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-3090KM 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 9.0 V
0.6 V Maximum Dropout Voltage at I

= 1 A

Fast Transient Response
1 µA Maximum Standby Current
Remote Voltage Sensing
Foldback Current Limiting
Overvoltage Protection
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, 9.0 V Regulator

Data Sheet

27468.80*

Always order by complete part number, e.g., SI-3090KM-TL ,
where "-TL" indicates tape and reel.

ABSOLUTE MAXIMUM RATINGS

Input Voltage, V

. . . . . . . . . . . . . 35 V

Output Current, I

. . . . . . . . . . . . . 1 A*

Enable Input Voltage, V

. . . . . . . . . V

Junction Temperature, T

. . . . +125°C

Storage Temperature Range,

. . . . . . . . . . . . -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-3090KM

Sanken Power Devices

from Allegro MicroSystems

Linear

Regulators

SI-3090KM
1 A, Low-Dropout,
9.0 V Regulator

115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036

Linear

Regulators

FUNCTIONAL BLOCK DIAGRAM

Recommended Operating Conditions

Min

Max

Units

DC Output Current

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-02138

SI-3090KM

1 A, Low-Dropout,

9.0 V Regulator

www.allegromicro.com

Linear

Regulators

ELECTRICAL CHARACTERISTICS

at T

= +25°C, V

= 2 V (unless otherwise noted).

Limits

Characteristic

Symbol

Test Conditions

Min.

Typ.

Max.

Units

Output Voltage

= 11 V, I

= 10 mA

8.82

9.00

9.18

O(off)

= 0 V

0.5

Output Volt. Temp. Coeff.

0°C

100°C

±1.0

mV/°C

Output Short-Circuit Current

= 11 V, See note

1.1

Overvoltage Protection

= 10 mA

Line Regulation

VI)

= 10 V ~ 20 V, I

= 10 mA

Load Regulation

IO)

= 11 V, I

= 0 A ~ 1.0 A

135

Dropout Voltage

Imin

- V

= 0.5 A

0.3

= 1.0 A

0.6

Ground Terminal Current

GND

= 11 V, I

= 0 mA, V

= 2.0 V

600

µA

= 11 V, V

= 0 V

1.0

µA

Enable Input Voltage

Output ON

2.0

Output OFF

0.8

Enable Input Current

= 2.0 V

µA

= 0 V

-5.0

µA

Ripple Rejection Ratio

PSRR

= 11 V, 100 Hz

120 Hz

Thermal Shutdown

= 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-3090KM

1 A, Low-Dropout,

9.0 V Regulator

www.allegromicro.com

Linear

Regulators

APPLICATIONS INFORMATION

Input Capacitor

22 µF). This is necessary either

when the input line includes inductance or when the wiring
is long.

Output Capacitor

47 µF). This device is not

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. The recommended ESR is
0.2~2

at T

= 25°C.

Reverse-Bias Protection Diode

(D1). Diode D1

provides reverse-bias protection between the input and
output. Sanken type SFPL-52 is recommended.

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.)

= 11 V, T

= 25°C)

Overvoltage Protection

GND Pin Current

Increased Output Voltage.

The output voltage (V

)

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 an 18 k

resistor be added between SENSE and GND to increase the
current in R

EXT

. The value of R

EXT

is then

EXT

= (V

9) × 10

/600

SI-3090KM
1 A, Low-Dropout,
9.0 V Regulator

115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036

Linear

Regulators

Determination of DC Input Voltage.

The minimum

input voltage V

(min) should be higher than the sum of the

fixed output voltage and the maximum rated dropout
voltage. If setting the output voltage lower than 2.0 V, the
minimum input voltage should be more than 2.4 V.

Overcurrent Protection.

The SI-3000KM 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.

APPLICATIONS INFORMATION (cont.)

Heat Radiation and Reliability.

The reliability of the

IC is directly related to the junction temperature (T

) in its

operation. Accordingly, careful consideration should be
given to heat dissipation.

The inner frame on which the integrated circuit is mounted
is connected to the GND terminal (pin 3). Therefore, it is
very effective for heat radiation to enlarge the copper area
that is connected to the GND terminal. The graph illus-
trates the effect of the copper area on the junction-to-
ambient thermal resistance (R

The junction temperature (T

) can be determined from

either of the following equations:

= (P

× R

) + T

= (P

× R

) + T

where P

= I

× (V

) and

= 6°C/W.

SI-3090KM

1 A, Low-Dropout,

9.0 V Regulator

www.allegromicro.com

Linear

Regulators

The products described herein are manufactured in Japan by Sanken

Electric Co., Ltd. for sale by Allegro MicroSystems, Inc.

Sanken and Allegro reserve the right to make, from time to time, such

departures from the detail specifications as may be required to permit
improvements in the performance, reliability, or manufacturability of its
products. Therefore, the user is cautioned to verify that the information
in this publication is current before placing any order.

When using the products described herein, the applicability and

suitability of such products for the intended purpose shall be reviewed at
the users responsibility.

Although Sanken undertakes to enhance the quality and reliability of

its products, the occurrence of failure and defect of semiconductor
products at a certain rate is inevitable.

Users of Sanken products are requested to take, at their own risk,

preventative measures including safety design of the equipment or
systems against any possible injury, death, fires or damages to society
due to device failure or malfunction.

Sanken products listed in this publication are designed and intended

for use as components in general-purpose electronic equipment or
apparatus (home appliances, office equipment, telecommunication
equipment, measuring equipment, etc.). Their use in any application
requiring radiation hardness assurance (e.g., aerospace equipment) is
not supported.

When considering the use of Sanken products in applications where

higher reliability is required (transportation equipment and its control
systems or equipment, fire- or burglar-alarm systems, various safety
devices, etc.), contact a company sales representative to discuss and
obtain written confirmation of your specifications.

The use of Sanken products without the written consent of Sanken in

applications where extremely high reliability is required (aerospace
equipment, nuclear power-control stations, life-support systems, etc.) is
strictly prohibited.

The information included herein is believed to be accurate and

reliable. Application and operation examples described in this publica-
tion are given for reference only and Sanken and Allegro assume no
responsibility for any infringement of industrial property rights,
intellectual property rights, or any other rights of Sanken or Allegro or
any third party that may result from its use.

EI16EI

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