Taiwan Semiconductor Corporation 1.5KE51

Overview

1.5KE51 from Taiwan Semiconductor is a unidirectional 1500W transient voltage suppressor (TVS) diode designed for high-energy surge protection in DC power rails and signal lines. It features a nominal breakdown voltage of 51 V, clamping voltage of 73.5 V at 21 A peak pulse current, working stand-off voltage of 41.3 V, and DO-201 axial package with <1 μA leakage above 41.3 V - used in automotive power supply input protection.

For engineers reviewing the 1.5KE51 datasheet, 1.5KE51 pinout, 1.5KE51 application, or 1.5KE51 equivalent, key selection criteria include clamping performance under 10/1000 μs surges, thermal derating behavior up to 175°C junction temperature, unidirectional polarity marking, and compliance with ISO 7637-2 Pulse 1/2a/2b/3a/3b immunity requirements.

Technical Context

The 1.5KE51 operates as a silicon avalanche diode with fast response time (<1.0 ps from 0 V to V_BR) and low dynamic impedance, enabling effective suppression of ESD and lightning-induced transients. Its unidirectional configuration provides forward conduction only during reverse overvoltage events, with VF = 3.5 V at 50 A for devices with V_BR ≤ 200 V.

It meets AEC-Q101 qualification for automotive use and supports steady-state power dissipation of 5 W at TL = 75°C on 16 mm × 16 mm copper pads. The device is rated for non-repetitive peak power of 1500 W at T_p = 1 ms and withstands 200 A peak forward surge current (8.3 ms half-sine).

Key Specifications

Pinout & Package

DO-201 package: axial leaded, cylindrical epoxy body with cathode band marking for unidirectional polarity. Leads are tinned for solderability; weight ≈ 0.090 g.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar transient voltage suppression applications.

Compared with 1.5KE51, SMAJ51A offers compact SMT integration at reduced surge capacity, while 1.5SMC51A delivers identical protection performance in a surface-mount package requiring board redesign - both serve distinct mechanical and power-class trade-offs.

Availability

1.5KE51 is available at Aetrix Electronics and suitable for automotive electronics, industrial power supplies, and LED lighting systems requiring stable component supply and long-term obsolescence management.

Supply support for 1.5KE51 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

Taiwan Semiconductor Corporation (TSC) is a vertically integrated semiconductor manufacturer specializing in discrete power devices, TVS diodes, and rectifiers with global distribution and AEC-Q101 validation capabilities.

The 1.5KE series was developed specifically for high-reliability transient suppression in automotive and industrial environments, emphasizing robust surge handling, thermal stability, and standardized JEDEC packaging.

FAQ

What is the clamping voltage of the 1.5KE51 under standard surge conditions?

The 1.5KE51 clamps to a maximum of 73.5 V when subjected to a 10/1000 μs waveform with a peak current of 21 A. This value is measured per IEC 61000-4-5 and ISO 7637-2 standards and represents the upper limit of voltage seen by downstream circuitry during worst-case transient events. The 1.5KE51 maintains this clamping performance across its full operating temperature range from −55°C to +175°C.

Is the 1.5KE51 unidirectional or bidirectional, and how is polarity identified?

The 1.5KE51 is a unidirectional TVS diode, meaning it clamps only during reverse-biased overvoltage events and conducts forward current like a standard diode. Polarity is marked by a cathode band on the DO-201 package body - the banded end connects to the protected line, while the anode connects to ground or the lower-potential reference. Bidirectional variants use "CA" suffixes (e.g., 1.5KE51CA), which the 1.5KE51 does not carry.

Does the 1.5KE51 meet automotive qualification standards?

The base 1.5KE51 is not AEC-Q101 qualified; however, the 1.5KE51H variant (with "H" suffix) is fully AEC-Q101 certified for automotive applications. Both share identical electrical specifications, but only the "H" version undergoes extended reliability testing including temperature cycling, high-temperature reverse bias, and ESD verification. For automotive designs requiring formal qualification, specify 1.5KE51H instead of 1.5KE51.

What is the maximum steady-state power dissipation for the 1.5KE51?

The 1.5KE51 has a steady-state power dissipation rating of 5 W when mounted on a 16 mm × 16 mm copper pad at lead temperature (T_L) = 75°C. This value applies only to continuous DC or low-frequency AC conditions - not transient events. During surge events, the device handles up to 1500 W for 1 ms, but thermal design must ensure average power remains within 5 W limits to avoid junction overheating.

How does the 1.5KE51 compare to the 1.5KE51A variant?

The 1.5KE51A differs from the 1.5KE51 in tighter breakdown voltage tolerance: 48.5–53.6 V (min/max) versus 45.9–56.1 V for the standard 1.5KE51. Both share identical clamping voltage (70.1 V vs. 73.5 V), working voltage (43.6 V vs. 41.3 V), and surge ratings. The "A" suffix indicates enhanced V_BR consistency, beneficial in designs where precise clamping onset is critical - such as protecting narrow-voltage-margin regulators.