ALLEGRO SI-8120JD-TL

SI-8120JD
Data Sheet
27469.51*
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Step-Down to 12.0 V, 1.5 A, DC/DC Converter
Designed to meet high-current requirements at high efficiency in
industrial and consumer applications; embedded core, memory, or logic
supplies; TVs, VCRs, and office or telecommunications equipment, the
SI-8120JD dc/dc step-down (buck) converter offers a constant 125 kHz
switching frequency essential for low EMI noise. The npn switch is
included on the die along with the oscillator, control, and logic circuitry
requiring only four external components for a regulated 12 V output at
up to 1.5 A. .
A wide input voltage range and integrated thermal and overcurrent
protection enhance overall system reliability. Reference accuracy and
excellent temperature characteristics are provided. An output-enable
input gives the designer complete control over power up, standby, or
power down.
This device is supplied in a 5-lead surface-mount plastic package
(TO-263) with ground tab to provide a low-resistance path for maximum
heat dissipation. A similar device in a flange-mounted (TO-220-style)
high-power package is the SI-8120JF.
ABSOLUTE MAXIMUM RATINGS
Input Voltage, VI . . . . . . . . . . . . .
43 V
Output Current, IO . . . . . . . . . . . 1.5 A*
Enable Input Voltage, VOE . . . . . . . . . . . 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 temperature. Under any set of conditions, do not
exceed a junction temperature of +125°C.
FEATURES
■ 11 V to 40 V Input Range
■ 1.5 A Output Current at 12 V
■ 2% Output Voltage Tolerance
■ Foldback Current Limiting
■ Constant 125 kHz Switching Frequency
■ 200 µA Maximum Standby Current
■ Soft Start Prevents Supply Voltage Dip
■ Remote Voltage Sensing
■ Exposed Pad for Superior Heat Dissipation
■ Thermal Protection
APPLICATIONS
■ TVs, VCRs, Electronic Games
■ Embedded Core, Memory, or Logic Supplies
■ Printers and Other Office Equipment
■ Industrial Machinery
■ Telecommunications Equipment
Always order by complete part number, e.g., SI-8120JD-TL ,
where “-TL” indicates tape and reel.
Sanken Power Devices
from Allegro MicroSystems
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SI-8120JD
Step-Down
to 12.0 V, 1.5 A,
DC/DC Converter
FUNCTIONAL BLOCK DIAGRAM
Allowable Package Power Dissipation
Recommended Operating Conditions
DC Input Voltage (IO ≤ 1 A)
(IO ≤ 1.5 A)
DC Output Current (VI ≥ 6.3 V)
Operating Junction Temp.
Min
Max
Units
14
15
0
-30
15
40
1.5
+125
V
V
A
°C
For the availability of parts meeting -40°C requirements, contact Allegro’s Sales Representative.
This data sheet is based on Sanken data sheet SSJ-01967
2
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036
Copyright © 2004, 2005 Allegro MicroSystems, Inc.
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SI-8120JD
Step-Down
to 12.0 V, 1.5 A,
DC/DC Converter
ELECTRICAL CHARACTERISTICS at TA = +25°C, VI = 24 V, IO = 0.5 A (unless otherwise noted).
Limits
Characteristic
Symbol
Output Voltage
Test Conditions
Min.
Typ.
Max.
Units
VO
11.76
12.0
12.24
V
Ref. Volt. Temp. Coeff.
aVref
—
±1.0
—
mV/°C
Output Short-Circuit Current
IOM
1.6
—
—
A
See note
Efficiency
η
—
88
—
%
Operating Frequency
f
—
125
—
kHz
Line Regulation
∆VO(∆VI)
VI = 18 V ~ 30 V, IO = 0.5 A
—
60
130
mV
Load Regulation
∆VO(∆IO)
VI = 24 V, IO = 0.2 A ~ 0.8 A
—
10
40
mV
IO = 0 A
—
7.0
—
mA
VCE = 0.3 V
—
—
200
µA
Quiescent Current
IIQ
Chip Enable Voltage
VCE
Converter turn-off voltage
—
—
0.5
V
Soft-Start Current
ISS
VSS = 0 V
—
—
-100
µA
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-8120JD
Test Circuit
C1 = 220 µF/50 V
C2 = 470 µF/25 V
C3 = 0.47 µF/10 V
L1 = 100 µH
D1 = Sanken SFPB-66
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SI-8120JD
Step-Down
to 12.0 V, 1.5 A,
DC/DC Converter
TYPICAL CHARACTERISTICS
(TA = 25°C)
Efficiency
Overcurrent Protection
Low-Voltage Behavior
Load Regulation
Temperature Stability
4
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036
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SI-8120JD
Step-Down
to 12.0 V, 1.5 A,
DC/DC Converter
APPLICATIONS INFORMATION
Input Capacitor (C1). Capacitors with low impedance
for high-frequency ripple current must be used.
