Taiwan Semiconductor Corporation 1KSMB68CAH

Overview

1KSMB68CAH from Taiwan Semiconductor is a bi-directional 1000W transient voltage suppressor (TVS) in DO-214AA (SMB) package, with breakdown voltage 64.6–71.4 V at 1 mA, stand-off voltage 58.1 V, clamping voltage 92.0 V at 10.9 A, and AEC-Q101 qualification for automotive-grade reliability.

For engineers reviewing the 1KSMB68CAH datasheet, 1KSMB68CAH pinout, 1KSMB68CAH application, or 1KSMB68CAH equivalent, key selection criteria include bi-directional clamping capability, ISO 7637-2 Pulse 1/2a/2b/3a/3b compliance, 1.0 ps response time, moisture sensitivity level 1, and UL 94V-0 molding compound - all critical for ESD and load-dump protection in harsh environments.

Technical Context

The 1KSMB68CAH is a glass-passivated, single-die bi-directional TVS diode designed to protect sensitive electronics against fast-rising transients such as ESD, EFT, and inductive switching spikes. Its junction-to-lead thermal resistance is 20°C/W, enabling effective power dissipation during 10/1000 µs surges up to 1000 W.

It operates across -55°C to +175°C junction temperature range and meets JESD201 Class 2 whisker resistance and RoHS/halogen-free requirements per IEC 61249-2-21. Polarity is marked by cathode band on the case, though bi-directional configuration eliminates functional polarity dependence.

Key Specifications

Pinout & Package

DO-214AA (SMB) package: molded plastic body with matte tin-plated leads, polarity indicated by cathode band; weight ≈ 0.110 g; UL 94V-0 rated compound.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMBJ64CA and 1.5KE68CA, the 1KSMB68CAH delivers lower clamping voltage (92.0 V), higher peak surge current (10.9 A), and surface-mount compatibility - making it optimal for automotive and industrial designs requiring high-reliability, automated production-ready TVS protection.

Availability

1KSMB68CAH is available at Aetrix Electronics and suitable for automotive power line protection, industrial sensor interface protection, LED driver surge suppression, and USB-C port ESD protection requiring stable component supply and AEC-Q101-compliant assurance.

Supply support for 1KSMB68CAH 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, rectifiers, and MOSFETs for automotive, industrial, and consumer markets.

The 1KSMBxxCAH series is part of TSC's AEC-Q101-qualified TVS portfolio, engineered specifically for robust transient immunity in 12 V and 24 V automotive electrical systems and harsh industrial environments.

FAQ

What does the 'CAH' suffix indicate in 1KSMB68CAH?

The 'CAH' suffix denotes bi-directional configuration - meaning the 1KSMB68CAH functions identically in both polarities and has no functional anode/cathode distinction. This makes it ideal for protecting AC signals, differential buses, or floating nodes where voltage transients may swing positive or negative relative to ground. The cathode band on the DO-214AA case serves only as a mechanical orientation marker, not an electrical polarity indicator.

Is 1KSMB68CAH suitable for ISO 7637-2 Pulse 5a (load dump) protection?

No - the 1KSMB68CAH is rated for ISO 7637-2 Pulses 1, 2a, 2b, 3a, and 3b, but not Pulse 5a (load dump), which requires higher energy handling (up to 150 V, 100 ms). For Pulse 5a, a dedicated load-dump suppressor like a TVS with ≥1500 W rating or a hybrid regulator-based solution is required. The 1KSMB68CAH's 1000 W rating and 92.0 V clamping are optimized for lower-energy transients.

What is the maximum reverse leakage current of 1KSMB68CAH at its stand-off voltage?

The maximum reverse leakage current of 1KSMB68CAH is 1.0 µA at V_WM = 58.1 V and T_A = 25°C. This ultra-low leakage ensures minimal impact on high-impedance circuits such as sensor bias networks or precision reference paths, preserving accuracy and power efficiency in always-on systems.

Can 1KSMB68CAH be used in place of a unidirectional TVS like 1KSMB68AH?

Yes, but only if bi-directional clamping is required - for example, on AC-coupled lines or symmetric interfaces. The 1KSMB68CAH provides identical V_BR, V_WM, and V_C specs as its unidirectional counterpart 1KSMB68AH, but with symmetrical behavior. However, substituting it in a unidirectional design adds no benefit and may increase cost; use 1KSMB68AH unless polarity-agnostic protection is explicitly needed.

Does 1KSMB68CAH require derating at elevated ambient temperatures?

Yes - the 1KSMB68CAH must be derated above T_A = 25°C per Figure 2 in the datasheet. At 75°C ambient, its 1000 W peak pulse power drops to approximately 70% of rated value. Designers must apply thermal modeling using R_θJA = 100°C/W and R_θJL = 20°C/W to ensure junction temperature remains ≤175°C during surge events, especially in enclosed or high-power-density layouts.