Taiwan Semiconductor Corporation UDZS7V5B

Overview

UDZS7V5B from Littelfuse (formerly LSC Semiconductor) is a surface-mount Zener diode with nominal zener voltage 7.5 V (7.28–7.60 V at I_Z = 5 mA), 400 mW power dissipation, and SOD-323 package. It provides precise voltage regulation in low-power biasing, reference, and overvoltage protection circuits for portable electronics and sensor signal conditioning.

For engineers reviewing the UDZS7V5B datasheet, UDZS7V5B pinout, UDZS7V5B application, or UDZS7V5B equivalent, key selection criteria include zener voltage tolerance (±2.5%), dynamic impedance (5 Ω max at 5 mA), temperature coefficient (+2.5 mV/K), reverse current (0.5 µA max at 5.3 V), and thermal resistance (340 °C/W).

Technical Context

This Zener diode operates in reverse breakdown to maintain stable voltage across its terminals under varying load or supply conditions. Its planar die construction ensures consistent V_Z distribution and low leakage (I_R ≤ 0.5 µA at 5.3 V), while the SOD-323 package enables high-density PCB layouts in space-constrained applications.

The device exhibits a positive temperature coefficient of +2.5 mV/K at I_Z = 5 mA, indicating voltage increases linearly with junction temperature. Its maximum operating junction temperature is 150 °C, and it meets RoHS 2002/95/EC and J-STD-020D Level 1 moisture sensitivity requirements.

Key Specifications

Pinout & Package

SOD-323 is a two-terminal ultra-small plastic surface-mount package with cathode-marked anode-cathode orientation. Dimensions: length 1.60–1.80 mm, width 1.15–1.35 mm, height 2.30–2.70 mm. Lead-free, halogen-free, UL 94V-0 compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX384-B7V5 and MMSZ4685, UDZS7V5B offers optimal balance of tight voltage tolerance, moderate power capability, and ultra-compact size-making it preferred for space-constrained, battery-sensitive designs requiring stable 7.5 V references.

Availability

UDZS7V5B is available at Aetrix Electronics and suitable for portable power monitoring, sensor signal conditioning, USB-C port protection, and industrial PLC input clamping requiring stable component supply and long-term lifecycle support.

Supply support for UDZS7V5B 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

Littelfuse (acquired LSC Semiconductor) is a global leader in circuit protection, power control, and sensing technologies, serving automotive, industrial, and consumer markets with high-reliability discrete components.

The UDZS series was designed specifically for high-accuracy, low-leakage voltage reference and clamping in miniaturized portable and IoT devices-emphasizing tight V_Z tolerance, SOD-323 scalability, and RoHS-compliant manufacturing.

FAQ

What is the maximum reverse current for UDZS7V5B at 5.3 V?

The maximum reverse current (I_R) is 0.5 µA at 5.3 V and T_A = 25 °C, per the Electrical Characteristics table. This low leakage ensures minimal quiescent power draw in battery-critical applications such as wearable sensors and remote monitors.

Can UDZS7V5B be used in place of a 7.5 V through-hole Zener like 1N4734A?

No-it is not a direct replacement due to different package (SOD-323 vs. DO-41), power rating (400 mW vs. 1 W), and thermal path. While both regulate near 7.5 V, UDZS7V5B requires PCB-level thermal design for 400 mW dissipation and cannot handle the same surge energy as the through-hole part.

What does the 'H2' marking on the UDZS7V5B package indicate?

The 'H2' marking identifies the specific device variant within the UDZS series and corresponds to the 7.5 V zener voltage bin. Per the marking table, 'H2' maps directly to UDZS7V5B and confirms compliance with the specified V_Z, I_Z, and Z_Z parameters at 5 mA test current.

Is UDZS7V5B suitable for temperature-compensated reference designs?

It has a +2.5 mV/K temperature coefficient, which is positive and unadjusted. For compensated references, it must be paired with a negative-TC element (e.g., forward-biased diode) or used in feedback loops with active compensation-not suitable as a standalone compensated reference.