STMicroelectronics ACST1220H-8BTR

Overview

ACST1220H-8BTR from STMicroelectronics is a 12 A, 800 V RMS AC switch with integrated overvoltage clamping (V_CL ≥ 850 V), Snubberless operation, and DPAK package. It functions as a self-protected triac-based AC power switch for inductive load control in high-noise industrial environments, delivering 2000 V/µs static dV/dt immunity at 150 °C and 9 A/ms dynamic commutation capability.

For engineers reviewing the ACST1220H-8BTR datasheet, ACST1220H-8BTR pinout, ACST1220H-8BTR application, or ACST1220H-8BTR equivalent, key selection criteria include its IEC 61000-4-5 transient robustness (2 kV line pulse), low 20 mA gate trigger current, 150 °C junction rating, and snubberless performance enabling EMI-compliant PCB designs per IEC 61000-4-4.

Technical Context

The ACST1220H-8BTR integrates a triac structure with an internal voltage-clamping crowbar circuit that activates during overvoltage events-clamping transients up to 2 kV (IEC 61000-4-5) or forcing safe conduction for <10 ms. Its gate-triggering threshold remains stable across -40 °C to 150 °C, with guaranteed I_GT ≤ 20 mA and V_GT ≤ 1 V.

Snubberless operation is enabled by high static dV/dt immunity (2000 V/µs at T_j = 150 °C) and strong dynamic commutation margin (dI/dt)_c ≥ 9 A/ms at 150 °C, eliminating external snubbers in resistive and inductive switching applications up to 800 V blocking.

Key Specifications

Pinout & Package

DPAK (TO-252) package: surface-mount, single-ended tab (OUT), UL94 V0 halogen-free molding, lead-free plating, ECOPACK2 compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BTB12-800CW and ACS108-8SN, the ACST1220H-8BTR uniquely combines 12 A capacity, 800 V blocking, and self-clamping overvoltage protection-enabling simplified, certified designs for industrial-grade AC switching without external protection or derating.

Availability

ACST1220H-8BTR is available at Aetrix Electronics and suitable for inrush current limiting circuits, heating resistor control, solid state relays, and capacitor discharge circuits requiring stable component supply and long-term industrial lifecycle support.

Supply support for ACST1220H-8BTR 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, digital, and mixed-signal ICs for automotive, industrial, and consumer markets.

The ACST family targets high-reliability AC power control, emphasizing self-protection, snubberless operation, and extended temperature capability for industrial appliance and automation applications.

FAQ

What is the maximum transient voltage the ACST1220H-8BTR can withstand without external protection?

The ACST1220H-8BTR withstands up to 2 kV non-repetitive line peak pulse voltage (per IEC 61000-4-5 with R = 8 Ω, L = 30 μH), thanks to its internal overvoltage clamping circuit that activates above 850 V. This eliminates the need for external MOVs or TVS diodes in standard surge test configurations.

Can the ACST1220H-8BTR replace a mechanical relay in heating applications?

Yes-it is designed as a solid-state relay alternative for resistive heating control, supporting 12 A RMS continuous current and zero-cross or phase-angle triggering. Its 150 °C junction rating and self-protection allow reliable operation in sealed enclosures where mechanical relays would suffer contact erosion or welding.

Does the DPAK package require heatsinking for 12 A operation?

At 12 A RMS full sine wave, the DPAK package requires a minimum 1.65 cm² copper pad (70 µm thick) for thermal relief. With this, junction temperature stays within 150 °C at T_C = 133 °C. For ambient >85 °C or intermittent duty, additional heatsinking is recommended to maintain R_th(j-c) ≤ 1.2 °C/W.

How does the ACST1220H-8BTR achieve snubberless performance?

It achieves snubberless operation through two intrinsic features: (1) 2000 V/µs static dV/dt immunity at 150 °C prevents false turn-on during voltage transients, and (2) ≥9 A/ms dynamic commutation capability ensures reliable turn-off even with high inductive kickback-both verified per IEC 61000-4-4 burst testing.