STMicroelectronics TS110-7UF

Overview

TS110-7UF from STMicroelectronics is a sensitive-gate, 700 V, 1.25 A RMS thyristor (SCR) designed for overvoltage crowbar protection and fault-sensing roles in circuit breakers. It features 100 µA max gate trigger current, 1250 V non-repetitive direct surge voltage, and TO-92/SMBflat-3L dual-package support - optimized for GFCI, AFCI, RCD, and RCBO applications requiring low-power triggering and high transient ruggedness.

For engineers reviewing the TS110-7UF datasheet, TS110-7UF pinout, TS110-7UF application, or TS110-7UF equivalent, this device delivers verified crowbar-based AC line transient protection per IEC 61000-4-5, low leakage (<100 µA at 125 °C), and robust dV/dt immunity (≥15 V/µs) - critical for reliable tripping in residual-current sensing circuits with limited gate drive.

Technical Context

The TS110-7UF operates as a self-protecting crowbar SCR: it latches on during overvoltage transients (e.g., IEC 61000-4-5 surges), diverting energy through the load for <10 ms, then recovers blocking capability after zero-current crossing. Its 100 µA IGT(Q1) enables direct interface with low-current sense amplifiers or comparators without external amplification.

It exhibits asymmetric voltage handling (1250 V VDSM direct, 850 V VRSM reverse), 1.4 V max VTM at 2.5 A, and 200 mΩ dynamic resistance - enabling low conduction loss and stable thermal performance up to 125 °C junction temperature. Thermal resistance is 75 °C/W (j-a, SMBflat-3L) with 5 cm² copper pad.

Key Specifications

Pinout & Package

TS110-7UF is supplied in SMBflat-3L surface-mount package (lead-free, halogen-free, UL94 V0 epoxy). Pin configuration is Gate–Anode–Cathode (GAK) in standard top-view orientation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar SCR crowbar protection applications.

Compared with S4006L and VS-1N6505, TS110-7UF uniquely combines sub-100 µA gate sensitivity, 700 V blocking, and SMBflat-3L packaging - enabling direct integration into compact, low-power RCD/GFCI modules without auxiliary drive circuitry or thermal derating.

Availability

TS110-7UF is available at Aetrix Electronics and suitable for ground fault interrupters, arc fault detectors, and overvoltage crowbar circuits requiring stable component supply, long-lifecycle availability, and RoHS-compliant packaging.

Supply support for TS110-7UF 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 microcontrollers, power devices, sensors, and analog ICs for industrial, automotive, and consumer markets.

The TS110-7 series belongs to ST's high-reliability protection thyristor product line, engineered specifically for residual-current and overvoltage safety functions in circuit breakers - emphasizing low IGT, high surge tolerance, and long-term leakage stability.

FAQ

What is the maximum allowable gate-cathode resistance for reliable triggering?

The datasheet specifies that IGT remains ≤100 µA with RGK = 220 Ω at 25 °C. Increasing RGK beyond 220 Ω raises IGT nonlinearly; for guaranteed triggering across temperature, RGK must not exceed 150 Ω. At 125 °C, IGT increases ~2.5×, so 150 Ω ensures margin under worst-case conditions.

Can TS110-7UF be used in bidirectional AC switching applications?

No - TS110-7UF is a unidirectional SCR. Its VRRM rating applies only to reverse polarity; it cannot block or conduct in the reverse direction like a TRIAC. For bidirectional line switching, use ST's T-series TRIACs (e.g., BT139-600E) instead.

How many IEC 61000-4-5 surge events can TS110-7UF survive?

Per DS8670 Rev 5, TS110-7UF survives ≥10 non-repetitive 1250 V VDSM surges (tp = 50 µs) with full recovery of VDRM after each event. Testing must follow Figure 15 circuit, with ≥5 seconds between surges and ambient temperature ≤40 °C to ensure no cumulative degradation.

Is thermal pad soldering required for SMBflat-3L package reliability?

Yes - the SMBflat-3L variant relies on thermal conduction through the cathode tab (Pin 3). The datasheet mandates a minimum 5 cm² copper area under the tab (with thermal vias) to achieve the rated 75 °C/W Rth(j-a). Omitting this pad causes junction temperature to exceed 125 °C at 1.25 A, risking premature failure.