Sanken SI-8008HD User manual

SI-8008HD
Description
The SI-8008HD DC voltage regulator is a DC-to-DC buck
convertor that attains an oscillation frequency of 150 kHz,
and has an integrated miniaturized choke coil, allowing it to
serve as a small, high efficiency power supply in a compact
TO-263 package.
The internal switching regulator function provides high
efficiency switching regulation without any need for adjustment.
The device requires only six external support components. The
optional soft start function requires an additional capacitor.
Optional on/off control can be performed using a transistor.
The SI-8008HD includes overcurrent and overtemperature
protection circuits.
Applications include:
▪DVD recorder
▪FPD TV
▪Telecommunications equipment
▪Office automation equipment, such as printers
▪On-board local power supply
▪Output voltage regulator for second stage of SMPS
(switched mode power supply)
Features and Benefits
▪5.5 A output current supplied in a small, surface mount
power package
▪High efficiency: 83% at VIN = 15 V, IO = 3.0 A,VO = 5 V
▪Requires only seven external components (optional soft
start requires an additional capacitor)
▪Oscillation circuit built-in (frequency 150 kHz typical)
▪Constant-current mode overcurrent protection circuit and
overtemperature protection circuit built-in
▪Soft start function built-in (can be implemented as an
on/off function; output-off state at low level)
▪Low current consumption during output-off state
DC-to-DC Step-Down Converter
Not to scale
Functional Block Diagram
Latch and
Driver
Overcurrent
Protection
Overtemperature
Protection
Reference
Voltage
Osc
Reset
Comparator
Error
Amplifier
1
3
4
2VO
U
Di C2
C4
VIN
C1
GND
ADJ
SW
IN
R1
R2
L1
PReg
On/Off
Soft Start
5
C3
SS
Di
FMB-G16L
(Sanken)
Package: TO263-5
27469.059

DC-to-DC Step-Down Converter
SI-8008HD
2
All performance characteristics given are typical values for circuit or
system baseline design only and are at the nominal operating voltage and
an ambient temperature, TA, of 25°C, unless otherwise stated.
Selection Guide
Part Number Output Voltage Adjustable Range
(V)
Efficiency,
Typ.
(%)
Input Voltage,
Max.
(V)
Output Current,
Max.
(A) Packing
SI-8008HD-TL 0.8 to 24 83 40 5.5 800 pieces per reel
Absolute Maximum Ratings
Characteristic Symbol Remarks Rating Units
DC Input Voltage VIN 43 V
Power Dissipation PD
Mounted on 40 mm × 40 mm exposed copper area on 40 mm
× 40 mm glass-epoxy PCB; limited by internal overtemperature
protection.
3W
Junction Temperature TJ
Internal overtemperature protection circuit may enable when TJ≥
130°C. During product operation, recommended TJ≤125°C. –40 to 150 °C
Storage Temperature Tstg –40 to 150 °C
Thermal Resistance (junction-to-case) RθJC
Mounted on 40 mm × 40 mm exposed copper area on 40 mm ×
40 mm glass-epoxy PCB. 3 °C/W
Thermal Resistance (junction-to-ambient air) RθJA
Mounted on 40 mm × 40 mm exposed copper area on 40 mm ×
40 mm glass-epoxy PCB. 33.3 °C/W
Recommended Operating Conditions*
Characteristic Symbol Remarks Min. Max. Units
DC Input Voltage Range VIN VIN (min) is the greater of 4.5 V or VO+3 V. See
remarks 40 V
DC Output Voltage Range VO0.8 24 V
DC Output Current Range IO
VIN ≥VO + 3 V; to be used within the allowable package
power dissipation characteristics (refer to Power Dissipation
chart).
0 3.5 A
Operating Junction Temperature Range TJOP –30 100 °C
Operating Temperature Range TOP
To be used within the allowable package power dissipation
characteristics (refer to Power Dissipation chart). –30 85 °C
*Required for normal device functioning according to Electrical Characteristics table.
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]
www.allegromicro.com

