STR5A464D

For Non-Isolated Buck Convertor
Off-Line PWM Controllers with Integrated Power MOSFET
STR5A464D
General Descriptions
Package
The STR5A464D is power ICs for switching power
supplies, incorporating a MOSFET and a current mode
PWM controller IC for non-isolated buck convertor.
Buck convertor can be designed with commercial
power input. Both positive and negative output
configuration are available.
The low standby power is accomplished by the
automatic switching between the PWM operation in
normal operation and the burst-oscillation under light
load conditions. The product achieves high
cost-performance power supply systems with few
external components.
DIP8
Features
Buck Converter Recommended Operating
Condition











FB
1
8
S/GND
VCC
2
7
S/GND
6
S/GND
5
S/GND
D/ST
4
Not to scale
Buck Convertor
Positve or Negative Output Configuration
Auto Standby Function
Operation
Normal Operation ----------------------------- PWM Mode
Light Load Operation ------------------------- Green Mode
Standby ---------------------------- Burst Oscillation Mode
Build-in Startup Function
(reducing power consumption at standby operation,
shortening the startup time)
Current Mode Type PWM Control
Build-in Error Amplifier for Phase Compensation
Random Switching Function
Leading Edge Blanking Function
Soft Start Function
Protections
Overload Protection (OLP); auto-restart
Overvoltage Protection (OVP); auto-restart
Thermal Shutdown with hysteresis (TSD); auto-restart
 Output Voltage (+)
Input Voltage
AC 85 V to AC 265 V
D/ST Input Voltage
Output Voltage Range*
 Output Voltage (–)
Input Voltage
≥ 40 V
> 11 V
< 27.5 V
AC 85 V～AC 265 V
D/ST Input Voltage
Output Voltage Range*
≥ 40 V
> – 27.5 V
< – 11 V
*Add zener diode or transistor (dropper) to VCC pin
when target output voltage is high.
Lineup
Typical Application Circuit
D1
 Electrical Characteristics
fOSC(AVG) = 60 kHz
VD/ST = 700V (max.)
D2
R3
R2
STR5A400
1
FB
S/GND
VCC
S/GND
2
8
C4
R1
C3
7
Products
RDS(ON) (max.)
IDLIM
STR5A464D
13.6 Ω
0.41 A
6
S/GND
VOUT
L1
DR1
5
4
D/ST
S/GND
(+)
L2
Applications
VAC
C1
C2
D3
C5
 White goods
R4
DR2
(-)
 Other SMPS
TC_STR5A400D_1_R1
STR5A464D-DS Rev.1.2
Feb.19, 2015
SANKEN ELECTRIC CO.,LTD.
1
STR5A464D
CONTENTS
General Descriptions ----------------------------------------------------------------------- 1
1. Absolute Maximum Ratings --------------------------------------------------------- 3
2. Electrical Characteristics ------------------------------------------------------------ 3
3. Functional Block Diagram ----------------------------------------------------------- 5
4. Pin Configuration Definitions ------------------------------------------------------- 5
5. Typical Application Circuit --------------------------------------------------------- 6
6. Package Outline ------------------------------------------------------------------------ 7
7. Marking Diagram --------------------------------------------------------------------- 7
8. Operational Description -------------------------------------------------------------- 8
8.1
Startup Operation of IC----------------------------------------------------- 8
8.2
Undervoltage Lockout (UVLO) ------------------------------------------- 8
8.3
Power Supply Startup and Soft Start Function ------------------------ 8
8.4
Constant Voltage (CV) Control ------------------------------------------- 9
8.5
Leading Edge Blanking Function ---------------------------------------- 12
8.6
Random Switching Function ---------------------------------------------- 12
8.7
Auto Standby Function ----------------------------------------------------- 12
8.8
Overload Protection (OLP) ------------------------------------------------ 12
8.9
Overvoltage Protection (OVP) -------------------------------------------- 13
8.10 Thermal Shutdown (TSD) ------------------------------------------------- 13
9. Design Notes --------------------------------------------------------------------------- 13
9.1
External Components------------------------------------------------------- 13
9.2
D/ST pin ----------------------------------------------------------------------- 14
9.3
Output Inductor Value Setting ------------------------------------------- 14
9.4
PCB Trace Layout and Component Placement ----------------------- 16
10. Pattern Layout Example ------------------------------------------------------------ 19
10.1 Positive Output --------------------------------------------------------------- 19
10.2 Negative Output ------------------------------------------------------------- 20
11. Reference Design of Power Supply ----------------------------------------------- 21
11.1 Positive Output --------------------------------------------------------------- 21
11.2 Negative Output ------------------------------------------------------------- 22
OPERATING PRECAUTIONS -------------------------------------------------------- 23
IMPORTANT NOTES ------------------------------------------------------------------- 24
STR5A464D-DS Rev.1.2
Feb.19, 2015
SANKEN ELECTRIC CO.,LTD.
2
STR5A464D
1.
Absolute Maximum Ratings
 The polarity value for current specifies a sink as "+," and a source as "−," referencing the IC.
 Unless otherwise specified, TA = 25 °C, 5 pin = 6 pin = 7 pin = 8 pin.
Parameter
Symbol
Test Conditions
Pins
Rating
Units
FB Pin Voltage
VFB
1–5
− 0.3 to 7
V
VCC Pin Voltage
VCC
2–5
− 0.3 to 32
V
D/ST Pin Voltage
VD/ST
4–5
− 0.3 to 700
V
4–5
1.7
A
4–5
− 0.2～0.97
A
–
1.55
W
Drain Peak Current
IDP
Single pulse,
Within 500 ns pulse
width,
VD/ST ≤ 400 V
Negative: Within 2 μs
pulse width
Maximum Switching Current
IDMAX
MOSFET Power Dissipation
PD1
Operating Ambient Temperature
TOP
–
− 40 to 125
°C
Storage Temperature
Tstg
–
− 40 to 125
°C
*
Junction Temperature
Tj
–
150
* When embedding this hybrid IC onto the printed circuit board (cupper area in a 15mm×15mm)
2.
Notes
°C
Electrical Characteristics
 The polarity value for current specifies a sink as "+," and a source as "−," referencing the IC.
 Unless otherwise specified, TA = 25 °C, VCC = 18 V, VD/ST = 10 V, 5 pin = 6 pin = 7 pin = 8 pin.
Parameter
Symbol
Test
Conditions
Pins
Min.
Typ.
Max.
