STMicroelectronics TS420-600T

Overview

TS420-600T from STMicroelectronics is a sensitive-gate 4 A, 600 V RMS silicon-controlled rectifier (SCR) in TO-220AB package, designed for low-gate-current triggering in crowbar protection and universal motor control circuits. It delivers 2.5 A average on-state current at 115 °C case temperature, supports 30 A non-repetitive surge (10 ms), and features 0.2 mA max gate trigger current (IGT) with 5 V/µs dV/dt immunity at 125 °C.

For engineers reviewing the TS420-600T datasheet, TS420-600T pinout, TS420-600T application, or TS420-600T equivalent, key selection criteria include gate sensitivity (≤200 µA), thermal resistance (Rth(j-c) = 3.0 °C/W), turn-on time (0.5 µs typ.), and TO-220AB mechanical compatibility for heatsink-mounted overvoltage protection and phase-control designs.

Technical Context

The TS420-600T operates as a unidirectional thyristor with latching behavior triggered by sub-milliampere gate current. Its low IGT (200 µA max) enables direct drive from microcontroller GPIOs or optocouplers without amplification, while its 600 V VDRM/VRRM rating supports 230 VAC mains-connected applications.

Thermal design relies on junction-to-case conduction (3.0 °C/W) and requires mechanical mounting to heatsinks per TO-220AB tab torque spec (0.4–0.6 N·m). The device exhibits 50 A/µs critical dl/dt and 5 V/µs dV/dt immunity at 125 °C-critical for noise-immune operation in motor commutation and crowbar circuits.

Key Specifications

Pinout & Package

TS420-600T uses the TO-220AB package with insulated tab, standard 3-pin vertical lead configuration, and mechanical mounting via M3 screw (recommended torque: 0.4–0.6 N·m). The plastic body meets UL 94 V0 and RoHS requirements.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar SCR-based control and protection applications.

Compared with BT169G-650R and TYN612, TS420-600T uniquely balances 4 A RMS capability, ultra-low 200 µA gate trigger, and TO-220AB thermal performance-making it optimal for space-constrained, microcontroller-driven crowbar and motor control where both sensitivity and power handling matter.

Availability

TS420-600T is available at Aetrix Electronics and suitable for AC motor control, overvoltage crowbar protection, and light dimming applications requiring stable component supply, long-term manufacturability, and consistent parametric performance across production batches.

Supply support for TS420-600T 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, specializing in power management, analog, MEMS, and microcontrollers for industrial, automotive, and consumer markets.

The TS420 belongs to ST's high-sensitivity SCR product line, engineered specifically for gate-energy-constrained applications such as opto-isolated motor control and fast-response overvoltage protection in compact power systems.

FAQ

Is TS420-600T compatible with zero-crossing trigger circuits?

No-it is not inherently zero-crossing compatible. As a standard SCR, it conducts until current falls below holding current (IH ≤ 5 mA). For zero-crossing operation, external circuitry (e.g., synchronized gate pulse generator) must ensure firing only near voltage zero to minimize EMI and inrush. Its fast tGT (0.5 µs) supports precise timing alignment.

Can TS420-600T replace a TRIAC in AC switching applications?

Only in half-wave or DC-biased AC applications. Unlike TRIACs, TS420-600T is unidirectional and cannot conduct reverse current. To emulate full-wave switching, two SCRs must be connected in inverse-parallel with coordinated gate timing-a common practice in high-reliability industrial controls where TRIAC dv/dt limitations are problematic.

What is the maximum recommended gate resistor value for reliable triggering?

Based on IGT ≤ 200 µA and VGT ≤ 0.8 V, a 1 kΩ gate resistor is validated in the datasheet for 10 mA IG drive. For direct 3.3 V MCU GPIO drive, R_G ≤ 15 kΩ ensures ≥220 µA worst-case current (accounting for V_OL ≈ 0.4 V), but 4.7 kΩ is preferred for noise margin and transient suppression.

Does TS420-600T require snubber circuits in inductive load switching?

Yes-especially with inductive loads like motors or solenoids. Its dV/dt rating (5 V/µs min) may be exceeded during turn-off due to L·di/dt-induced voltage spikes. A standard RC snubber (e.g., 100 Ω + 100 nF) across anode–cathode limits dV/dt and prevents false re-triggering, extending device lifetime and system reliability.