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-3025ZF voltage regulator offers the
reduced dropout voltage and low quiescent current essential for im-
proved efficiency. This device delivers a regulated output at up to 3 A.
Integrated thermal and overcurrent protection enhance overall system
reliability. Devices with an adjustable 1.2 ~ 5 V output or a 3.3 V fixed
output 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 700 mV at 3 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 fully molded TO-220-style 5-lead
flange-mounted , high power, isolated plastic package. A similar device
in a lower-power surface-mount plastic package is the SI-3025ZD.
FEATURES
■3 A Output Current at 2.5 V
■0.7 V Maximum Dropout Voltage at IO = 3 A
■1 µA Maximum Standby Current
■Remote Voltage Sensing
■Foldback Current Limiting
■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
High-Current, Low-Dropout, 2.5 V Regulator
Data Sheet
27468.27*
Always order by complete part number, e.g., SI-3025ZF .
ABSOLUTE MAXIMUM RATINGS
Input Voltage, VI. . . . . . . . . . . . . 10 V
Output Current, IO. . . . . . . . . . . . . 3 A*
Enable Input Voltage, VE. . . . . . . . 6 V
Junction Temperature, TJ. . . . +125°C
Storage Temperature Range,
TS. . . . . . . . . . . . -40°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-3025
ZF
Linear
Regulators
Sanken Power Devices
from Allegro MicroSystems
SI-3025ZF
High-Current,
Low-Dropout,
2.5 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 Input Voltage — 6 V
DC Output Current 0 3 A
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-02578
SI-3025ZF
High-Current,
Low-Dropout,
2.5 V Regulator
www.allegromicro.com
Linear
Regulators
3
ELECTRICAL CHARACTERISTICS at TA = +25°C, VE = 2 V (unless otherwise noted).
Limits
Characteristic Symbol Test Conditions Min. Typ. Max. Units
Output Voltage VOVI = 3.3 V, IO = 10 mA 2.45 2.50 2.55 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 = 3.3 V, see note 3.2 — — A
Line Regulation ∆VO(∆VI) VI = 3.0 ~ 5.0 V, IO = 10 mA — — 10 m V
Load Regulation ∆VO(∆IO) VI = 3.3 V, IO = 0 A ~ 3.0 A — — 40 m V
Dropout Voltage
V
Imin
- V
O
IO = 3.0 A — — 0.7 V
Ground Terminal Current IGND VI = 3.3 V, IO = 0 mA, VE = 2.0 V — 1.0 1.5 m A
VI = 3.3 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 = 2.7 V — — 100 µ A
IEL VE = 0 V — 0 -5.0 µ A
Ripple Rejection Ratio PSRR VI = 3.3 V, 100 Hz ≤ f ≤ 120 Hz — 60 — dB
Thermal Shutdown TJ135 152 — °C
Typical values are given for circuit design information only.
Note: Output short-circuit current is at point where output voltage has decreased 5% below VO(nom).
SI-3025ZF
High-Current,
Low-Dropout,
2.5 V Regulator
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036
Linear
Regulators
4
TYPICAL CHARACTERISTICS
(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-3025ZF
High-Current,
Low-Dropout,
2.5 V Regulator
www.allegromicro.com
Linear
Regulators
5
APPLICATIONS INFORMATION
Input Capacitor (CI, approximately 10 µF). This is
necessary either when the input line includes inductance or
when the wiring is long.
Output Capacitor (CO, > 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.
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.
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 6.8 kΩ
resistor be added between SENSE and GND to increase the
current in REXT. The value of REXT is then
REXT = (VO – 2.5) × 106/458
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 (TJ) in its
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 (TJ) can be determined from
either of the following equations:
TJ = (PD × RθJA) + TA
or TJ = (PD × RθJC) + TC
where PD = IO × (VI – VO) and
RθJC = 5°C/W.
Parallel Operation. Parallel operation to increase load
current is not permitted.
SI-3025ZF
High-Current,
Low-Dropout,
2.5 V Regulator
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036
Linear
Regulators
6
Dimensions in Millimeters
Terminal Finish: Sn–3Ag–0.5Cu, 2nd level interconnect category (e1)
Product Weight: Approx. 2.3 g
Terminal spacing is measured at lead tips.
SI-3025ZF
High-Current,
Low-Dropout,
2.5 V Regulator
www.allegromicro.com
Linear
Regulators
7
Shipping Container Dimensions in Millimeters
Primary Packing: A U-shaped cardboard separator (Fig. 1) is
used to accommodate a maximum of 100 pieces (5 × 20) and, if
less than 100 pieces, a shock absorber shall be placed in the
vacant space. Each thin primary carton (Fig. 2) will contain a
maximum of 400 pieces in four rows.
Secondary Packing: The secondary carton (Fig. 3) contains
nine thin cartons.
EI16EI
SI-3025ZF
High-Current,
Low-Dropout,
2.5 V Regulator
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036
Linear
Regulators
8
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.
