December 2009 Doc ID 8766 Rev 5 1/13
13
ACST4
Overvoltage protected AC switch
Features
■Triac with overvoltage protection
■Low IGT (<10 mA) or high immunity
(IGT<35 mA) version
■High noise immunity: static dV/dt > 1000 V/µs
■TO-220FPAB insulated package: 1500 V rms
Benefits
■Enables equipment to meet IEC 61000-4-5
■High off-state reliability with planar technology
■Needs no external overvoltage protection
■Reduces the power passive component count
■High immunity against fast transients
described in IEC 61000-4-4 standards
Applications
■AC mains static switching in appliance and
industrial control systems
■Drive of medium power AC loads such as:
– Universal motor of washing machine drum
– Compressor for fridge or air conditioner
Description
The ACST4 series belongs to the ACS™/ACST
power switch family built with A.S.D.® (application
specific discrete) technology. This high
performance device is suited to home appliances
or industrial systems, and drives loads up to 4 A.
This ACST4 switch embeds a Triac structure and
a high voltage clamping device able to absorb the
inductive turn-off energy and withstand line
transients such as those described in the
IEC 61000-4-5 standards. The ACST410 needs
only a low gate current to be activated (IGT < 10
mA) and still shows a high noise immunity
complying with IEC standards such as
IEC 61000-4-4 (fast transient burst test).
Figure 1. Functional diagram
TM: ACS is a trademark of STMicroelectronics.
®: A.S.D. is a registered trademark of
STMicroelectronics
Table 1. Device summary
Symbol Value Unit
IT(RMS) 4A
VDRM/VRRM 800 V
IGT (ACST410) 10 mA
IGT (ACST435) 35 mA
OUT
COM
G
TO-220FPAB
ACST410-8FP
ACST435-8FP
DPAK
ACST410-8B
ACST435-8B
G
OUT
COM
G
COM
OUT
www.st.com
Characteristics ASCT4
2/13 Doc ID 8766 Rev 5
1 Characteristics
Table 2. Absolute ratings (limiting values)
Symbol Parameter Value Unit
IT(RMS) On-state rms current (full sine wave)
TO-220FPAB Tc = 102 °C 4
A
DPAK Tc = 112 °C
DPAK with
0.5 cm2 copper Tamb = 60 °C 1
ITSM
Non repetitive surge peak on-state current
Tj initial = 25 °C, ( full cycle sine wave)
F = 60 Hz tp = 16.7 ms 32 A
F = 50 Hz tp = 20 ms 30 A
I2tI
2t for fuse selection tp = 10 ms 6 A2s
dI/dt Critical rate of rise on-state current
IG = 2 x IGT, (tr ≤ 100 ns) F = 120 Hz Tj = 125 °C 100 A/µs
VPP Non repetitive line peak pulse voltage (1) Tj = 25 °C 2 kV
PG(AV) Average gate power dissipation Tj = 125 °C 0.1 W
PGM Peak gate power dissipation (tp = 20 µs) Tj = 125 °C 10 W
IGM Peak gate current (tp = 20 µs) Tj = 125 °C 1.6 A
Tstg Storage temperature range -40 to +150 °C
Tj Operating junction temperature range -40 to +125 °C
Tl Maximum lead solder temperature during 10 ms (at 3 mm from plastic case) 260 °C