Units
Notes
Power Supply Startup Operation
Operation Start Voltage
VCC(ON)
2–5
13.6
15.0
16.6
V
Operation Stop Voltage
VCC(OFF)
2–5
7.3
8.0
8.7
V
VCC = 12 V
2–5
–
–
2.0
mA
VSTARTUP
VCC = 13.5 V
4–5
19
29
39
V
ISTARTUP
VCC = 13.5 V
VD/ST = 100 V
2–5
− 2.7
− 1.5
− 0.5
mA
fOSC(AVG)
VFB= 2.44 V
4–5
53
60
67
kHz
Δf
4–5
–
2.8
–
kHz
VFB(REF)
1–5
2.44
2.50
2.56
V
1–5
− 2.4
− 0.8
−
μA
Circuit Current in Operation
Startup Circuit Operation Voltage
Startup Current
PWM Operation
Average PWM Switching
Frequency
PWM Frequency Modulation
Deviation
Feedback Reference Voltage
ICC(ON)
Feedback Current
IFB(OP)
Minimum Sampling Time
tFBMS
1－5
–
–
2.5
μs
Standby Drain Current
IDSTB
4–5
–
50
–
mA
Standby Operation Cycle
TSTBOP
4–5
530
740
940
μs
Maximum ON Duty
DMAX
4–5
50
57
64
%
STR5A464D-DS Rev.1.2
Feb.19, 2015
VFB = 2.3 V
SANKEN ELECTRIC CO.,LTD.
3
STR5A464D
Parameter
Symbol
Test
Conditions
Pins
Min.
Typ.
Max.
Units
tBW
–
–
230
–
ns
IDLIM
4–5
0.37
0.41
0.45
A
VCC(OVP)
2–5
27.5
29.3
31.3
V
VFB= 0 V
4–5
–
72
–
ms
VFB= 2.6 V
4–5
3.5
5.2
6.8
ms
Tj(TSD)
–
135
–
–
°C
Tj(TSDHYS)
–
–
70
–
°C
Tj = 125 °C
VD/ST = 584 V
4–5
–
–
50
µA
ID = 41 mA
4–5
–
11
13.6
Ω
tf
4–5
–
–
250
ns
θj-C
–
–
–
15
°C/W
Notes
Protection
Leading Edge Blanking Time(1)
Drain Current Limit
OVP Threshold Voltage
OLP Delay Time at Startup
Standby Blanking Time at
Startup
Thermal Shutdown Operating
Temperature(1)
Thermal Shutdown Hysteresis(1)
tOLP
tSTB(INH)
Power MOSFET
Drain Leakage Current
On Resistance
Switching Time
Thermal Characteristics
Thermal Resistance Junction to
Case(1)(2)
(1)
(2)
IDSS
RDS(ON)
Design assurance
Case temperature (TC) measured at the center of the case top surface
STR5A464D-DS Rev.1.2
Feb.19, 2015
SANKEN ELECTRIC CO.,LTD.
4
STR5A464D
3.
Functional Block Diagram
2
VCC
STARTUP
D/ST
4
UVLO
OVP
REG
PROTECTION
TSD
DRV
PWM
OSC
S Q
R
OCP
1
FB
S/H
E/A
Feedback
Control
VFB(REF)
LEB
S/GND
5, 6, 7, 8
BD_STR5A400D_R1
4.
Pin Configuration Definitions
Pin
Name
FB
1
8
S/GND
1
FB
VCC
2
7
S/GND
2
VCC
6
S/GND
3
–
4
D/ST
5
S/GND
D/ST
4
Descriptions
Constant voltage control signal input
Power supply voltage input for control part
and overvoltage protection (OVP) signal
input
(Pin removed)
MOSFET drain and startup current input
5
6
7
S/GND
MOSFET source and ground
8
STR5A464D-DS Rev.1.2
Feb.19, 2015
SANKEN ELECTRIC CO.,LTD.
5
STR5A464D
5.
Typical Application Circuit
Figure 5-1 and Figure 5-2 are the example circuits in buck-converter configuration. In order to enhance the heat
dissipation, the wide pattern layout of S pin (5 through 8 pin) is recommended.
When the target output voltage ｜VOUT｜is higher than 27.5 V, zener diode DZ1 is connected to D1 in serial as
shown in Figure 5-3. The output voltage should be in the range of equation (1) or (2) according to the configuration,
where VZ is the zener voltage.
Positive Output: 11V  VOUT  VZ  27.5V
(1)
Negative Output: 11V  VOUT  VZ  27.5V
(2)
D1
FB
S/GND
VCC
S/GND
2
R3
R2
STR5A400
1
D2
8
7
R1
C4
C3
NC
6
S/GND
L1
DR1
D/ST
C1
L2
VOUT
5
4
S/GND
(+)
C5
C2
R4
D3
VAC
DR2
(-)
TC_STR5A400D_2_R1
Figure 5-1 Positive Output (+)
D1
FB
S/GND
VCC
S/GND
2
R3
R2
STR5A400
1
D2
8
7
R1
C4
C3
NC
6
S/GND
L1
DR1
D/ST
C1
D3
5
4
VOUT
(-)
S/GND
C5
C2
VAC
R4
L2
DR2
(+)
TC_STR5A400D_3_R2
Figure 5-2 Negative Output (–)
U1
D1
DZ1
D2
(+)
VCC
2
C4
S
C3
5,6,7,8
TC_STR5A400D_4_R1
Figure 5-3 Absolute value of target output voltage |VOUT| is high
STR5A464D-DS Rev.1.2
Feb.19, 2015
SANKEN ELECTRIC CO.,LTD.
6
STR5A464D
6.
Package Outline
DIP8
NOTES:
1) Units：mm (inch)
2) Control dimension is in inches. (values in mm are for reference)
3) Pb-free. Device composition compliant with the RoHS directive
7.
Marking Diagram
DIP8
8
5A4××D
Part Number
SKYMD
1
Lot Number
Y = Last Digit of Year (0-9)
M = Month (1-9,O,N or D)
D = Period of days (1 to 3)
1 : 1st to 10th
2 : 11th to 20th
3 : 21st to 31st
Sanken Control Number
STR5A464D-DS Rev.1.2
Feb.19, 2015
SANKEN ELECTRIC CO.,LTD.
7
STR5A464D
8.
Operational Description
 All of the parameter values used in these descriptions
are typical values, unless they are specified as
minimum or maximum.
 With regard to current direction, "+" indicates sink
current (toward the IC) and "–" indicates source
current (from the IC).
 The reference ground of the value of voltage is S/GND
pin in this section.
Figure 8-1 shows the current path in normal operation.
