Designed to meet the high-current requirements in industrial and
consumer applications; embedded core, memory, or logic supplies; TVs,
VCRs, and office equipment, the SI-3033KM voltage regulator offers
the reduced dropout voltage and low quiescent current essential for
improved efficiency. This device delivers a regulated output at up to
1 A. Integrated thermal and overcurrent protection enhance overall
system reliability. Devices with other output voltages are also available.
Quiescent current does not increase significantly as the dropout
voltage is approached, an ideal feature in standby/resume power systems
where data integrity is crucial. Regulator accuracy and excellent
temperature characteristics are provided by a bandgap reference. An
LS-TTL/CMOS-compatible input gives the designer complete control
over power up, standby, or power down. A pnp pass element provides a
dropout voltage of less than 600 mV at 1 A of load current. Low output
voltages eliminate the need for expensive PWM buck converters. The
low dropout voltage permits more efficient regulation before output
regulation is lost.
This device is supplied in a 5-lead TO-252 style surface-mount
plastic package with ground tab to provide a low-resistance path for
maximum heat dissipation.
FEATURES
1 A Output Current at 3.3 V
0.6 V Maximum Dropout Voltage at I
O
= 1 A
Fast Transient Response
1 µA Maximum Standby Current
Remote Voltage Sensing
Foldback Current Limiting
Ground Tab for Superior Heat Dissipation
Thermal Protection
APPLICATIONS
TVs, VCRs, Electronic Games
Embedded Core, Memory, or Logic Supplies
Printers and Other Office Equipment
Industrial Machinery
Secondary-Side Stabilization of Multi-Output SMPS
1 A, Low-Dropout, 3.3 V Regulator
Data Sheet
27468.32*
Always order by complete part number, e.g., SI-3033KM-TL ,
where "-TL" indicates tape and reel.
ABSOLUTE MAXIMUM RATINGS
Input Voltage, V
I
. . . . . . . . . . . . . 17 V
Output Current, I
O
. . . . . . . . . . . . . 1 A*
Enable Input Voltage, V
E
. . . . . . . . . V
I
Junction Temperature, T
J
. . . . +125°C
Storage Temperature Range,
T
S
. . . . . . . . . . . . -30°C to +125°C
* Output current rating is limited by input
voltage, duty cycle, and ambient tempera-
ture. Under any set of conditions, do not
exceed a junction temperature of +125°C.
SI-3033KM
Sanken Power Devices
from Allegro MicroSystems
Linear
Regulators
SI-3033KM
1 A, Low-Dropout,
3.3 V Regulator
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036
Linear
Regulators
2
FUNCTIONAL BLOCK DIAGRAM
Copyright © 2004, 2005 Allegro MicroSystems, Inc.
Recommended Operating Conditions
Min
Max
Units
DC Output Current
0
1
A
Operating Ambient Temp.
-30
+100
°C
Operating Junction Temp.
-20
+100
°C
For the availability of parts meeting -40°C requirements,
contact Allegro's Sales Representative.
Allowable Package Power Dissipation
This data sheet is based on Sanken data sheet SSJ-01992
SI-3033KM
1 A, Low-Dropout,
3.3 V Regulator
www.allegromicro.com
Linear
Regulators
3
ELECTRICAL CHARACTERISTICS
at T
A
= +25°C, V
E
= 2 V (unless otherwise noted).
Limits
Characteristic
Symbol
Test Conditions
Min.
Typ.
Max.
Units
Output Voltage
V
O
V
I
= 5 V, I
O
= 10 mA
3.234
3.300 3.366
V
V
O(off)
V
E
= 0 V
--
--
0.5
V
Output Volt. Temp. Coeff.
a
VO
0°C
T
J
100°C
--
±0.3
--
mV/°C
Output Short-Circuit Current
I
OM
V
I
= 5 V, See note
1.1
--
--
A
Line Regulation
V
O(
VI)
V
I
= 5 V ~ 10 V, I
O
= 10 mA
--
--
15
mV
Load Regulation
V
O(
IO)
V
I
= 5 V, I
O
= 0 A ~ 1.0 A
--
--
50
mV
Dropout Voltage
V
Imin
- V
O
I
O
= 0.5 A
--
--
0.4
V
I
O
= 1.0 A
--
--
0.6
V
Ground Terminal Current
I
GND
V
I
= 5 V, I
O
= 0 mA, V
E
= 2.0 V
--
--
350
µA
V
I
= 5 V, V
E
= 0 V
--
--
1.0
µA
Enable Input Voltage
V
EH
Output ON
2.0
--
--
V
V
EL
Output OFF
--
--
0.8
V
Enable Input Current
I
EH
V
E
= 2.0 V
--
--
40
µA
I
EL
V
E
= 0 V
--
0
-5.0
µA
Ripple Rejection Ratio
PSRR
V
I
= 5 V, 100 Hz
f
120 Hz
--
55
--
dB
Thermal Shutdown
T
J
I
O
= 10 mA
135
150
--
°C
Typical values are given for circuit design information only.
Note: Output short-circuit current is at point where output voltage has decreased 5%.
SI-3033KM
1 A, Low-Dropout,
3.3 V Regulator
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036
Linear
Regulators
4
TYPICAL CHARACTERISTICS
(V
I
= 5 V, T
A
= 25°C)
Dropout Voltage
Low-Voltage Behavior
GND Pin Current
Line Regulation
Load Regulation
ENABLE Control Voltage
Overcurrent Protection
ENABLE Control Current
Thermal Protection
SI-3033KM
1 A, Low-Dropout,
3.3 V Regulator
www.allegromicro.com
Linear
Regulators
5
APPLICATIONS INFORMATION
Input Capacitor
(C
I
,
22 µF). This is necessary either
when the input line includes inductance or when the wiring
is long.
Output Capacitor
(C
O
,
22 µF). This device is designed
for use with a very low ESR output capacitor such as a
ceramic capacitor. Output oscillation may occur with an
aluminum capacitor at low temperatures.
ENABLE Input
. The ENABLE (control) input features
an internal pull-down resistor. Leaving this input open
causes the output to turn off.
Parallel Operation.
Parallel operation to increase load
current is not permitted.
TYPICAL CHARACTERISTICS (cont.)
(V
I
= 5 V, T
A
= 25°C)
GND Pin Current
Increased Output Voltage.
The output voltage (V
O
)
may be increased by inserting a resistor (R
EXT
) between
SENSE and OUTPUT. The current flowing into SENSE is
typically 90 µA ±30%. To minimize the effect of I
SENSE
and temperature on R
EXT
, it is recommended that a 13 k
resistor be added between SENSE and GND to increase the
current in R
EXT
. The value of R
EXT
is then
R
EXT
= (V
O
3.3) × 10
6
/300
PDF 
ZIP