Designed to meet high-current requirements at high efficiency in
industrial and consumer applications; embedded core, memory, or logic
supplies; TVs, VCRs, and office equipment, the SPI-8002TW dc/dc
step-down (buck) converter offers a constant 250 kHz switching fre-
quency essential for small external components. The n-channel high-
current FET is included on the die along with the oscillator, control, and
logic circuitry.
A wide input voltage range and integrated thermal and overcurrent
protection enhance overall system reliability. Reference accuracy and
excellent temperature characteristics are provided. A chip-enable input
gives the designer complete control over power up, standby, or power
down.
This device is supplied in a 16-lead surface-mount plastic SOIC
with exposed pad to provide a low-resistance path for maximum power
dissipation, low junction temperature, and improved reliability.
FEATURES
To 38 V Input Range
Adjustable 1 V to 24 V Output Range
1% Output Voltage Tolerance
To 1.5 A Output Current
Foldback Current Limiting
Constant 250 kHz Switching Frequency
1.0 A Maximum Standby Current
1.0 V Feedback Reference Voltage
Soft Start Avoids 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
Dual 1.5 A, DC/DC Step-Down Converter
Data Sheet
27469.302.1
Always order by complete part number, e.g., SPI-8002TW-TL ,
where "-TL" indicates tape and reel.
ABSOLUTE MAXIMUM RATINGS
Input Voltage, V
I
, V
CC
, V
CE
. . . . . 40 V
Output Current, I
O
. . . . . . . . . . . 1.5 A*
Junction Temperature, T
J
. . . . +135°C
Storage Temperature Range,
T
S
. . . . . . . . . . . . -40°C to +135°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 +135°C.
SPI-8002TW
Sanken Power Devices
from Allegro MicroSystems
Switching
Regulators
SPI-8002TW
Dual 1.5 A, DC/DC
Step-Down Converter
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036
Switching
Regulators
2
FUNCTIONAL BLOCK DIAGRAM
Copyright © 2004, 2005 Allegro MicroSystems, Inc.
Recommended Operating Conditions
Min
Max
Units
DC Input Voltage, V
I
*
V
O
+ 3
38
V
DC Input Voltage, V
CC
4.5
38
V
DC Output Current, I
O
0
1.5
A
DC Output Voltage, V
O
1
24
V
Operating Junction Temp.
-30
+135
°C
*The recommended maximum value is 38 V when the
output value is more than 4.75 V, derated linearly to 8 V
when the output is 1 V.
For the availability of parts meeting -40°C require-
ments, contact Allegro's Sales Representative.
Allowable Package Power Dissipation
This data sheet is based on Sanken data sheet SSJ-02285
SPI-8002TW
Dual 1.5 A, DC/DC
Step-Down Converter
www.allegromicro.com
Switching
Regulators
3
ELECTRICAL CHARACTERISTICS
at T
A
= +25°C, V
I
= V
CC
= 15 V (unless otherwise noted).
Limits
Characteristic
Symbol
Test Conditions
Min.
Typ.
Max.
Units
Internal Reference Voltage
V
ref
V
I
= 10 V, V
O
= 1 V, I
O
= 0.1 A
0.996
1.006 1.016
V
Ref. Volt. Temp. Coeff.
a
Vref
V
I
= 10 V, V
O
= 1 V, I
O
= 0.1 A
--
±0.1
--
mV/°C
Output Short-Circuit Current
I
OM
See note
1.6
--
--
A
Efficiency
V
O
= 5 V, I
O
= 0.5 A, I
I
includes I
CC
--
78
--
%
V
CC
= 5 V, V
O
= 5 V, I
O
= 0.5 A,
--
81
--
%
I
I
does not include I
CC
Operating Frequency
f
V
O
= 5 V, I
O
= 0.5 A
215
250
285
kHz
Line Regulation
V
O(
VI)
V
I
= V
CC
= 10 V ~ 20 V, V
O
= 5 V, I
O
= 1 A
--
30
60
mV
Load Regulation
V
O(
IO)
V
O
= 5 V, I
O
= 0.2 A ~ 1.5 A
--
10
40
mV
Supply Current
I
CC
I
O
= 0 A
--
8.5
--
mA
Quiescent Current
I
IQ
V
CC
= 5 V, I
O
= 0 A, V
O
12 V
--
4.0
--
mA
V
CE
= 0 V or open
--
--
1.0
µA
I
CCQ
V
CE
= 0 V or open
--
--
1.0
µA
Chip Enable Voltage
V
CEH
2.0
--
--
V
V
CEL
--
--
0.8
V
Chip Enable Input Current
I
CE
V
CE
= 20 V
--
95
--
µA
Soft-Start Voltage
V
SS
Converter turn-off voltage
--
--
0.5
V
Soft-Start Current
I
SS
V
SS
= 0 V
--
-60
-80
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 V
O(nom)
.
Test Circuit
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