During the on state of internal MOSFET, the energy is
stored in the inductor, L2. When the MOSFET turns off,
C4 is charged by the inductor current through D1 and
D2.
In normal operation, the voltage between VCC pin
and S/GND pin is calculated as follows, where VFD1,
VFD2 and VFD3 are the forward voltage of D1, D2 and D3
respectively:
VCC  VOUT  VFD 3  VFD1  VFD 2 
8.1 Startup Operation of IC
(4)
Figure 8-1 shows the circuit around VCC pin.
ISTRTUP
D2
Normal
Operation
STARTUP
Contro1
VCC
D/ST
C2
C3
C4
S/GND
VOUT
(＋)
L2
VIN
D3
C5
R4
(－)
Figure 8-1 VCC pin peripheral circuit at positive output
t START  C4 
VCC( ON )－VCC( INT )
(3)
I STARTUP
where,
tSTART : Startup time of IC (s)
VCC(INT) : Initial voltage on VCC pin (V)
STR5A464D-DS Rev.1.2
Feb.19, 2015
Figure 8-2 shows the relationship of VCC pin voltage
and circuit current ICC. When VCC pin voltage increases
to VCC(ON) = 15.0 V, the control circuit starts switching
operation and the circuit current ICC increases.
When VCC pin voltage decreases to VCC(OFF) = 8.0 V,
the control circuit stops operation by Undervoltage
Lockout (UVLO) circuit, and reverts to the state before
startup.
Circuit current, ICC
ICC（ON）
Stop
The IC incorporates the startup circuit. The circuit is
connected to D/ST pin. When D/ST pin voltage reaches
to Startup Circuit Operation Voltage V STARTUP = 29 V,
the startup circuit starts operation.
During the startup process, the constant current,
ISTARTUP = − 1.5 mA, charges C4 at VCC pin. When
VCC pin voltage increases to VCC(ON) = 15.0 V, the
control circuit starts switching operation.
After switching operation begins, the startup circuit
turns off automatically so that its current consumption
becomes zero.
The approximate value of auxiliary winding voltage is
about 18V, taking account of the winding turns of D
winding so that VCC pin voltage becomes Equation (3)
within the specification of input and output voltage
variation of power supply.
The approximate startup time tSTART is calculated as
follows:
8.2 Undervoltage Lockout (UVLO)
VCC（OFF）
Start
Startup
D1
U1
VCC pin
VCC（ON） voltage
Figure 8-2 Relationship between
VCC pin voltage and ICC
8.3 Power Supply Startup and Soft Start
Function
The IC has the Soft Start Function. This function
reduces the voltage and the current stress of MOSFET
and freewheel diode.
Figure 8-3 shows the startup waveforms.
Since the voltage of internal comparator is low at
startup, the IC is in no load condition.
The IC has the Standby Blanking Time at Startup,
tSTB(INH) = 5.2 ms, that inhibits the burst oscillation mode
so that the soft start is operated after the IC starts.
The IC activates the soft start circuitry during the
startup period. Soft start time is fixed to around 5.2 ms.
During the soft start period, the over current threshold is
increased step-wisely (7 steps). The IC does switching
SANKEN ELECTRIC CO.,LTD.
8
STR5A464D
operation by the frequency responding to FB pin voltage
until the output becomes setting voltage.
The tLIM is the period until FB pin voltage reaches
1.6 V after the IC starts. When tLIM is tOLP of 72 ms and
more, the IC stops switching operation. Thus, it is
necessary to adjust the value of output capacitor so that
the tLIM is less than tOLP.
If VCC pin voltage reaches VCC(OFF) and a startup
failure occurs as shown in Figure 8-4, increase the C4
value or decrease the C5 value. Since the larger
capacitance causes the longer startup time of IC, it is
necessary to check and adjust the startup process based
on actual operation in the application.
Since the Leading Edge Blanking Function (refer to
Section 8.5) is deactivated during the soft start period,
there is the case that ON time is less than the leading
edge blanking time, tBW = 230 ns.
8.4 Constant Voltage (CV) Control
The IC achieves the constant voltage (CV) control of
the power supply output by using the peak-current-mode
control method, which enhances the response speed and
provides the stable operation.
The IC controls the peak value of the voltage of
build-in sense resistor (VROCP) to be close to target
voltage (VSC), comparing VROCP with VSC by internal FB
comparator.
The IC sampless the FB pin voltage at the sampling
point that is tFBFS = 2.5 μs (max.) after the power
MOSFET turns off, by pulse-by-pulse.
Feedback Control circuit receives the target voltage,
VSC, reversed FB pin voltage by an error amplifier (refer
to Figure 8-5 and Figure 8-6).
U1
Feedback
Control
Startup of IC
VCC pin
voltage
FB comp
Normal opertion
Startup of SMPS
+
VSC
R2 R3
E/A
+
-
S/H
1
FB
tSTART
VCC(ON)
VCC(OFF)
R1
PWM
Control
ROCP
4
tSTB(INH)
Time
C3
VROCP
L2
S/GND
D/ST
ION
Soft start period
approximately 5.2 ms (fixed)
D/ST pin
current, ID
VOUT
(＋)
5,6,7,8
D3
C2
R1
C5
(－)
Figure 8-5 FB pin peripheral circuit at positive output
Time
tLIM < tOLP
FB pin voltage
VFB(REF)
1.6V
Time
-
VSC
+
VROCP
FB comparator Voltage on both side of ROCP
Figure 8-3 Startup waveforms
Drain current,
ION
VCC pin
voltage
Startup success
IC starts operation
Target operating
voltage
VCC(ON)
Increase with rising of
output voltage
Figure 8-6 Drain current ID and FB comparator
in steady operation
VCC(OFF)
Startup failure
Time
Startup time of IC, tSTART
Figure 8-4 VCC pin voltage during startup period
STR5A464D-DS Rev.1.2
Feb.19, 2015
 Light Load Conditions
The FB pin voltage increases with the increase of the
output voltage when the output load becomes light.
Accordingly, the output voltage of internal error
amplifier (target voltage VSC) decreases. As a result,
the peak value of VROCP is controlled to be lower so
that the peak of the drain current decreases. This
control prevents the output voltage from increasing.
SANKEN ELECTRIC CO.,LTD.
9
STR5A464D
 Heavy Load Conditions
The control circuit performs reverse operations to the
former. The target voltage VSC of internal comparator
becomes higher and the peak drain current increases.
This control prevents the output voltage from
decreasing.
U1
Contro1
C2
Figure 8-7shows the output current path in case that
the output voltage is positive. Figure 8-8 shows the
operational waveforms.
