STMicroelectronics TPN3021RL

Overview

TPN3021RL from STMicroelectronics is a tripolar overvoltage protection device based on Trisil™ technology, designed for high-speed data line protection in T1/E1 and Ethernet network interfaces. It provides symmetric common-mode and differential-mode protection with 28 V breakdown voltage (VBO), ≤4 µA leakage at 22 V stand-off, 30 mA minimum holding current (IH), and 200 A peak surge current (2/10 µs). It is used in telecom line interface cards to prevent damage from lightning-induced transients.

For engineers reviewing the TPN3021RL datasheet, TPN3021RL pinout, TPN3021RL application, or TPN3021RL equivalent, key selection criteria include tripolar crowbar action, low 16 pF capacitance at 0 V bias, SO-8 package compatibility, UL94 V0 resin compliance, and GR-1089 Core / ITU-T K21 standard support.

Technical Context

The TPN3021RL implements a triple crowbar architecture using bidirectional silicon avalanche thyristors (Trisils) arranged in a symmetrical tripolar configuration - two back-to-back devices between line pairs (Rx+/Tx+, Rx−/Tx−) and one referenced to GND. This enables simultaneous clamping in both common-mode and differential-mode surge events without signal distortion.

Its static triggering is defined by VBO ≤ 38 V at IBO = 300 mA, with dynamic turn-on sustained by ≥30 mA holding current. Thermal resistance Rth(j-a) is 170 °C/W, and it operates across −40 °C to +150 °C junction temperature, supporting robust deployment in uncontrolled telecom environments.

Key Specifications

Pinout & Package

TPN3021RL is housed in a standard SO-8 plastic package (JEDEC MS-012AC) with 1.27 mm pitch, UL94 V0 rated epoxy, and lead-free finish. Pin 1 is NC; Pins 2–4 and 6 are NC; Pin 5 is GND; Pin 7 is Rx+/Tx+; Pin 8 is Rx−/Tx−.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar tripolar overvoltage protection applications.

Compared with TPN3021RL, TPN3022RL raises breakdown margin for higher-voltage systems, while TPN2021RL reduces surge rating to match less demanding installation environments - both maintain identical pinout, thermal profile, and crowbar timing behavior.

Availability

TPN3021RL is available at Aetrix Electronics and suitable for DSL line interface cards, Ethernet PHY protection, T1/E1 channel banks, and telecom central office equipment requiring stable component supply and long-term lifecycle assurance.

Supply support for TPN3021RL 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 protection devices for industrial, automotive, and communications markets.

The TPN series belongs to ST's Trisil™ overvoltage protection product line, engineered specifically for fail-safe, high-reliability surge suppression in telecom infrastructure and high-speed data interfaces.

FAQ

What is the recommended external series resistor for TPN3021RL in GR-1089 Core first-level protection?

A minimum 10 Ω series resistor is required to limit current during 2500 V, 2/10 µs surges per GR-1089 Core first-level testing. This value ensures the device remains within its 200 A IPP rating while allowing full clamping action without thermal runaway.

Does TPN3021RL require a heatsink in typical telecom line card operation?

No heatsink is required. With Rth(j-a) = 170 °C/W and typical surge duty cycles (<1 event/hour), junction temperature rise remains below 25 °C above ambient. PCB copper pour on Pin 5 (GND) provides sufficient thermal dissipation for continuous operation.

Can TPN3021RL be used in AC-powered telephone line interfaces?

Yes - its 22 V VRM and 28 V VBO allow safe use on −48 V DC telecom lines with superimposed AC ringing (e.g., 90 V RMS, 20 Hz). The device remains non-conductive during normal ringing and triggers only during overvoltage transients exceeding VBO.

How does TPN3021RL behave after a 200 A surge event?

After a single 200 A, 2/10 µs surge, TPN3021RL enters a low-impedance latched state (crowbar mode) until current falls below 30 mA IH. System-level current limiting (e.g., fuse or PTC) must interrupt power to reset the device - it does not auto-recover.