Any and all SANYO products described or contained herein do not have specifications that can handle
applications that require extremely high levels of reliability, such as life-support systems, aircraft's
control systems, or other applications whose failure can be reasonably expected to result in serious
physical and/or material damage. Consult with your SANYO representative nearest you before using
any SANYO products described or contained herein in such applications.
SANYO assumes no responsibility for equipment failures that result from using products at values that
exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges,or other
parameters) listed in products specifications of any and all SANYO products described or contained
herein.
Thick Film Hybrid IC
3.3V/5A Single Output Separate Excitation
Chopper Regulator
Ordering number:EN6106
STK740-441
SANYO Electric Co.,Ltd. Semiconductor Company
TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110-8534 JAPAN
63099RM (KT) No.61061/10
1
12
11
2.54=27.94
0.5
2.54
37.0
4.5
2.9
5.0
0.5
25.5
25.5
Package Dimensions
unit:mm
4171-SIP12
[STK740-441]
SANYO : SIP-12
Overview
The STK740-441 is a separate-excitation step-down
chopper regulator hybrid IC for the secondstage circuit
and optimal as a 3.3V local power supply for use in logic
circuit that includes both 5V and 3.3V systems. This IC
incorporates in the package all the necessary circuits for
a chopper regulator including power switch, error
amplifier, soft start, shutdown type output short protec-
tion, low-voltage malfunction prevention, on/off, and
snubber circuits. Therefore, external components re-
quired are input and output capacitors and choke coil
only and this allows this IC to be used to construct a
large-current (5A) chopper regulator as if a 3-pin regula-
tor were used.
Applications
3.3V local power supply for the logic circuit where
both 5V and 3.3V systems are constructed togeter.
Features
Adoption of Sanyo IMST ; Insulated Metal Substrate
Technology, allows the circuit to be operated without
using a heat sink (see "No Fin Output Current Derat-
ing" chart in the page 6).
Slim package reduces mounting space.
Typical efficiency of 88% at DC 5V input, 2.5A output.
Fine adjustment of output voltage enable.
50 kHz operating frequency.
Low-R
ON
resistance power MOSFET adopted.
Low-V
F
Schottky barrier diode adopted.
STK740-441
No.61062/10
Electrical Characteristics
at Tc = 25C, in the specified circuit, V
IN
= 5V, I
O
= 1A, unless othrwise specified
Specifications
Maximum Ratings
at Ta = 25C, Tc = 25C, unless otherwise specified.
C
C
Recommended Operating Conditions
at Ta = 25C
Series Construction
This product is listed in a product series due to its property such as output voltage, output current, package, and other
similar items. Since some prducts listed in the table below is under development, please refer to your Sanyo sales
representative for details.
Type number
Input voltage
4 to 8V
4 to 8V
4 to 8V
8 to 18V
2.5V
2.5V
3.3V
5.0V
Output voltage Output current
Package dimensions
(output pins not included)
STK740-411
STK740-420
STK740-441
STK740-450
STK740-471
STK740-470
STK740-480
STK740-490
26
37
4.5mm,12pins
25.5
46.6
8.5mm,12pins
26
37
4.5mm,12pins
25.5
46.6
8.5mm,12pins
26
37
4.5mm,12pins
25.5
46.6
8.5mm,12pins
25.5
46.6
8.5mm,12pins
25.5
46.6
8.5mm,12pins
5A
10A
5A
10A
5A
5A
10A
15A
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Tc=+25 to +85C
* : Under planning
STK740-441
No.61063/10
Block Diagram
Snubber circuit
Drive circuit
Oscillator
Reference voltage
Error amplifier
On/off circuit
Soft start circuit
Short protection circuit
PWM
Phase
compensation
12
11
6
Low-voltage
malfunction
prevention circuit
SUB
TR1
D1
10
9
8
7
2
3
4
1
5
V
IN
V
CC
GND
OUT
A
V
S
V
ADJ
F
B
ON/OFF
Pin Descriptions
Number
Pin name
Description
1
ON/OFF
Remote on/off switching
2
VS
Output voltage sensing
3
VADJ
Output voltage fine adjustment
4
FB
Feedback (error amplifier output), phase compensation
5
GND
Ground
6
VCC
Power supply for control block
7, 8
A
Flywheel diode anode
9, 10
OUT
Output
11, 12
VIN
Input supply voltage
STK740-441
No.61064/10
Test Circuit
1
2
3
4
5
6
7
8
9
10
11
12
DC
INPUT
GND
OUTPUT
(3.3V)
ON/OFF
Vo adjust
L1
GND
C1
C2
FB
C1
: 220
F/10V (OS capacitor)
C2
: 2200
F/6.3V
L1
: 30
H
FB
: Ferrite-bead core
Overvoltage Protection Circuit
In a constant-voltage power supply circuit output voltage may generally exceed the stipulated rating (equivalent to input
voltage) when the circuit is broken down or the IC and the printed circuit board is wrongly soldered. Therefore overvoltage
protection circuit is recommended to use to minimize the damages caused by the overvoltage.