In this case, the operation range satisfies the
Equation (5), (6) and (7).
VOUT  DMAX  VIN  VRON 
(5)
VIN  VSTARTUP (max .)
(6)
V
CC( OFF )


(max .)  VF  VOUT  VCC(OVP ) (min .)  VF

(7)
where,
VIN: C2 voltage
VOUT: output voltage
DMAX: Maximum ON Duty
VRON: on voltage of internal MOSFET
VSTARTUP (max.): maximum value of Startup Circuit
Operation Voltage
VCC(OFF) (max.): maximum value of Operation Stop
Voltage
VCC(OVP) (min.): minimum value of OVP Threshold
Voltage
VF: summation of forward voltage of D1 and D2
C4
C3
IL
ROCP
VIN
Buck-Converter Operation at
Positive Output
D2
D1
FB
VROCP
D/ST
8.4.1
VCC
L2
S/GND
VOUT
(＋)
VL
ION
(MOSFET ON) D3
IOFF
(MOSFET OFF)
C5
R4
(－)
Figure 8-7 Output current flow at positive output
(2) PWM Off-Time Period
When the internal power MOSFET turns off, the
freewheeling diode, D3, is forward biased by the
back electromotive force in the inductor, L2 and D3
turns on. Then the energy stored in L2 during the
PWM on-time flows through the IOFF path shown in
Figure 8-7.
After the Average PWM Switching Cycle, 1 /
fOSC(AVG), the internal power MOSFET turns-on
again, and the PWM on-time period repeats as
shown in Figure 8-8.
VL
MOSFET
ON
OFF
ON
VIN-VRON-VOUT
0
t
-(VOUT-VFD3)
IL
t
ION
t
IOFF
When the output voltage is positive, the current
control of internal PWM is described in the following.
t
(1) PWM On-Time Period
At startup or during normal operation before the
current reaches the target level, internal power
MOSFET turns on and the current flows through the
ION path shown in Figure 8-7. When ION flows
through the internal current detection resistor, ROCP,
IC detects VROCP that is the voltage between both
ends of ROCP. The divided voltage of C3 is input to
FB pin. The target voltage, VSC is made from FB pin
voltage. When the current detection voltage, VROCP,
reaches to VSC, the power MOSFET turns off.
STR5A464D-DS Rev.1.2
Feb.19, 2015
1/fOSC(AVG)
Figure 8-8 Operational waveforms at positive output
SANKEN ELECTRIC CO.,LTD.
10
STR5A464D
Buck-Converter Operation at
Negative Output
U1
Figure 8-9 shows the output current path in case
that the output voltage is negative. Figure 8-10 shows
1(2)
C3
C4
4
D
VOUT  MAX  VIN  VRON 
1  D MAX
(8)
VIN  VSTARTUP (max .)
(9)

VOUT
(－)
D3
5~8
D/ST
S/GND
IL
C2
VIN

FB
D2
D1
ROCP
In this case, the operation range satisfies the Equation
(8), (9) and (10) .
CC( OFF )
2(1)
VROCP
the operational waveforms.
V
VCC
Contro1
8.4.2
ION
(MOSFET ON) VL
IOFF
(MOSFET OFF)
C5
R4
L2
(＋)
(max .)  VF  VOUT  VCC(OVP ) (min .)  VF

(10)
where,
VIN: C2 voltage
VOUT: output voltage
DMAX: Maximum ON Duty
VRON: on voltage of internal MOSFET
VSTARTUP (max.): Maximum value of Startup Circuit
Operation Voltage
VCC(OFF) (max.): Maximum value of Operation Stop
Voltage
VCC(OVP) (min.): Minimum value of OVP Threshold
Voltage
VF: Summation of forward voltage of D1 and D2
Figure 8-9 Output current flow at negative output
(2) PWM Off-Time Period
When the internal power MOSFET turns off, the
freewheeling diode, D3, is forward biased by the
back electromotive force in the inductor, L2 and D3
turns on. Then the energy stored in L2 during the
PWM on-time flows through the IOFF path shown in
Figure 8-9.
After the Average PWM Switching Cycle, 1 /
fOSC(AVG), the internal power MOSFET turns-on
again, and the PWM on-time period repeats as
shown in Figure 8-10.
In negative (–) output configuration, the output current
is supplied only in the off period. Thus, output ripple
becomes larger compared with positive (+) output
configuration.
When the output voltage is negative, the current control
of internal PWM is described in the following.
(1) PWM On-Time Period
At startup or during normal operation before the
current reaches the target level, internal power
MOSFET turns on and the current flows through the
ION path shown in Figure 8-9.
When ION flows through the internal current
detection resistor, ROCP, the IC detects VROCP that is
the voltage of both end of ROCP. The divided voltage
of C3 is input to FB pin. The target voltage, VSC is
made from FB pin voltage.
When the current detection voltage, VROCP, reaches
to VSC, the power MOSFET turns off.
VL
MOSFET
ON
OFF
ON
VIN‐VRON
t
0
-(VOUT-VFD3)
IL
t
ION
t
IOFF
t
1/fOSC(AVG)
Figure 8-10 Operational waveforms at negative output
STR5A464D-DS Rev.1.2
Feb.19, 2015
SANKEN ELECTRIC CO.,LTD.
11
STR5A464D
8.5 Leading Edge Blanking Function
Since the IC uses the peak-current-mode control
method for the constant voltage control of output, there
is a case that the power MOSFET turns off due to
unexpected response of FB comparator or overcurrent
protection circuit (OCP) to the steep surge current in
turning on a power MOSFET.
In order to prevent this response to the surge
voltage in turning-on the power MOSFET, the
Leading Edge Blanking (tBW = 230 ns) is built-in.
Switching
Frequency,
fOSC
Normal operation
60kHz
B
About
23kHz
A
Burst
oscillation mode
Green mode
TSTBOP = 740 µs
Output power
PO(MAX)
Light load
Figure 8-12 Relationship between PO and fOSC
tBW
Point A
ID
TSTBOP
Time
Surge pulse voltage width at turning on
Point B
ID
TSTBOP
Figure 8-11 Leading Edge Blanking
Time
8.6 Random Switching Function
The IC modulates its switching frequency
randomly by superposing the modulating frequency
on fOSC(AVG) in normal operation. This function
reduces the conduction noise compared to others
without this function, and simplifies noise filtering of
the input lines of power supply.
8.7 Auto Standby Function
Auto Standby Function automatically changes the
oscillation mode to green mode or burst oscillation mode,
when the output load becomes lower, the drain current
ID decreases and the oscillation frequency becomes
lower gradually (Green Mode) as shown in Figure 8-12.
