STMicroelectronics P0118MA 2AL3

Overview

P0118MA 2AL3 from STMicroelectronics is a sensitive high-immunity silicon-controlled rectifier (SCR) in TO-92 package, rated for 600 V repetitive peak off-state voltage (VDRM/VRRM), 0.8 A RMS on-state current (IT(RMS)), and ultra-low gate trigger current (IGT) of 0.5–5 µA. It enables reliable latching in low-power pilot circuits where gate drive current is severely constrained, such as ground fault circuit interrupters (GFCIs) and smoke detector standby power control.

For engineers reviewing the P0118MA 2AL3 datasheet, P0118MA 2AL3 pinout, P0118MA 2AL3 application, or P0118MA 2AL3 equivalent, this device is selected for ultra-low IGT sensitivity, 600 V blocking capability, TO-92 thermal performance (Rth(j-a) = 150 °C/W), and compatibility with high-dV/dt environments up to 75 V/µs at 125 °C junction temperature.

Technical Context

This SCR operates as a latching unidirectional switch triggered by minimal gate current, with holding current (IH) ≤ 5 mA and latching current (IL) ≤ 6 mA - enabling stable conduction initiation and maintenance under weak gate drive. Its dV/dt immunity (≥75 V/µs at Tj = 125 °C) and low dynamic resistance (Rd ≤ 600 mΩ) ensure robust turn-on against transient noise and low conduction loss.

The device uses planar passivated junction technology for stable parameter drift over temperature, with gate-cathode leakage (IRG) ≤ 10 µA at 125 °C and threshold voltage (Vt0) ≤ 0.95 V. Thermal design is supported by defined junction-to-ambient resistance (150 °C/W on FR4) and surge rating (ITSM = 7 A, tp = 10 ms).

Key Specifications

Pinout & Package

Package: TO-92 (plastic epoxy, UL94 V0 compliant). Dimensions per ST Table 5: A = 1.35 mm, B = 4.70 mm, C = 2.54 mm, D = 4.40 mm, E = 12.70 mm, F = 3.70 mm, a = 0.50 mm.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TS118-600 and BT169G, P0118MA 2AL3 uniquely combines 600 V rating, sub-5 µA IGT, and TO-92 thermal performance-making it the only option for safety-critical, ultra-low-power AC switching where gate drive headroom is <1 µA.

Availability

P0118MA 2AL3 is available at Aetrix Electronics and suitable for ground fault interruption, smoke detector power management, and solid-state relay pilot circuits requiring stable component supply, long-lifecycle support, and consistent parametric performance across production batches.

Supply support for P0118MA 2AL3 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, power, MCU, and sensor solutions for industrial, automotive, and consumer markets.

The P011xx series belongs to ST's high-immunity SCR product line, engineered specifically for safety-critical, low-power AC control applications where gate drive current is limited and reliability under electrical stress is paramount.

FAQ

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

For guaranteed turn-on at 25 °C, RGK must be ≤1 kΩ per Figure 6. At elevated temperatures (125 °C), RGK should not exceed 500 Ω to maintain IGT ≤5 µA and prevent misfiring. Higher values reduce dV/dt immunity and increase required IGT.

Can P0118MA 2AL3 replace P0111MA in an existing design?

No - P0111MA has IGT = 4–25 µA, while P0118MA 2AL3 has IGT = 0.5–5 µA. Substituting the more sensitive part may cause false triggering due to noise coupling unless gate circuit impedance and layout are re-optimized for lower dV/dt susceptibility.

What is the recommended PCB pad layout for thermal performance?

Use a minimum 5 cm² copper area under the TO-92 leads (per Figure 4), with thermal vias connecting top and bottom layers. Avoid narrow traces on anode/cathode paths; keep gate trace short and shielded from noisy nodes to preserve low-IGT integrity.

Does P0118MA 2AL3 meet IEC 61000-4-4 (EFT) immunity requirements?

While not certified to IEC standards itself, its 75 V/µs dV/dt rating at 125 °C and low IGT make it suitable for designs targeting Level 3/4 EFT immunity when combined with proper gate RC filtering (e.g., 100 Ω + 100 pF) and layout isolation per ST AN4377.