed output voltage and the maximum rated dropout

voltage.

Increased Output Voltage. The output voltage (V

may be increased by inserting a resistor (R

SENSE and OUTPUT. The current flowing into SENSE is

typically 90 µA ±30%. To minimize the effect of I

SENSE

and temperature on R

resistor be added between SENSE and GND to increase the

current in R

R

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Overcurrent Protection. The SI-3000ZD series has a

built-in fold-back type overcurrent protection circuit, which

limits the output current at a start-up mode. It thus cannot

be used in applications that require current at the start-up

mode such as:

(1) constant-current load,

(2) power supply with positive and negative outputs to

common load (a center-tap type power supply), or

(3) raising the output voltage by putting a diode or a

resistor between the device ground and system ground.

Thermal Protection. Circuitry turns off the pass

transistor when the junction temperature rises above 135°C.

It is intended only to protect the device from failures due to

excessive junction temperatures and should not imply that

output short circuits or continuous overloads are permitted.

Heat Radiation and Reliability. The reliability of the

IC is directly related to the junction temperature (T

operation. Accordingly, careful consideration should be

given to heat dissipation. The graph on page 2 illustrates

the effect of thermal resistance on the allowable package

power dissipation.

When mounting to a heat sink, apply silicone grease (Shin-

Etsu Chemical G746, Dow Corning Toray Silicone SC102,

or Toshiba Silicone SY6260). Recommended mounting

hardware torque: 0.588 ~ 0.686 Nm or 6.0 ~ 7.0 kgf•cm

(4.34 ~ 5.06 lbf•ft).

The junction temperature (T

either of the following equations:

T

or

T

where P

Parallel Operation. Parallel operation to increase load

current is not permitted.