In order to reduce the switching loss, the number of
switching is reduced in green mode and the switching
operation is stopped during a constant period in burst
oscillation mode.
Figure 8-13 shows the drain current waveforms of
point A and B in Figure 8-12.
The burst oscillation mode operates by the Standby
Operation Cycle, TSTBOP = 740 ms. In light load, the
number of minimum switching times is one in TSTBOP as
shown in Figure 8-13.
Since the oscillator of burst oscillation cycle setting
and the oscillator of switching oscillation frequency
setting are not synchronized each other, the switching
frequency may be high.
Figure 8-13 Switching waveform at burst oscillation
mode
8.8 Overload Protection (OLP)
When output power reaches certain power, the drain
current of MOSFET is limited by IDLIM and the output
voltage decreases. Thus, the current characteristic is as
shown in Figure 8-14. The switching frequency is
decreased with decreasing output voltage in order to
inhibit increasing output current at low output voltage.
When output voltage decreases in the state such as
output short mode, FB pin voltage decreases.
After it passes Startup OLP Delay Time, tOLP = 72 ms
from the period when FB pin voltage decreases to
VFB(REF) = 2.50 V or less, when FB pin voltage is 1.6 V
or less, the IC stops switching operation and restarts
After the output voltage increases, until the FB pin
voltage keeps about 1.6 V and more, the IC repeats the
intermittent operation.
Output voltage,
VOUT
CV mode
Output current, IOUT
Figure 8-14 Overload characteristics
STR5A464D-DS Rev.1.2
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STR5A464D
8.9 Overvoltage Protection (OVP)
When a voltage between VCC pin and S/GND
terminal increases to VCC(OVP) = 29.3 V or more,
Overvoltage Protection (OVP) is activated and stops
switching operation.
When OVP is activated, VCC pin voltage decreases to
Operation Stop Voltage VCC(OFF) = 8.0 V. After that, the
IC reverts to the initial state by Undervoltage Lockout
(UVLO) circuit, and the IC starts operation when VCC
pin voltage increases to VCC(ON) = 15.0 V by Startup
Current. Thus the intermittent operation by UVLO is
repeated in OVP condition.
This intermittent operation reduces the stress of parts
such as power MOSFET and secondary side rectifier
diode. In addition, this operation reduces power
consumption because the switching period in this
intermittent operation is short compared with oscillation
stop period. When the abnormal condition is removed,
the IC returns to normal operation automatically.
The approximate value of output voltage VOUT(OVP) in
OVP condition is calculated by using Equation (11).
VOUT (OVP )  VCC(OVP )  VFD1  VFD 2  VFD 3
Junction Temperature,
Tj
Tj(TSD)
Tj(TSD)−Tj(TSD)HYS
Bias assist
function
ON
ON
OFF
OFF
VCC pin voltage
VCC(ON)
VCC(BIAS)
VCC(OFF)
Drain current
ID
Figure 8-15 TSD operational waveforms
9.
Design Notes
(11)
9.1 External Components
where,
VOUT(OVP): voltage of between VOUT(+) and VOUT(−)
VFD1: forward voltage of D1
VFD2: Forward voltage of D2
VFD3: Forward voltage of D3
Take care to use properly rated, including derating as
necessary and proper type of components.
D1
D2
R3
R2
STR5A400
1
8.10 Thermal Shutdown (TSD)
FB
S/GND
VCC
S/GND
2
Figure 8-15 shows the Thermal Shutdown (TSD)
operational waveforms.
When the temperature of control circuit increases to
Tj(TSD) = 135 °C (min.) or more, the TSD is activated,
and the IC stops switching operation. After that, VCC
pin voltage decreases. When the VCC pin voltage
decreases to about 9.4 V, the bias assist function is
activated and VCC pin voltage is kept to over the
VCC(OFF).
When the temperature reduces to less than
Tj(TSD)−Tj(TSD)HYS, the Bias Assist function is disabled
and the VCC pin voltage decreases to VCC(OFF). At that
time, the IC stops operation by the Undervoltage
Lockout (UVLO) circuit and reverts to the state before
startup. After that, the startup circuit is activated, the
VCC pin voltage increases to VCC(ON), and the IC starts
switching operation again. In this way, the intermittent
operation by TSD and UVLO is repeated while there is
an excess thermal condition.
When the fault condition is removed, the IC returns to
normal operation automatically.
STR5A464D-DS Rev.1.2
Feb.19, 2015
8
C4
R1
C3
7
6
S/GND
VOUT
L1
DR1
5
4
D/ST
S/GND
(+)
L2
VAC
C1
C2
D3
C5
R4
DR2
(-)
Figure 9-1 Peripheral circuit of IC
 Input and Output Electrolytic Capacitor
Apply proper derating to ripple current, voltage, and
temperature rise. Use of high ripple current and low
impedance types, designed for switch mode power
supplies, is recommended.
The value of output capacitor is about 56 μF to 220
μF.
The value of output capacitor, C5, is recommended
according to VOUT as follows;
C5 = 220 μF to 470 μF for 11 V ≤ VOUT < 15 V.
C5 = 100 μF to 220 μF for 15 V ≤ VOUT < 27.5 V.
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STR5A464D
 Inductor
Apply proper design margin to core temperature rise by
core loss and copper loss.
The value of inductor should be designed so that the
inductor current does not saturate.
The on time must be longer than Leading Edge Blanking
Time in order to control the output voltage constantly. In
the universal input voltage design, the on time becomes
short in the condition of maximum AC input voltage and
light road. Be careful not to reduce the value of inductor
( ≥ 820 μH recommended) too much.
 VCC Pin Peripheral Circuit
The reference value of C4 (see Figure 9-1) is
generally from 10 μF to 47 μF. The startup time is
determined by the value of C4 (refer to Section 8.1
Startup Operation).
 FB Pin Peripheral Circuit
The divided voltage of output voltage, VOUT(+), is
input to FB pin as shown in Figure 9-1.
C3 is capacitor for smoothing of output. The value of
C3 depends on the value of output electrical capacitor
and is 0.022 μF to 0.22 μF.
When C3 value is set larger, the line regulation
characteristic becomes better. But the dynamic
response of the output voltage becomes worse.
R1, R2 and R3 is set by the reference voltage,
VFB(REF) = 2.50 V, and the output voltage, VOUT. When
S/GND pin is ground reference, there is the
relationship as following Equation (9).
