Transient-protected AC power
switches
www.st.com/thyristors
ACST10 and ACST12 - rugged control of AC motors
in home appliances
The ACST10 and ACST12 series belongs to the ACS/ACST
family using ASD (application-specific discrete) planar
technology. These high-performance devices are adapted
to home appliances or industrial systems. They embed 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-x
standards.
The ACST10/12 devices have been designed to control
medium-power loads up to 12 A, such as AC motors in
home appliances. They also provide high transient thermal
performance to manage compressor inrush currents or
high-torque operating conditions in AC motors.
Key features
Triac structure with overvoltage crowbar technology
Low I GT (< 10 mA) version, or high immunity
(IGT < 35 mA) version
High noise immunity: static dV/dt > 2 kV/µs
Through-the-hole and SMD versions
Key benefits
Enables equipment to meet IEC 61000-4-5 without
any external protection
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 6100-4-4 standards
Target applications
Compressor on/off control of fridges
Drum motors in phase angle control mode
In addition to the overvoltage ruggedness that all ACST
provide, the ACST10/12 propose a static dV/dt specified
at a minimum of 2000 V/µs, one of the highest noise
immunity levels available on the market. Their voltage
ruggedness and high immunity level, as well as
being static switches (without moving parts), make the
ACST10/12 the perfect solution to replace relays in the
control of fridge compressors, which are connected
24 hours a day to the mains. Compared to standard
Triacs, the new ACST10/12 considerably simplify the
power stage of AC load control circuits: no need for an
RC circuit, varistor, or even gate buffer circuit. This new
series secures operation, even in dense or harsh
operating conditions, with minimal BOM for external
components.
New ACST10/12: easy but rugged application design
© STMicroelectronics - March 2009 - Printed in Italy - All rights reserved
The STMicroelectronics corporate logo is a registered trademark of the STMicroelectronics group of companies. ASD and ACS are trademarks of STMicroelectronics
All other names are the property of their respective owners.
For more information on ST products and solutions,
visit www.st.com
Order code: FLACST120309
ACST10 and ACST12 - especially designed for motor control
The technical and standards constraints were taken into account at the design stage in order to make all the
parameters of the ACST10/12 suitable for fridge-compressor control and universal drum motor control.
Furthermore, in addition to the basic THB and HTRB reliability tests, several specific functional reliability tests have
been performed such as overvoltage robustness test, repetitive 450 k cycles inrush current test, stalled rotor test and
repetitive dI/dt robustness test. All the test conditions plus test results used for the qualification of the ACST10/12
series are summarized in the available qualification report.
Product table
Typical application diagram
Part number ITRMS
(A)
IGT
(mA)
dV/dt
(V/µs)
(di/dt)c
(A/ms) Package
ACST10-7CT
10 A
35 mA
2000
12
TO-220AB
ACST10-7CFP
10 A
35 mA
2000
12
TO-220FPAB
ACST10-7ST
10 A
10 mA
200
4.4
TO-220AB
ACST10-7SFP
10 A
10 mA
200
4.4
TO-220FPAB
ACST12-7CT
12 A
35 mA
2000
14
TO-220AB
ACST12-7CG(-TR)
12 A
35 mA
2000
14
D²PACK
ACST12-7ST
12 A
10 mA
200
5.3
TO-220AB
ACST12-7SG(-TR)
12 A
10 mA
200
5.3
D²PACK
Rg
ACST
Power supply
AC mains
Gate
driver
logic circuitry
Compressor Universal motor
Motor direction
setting
Speed motor
regulation
Electronic
starter
Electronic
thermostat
Compressor on/off control
1
2
3
PTC
ACST
Rg
AC mains
Stator
MCU
12V
Ro tor
ACST
Vcc MCU
Drum motor in phase angle control mode
1
/
2
100%