VINS(RMS) Insulation rms voltage TO-220FPAB 1500 V
1. According to test described in IEC 61000-4-5 standard and Figure 19.
Table 3. Electrical characteristics
Symbol Test conditions Quadrant TjACST410 ACST435 Unit
IGT(1) VOUT = 12 V, RL = 33 ΩI - II - III 25 °C MAX. 10 35 mA
VGT VOUT = 12 V, RL = 33 ΩI - II - III 25 °C MAX. 1.0 1.1 V
VGD VOUT = VDRM, RL = 3.3 kΩI - II - III 125 °C MIN. 0.2 V
IH(2) IOUT = 500 mA 25 °C MAX. 20 25 mA
ILIG = 1.2 x IGT I - II - III 25 °C MAX. 40 60 mA
dV/dt (2) VOUT = 67 % VDRM, gate open 125 °C MIN. 500 1000 V/µs
(dI/dt)c(2) Without snubber 125 °C MIN. 5 A/ms
(dI/dt)c(2) (dV/dt)c = 15 V/µs 125 °C 2 A/ms
VCL ICL = 0.1 mA, tp = 1 ms 25 °C MIN. 850 V
1. Minimum IGT is guaranteed at 5% of IGT max
2. For both polarities of OUT pin referenced to COM pin
ASCT4 Characteristics
Doc ID 8766 Rev 5 3/13
Table 4. Static characteristics
Symbol Test conditions Value Unit
VTM(1)
1. For both polarities of OUT pin referenced to COM pin
IOUT = 5.6 A, tp = 500 µs Tj = 25 °C MAX. 1.7 V
VT0(1) Threshold voltage Tj = 125 °C MAX. 0.9 V
Rd(1) Dynamic resistance Tj = 125 °C MAX. 110 mΩ
IDRM
IRRM VOUT = VDRM/ VRRM
Tj = 25 °C MAX. 20 µA
Tj = 125 °C MAX. 500 µA
Table 5. Thermal resistances
Symbol Parameter Value Unit
Rth(j-a)
Junction to ambient TO-220FPAB 60 °C/W
Junction to ambient (soldered on 0.5 cm2 copper pad) DPAK 70
Rth(j-c) Junction to case for full cycle sine wave conduction TO-220FPAB 4.6 °C/W
DPAK 2.6
Figure 2. Maximum power dissipation versus
on-state rms current
Figure 3. On-state rms current versus case
temperature (full cycle)
0
1
2
3
4
5
6
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
180°
α= 180°
P(W)
IT(RMS)(A)
IT(RMS)(A)
0
1
2
3
4
5
0 25 50 75 100 125
α=180°
TO220FPAB
DPAK
TC(°C)
Characteristics ASCT4
4/13 Doc ID 8766 Rev 5
Figure 4. On-state rms current versus
ambient temperature (free air
convection, full cycle)
Figure 5. Relative variation of thermal
impedance versus pulse duration
Figure 6. Relative variation of gate trigger
current (IGT) and voltage (VGT)
versus junction temperature
Figure 7. Relative variation of holding
current (IH) and latching current (IL)
versus junction temperature
Figure 8. Surge peak on-state current
versus number of cycles
Figure 9. Non repetitive surge peak on-state
current and corresponding value of
I2t versus sinusoidal pulse width
IT(RMS)(A)
0.0
0.5
1.0
1.5
2.0
0 25 50 75 100 125
α=180°
TO-220FPAB
DPAK with copper
surface = 0.5 cm
2
Ta(°C)
K = [Zth / Rth]
1.0E-02
1.0E-01
1.0E+00
1.0E-03 1.0E-02 1.0E-01 1.0E+00 1.0E+01 1.0E+02 1.0E+03
Z
th(j-a)
Z
th(j-c)
TO-220FPAB
DPAK
Tp(s)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
-50 -25 0 25 50 75 100 125
IGT Q3
IGT Q1-Q2
V Q1-Q2-Q3
GT
IGT,V
GT[Tj] / IGT,V
GT[Tj= 25 °C]
(typical values)
Tj(°C)
0.0
0.5
1.0
1.5
2.0
2.5
-50 -25 0 25 50 75 100 125
IH,I
L[Tj] / IH,I
L[Tj= 25 °C]
Tj(°C)
IH
IL
(typical values)
ITSM(A)
0
5
10
15
20
25
30
35
1 10 100 1000
Non repetitive
T
j
initial=25 °C
One cycle
t=20ms
Repetitive
T
C
=102°C
Number of cycles
1
10
100
1000
0.01 0.10 1.00 10.00
t (ms)
p
ITSM(A), I²t (A²s)
dl /dt limitation: 100 A / µs Tjinitial = 25 °C
ITSM
I²t
ASCT4 Characteristics
Doc ID 8766 Rev 5 5/13
Figure 10. On-state characteristics
(maximum values)
Figure 11. Relative variation of critical rate of
decrease of main current (dI/dt)c
versus junction temperature
1
10
100
012345