The target value of R1 is about 10 kΩ to 22 kΩ. R2
and R3 should be adjusted in actual operation
condition.
VOUT  VFB ( REF) 
⇒
VOUT  VFD 2  VFD 3

R1
R1  R 2  R 3
R4 
VOUT
3mA
(13)
9.2 D/ST pin
The internal power MOSFET connected to D/ST pin
is permanently damaged when the D/ST pin voltage and
the current exceed the Absolute Maximum Ratings.
The D/ST pin voltage is tuned to be less than about
90 % of the Absolute Maximum Ratings (630 V) in all
condition of actual operation, and the value of
transformer and components should be selected based on
actual operation in the application.
And the D/ST pin voltage in normal operation is tuned
to be less than 560 V.
9.3 Output Inductor Value Setting
In general, the inductance value is set so that the
inductance current becomes Continuous Conduction
Mode (CCM) in normal operation.
On duty, D, is set within the range of Equation (14);
t ON ( MIN )  f OSC ( AVG )  D  D MAX
(14)
where,
tON(MIN): minimum on time, ≥ 400 ns
fOSC(AVG): Average PWM Switching Frequency 60 kHz
DMAX: Maximum ON Duty 57 %
(R1  R 2  R3)
 VFD 2  VFD 3
R1
VFB ( REF)
 Bleeder resistance
For light load application, the breeder resistance, R4,
should be connected to both ends of output capacitor,
C5, as shown in Figure 9-1, in order to prevent the
increase of output voltage.
The value of R4 should satisfy Equation (10). R4
should be adjusted in actual operation condition.
(12)
9.3.1
Where,
VFD2: forward voltage of D2
VFD3: forward voltage of D3
Positive Output
Figure 9-2 shows the output current flow, Figure
9-3 shows the operational waveforms
U1
The VF of D2 and D3 affects the output voltage. Thus,
diodes of the low VF should be selected.
 Freewheeling diode
D3 is freewheeling diode shown in Figure 9-1. When
the internal power MOSFET turns on, recovery
current flows through D3. Recovery current affects
power loss and noise. The VF affects the output
voltage. Thus, fast recovery and low V F characteristic
diode should be selected.
VL
D/ST
L2
S/GND
(+)
IL
VRON
ION
VIN
C2
VOUT
VFD3
IOFF
D3
C5 R4
(-)
Figure 9-2 The output current flow at positive output
STR5A464D-DS Rev.1.2
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STR5A464D
D
VL
VIN-VRON-VOUT
t ON
V  VFD 3
 OUT
t ON  t OFF
VIN  VRON
(19)
Average switching frequency, fOSC(AVG) is as follows;
t
0
-(VOUT-VFD3)
IL
f OSC ( AVG ) 
ΔIOFF
IR
IO(AVG)
IRP
tOFF
Figure 9-3 Operational waveforms at positive output
The condition of CCM operation is expressed as
follows;
IR
0
2
(15)
where,
IO(AVG): average output current, IO, (average of IL)
IR: output ripple current
There are relationship between ΔION and ΔIOFF and IR
as follows;
I ON 
VIN  VRON  VOUT
 t ON
L
I OFF 
VOUT  VFD 3
 t OFF
L
I ON  I OFF  I R
V OUT VFD 3
 1  D 
I R  f OSC ( AVG )
(21)
In the universal input voltage design, be careful not to
reduce the value of inductor too much.
(≥ 820 μH recommended)
The maximum ripple current, IRP, and minimum ripple
current IRL, are as follows;
I RP  I O( AVG ) 
IR
 I DLIM
2
(22)
I RL  I O( AVG ) 
IR
2
(23)
The saturation current of inductor should be selected
to be larger than IDLIM.
(16)
9.3.2
(17)
(18)
where,
tON: on time
tOFF: off time
ΔION: inductor current change during on time
ΔIOFF: inductor current change during off time
VIN: input voltage (C2 voltage)
VFD3 : forward voltage of D3
VOUT: output voltage
VRON: the voltage between D/ST pin and S/GND pin
during on time
Using Equation (16), (17) and (18), D is the transfer
factor of VOUT and ( VIN  VRON ) as shown in Equation
(19).
STR5A464D-DS Rev.1.2
Feb.19, 2015
Using Equation (16) to (20), the inductance of L2, L,
is expressed as follows;
L
t
I O( AVG ) 
(20)
IRL
ΔION
tON
1
t ON  t OFF
Negative Output
Figure 9-4 shows the output current flow, Figure
9-5 shows the operational waveforms
Since output current is flowed in off time, the
output ripple becomes larger than positive output.
U1
VFD3
4 D/ST
S/GND 5~8
(-)
D3
VRON
ION
VIN
C2
C5 R4
IL
VL
L2
IOFF
VOUT
(+)
Figure 9-4 The output current flow at negative output
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STR5A464D
Using Equation (25), (26) and (27), D is as shown in
Equation (19).
VL
VIN-VRON
D
t
0
-(VOUT+VFD3)
IL
f OSC ( AVG ) 
IR
IO(AVG)
IRP
IRL
ΔION
(28)
Average switching frequency, fOSC(AVG) is as follows;
ΔIOFF
t
tON
t ON
VOUT  VFD 3

t ON  t OFF VIN  VRON  VOUT  VFD 3
t ON
1
 t OFF
(29)
Using Equation (25), (26), (27), (28) and (29), the
inductance of L2, L, is expressed as follows;
tOFF
L
V
IN
 VRON
D
I R  f OSC ( AVG )
(30)
Figure 9-5 Operational waveforms at negative output
The condition of CCM operation is expressed as
follows;
I O( AVG ) 
IR
0
2
(24)
where,
IO(AVG): average output current, IO, (average of IL)
IR: output ripple current
There are relationship between ΔION and ΔIOFF and IR
as follows;
I ON 
I OFF 
VIN  VRON
 t ON
L
VOUT  VFD 3
 t OFF
L
I ON  I OFF  I R
(25)
(26)
In the universal input voltage design, be careful not to
reduce the value of inductor too much.
(≥ 820 μH recommended)
The maximum ripple current, IRP, and minimum ripple
current IRL, are as follows;
I RP  I L ( AVG ) 
IR
2
(31)
I RL  I L ( AVG ) 
IR
2
(32)
where,
IL(AVG): average current of inductor
Average output current, IO(AVG), is the average current
during off time. IO(AVG) is as follows;
I O( AVG )  I L( AVG )  (1  D)
(33)
Using Equation (31) and (33), the peak current of
inductor, IRP , is calculated as follows:
(27)
where,
tON: on time
tOFF: off time
ΔION: inductor current change during on time
ΔIOFF: inductor current change during off time
VIN: input voltage (C2 voltage)
VFD3 : forward voltage of D3
VOUT: output voltage
VRON: the voltage between D/ST pin and S/GND pin
during on time
I RP 
IO
I
 R  I DLIM
1 D 2
(34)
The saturation current of inductor should be selected
to be larger than IDLIM.