DC-to-DC Step-Down Converter
SI-8008HD
3
SI-8008HD
(a)
V
O
on/off
control only
(c)
V
O
on/off and
soft start control
(b)
Soft start
only
C3
SS
5
SI-8008HD
SS
5
SI-8008HD
SS
5
System
TTL
C3
System
TTL
Terminal List Table
Name Number Function
IN 1 Supply voltage
SW 2 Regulated supply output
GND 3 Ground terminal
ADJ 4 Terminal for resistor bridge feedback
SS 5
The SS terminal is used to enable soft start and to control on/off operation of the IC output,
VO(see figure 2). If neither soft start nor on/off control is used, leave pin open.
To enable soft start, connect a capacitor between SS and ground. To control on/off
operation, connect an NPN bipolar transistor, in a TTL open collector output configuration,
between the SS terminal and GND. Turn off is done by decreasing VSSL below its rated
level.
When both soft start and VOon/off are used, a protection measure such as current limiting
is required because, if the capacitance of C3 large, the discharge current of C3 flows
across the transistor for on/off operation. Because a pull-up type resistor is provided inside
the IC, no external voltage can be applied.
Pin-out Diagram
Figure 2. Alternative configurations for SS pin. If neither soft start nor VOon/off is required, the SS pin is left open.
ELECTRICAL CHARACTERISTICS1,valid at TA= 25°C, VO= 5 V (adjusted), R1 = 4.2 kΩ, R1 = 0.8 kΩ
Characteristic Symbol Test Conditions Min. Typ. Max. Units
Reference Voltage VADJ VIN = 15 V, IO = 0.2 A 0.784 0.800 0.816 V
Reference Voltage Temperature Coefficient ∆VADJ
/∆TV
IN = 15 V, IO = 0.2 A, TC= 0 to 100 °C – ±0.1 – mV/°C
Efficiency2ηVIN = 15 V, IO = 3 A – 83 – %
Operating Frequency fOVIN = 15 V, IO = 3 A – 150 – kHz
Line Regulation VLine VIN = 10 to 30 V, IO = 3 A – 60 80 mV
Load Regulation VLoad VIN = 15 V, IO = 0.2 to 5.5 A – 20 50 mV
Overcurrent Protection Threshold Current ISVIN = 15 V 5.6 6.5 7.5 A
SS Terminal On/Off Operation Threshold Voltage VSSL – – 0.5 V
SS Terminal On/Off Operation Outflow Current ISSL VSSL = 0 V – 10 30 μA
Quiescent Current 1 IqVIN = 15 V, IO = 0 A – 6 – mA
Quiescent Current 2 Iq(off) VIN = 15 V, VSS = 0 V – 200 400 μA
1Using circuit shown in Typical Application Circuit diagram.
2Efficiency is calculated as: η(%) = ([VO× IO] × [VIN × IIN]) × 100.
12345
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]
www.allegromicro.com

DC-to-DC Step-Down Converter
SI-8008HD
4
6
5
4
3
2
1
0
0 20 40 60 80 100 120 140 180160
T
J
(°C)
V
O
(V)
Overtemperature
Protection:
Output Voltage versus
Junction Temperature
V
IN = 15 V, IO= 10 mA
OTP On
OTP Off
Performance Characteristics
at TA= 25°C, VO= 5 V adjusted, , R1 = 4.2 kΩ, R2 = 0.8 kΩ
90
80
70
60
50
40
0123456
η(%)
6.00
5.00
4.00
3.00
2.00
1.00
0
5.06
5.04
5.02
5.00
4.98
4.96
4.94
4.92
012345678
V
O
(V)
Efficiency versus
Output Current
Low Voltage
Behavior:
Output Voltage
versus
Supply Voltage
8V
30 V
012 5436
Load Regulation:
Output Voltage
versus
Output Current
V
O
(V)
I
O
(A)
V
IN
(V)
I
O
(A)
15 V
40 V V
IN
I
O
V
IN
0A
40 V
30 V
20 V
10 V
8V
2A
1A
5.5 A
4A
3A
V
IN
10 V
15 V
8V
20 V
40 V
30 V
0
2
1
3
5
4
6
024 86
Overcurrent
Protection:
Output Voltage
versus
Output Current
V
O
(V)
I
O
(A)
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]
www.allegromicro.com

