si-3033zf Allegro MicroSystems, Inc., si-3033zf Datasheet - Page 5

• Manufacturer Part Number: si-3033zf
• Description: High-current, Low-dropout, 3.3 V Regulator
• Manufacturer: Allegro MicroSystems, Inc.

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
and temperature on R
resistor be added between SENSE and GND to increase the
current in R
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.
www.allegromicro.com
EXT
R
I
. The value of R
(min) should be higher than the sum of the
EXT
= (V
I
EXT
, approximately 10 µF). This is
O
, > 47 µF). This device is not
, it is recommended that a 9.1 k
O
– 3.3) × 10
EXT
is then
6
/453
APPLICATIONS INFORMATION
EXT
) between
SENSE
O
)
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:
or
where P
Parallel Operation. Parallel operation to increase load
current is not permitted.
R
D
JC
= I
= 5°C/W.
O
× (V
T
T
J
J
I
– V
= (P
= (P
O
D
D
) and
× R
J
× R
) can be determined from
JA
JC
3.3 V Regulator
) + T
) + T
High-Current,
Low-Dropout,
SI-3033ZF
A
C
J
) in its
5