Taiwan Semiconductor Corporation 1SMB5954

Overview

1SMB5954 from Taiwan Semiconductor is a surface-mount 3 W Zener diode with nominal zener voltage 160 V, test current 2.3 mA, and maximum DC zener current 9 mA. It features glass-passivated junction, DO-214AA (SMB) package, and operates over -55°C to +150°C junction temperature range. It serves as precision voltage reference or overvoltage clamp in high-voltage DC/DC converters.

For engineers reviewing the 1SMB5954 datasheet, 1SMB5954 pinout, 1SMB5954 application, or 1SMB5954 equivalent, key selection criteria include its 160 V nominal zener voltage, low leakage (0.25 μA at 121.6 V), 6500 Ω dynamic impedance at 1 mA, and compliance with J-STD-020 moisture sensitivity level 1.

Technical Context

The 1SMB5954 is a single-die, unidirectional Zener diode optimized for stable voltage regulation under reverse-bias conditions. Its 160 V nominal zener voltage is specified at 2.3 mA test current, with ±5% tolerance and positive temperature coefficient above ~100 V.

Thermal performance is defined by 25°C/W junction-to-lead resistance and 226°C/W junction-to-ambient resistance (at TA = 25°C). It supports surge power handling per Fig.2 and exhibits low inductance suitable for high-frequency transient suppression.

Key Specifications

Pinout & Package

DO-214AA (SMB) surface-mount package with cathode indicated by band-marked end. Matte tin-plated leads, UL 94V-0 molding compound, 0.100 g typical weight.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Zener diode applications.

Compared with 1SMB5954, the 1N5954B offers identical nominal voltage but lower power and different package-requiring mechanical redesign and derating for thermal reliability-while the 1.5SMC160A serves a fundamentally different circuit function (transient clamping vs. DC regulation), making it unsuitable as a functional substitute.

Availability

1SMB5954 is available at Aetrix Electronics and suitable for switching mode power supplies, on-board DC/DC converters, and lighting applications requiring stable component supply, RoHS-compliant sourcing, and moisture-insensitive SMT placement.

Supply support for 1SMB5954 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 analog and discrete semiconductor manufacturer headquartered in Hsinchu, Taiwan, serving industrial, computing, and consumer markets since 1979.

The 1SMB59xx series is part of TSC's high-voltage Zener diode product line, engineered for precision voltage regulation and robust transient response in compact surface-mount power conversion systems.

FAQ

What is the nominal zener voltage and tolerance of the 1SMB5954?

The 1SMB5954 has a nominal zener voltage of 160 V with a ±5% tolerance, measured at 2.3 mA test current and 25°C ambient temperature. This tolerance is confirmed in the Electrical Specifications table on page 2 of the M2102 datasheet revision, where min/typ/max values are listed as 152.00 V / 160.00 V / 168.00 V. The 1SMB5954 maintains this specification across its qualified operating temperature range.

Can the 1SMB5954 be used in place of a 1N5954B?

No-the 1SMB5954 is not a drop-in replacement for the 1N5954B. While both share 160 V nominal zener voltage, the 1N5954B is a 1.0 W DO-41 axial device with higher zener impedance (7000 Ω) and different thermal characteristics. The 1SMB5954 delivers 3 W at TL = 75°C and uses DO-214AA packaging, requiring distinct PCB layout, thermal relief, and assembly process validation. Substitution must account for these differences in the 1SMB5954 design context.

What is the maximum allowable DC zener current for continuous operation of the 1SMB5954?

The maximum DC zener current (I_ZM) for the 1SMB5954 is 9 mA, as specified in the Electrical Specifications table. Exceeding this value risks exceeding the 3 W total power dissipation limit, especially when combined with ambient temperature rise or insufficient PCB copper area. Derating is required above 75°C lead temperature per the Absolute Maximum Ratings table.

Does the 1SMB5954 meet RoHS and halogen-free requirements?

Yes-the 1SMB5954 is RoHS compliant and halogen-free per IEC 61249-2-21, as explicitly stated in the FEATURES section of the M2102 datasheet. The device uses matte tin-plated leads and UL 94V-0 compliant molding compound, satisfying environmental compliance mandates for industrial and consumer electronics sold in EU, China, and North America.

What is the leakage current specification for the 1SMB5954, and at what voltage is it measured?

The 1SMB5954 has a maximum leakage current (I_R) of 0.25 μA, measured at 121.6 V reverse voltage (80% of nominal V_Z). This value is critical for low-power bias networks and ensures minimal current draw in high-impedance voltage divider configurations commonly used in feedback loops of DC/DC converters.