Sample the overvoltage protection circuit
DC
INPUT
GND
OUTPUT
GND
Regulator
FUSE
SCR
CR
STK740-441
No.61065/10
Sample Characteristics
at Ta = 25C, in the test circuit
Output Voltage vs.Output Current
3.0
3.1
3.2
3.3
3.4
3.5
3.6
0
2
1
3
4
5
6
Output Current Io[A]
Output Voltage Vo[V]
Efficiency vs.Output Current
50
60
70
80
90
100
0
2
1
3
4
5
6
Output Current Io[A]
Efficiency
[%]
V
IN
=5V
V
IN
=5V
STK740-441
No.61066/10
Output Voltage vs.Input Voltage
3.0
3.1
3.2
3.3
3.4
3.5
3.6
2
4
3
5
6
7
8
Input Voltage V
IN
[V]
Output Voltage Vo[V]
No Fin Output Current Derating
0.0
1.0
2.0
3.0
4.0
5.0
6.0
-10
0
10
20
30
40
50
60
70
80
90
100
Ambient Temperature Ta[
C]
Output Current Io[A]
I
O
=5A
V
IN
=5V
STK740-441
No.61067/10
No Fin
Tc vs.Output Current
0
10
20
30
40
50
60
70
0
1
2
3
4
5
6
Output Current Io[A]
Tc Heat up
Tc[deg.]
Power Dissipation vs Output Current
0.0
1.0
2.0
3.0
4.0
0
2
1
3
4
5
6
Output Current Io[A]
Power Dissipation P
D
[W]
V
IN
=5V
V
IN
=5V
STK740-441
No.61068/10
Eveluation Board
The evaluation board is provided to evaluate this hybrid IC
Equivalent Circuit
1
2
3
4
5
6
7
8
9
10
11
12
V
I
N
GND
Vs
GND
L1
C2
C1
FB1
IC1
Vo
ON/O FF
R2
Parts Table
Part name
Requirements
Number
Manufacturer
Notes
C1
Electrolytic capacitor
220
F/10V
2200
F/6.3V
1
Sanyo Electronic component co., ltd.
OS capacitor
C2
Electrolytic capacitor
1
Sanyo Electronic component co., ltd.
Low impedance (CG)
R2
Resistor
100
1
R3
Jumper
1
R6
Jumper
1
Use a fuse resistor (20 to 30
) when needed
FB1
Ferrite-bead core
BL02RN1-R62
1
Murata manufacturing co., ltd.
L1
Choke coil
HK-10S100-4500
1
Toho zinc co., ltd.
45
H, 5A
Notes on pattern designing
1 Place V
CC
pin (pin 6) and V
IN
pins (pin 11 and 12) lines separately and use an input capacitor (+) for connection.
2 Place GND pin (pin 5) and A pin (pins 7 and 8) lines separately.
3 Connect A pin (pins 7 and 8) with the input capacitor () through a Ferrite-bead core.
4 Connect GND pin (pin 5) with the input capacitor () or the output capacitor (). However, connect with the
output capacitor () unless otherwise specified.
5 Shorten the length of the line between the input capacitor () and the output capacitor () as well as possible.
6 Connect V
S
pin (pin 2) with the output capacitor (+).
STK740-441
No.61069/10
Perspective Wiring Layout
(from soldered side)
Circuit Pattern
(soldered side)
C1a
C1b
C1c
C8
CN1
R6
IC1
FB1
L1
C2a
C9
CN 2
CN 3
C4
C5
C6
R5 R1R2
R3
C2b
C2c
STK740-400 TEST-B
GND
+Vo
+Vs
ON/OFF
S-GND
GND
VIN
Specifications of any and all SANYO products described or contained herein stipulate the performance,
characteristics, and functions of the described products in the independent state, and are not guarantees
of the performance, characteristics, and functions of the described products as mounted in the customer's
products or equipment. To verify symptoms and states that cannot be evaluated in an independent device,
the customer should always evaluate and test devices mounted in the customer's products or equipment.
SANYO Electric Co., Ltd. strives to supply high-quality high-reliability products. However, any and all
semiconductor products fail with some probability. It is possible that these probabilistic failures could
give rise to accidents or events that could endanger human lives, that could give rise to smoke or fire,
or that could cause damage to other property. When designing equipment, adopt safety measures so
that these kinds of accidents or events cannot occur. Such measures include but are not limited to protective
circuits and error prevention circuits for safe design, redundant design, and structural design.
In the event that any or all SANYO products(including technical data,services) described or
contained herein are controlled under any of applicable local export control laws and regulations,
such products must not be expor ted without obtaining the expor t license from the author ities
concerned in accordance with the above law.
No part of this publication may be reproduced or transmitted in any form or by any means, electronic or
mechanical, including photocopying and recording, or any information storage or retrieval system,
or otherwise, without the prior written permission of SANYO Electric Co. , Ltd.
Any and all information described or contained herein are subject to change without notice due to
product/technology improvement, etc. When designing equipment, refer to the "Delivery Specification"
for the SANYO product that you intend to use.
Information (including circuit diagrams and circuit parameters) herein is for example only ; it is not
guaranteed for volume production. SANYO believes information herein is accurate and reliable, but
no guarantees are made or implied regarding its use or any infringements of intellectual property rights
or other rights of third parties.
This catalog provides information as of June, 1999. Specifications and information herein are subject to
change without notice.
STK740-441
PS No.610610/10
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