Tj= 125 °C
Tj= 25 °C
ITM(A)
VTM(V)
Tjmax:
Vto = 0.90 V
Rd= 110 mΩ
0
1
2
3
4
5
6
7
25 50 75 100 125
8
Tj(°C)
(dI/dt)c[Tj] / (dl/dt)c[Tj= 125 °C]
Figure 12. Relative variation of static dV/dt
immunity versus junction
temperature (gate open)
Figure 13. Relative variation of leakage
current versus junction
temperature
0
1
2
3
4
5
6
25 50 75 100 125
dV/dt [Tj] / dV/dt [Tj= 125 °C]
VD=V
R= 536 V
Tj(°C)
25 50 75 100 125
VDRM =V
RRM = 800V
VDRM =V
RRM = 600 V
VDRM =V
RRM = 200 V
IDRM/IRRM [Tj;V
DRM /V
RRM] / IDRM/IRRM [Tj= 125 °C; 800 V]
1.0E-03
1.0E-02
1.0E-01
1.0E+00
Tj(°C)
Different blocking voltages
Figure 14. Relative variation of the clamping
voltage (VCL) versus junction
temperature (minimum values)
Figure 15. Thermal resistance junction to
ambient versus copper surface
under tab
0.85
0.90
0.95
1.00
1.05
1.10
1.15
-50 -25 0 25 50 75 100 125
V[T
j] / V [Tj= 25 °C]
CL CL
Tj(°C)
0
10
20
30
40
50
60
70
80
90
100
0 5 10 15 20 25 30 35 40
Rth(j-a)(°C/W)
DPAK
SCU
(cm²)
Printed circuit board FR4,
copper thickness = 35 µm
Application information ASCT4
6/13 Doc ID 8766 Rev 5
2 Application information
2.1 Typical application description
The ACST4 device has been designed to control medium power load, such as AC motors in
home appliances. Thanks to its thermal and turn off commutation performances, the ACST4
switch is able to drive an inductive load up to 4 A with no turn off additional snubber. It also
provides high thermal performances in static and transient modes such as the compressor
inrush current or high torque operating conditions of an AC motor. Thanks to its low gate
triggering current level, the ACST4 can be driven directly by an MCU through a simple gate
resistor as shown Figure 16 and Figure 17.
Figure 16. Compressor control – typical diagrams
Compressor
Electronic
starter
Electronic
thermostat
ACST
Rg
ACST
Power supply
AC Mains
Gate
Driver
logical circuitry
1
2
3
PTC
Compressor with integrated e-starter
Compressor
Start
switch
Run
switch
PTC
Rg
ACST
Power supply
Gate
Driver
ACST
Rg
AC Mains
Compressor with external electronic drive
ASCT4 Application information
Doc ID 8766 Rev 5 7/13
Figure 17. Universal drum motor control – typical diagram
2.2 AC line transient voltage ruggedness
In comparison with standard Triacs, which are not robust against surge voltage, the ACST4
is self-protected against over-voltage, specified by the new parameter VCL. The ACST4
switch can safely withstand AC line transient voltages either by clamping the low energy
spikes, such as inductive spikes at switch off, or by switching to the on state (for less than 10
ms) to dissipate higher energy shocks through the load. This safety feature works even with
high turn-on current ramp up.
The test circuit of Figure 18 represents the ACST4 application, and is used to stress the
ACST switch according to the IEC 61000-4-5 standard conditions. With the additional effect
of the load which is limiting the current, the ACST switch withstands the voltage spikes up to
2 kV on top of the peak line voltage. The protection is based on an overvoltage crowbar
technology. The ACST4 folds back safely to the on state as shown in Figure 19. The ACST4
recovers its blocking voltage capability after the surge and the next zero current crossing.
Such a non repetitive test can be done at least 10 times on each AC line voltage polarity.