9.4 PCB Trace Layout and Component
Placement
Since the PCB circuit trace design and the component
layout significantly affects operation, EMI noise, and
power dissipation, the high frequency PCB trace should
STR5A464D-DS Rev.1.2
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STR5A464D
be low impedance with small loop and wide trace.
In addition, the ground traces affect radiated EMI noise,
and wide, short traces should be taken into account.
Figure 9-6 shows the circuit design example.
(1) Main Circuit Trace Layout
This is the main trace containing switching currents,
and thus it should be as wide trace and small loop as
possible.
(2) Freewheeling Loop Layout
This is the trace for the current of freewheeling
diode, D3, and thus it should be as wide trace and
small loop as possible.
(3) Control Ground Trace Layout
Since the operation of IC may be affected from the
large current of the main trace that flows in control
ground trace, the control ground trace should be
separated from main trace and connected at single
point grounding.
the IC are distant from each other, placing a
capacitor such as film capacitor Cf (about 0.1 μF to
1.0 μF) close to the VCC pin and the S/GND pin is
recommended.
(5) FB Trace Layout
The divided voltage by R2, R3 and R1 of output
voltage is input to FB.
In order to increase the detection accuracy, R3 and
R1 should be connected to bottom of C3 and
S/GND, The trace between R1, R2 and FB pin
should be as short as possible.
(6) Thermal Considerations
Because the power MOSFET has a positive thermal
coefficient of RDS(ON), consider it in thermal design.
Since the copper area under the IC and the S/GND pin
trace act as a heatsink, its traces should be as wide as
possible.
(4) VCC Trace Layout
This is the trace for supplying power to the IC, and
thus it should be as small loop as possible. If C4 and
(6) Trace of S/GND pin should be wide
for heat release
D1
D2
(4) Loop of the power supply should be small
R3
(5) The trace between
R1, R2 and FB pin
should be as short as
possible.
R2
1
FB
S/GND
2
VCC
S/GND
8
C3
C4
R1
7
6
S/GND
VOUT
5
4
D/ST
(＋)
S/GND
L2
U1
C5
D3
C2
R4
(－)
(1)Main trace should be wide
trace and small loop
(2) Freewheeling Loop trace should be
wide trace and small loop
(3) Control GND trace should be
connected at a single point
Figure 9-6 Peripheral circuit example around the IC at positive output
STR5A464D-DS Rev.1.2
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STR5A464D
(6) Trace of S/GND pin should be wide
for heat release
D1
D2
(4) Loop of the power supply should be small
R3
(5) The trace between
R1, R2 and FB pin
should be as short as
possible.
R2
1
FB
S/GND
VCC
S/GND
2
8
C3
C4
R1
7
6
S/GND
D/ST
VOUT
D3
5
4
(－)
S/GND
U1
C2
C5
R4
L2
(＋)
(1)Main trace should be wide
trace and small loop
(2) Freewheeling Loop trace should be
wide trace and small loop
(3) Control GND trace should be
connected at a single point
Figure 9-7 Peripheral circuit example around the IC at negative output
STR5A464D-DS Rev.1.2
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STR5A464D
10. Pattern Layout Example
10.1 Positive Output
The following show the PCB pattern layout example and the schematic of circuit using STR5A464D series. The
PCB pattern layout example is made usable to other ICs in common. The parts in Figure 10-1 are only used.
Figure 10-1 PCB circuit trace layout example for positive output circuit
Z1
1
FB
S/GND
VCC
S/GND
2
D5
JW10
R2
R3
D6
8
7
R1
C4
C5
6
S/GND
L2
L1
D/ST
VAC
D4
S/GND
D3
C1
VOUT
5
4
C2
(+)
D7
C6
R6
F1
JW9
D2
D1
(-)
TC_STR5A400D_5_R1
Figure 10-2 Circuit schematic for PCB circuit trace layout for positive output circuit
STR5A464D-DS Rev.1.2
Feb.19, 2015
SANKEN ELECTRIC CO.,LTD.
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STR5A464D
10.2 Negative Output
The following show the PCB pattern layout example and the schematic of circuit using STR5A464D.
The above circuit symbols correspond to these of Figure 10-3.
Figure 10-3 PCB circuit trace layout example for negative output circuit
D5
R2
Z1
1
FB
S/GND
VCC
S/GND
2
D6
R3
8
7
R1
C4
C5
6
S/GND
L1
JW1
D/ST
VAC
DR4
VOUT
D7
5
4
S/GND
(-)
DR3
C1
C2
F1
L2
DR2
DR1
C6
C7
R6
L3
(+)
TC_STR5A400D_6_R2
Figure 10-4 Circuit schematic for PCB circuit trace layout for negative output circuit
STR5A464D-DS Rev.1.2
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STR5A464D
11. Reference Design of Power Supply
11.1 Positive Output
As an example, the following show the power supply specification, the circuit schematic, the bill of materials, and
the transformer specification.
 Power supply specification
IC
Input voltage
Maximum output power
Output voltage
Output current
STR5A464D
AC 85 V～AC 265 V
3 W (max.)
15 V
0.2 A
 Circuit schematic
D1
FB
S/GND
VCC
S/GND
2
R3
R2
U1
1
D2
8
7
R1
C4
C3
6
S/GND
F1
L2
L1
DR1
D/ST
C1
VOUT
5
4
S/GND
(+)
C5
C2
VAC
R4
D3
DR2
(-)
TC_STR5A400D_7_R1
 Bill of materials
Symbol
DR1
DR2
F1
L1
L2
C1
C2
C3
C4
C5
R1
R2
R3
R4
D1
D2
D3
U1
(1)
(2)
Ratings(1)
Part type
General
General
Fuse
(2)
(2)
(2)
(2)
CM inductor
Inductor
Electrolytic
Electrolytic
Ceramic
Electrolytic
Electrolytic, Low impedance
General
General
General
General
Fast recovery
Fast recovery
Fast recovery
IC
600 V, 1 A
600 V, 1 A
250 V, 1 A
680μH
1 mH
400 V, 4.7 μF
400 V, 4.7μF
50 V, 0.22 µF
50 V, 10 µF
50 V, 220 µF
10 kΩ
47 kΩ
5.6 kΩ
4.7 kΩ
200V, 1 A
500 V, 1 A
500 V, 1 A
Recommended
Sanken Parts
AM01A
AM01A
SJPL-D2
SJPD-D5
SJPD-D5
STR5A464D
Unless otherwise specified, the voltage rating of capacitor is 50 V or less and the power rating of resistor is 1/8 W or less.