DC-to-DC Step-Down Converter
SI-8008HD
5
Thermal Performance Characteristics
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
–25 0 25 50 75 100 125
Power Dissipation versus Ambient Temperature
T
J(max) = 125°C; Mounted on glass-epoxy PCB (40 mm
× 40 mm),
with varying exposed copper areas
P
D
(W)
T
A
(°C)
Cu Area: 1600 mm2
RθJA = 33.3°C/W
Cu Area: 800 mm2
RθJA = 37°C/W
Cu Area: 400 mm2
RθJA = 44°C/W
Cu Area: 100 mm2
RθJA = 53°C/W
Device Thermal Resistance versus Exposed Copper Area on PCB
Glass-epoxy PCB, 40 mm × 40 mm
Copper Area (mm
2
)
55
50
45
40
35
30
0 800 1000 1200 1400 1600200 400 600 1800
RθJA(°C/W)
The application must be designed to ensure that the TJ(max)
of the device is not exceeded during operation. To do so, it is
necessary to determine values for maximum power dissipation,
PD(max), and ambient temperature, TA(max).
The relationships of TJ, PD, TA, and case temperature, TC, are as
shown in the following formulas:
TJ–T
C
RθJC
PD=TJ–T
A
RθJA
PD=
and .
PDcan be calculated from input values:
⎟
⎟
⎠
⎞
⎜
⎜
⎝
⎛−⋅−
⎟
⎟
⎠
⎞
⎜
⎜
⎝
⎛−⋅=
IN
O
OF
x
OOD
V
V
IVIVP 11
100
H
where:
VOis output voltage in V,
VIN is input supply voltage in V,
IOis output current in A,
ηxis IC efficiency in percent (varies with VIN and IO; refer to
efficiency performance curves for value), and
VFis forward voltage for the input diode, Di. In these tests, the
Sanken FMB-G16L was used, at 0.55 V. For application design,
obtain thermal data from the datasheet for the diode.
PDis substantially affected by the heat conductance properties of
the application, in particular any exposed copper area on the PCB
where the device is mounted. The relationships of PD, TA, and
copper area is represented in the Power Dissipation chart.
RθJA for a given copper area can be determined form the Device
Thermal Resistance chart. This can be substituted into the formula
above to determine the TJ (max) allowable in the application.
Generally, more than 10% to 20% derating is required.
Because the heat dissipation capacity of the copper area depends
substantively on how it is used in the actual application, thermal
characteristics of the application must be confirmed by testing.
TCis determined by connecting a thermocouple to the device as
shown here:
Thermocouple mount
at tab center
And analyzing the results using the following formula:
TJ=PD×RθJC +TC,
for this device, RθJC is 3 °C/W.
Power Dissipation versus Output Current
10
9
8
7
6
5
4
3
2
1
0
0123456
PD(W)
IO(A)
8
15
20
40
VIN (V)
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]
www.allegromicro.com

DC-to-DC Step-Down Converter
SI-8008HD
6
Component Selection
VIN 1
GND GND
2
4
3
GNDSS
IN SW
ADJ
C1 C2
L1
Di
VO
R1
R2
IADJ
C4 5
C3
Soft Start Only
SI-8008HD
Component Rating
C1 1500 μF
C2 1000 μF
C3 0.1 μF (For soft start function)
C4 4.7 μF (GRM32ER71H475KA88L)
Di FMB-G16L (Sanken)
L1 100 μH
All external components should be mounted as close as possible
to the SI-8008HD. The ground of all components should be
connected at one point near GND pin (pin 3).
Recommended PCB Layout Recommended Solder Pad Layout
Typical Application Diagram
Diode Di A Schottky-barrier diode must be used for Di. If other
diode types are used, such as fast recovery diodes, the IC may be
destroyed because of the reverse voltage applied by the recovery
voltage or ON voltage.
Choke Coil L1 If the winding resistance of the choke coil is too
high, the efficiency may be reduced below rating. Because the
overcurrent protection start current is approximately 6.5 A, atten-
tion must be paid to the heating of the choke coil by magnetic
saturation due to overload or short-circuited load.
Capacitors C1, C2, C3, and C4 Because for SMPS, large
ripple currents flow across C1 and C2, capacitors with high
frequency and low impedance must be used. If the impedance of
C2 is too high, the switching waveform may not be normal at low
temperatures. Do not use either OS or tantalum types of capaci-
tors for C2, because those cause an abnormal oscillation.
The device is stabilized, and for proper operation, C1 and C4
must be located close to the device (see layout diagram, below).
C3 is required only if the soft start function is used. If not using
soft-start, leave the SS terminal open. A pull-up resistor is pro-
vided inside the IC.
Resistor Bridge R1 and R2 comprise the resistor bridge for the
output voltage, VO, and are calculated as follows:
()()
) , and
(()
Ω
×
===Ω
×
−
=
−
=
−−
k
I
V
R2
V
IVV
R1
ADJ
ADJO
ADJ
ADJO
8.0
101
8.0
101
8.0
33
IADJ should always be set to 1 mA. Note that R2 should always be
present to ensure stable operation, even if VO, is set to 0.8 V (that
is, even if there is no R1). VOshould be at least VIN + 8%.
6.8±0.1
11±0.2
9±0.2
9±0.1
3.7±0.05
4±0.1
1.7±0.1
1±0.05
(mm)
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]
www.allegromicro.com