Universal motor
Motor direction
setting
Speed motor
regulation
Rg
AC Mains
Stator
MCU
Vcc
12V
ACST
Rotor
MCU
Application information ASCT4
8/13 Doc ID 8766 Rev 5
Figure 18. Overvoltage ruggedness test circuit for resistive and inductive loads for
IEC 61000-4-5 standards
Figure 19. Typical current and voltage waveforms across the ACST4 during
IEC 61000-4-5 standard test
AC Mains
R
Filtering unit
Rg
Model of the load
Rgene
Surge generator
ACST4
2kV surge
L
R = 23 , L = 2 µH, Vsurge = 2 kV
Rg = 220 (ACST410-8), 68 (ACST435-8)
Ω
ΩΩ
I
V
0
0
Vpeak =V
CL
1.2/50 µs voltage surge
8/20 µs current surge
Ipeak = 90 A
dI/dt = 130 A/µs
ASCT4 Ordering information scheme
Doc ID 8766 Rev 5 9/13
3 Ordering information scheme
Figure 20. Ordering information scheme
ACS T 4 10 - 8 B TR
AC switch
Topology
On-state rms current
Repetitive peak off-state voltage
Package
T = Triac
4 = 4 A
8 = 800V
TR = Tape and reel
Blank = Tube
Triggering gate current
Delivery mode
10 = 10 mA
35 = 35 mA
B = DPAK
FP = TO-220FPAB
Package information ASCT4
10/13 Doc ID 8766 Rev 5
4 Package information
●Epoxy meets UL94, V0
●Cooling method: by conduction (C)
●Recommended torque value(TO220FPAB): 0.4 to 0.6 N·m
In order to meet environmental requirements, ST offers these devices in different grades of
ECOPACK® packages, depending on their level of environmental compliance. ECOPACK®
specifications, grade definitions and product status are available at: www.st.com.
ECOPACK® is an ST trademark.
Table 6. TO-220FPAB dimensions
Ref.
Dimensions
Millimeters Inches
Min. Max. Min. Max.
A 4.4 4.6 0.173 0.181
B 2.5 2.7 0.098 0.106
D 2.5 2.75 0.098 0.108
E 0.45 0.70 0.018 0.027
F 0.75 1 0.030 0.039
F1 1.15 1.70 0.045 0.067
F2 1.15 1.50 0.045 0.059
G 4.95 5.20 0.195 0.205
G1 2.4 2.7 0.094 0.106
H 10 10.4 0.393 0.409
L2 16 Typ. 0.63 Typ.
L3 28.6 30.6 1.126 1.205
L4 9.8 10.6 0.386 0.417
L5 2.9 3.6 0.114 0.142
L6 15.9 16.4 0.626 0.646
L7 9.00 9.30 0.354 0.366
Dia. 3.00 3.20 0.118 0.126
H
A
B
Dia
L7
L6
L5
F1
F2
F
D
E
L4
G1
G
L2
L3
ASCT4 Package information
Doc ID 8766 Rev 5 11/13
Figure 21. Footprint (dimensions in mm)
Table 7. DPAK dimensions
Ref.
Dimensions
Millimeters Inches
Min. Max. Min. Max.
A 2.20 2.40 0.086 0.094
A1 0.90 1.10 0.035 0.043
A2 0.03 0.23 0.001 0.009
B 0.64 0.90 0.025 0.035
B2 5.20 5.40 0.204 0.212
C 0.45 0.60 0.017 0.023
C2 0.48 0.60 0.018 0.023
D 6.00 6.20 0.236 0.244
E 6.40 6.60 0.251 0.259
G 4.40 4.60 0.173 0.181
H 9.35 10.10 0.368 0.397
L2 0.80 typ. 0.031 typ.
L4 0.60 1.00 0.023 0.039
V2 0° 8° 0° 8°
H
L4
G
B
L2
E
B2
D
A1
R
R
C
A
C2
0.60 MIN.
V2
A2
6.7
6.7 3 3 1.6
1.6
2.3
2.3
Ordering information ASCT4
12/13 Doc ID 8766 Rev 5
5 Ordering information
Table 8. Ordering information
6 Revision history
Table 9. Document revision history
Order code Marking Package Weight Base Qty Delivery mode
ACST410-8B
ACST4108
DPAK 1.5 g 50 Tube
ACST410-8BTR DPAK 1.5 g 1000 Tape and reel
ACST410-8FP TO-220FPAB 2.4 g 50 Tube
ACST435-8B
ACST4358
DPAK 1.5 g 50 Tube
ACST435-8BTR DPAK 1.5 g 1000 Tape and reel
ACST435-8FP TO-220FPAB 2.4 g 50 Tube
Date Revision Changes
Jan-2003 3A Previous update.
04-Jul-2007 4 Reformatted to current standard. Added package.
18-Dec-2009 5 VDRM/VRRM updated to 800 V. Order codes updated.
ASCT4
Doc ID 8766 Rev 5 13/13
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