SI-3018KM-TL - Allegro MicroSystems Europe Ltd.

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-3018KM 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 1.8 V

■0.6 V Maximum Dropout Voltage at IO = 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, 1.8 V Regulator

Data Sheet

27468.19*

Always order by complete part number, e.g., SI-3018KM-TL ,

where “-TL” indicates tape and reel.

ABSOLUTE MAXIMUM RATINGS

Input Voltage, VI. . . . . . . . . . . . . 17 V

Output Current, IO. . . . . . . . . . . . . 1 A*

Enable Input Voltage, VE. . . . . . . . . VI

Junction Temperature, TJ. . . . +125°C

Storage Temperature Range,

TS. . . . . . . . . . . . -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-3018

Sanken Power Devices

from Allegro MicroSystems

Linear

Regulators

SI-3018KM

1 A, Low-Dropout,

1.8 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 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-02296

SI-3018KM

1 A, Low-Dropout,

1.8 V Regulator

www.allegromicro.com

Linear

Regulators

ELECTRICAL CHARACTERISTICS at TA = +25°C, VE = 2 V (unless otherwise noted).

Limits

Characteristic Symbol Test Conditions Min. Typ. Max. Units

Output Voltage VOVI = 2.5 V, IO = 10 mA 1.764 1.800 1.836 V

VO(off) VE = 0 V — — 0.5 V

Output Volt. Temp. Coeff. aVO 0°C ≤ TJ ≤ 100°C — ±0.3 — mV/°C

Output Short-Circuit Current IOM VI = 2.5 V, See note 1.1 — — A

Line Regulation ∆VO(∆VI) VI = 2.5 V ~ 6 V, IO = 10 mA — — 15 m V

Load Regulation ∆VO(∆IO) VI = 2.5 V, IO = 0 A ~ 1.0 A — — 40 m V

Dropout Voltage

Imin

- V

IO = 0.5 A — — 0.6 V

IO = 1.0 A — — 0.6 V

Ground Terminal Current IGND VI = 2.5 V, IO = 0 mA, VE = 2.0 V — — 350 µA

VI = 2.5 V, VE = 0 V — — 1.0 µA

Enable Input Voltage VEH Output ON 2.0 — — V

VEL Output OFF — — 0.8 V

Enable Input Current IEH VE = 2.0 V — — 40 µA

IEL VE = 0 V — 0 -5.0 µ A

Ripple Rejection Ratio PSRR VI = 2.5 V, 100 Hz ≤ f ≤ 120 Hz — 55 — dB

Thermal Shutdown TJIO = 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-3018KM

1 A, Low-Dropout,

1.8 V Regulator

115 Northeast Cutoff, Box 15036

Worcester, Massachusetts 01615-0036

Linear

Regulators

TYPICAL CHARACTERISTICS

(VI = 2.5 V, TA = 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-3018KM

1 A, Low-Dropout,

1.8 V Regulator

www.allegromicro.com

Linear

Regulators

APPLICATIONS INFORMATION

Input Capacitor (CI, ≥22 µF). This is necessary either

when the input line includes inductance or when the wiring

is long.

Output Capacitor (CO, ≥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.)

(VI = 2.5 V, TA = 25°C)

 GND Pin Current

Increased Output Voltage. The output voltage (VO)

may be increased by inserting a resistor (REXT) between

SENSE and OUTPUT. The current flowing into SENSE is

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

and temperature on REXT, it is recommended that a 7.5 kΩ

resistor be added between SENSE and GND to increase the

current in REXT. The value of REXT is then

REXT = (VO – 1.8) × 106/290

SI-3018KM

1 A, Low-Dropout,

1.8 V Regulator

115 Northeast Cutoff, Box 15036

Worcester, Massachusetts 01615-0036

Linear

Regulators

APPLICATIONS INFORMATION (cont.)

Determination of DC Input Voltage. The minimum

input voltage VI(min) should be higher than the sum of the

fixed output voltage and the maximum rated dropout

voltage.

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.

Heat Radiation and Reliability. The reliability of the

IC is directly related to the junction temperature (TJ) 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 (RθJA).

The junction temperature (TJ) can be determined from

either of the following equations:

TJ = (PD × RθJA) + TA

or TJ = (PD × RθJT) + TT

where PD = IO × (VI – VO) and

RθJT = 6°C/W.

SI-3018KM

1 A, Low-Dropout,

1.8 V Regulator

www.allegromicro.com

Linear

Regulators

Dimensions in Millimeters

Recommended Land Pattern

Terminal Finish: Pure Sn, 2nd level interconnect category (e3)

Product Weight: Approx. 0.33 g

3000 pieces per reel.

Tab Temperature

(TT) Measured Here

SI-3018KM

1 A, Low-Dropout,

1.8 V Regulator

115 Northeast Cutoff, Box 15036

Worcester, Massachusetts 01615-0036

Linear

Regulators

Tape and Reel Dimensions in Millimeters

W1: 16.4 +2/-0 mm

W2: 22.4 mm Max.

W3: 16.4 +3/-0.5 mm

SI-3018KM

1 A, Low-Dropout,

1.8 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 pr oducts described her ein, the applicability and

suitability of such pr oducts for the intended purpose shall be r eviewed at

the users responsibility .

Although Sanken undertakes to enhance the quality and r eliability of

its pr oducts, the occurr ence of failur e and defect of semiconductor

pr oducts at a certain rate is inevitable.

Users of Sanken pr oducts ar e r equested to take, at their own risk,

pr eventative measur es including safety design of the equipment or

systems against any possible injury , death, fir es or damages to society

due to device failure or malfunction.

Sanken pr oducts listed in this publication are designed and intended

for use as components in general-purpose electr onic equipment or

apparatus (home appliances, office equipment, telecommunication

equipment, measuring equipment, etc.). Their use in any application

r equiring radiation har dness assurance (e.g., aerospace equipment) is

not supported.

When considering the use of Sanken pr oducts in applications wher e

higher r eliability is r equired (transportation equipment and its contr ol

systems or equipment, fir e- or burglar-alarm systems, various safety

devices, etc.), contact a company sales r epresentative to discuss and

obtain written confirmation of your specifications.

The use of Sanken pr oducts without the written consent of Sanken in

applications wher e extremely high r eliability is requir ed (aer ospace

equipment, nuclear power-contr ol stations, life-support systems, etc.) is

strictly pr ohibited.

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