It is necessary to be adjusted based on actual operation in the application.
STR5A464D-DS Rev.1.2
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STR5A464D
11.2 Negative Output
As an example, the following show the power supply specification, the circuit schematic, the bill of materials, and
the transformer specification.
 Power supply specification
IC
Input voltage
Maximum output power
Output voltage
Output current
STR5A464D
AC 85 V～AC 265 V
3 W (max.)
− 15 V
0.2 A
 Circuit schematic
D1
R2
U1
1
FB
S/GND
VCC
S/GND
2
D2
R3
8
7
R1
C4
C3
6
S/GND
L1
F1 DR1
D/ST
C1
D3
5
4
VOUT
S/GND
(-)
C5
C2
VAC
R4
L2
DR2
(+)
TC_STR5A400D_8_R1
 Bill of materials
Symbol
DR1
DR2
F1
L1
L2
C1
C2
C3
C4
C5
R1
R2
R3
R4
D1
D2
D3
U1
(1)
(2)
Ratings(1)
Part type
General
General
Fuse
(2)
(2)
(2)
(2)
CM inductor
Inductor
Electrolytic
Electrolytic
Ceramic
Electrolytic
Electrolytic, Low impedance
General
General
General
General
Fast recovery
Fast recovery
Fast recovery
IC
600 V, 1 A
600 V, 1 A
250 V, 1 A
680μH
1 mH
400 V, 10 μF
400 V, 10 μF
50 V, 0.22 µF
50 V, 10 µF
50 V, 220 µF
10 kΩ
47 kΩ
5.6 kΩ
4.7 kΩ
200 V, 1 A
500 V, 1 A
500 V, 1 A
Recommended
Sanken Parts
AM01A
AM01A
SJPL-D2
SJPD-D5
SJPD-D5
STR5A464D
Unless otherwise specified, the voltage rating of capacitor is 50 V or less and the power rating of resistor is 1/8 W or less.
It is necessary to be adjusted based on actual operation in the application.
STR5A464D-DS Rev.1.2
Feb.19, 2015
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STR5A464D
OPERATING PRECAUTIONS
In the case that you use Sanken products or design your products by using Sanken products, the reliability largely
depends on the degree of derating to be made to the rated values. Derating may be interpreted as a case that an operation
range is set by derating the load from each rated value or surge voltage or noise is considered for derating in order to
assure or improve the reliability. In general, derating factors include electric stresses such as electric voltage, electric
current, electric power etc., environmental stresses such as ambient temperature, humidity etc. and thermal stress caused
due to self-heating of semiconductor products. For these stresses, instantaneous values, maximum values and minimum
values must be taken into consideration. In addition, it should be noted that since power devices or IC’s including power
devices have large self-heating value, the degree of derating of junction temperature affects the reliability significantly.
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 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 the 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 the product pins, and wrong connections. Ensure all test parameters are
within the ratings specified by Sanken for the products.
Remarks About Using Thermal Silicone Grease
 When thermal silicone grease is used, it shall be applied evenly and thinly. If more silicone grease than required is
applied, it may produce excess stress.
 The thermal silicone grease that has been stored for a long period of time may cause cracks of the greases, and it
cause low radiation performance. In addition, the old grease may cause cracks in the resin mold when screwing the
products to a heatsink.
 Fully consider preventing foreign materials from entering into the thermal silicone grease. When foreign material
is immixed, radiation performance may be degraded or an insulation failure may occur due to a damaged insulating
plate.
 The thermal silicone greases that are recommended for the resin molded semiconductor should be used.
Our recommended thermal silicone grease is the following, and equivalent of these.
Type
Suppliers
G746
Shin-Etsu Chemical Co., Ltd.
YG6260 Momentive Performance Materials Japan LLC
SC102
Dow Corning Toray Co., Ltd.
Soldering
 When soldering the products, please be sure to minimize the working time, within the following limits:
• 260 ± 5 °C
10 ± 1 s (Flow, 2 times)
• 380 ± 10 °C 3.5 ± 0.5 s (Soldering iron, 1 time)
 Soldering should be at a distance of at least 1.5 mm from the body of the products.
Electrostatic Discharge
 When handling the products, the operator must be grounded. Grounded wrist straps worn should have at least 1MΩ
of resistance from the operator to ground to prevent shock hazard, and it should be placed near the operator.
 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 order to prevent
leak voltages generated by them from being applied to the products.
 The products should always be stored and transported in Sanken shipping containers or conductive containers, or
be wrapped in aluminum foil.
STR5A464D-DS Rev.1.2
Feb.19, 2015
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STR5A464D
IMPORTANT NOTES
 The contents in this document are subject to changes, for improvement and other purposes, without notice. Make
sure that this is the latest revision of the document before use.
 Application examples, operation examples and recommended examples described in this document are quoted for
the sole purpose of reference for the use of the products herein and Sanken can assume no responsibility for any
infringement of industrial property rights, intellectual property rights, life, body, property or any other rights of
Sanken or any third party which may result from its use.
 Unless otherwise agreed in writing by Sanken, Sanken makes no warranties of any kind, whether express or
implied, as to the products, including product merchantability, and fitness for a particular purpose and special
environment, and the information, including its accuracy, usefulness, and reliability, included in this document.
 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 the 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 apparatus (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.), and whenever long life expectancy is required even in general purpose
electronic equipment or apparatus, please contact your nearest Sanken sales representative to discuss, prior to the
use of the products herein. The use of Sanken products without the written consent of Sanken in the applications
where extremely high reliability is required (aerospace equipment, nuclear power control systems, life support
systems, etc.) is strictly prohibited.
 When using the products specified herein by either (i) combining other products or materials therewith or (ii)
physically, chemically or otherwise processing or treating the products, please duly consider all possible risks that
may result from all such uses in advance and proceed therewith at your own responsibility.
 Anti radioactive ray design is not considered for the products listed herein.
 Sanken assumes no responsibility for any troubles, such as dropping products caused during transportation out of
Sanken’s distribution network.
 The contents in this document must not be transcribed or copied without Sanken’s written consent.
STR5A464D-DS Rev.1.2
Feb.19, 2015
SANKEN ELECTRIC CO.,LTD.
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