DC-to-DC Step-Down Converter
SI-8008HD
7
(R0.45)
2.00 ±0.10
1.30 +0.10
–0.05
Branding
XXXXXXXX
XXXXXXXX
XXXXXXXX
XXXXXXXX
Dimensions do not include mold protrusion
Heastsink side flash: 0.8 mm maximum
Dimensions in millimeters
Branding codes (exact appearance at manufacturer discretion):
1st line: SK
2nd line, lot: YMW X
Where: Y is the last digit of the year of manufacture
M is the month (1to 9, O, N, D)
W is the week of the month (1to 5)
X is the device subtype suffix number
3rd line, type: 8008HD
12345
4×P1.70 ±0.25
(4.40)
(8.00)
9.90 ±0.20
10.00 ±0.02
3XR0.30
3XR0.30
Ø1.5 ±0.20
4.50 ±0.20
0.10 ±0.15
(0.75)
(4.60)
0.88 ±0.10
0.80 ±0.10
9.20 ±0.20
(6.80) 2.20 ±0.20
15.30 ±0.30
4.90 ±0.20
(0.50)
2.54 ±0.30
2.40 ±0.20
(R0.30)
(0.75)
(0.40)
++
2XR0.30
6º
0º
3º
3º3º
3º
15º
PACKAGE OUTLINE DRAWING
RoHS directive compliant
Device pins lead (Pb) free
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]
www.allegromicro.com

DC-to-DC Step-Down Converter
SI-8008HD
8
TAPE AND REEL SPECIFICATION
16.0
4.0 ±0.10
11.5 ±0.05 1.75 ±0.10
2.0 ±0.10
Ø1.5 MIN
Material: Conductive polysterene
Camber < 1 mm over 100 mm length of tape
Pocket inner widths measured 0.3 mm above floor of cavity
View A-A View B-B
B
B
AA
24.3 ±0.03
0.4 ±0.05
15.7
Ø1.5 +0.1
–0.0
10.6
3.9
4.9
Material: conductive polysterene
Camber < 1 mm over 100 length of tape
Pocket inner widths measured 0.3 mm above floor of pocket
Pocket position relative to sprocket hole measured to true position of pocket
10 sprocket hole pitch cumulative ±0.2 mm
Pocket center and pocket hole center ±0.3 mm
Surface resistivity < 107Ω/ cm2
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]
www.allegromicro.com

DC-to-DC Step-Down Converter
SI-8008HD
9
PACKING SPECIFICATION
341
344
65
Inner Carton
800 pieces per reel
2 reels per carton
Outer Carton
3 inner cartons per outer carton
Dimensions in mm
230
350
450
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]
www.allegromicro.com

DC-to-DC Step-Down Converter
SI-8008HD
10
WARNING— These devices are designed to be operated at lethal voltages and energy levels. Circuit designs
that embody these components must conform with applicable safety requirements. Precautions must be
taken to prevent accidental contact with power-line potentials. Do not connect grounded test equipment.
The use of an isolation transformer is recommended during circuit development and breadboarding.
Cautions for Use
• Operation of the product in parallel to increase current is not
permitted.
• Although the product has an internal overtemperature protection
circuit, that is intended only to protect the product from temporary
excess heating due to overloads. Long-term reliability cannot
be guaranteed when the product is operated under continuous
overload conditions.
Because reliability can be affected adversely by improper storage
environments and handling methods, please observe the following
cautions.
Cautions for Storage
• Ensure that storage conditions comply with the standard
temperature (5°C to 35°C) and the standard relative humidity
(around 40 to 75%); avoid storage locations that experience
extreme changes in temperature or humidity.
• Avoid locations where dust or harmful gases are present and
avoid direct sunlight.
• Reinspect for rust on leads and solderability of products that have
been stored for a long time.
Cautions for Testing and Handling
When tests are carried out during inspection testing and other
standard test periods, protect the products from power surges
from the testing device, shorts between adjacent products, and
shorts to the heatsink.
Electrostatic Discharge
• When handling the products, operator must be grounded.
Grounded wrist straps worn should have at least 1 MΩof
resistance to ground to prevent shock hazard.
• Workbenches where the products are handled should be
grounded and be provided with conductive table and floor mats.
• When using measuring equipment such as a curve tracer, the
equipment should be grounded.
• When soldering the products, the head of soldering irons or the
solder bath must be grounded in other to prevent leak voltages
generated by them from being applied to the products.
• The products should always be stored and transported in our
shipping containers or conductive containers, or be wrapped in
aluminum foil.
Soldering
• When manually soldering the products, please be sure to
minimize the working time, within the following limits:
Soldering Iron Temperature
(°C)
Time
(s)
380±10 3
(once only)
• Reflow soldering can be performed a maximum of twice, using
the following recommended profile:
230
30 ±10s
90 ±30s
180
150
250
Time
Temperature (°C)
250°C Maximum
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]
www.allegromicro.com

