STMicroelectronics ACST1035-7T

Overview

ACST1035-7T from STMicroelectronics is a 10 A, 700 V insulated triac with overvoltage crowbar protection and high static dV/dt immunity (≥2000 V/µs), designed for AC mains switching in home appliances and industrial controls. It integrates clamping functionality to absorb inductive turn-off energy, eliminates need for external MOVs or snubbers, and drives universal motors and compressors up to 10 A RMS without auxiliary protection.

For engineers reviewing the ACST1035-7T datasheet, ACST1035-7T pinout, ACST1035-7T application, or ACST1035-7T equivalent, this device is selected for robust IEC 61000-4-4/4-5 transient immunity, gate-triggering simplicity with 35 mA max IGT, and thermal reliability in TO-220FPAB package with 1500 V_RMS insulation.

Technical Context

The ACST1035-7T implements A.S.D.® (Application Specific Discrete) planar triac technology with integrated overvoltage crowbar circuitry that triggers into conduction during line surges ≥850 V, clamping transients up to 2 kV peak per IEC 61000-4-5. Its 2000 V/µs static dV/dt rating ensures reliable blocking under fast EFT noise without false triggering.

It operates across -40 °C to +125 °C junction temperature, supports 105 A non-repetitive surge current (20 ms, 50 Hz), and delivers low on-state voltage (V_TM ≤ 1.5 V at 14.1 A) with dynamic resistance ≤35 mΩ - enabling efficient power delivery to inductive loads like compressor windings and drum motors.

Key Specifications

Pinout & Package

ACST1035-7T uses TO-220AB package: insulated plastic case with metal tab (COM), three leads (COM, OUT, GATE), and UL94 V0 epoxy molding. Mounting torque: 0.4–0.6 N·m.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar AC switch applications.

Compared with BTB12-700CW and ACS108-7SN, ACST1035-7T uniquely combines 10 A rating, 2000 V/µs dV/dt, and integrated crowbar in an insulated TO-220AB package - delivering highest functional integration for appliance-grade AC switching where reliability and component count matter.

Availability

ACST1035-7T is available at Aetrix Electronics and suitable for compressor control in refrigeration systems, universal motor drive in washing machines, and industrial AC load switching requiring stable component supply and long-term lifecycle support.

Supply support for ACST1035-7T includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, MCU, power, and sensor solutions for industrial, automotive, and consumer markets.

The ACST series belongs to ST's ACS™/ACST power switch family built with A.S.D.® technology, specifically engineered for robust, snubberless AC mains switching in home appliances and industrial equipment demanding high surge immunity and long service life.

FAQ

What is the maximum continuous load current supported by ACST1035-7T?

The ACST1035-7T supports 10 A RMS continuous current when mounted on a heatsink maintaining case temperature ≤105 °C (TO-220AB). At ambient conditions with free-air convection, derating applies: 5.5 A at 50 °C ambient per Figure 4. Thermal performance is validated per I²t = 66 A²s for fuse coordination.

Does ACST1035-7T require a heatsink in typical appliance applications?

Yes - a heatsink is required for sustained 10 A operation. With R_th(j-c) = 1.7 °C/W, a 10 °C/W heatsink keeps junction temperature ≤125 °C at 10 A and 25 °C ambient. For intermittent loads (e.g., compressor startup), short-term operation without heatsink is possible but not recommended beyond 10 seconds.

How does the overvoltage crowbar function differ from a standard MOV-based protection?

Unlike MOVs that clamp and degrade over time, ACST1035-7T's crowbar actively switches to conduction during overvoltage events ≥850 V, diverting surge current through the load for ≤10 ms. It recovers full blocking capability after the next zero-crossing and withstands ≥10 such events per polarity - offering deterministic, repeatable, and maintenance-free protection.

Can ACST1035-7T be used with zero-crossing detection circuits?

Yes - its high dV/dt immunity (2000 V/µs) prevents false triggering during zero-crossing transitions. When paired with a zero-crossing optocoupler (e.g., MOC3041), it enables low-EMI phase-angle control while retaining full surge protection. Gate timing must respect minimum pulse width (≥20 µs) and peak current (≤1.6 A) per datasheet.