Taiwan Semiconductor Corporation 1SMA4756

Overview

1SMA4756 from Taiwan Semiconductor is a 1 W, 47 V ±5% surface-mount Zener diode in DO-214AC (SMA) package, featuring 5.5 mA test current, 80 Ω dynamic impedance at IZT, 0.25 µA leakage at 35.8 V, and junction temperature range of −55°C to +175°C. It delivers stable voltage regulation in power supply feedback loops and overvoltage protection circuits.

For engineers reviewing the 1SMA4756 datasheet, 1SMA4756 pinout, 1SMA4756 application, or 1SMA4756 equivalent, key selection criteria include nominal Zener voltage tolerance, surge current capability (95 A), thermal derating behavior, and compliance with JESD201 Class 2 whisker resistance and J-STD-020 Level 1 moisture sensitivity.

Technical Context

The 1SMA4756 operates as a single-die, glass-passivated Zener diode optimized for precision voltage reference and transient suppression in DC power rails. Its 47 V nominal breakdown voltage is specified at 5.5 mA test current with ±5% tolerance, and its 80 Ω dynamic impedance ensures stable regulation under moderate load variation.

Designed for surface-mount assembly on PCBs with 5 mm × 5 mm copper pads, the device supports non-repetitive peak surge power up to 60 W (100 µs pulse) and maintains leakage below 0.25 µA at 35.8 V reverse bias - critical for low-power standby circuits and high-impedance sensing nodes.

Key Specifications

Pinout & Package

DO-214AC (SMA) package with cathode-indicating band; two-terminal unidirectional configuration. Matte tin-plated leads meet J-STD-002 solderability requirements and JESD201 Class 2 whisker resistance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 1SMA4756, the 1N4756A requires layout change due to through-hole packaging and exhibits higher dynamic impedance, while the SZ1SMA4756 offers identical SMT fit with optional tighter tolerance - making it a direct form-fit replacement where precision is critical.

Availability

1SMA4756 is available at Aetrix Electronics and suitable for industrial power supplies, automotive electronics, telecom infrastructure, and IoT sensor nodes requiring stable component supply and long-lifecycle support.

Supply support for 1SMA4756 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, rectifiers, and protection components with global distribution and AEC-Q101 qualified offerings.

The 1SMA47xx series targets cost-sensitive, high-reliability Zener regulation in consumer, industrial, and automotive applications - emphasizing robustness, automated assembly compatibility, and extended temperature operation.

FAQ

What is the Zener voltage tolerance for 1SMA4756?

The 1SMA4756 has a nominal Zener voltage of 47 V with a standard tolerance of ±5%, meaning the actual measured V_Z falls between 44.65 V and 49.35 V when tested at 5.5 mA and 30°C lead temperature. This tolerance is guaranteed per JEDEC registration and applies across the full operating temperature range of −55°C to +175°C. The 1SMA4756 datasheet specifies this tolerance in Note 1 of the Electrical Specifications table.

Does 1SMA4756 support reflow soldering without moisture preconditioning?

Yes, the 1SMA4756 is rated at Moisture Sensitivity Level 1 per J-STD-020, meaning it can be subjected to standard Pb-free reflow profiles (e.g., JEDEC J-STD-020D peak of 260°C) without prior baking. This eliminates handling steps and reduces manufacturing risk. The 1SMA4756's DO-214AC package uses UL 94V-0 compliant molding compound and matte tin-plated leads that meet J-STD-002 solderability requirements.

What is the maximum non-repetitive surge current for 1SMA4756?

The 1SMA4756 supports a peak forward surge current (I_FSM) of 30 A for an 8.3 ms single half-sine waveform, as defined in the Absolute Maximum Ratings table. Its non-repetitive peak surge power (P_ZSM) is 60 W under 100 µs square pulse conditions. These ratings enable the 1SMA4756 to absorb transient energy in DC input stages without failure, provided thermal recovery time between events is observed.

How does the dynamic impedance of 1SMA4756 affect regulation performance?

The 1SMA4756 exhibits a dynamic impedance (Z_ZT) of 80 Ω at 5.5 mA test current, which directly determines how much the Zener voltage shifts under load variation. For example, a ±1 mA change in current causes approximately ±80 mV deviation in V_Z. This value is lower than many competing 47 V Zeners (e.g., 1N4756A at 100 Ω), giving the 1SMA4756 tighter regulation in feedback circuits where current stability is limited.

Is 1SMA4756 suitable for automotive under-hood applications?

Yes, the 1SMA4756 is suitable for automotive under-hood applications due to its −55°C to +175°C junction temperature range, JESD201 Class 2 whisker resistance, and glass-passivated junction that resists corrosion and parameter drift under thermal cycling. While not AEC-Q101 certified out-of-box, its construction and specifications align with requirements for engine control module voltage references and load-dump clamps - subject to customer qualification per application.