DC-to-DC Step-Down Converter
SI-8008HD
11
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 im-
provements 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.
The information included herein is believed to be accurate and reliable. Application and operation examples described in this document are given
for reference only and Sanken assumes no responsibility for any infringement of industrial property right, intellectual property rights or any other
rights of Sanken or any third party which may result from its use.
When using the products herein, the applicability and suitability of such products for the intended purpose shall be the users responsibility to
determine.
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 document are designed and intended for the use as components in general purpose electronic equipment or appara-
tus (home appliances, office equipment, telecommunication equipment, measuring equipment, etc.). When considering the use of Sanken products in
the applications where higher reliability is required (transportation equipment and its control systems, traffic signal control systems or equipment,
fire/crime alarm systems, various safety devices, etc.), please contact your nearest Sanken sales representative to discuss and obtain written confir-
mation of your specifications.
The use of Sanken products without the written consent of Sanken in the applications where extremely high reliability is required (aerospace equip-
ment, nuclear power control systems, life support systems, etc.) is strictly prohibited. Anti-radioactive ray design is not considered for the products
listed herein.
Copyright © 2007 Allegro MicroSystems, Inc.
This datasheet is based on Sanken datasheet SSJ-03118
For the latest version of this document, visit our website:
www.allegromicro.com
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]
www.allegromicro.com

DC-to-DC Step-Down Converter
SI-8008HD January, 2008
Sanken Electric Co., Ltd.
I02-009EB-080130
<Worldwide Contacts>
Asia Pacific
China
Sanken Electric Hong Kong Co., Ltd.
Suite 1026 Ocean Centre, Canton Road, Tsimshatsui, Kowloon, Hong Kong
Tel: [phone]
Fax: [phone]
Sanken Electric (Shanghai) Co., Ltd.
Room3202, Maxdo Centre, Xingyi Road 8, Changning district, Shanghai, China
Tel: [phone]
Fax: [phone]
Taiwan Sanken Electric Co., Ltd.
Room 1801, 18th Floor, 88 Jung Shiau East Road, Sec. 2, Taipei 100, Taiwan R.O.C.
Tel: [phone]
Fax: [phone]
India
Saket Devices Pvt. Ltd.
Office No.13, First Floor, Bandal - Dhankude Plaza, Near PMT Depot, Paud Road, Kothrud, Pune - 411 038, India
Tel: [phone]
91-20-2528-5449
Fax: [phone]
Japan
Sanken Electric Co., Ltd. Overseas Sales Headquaters
Metropolitan Plaza Bldg. 1-11-1 Nishi-Ikebukuro, Toshima-ku, Tokyo 171-0021, Japan
Tel: [phone]
Fax: [phone]
Korea
Sanken Electric Korea Co., Ltd.
Mirae Asset Life Bldg. 6F, 168 Kongduk-dong, Mapo-ku, Seoul, 121-705, Korea
Tel: [phone]
Fax: [phone]
Singapore
Sanken Electric Singapore Pte. Ltd.
150 Beach Road, #14-03 The Gateway West, Singapore 189720
Tel: [phone]
Fax: [phone]

DC-to-DC Step-Down Converter
SI-8008HD January, 2008
Sanken Electric Co., Ltd.
I02-009EB-080130
Europe
United Kingdom
Sanken Power Systems (UK) Limited
Pencoed Technology Park Pencoed, Bridgend CF35 5HY. UK
Tel: [phone]
Fax: [phone]
North America
United States
Allegro MicroSystems, Inc.
115 Northeast Cutoff, Worcester, Massachusetts 01606, U.S.A.
Tel: [phone]
Fax: [phone]
Allegro MicroSystems, Inc. (Southern California)
14 Hughes Street, Suite B105, Irvine, CA92618
Tel: [phone]
Fax: [phone]