STMicroelectronics AVS08CB

Overview

AVS08CB from STMicroelectronics is an insulated automatic voltage switch for 110/220V AC mains selection in SMPS < 200W, comprising a dedicated controller (AVS1BCP08 in DIP-8) and a high-sensitivity TRIAC (TO-220AB) with VDRM = ±500 V, IT(RMS) = 5 A at TC = 100°C, and integrated zero-crossing detection. It enables safe, spike-free mode retention during voltage transitions in offline power supplies.

For engineers reviewing the AVS08CB datasheet, AVS08CB pinout, AVS08CB application, or AVS08CB equivalent, this device supports dual-voltage AC input auto-detection, provides programmable mode-lock behavior via MODE pin, integrates shunt regulation and oscillator timing, and delivers robust immunity against line disturbances in compact offline converters.

Technical Context

The AVS08CB system implements a two-chip architecture: the AVS1BCP08 controller performs mains peak voltage detection (VM pin, 4.08–4.42 V threshold), generates synchronized triggering pulses for the TRIAC, and includes a built-in 44 kHz oscillator (R=91kΩ, C=100pF). Its MODE pin configures lock-on behavior during 220V→110V drop to prevent re-triggering spikes on recovery.

The integrated TRIAC (AVS08CB package) features optimized gate sensitivity (IGT ≤ 10 mA typical), dI/dt rating of 20 A/µs (repetitive), and thermal resistance Rth(j-c) = 4.0 °C/W (AC, 360° conduction), enabling efficient heat dissipation in TO-220AB without external heatsink for ≤200W designs.

Key Specifications

Pinout & Package

AVS08CB refers to the complete assembly: controller (AVS1BCP08, DIP-8) and TRIAC (TO-220AB) supplied as matched pair. The TRIAC package is TO-220AB with isolated mounting base (2500 V_RMS isolation), while the controller uses standard DIP-8 plastic body.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar automatic voltage switching applications.

Compared with ST7FLITE09Y0M6 and L6564H, AVS08CB delivers fully autonomous, hardware-based voltage selection with guaranteed spike suppression and minimal external components-ideal for cost-sensitive, safety-critical SMPS where firmware overhead or layout complexity must be avoided.

Availability

AVS08CB is available at Aetrix Electronics and suitable for universal-input SMPS, industrial AC-DC adapters, and medical equipment power inputs requiring stable component supply and long-term lifecycle support.

Supply support for AVS08CB 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, designing and manufacturing analog, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

AVS08CB belongs to ST's legacy power management and AC-DC interface product line, engineered specifically for reliable, maintenance-free automatic mains voltage selection in offline power conversion systems.

FAQ

What is the maximum ambient temperature for AVS08CB operation?

The AVS08CB TRIAC is rated for Toper = 0 to +70°C ('C' grade), and its thermal resistance Rth(j-c) = 4.0 °C/W (AC) means junction temperature remains within 125°C limit when case temperature stays ≤100°C. With proper PCB copper area (≥10 cm²), it operates reliably at 50°C ambient in 200W designs.

Does AVS08CB require external zero-cross detection circuitry?

No. The AVS1BCP08 controller includes an integrated zero-crossing detector referenced to VM pin, with 110 mV typical threshold and 50 mV hysteresis. It directly senses rectified mains waveform and generates synchronized gate pulses-no optocoupler, comparator, or external timing components are needed.

How does the MODE pin affect behavior during voltage sags?

When MODE is tied to VSS (−9 V), the controller locks into the last valid mode (e.g., 220V) during a sag to 110V and maintains that state until manually reset. When tied to VDD (0 V), it continuously adapts-switching to 110V mode during sag and back to 220V upon recovery, risking transient spikes if restoration is fast.

Can AVS08CB be used with 60 Hz mains without modification?

Yes. The controller's zero-cross detection and oscillator are frequency-agnostic. Its 44 kHz internal clock and 50/60 Hz full compatibility are explicitly specified in the datasheet. No component changes or firmware updates are required for 60 Hz operation-only the RC timing network remains unchanged.