Output Capacitor (C2). Capacitors with low impedance
for high-frequency ripple current must be used. Especially
when the C2 impedance is high, the switching waveform
may not be normal at low temperatures. Film or tantalum
capacitor for C2 may cause abnormal oscillations.
Catch Diode (D1). Diode D1 must be a Schottky diode.
Other diode types will result in increased forward voltage
spikes, reverse current flow, increased IC power dissipation during the off period, and possible destruction of the
IC.
Choke Coil (L1). If the winding resistance of the choke
coil is too high, the circuit efficiency will decrease. As the
overcurrent protection start current is approximately 2.5 A,
attention must be paid to the heating of the coil by magnetic
saturation due to overload. To reduce the output ripple, the
inductor may be increased at the expense of excessive
board area and cost.
SI-8120JD
www.allegromicro.com
Soft-Start Capacitor (C3). Soft start for the converter
is enabled by connecting a capacitor between terminal 5
and ground. The converter may be turned off by decreasing
the terminal 5 voltage below 0.5 V with either an npn
small-signal transistor or the output of open-collector TTL.
If both a large soft-start capacitor and on/off control are
desired, collector current limiting must be used to prevent
transistor damage. No external voltage can be applied to
terminal 5.
Parallel Operation. Parallel operation to increase load
current is not permitted.
Overcurrent Protection. The SI-8000JD 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.
Typical Application
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SI-8120JD
Step-Down
to 12.0 V, 1.5 A,
DC/DC Converter
APPLICATIONS INFORMATION (cont.)
Thermal Protection. Circuitry turns off the switching
transistor when the junction temperature rises above 150°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 illustrates the effect of the copper area on the junction-toambient thermal resistance (RθJA).
The junction temperature (TJ) can be determined from
either of the following equations:
TJ = (PDRθJA) + TA
or
TJ = (PDRθJC) + TC
where PD = VIII – VOIO – VFIO(1 – [VO/VI])
or the adjacent graph,
VF = the Schottky diode forward voltage, and
RθJC =3°C/W.
6
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036
Layout Guideline
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SI-8120JD
Step-Down
to 12.0 V, 1.5 A,
DC/DC Converter
Dimensions in Millimeters
Tab Temperature
(TT) Measured Here
Recommended Land Pattern
Notes:
1. Dimensions do not include mold protrusions.
2. ( ) Is reference.
3. [ ] Is assembly out quality.
4. Heat sink side flash: 0.8 mm max.
5. Terminal finish: pure Sn, 2nd level interconnect category (e3)
6. Product weight: approximately 1.48 g
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SI-8120JD
Step-Down
to 12.0 V, 1.5 A,
DC/DC Converter
Tape and Reel Dimensions in Millimeters
Tape Specifications
1. Material: conductive polystyrene.
2. Allowable camber: 1 mm/100 mm maximum.
3. A0 (10.6 mm) and B0 (15.7 mm) measured on a plane
0.3 mm above the bottom of the pocket.
4. K0 (4.9 mm) is measured from a plane on the inside
bottom of the pocket to the surface of the carrier.
5. Ten pitches cumulative tolerance on tape ±0.2 mm.
6. The space between parts and cavity must not exceed
±0.3 mm from its normal position in any direction.
7. Surface resistivity of embossment: 107 ohm/cm2 max.
8. K1 = 3.9 mm.
Detail C
8
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036
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SI-8120JD
Step-Down
to 12.0 V, 1.5 A,
DC/DC Converter
Shipping Container Dimensions in Millimeters
Inner Box
2 reels per box, 800 pieces per reel
Outer Box
Maximum 3 inner boxes per outer box
EI16EI
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SI-8120JD
Step-Down
to 12.0 V, 1.5 A,
DC/DC Converter
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 publication 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.
10
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036