Diodes Incorporated ZMM5238B-7

Overview

ZMM5238B-7 from Diodes Incorporated is a 500mW surface-mount Zener diode with a nominal zener voltage of 8.7V (min 8.27V, max 9.14V) at 20mA test current, 8Ω typical zener impedance at 20mA, and +0.065%/°C temperature coefficient - used for precision voltage reference and overvoltage protection in low-power analog power rails.

For engineers reviewing the ZMM5238B-7 datasheet, ZMM5238B-7 pinout, ZMM5238B-7 application, or ZMM5238B-7 equivalent, key selection criteria include its MiniMELF glass package, 300°C/W junction-to-ambient thermal resistance, reverse leakage current ≤3.0µA at 6.5V, and suitability for space-constrained voltage regulation in sensor signal conditioning and microcontroller reset circuits.

Technical Context

This device operates as a two-terminal silicon Zener diode optimized for stable voltage clamping and reference generation in DC bias networks. It exhibits a well-defined breakdown knee at 20mA with low dynamic impedance (8Ω typical), enabling tight regulation under moderate load variation.

The +0.065%/°C temperature coefficient indicates positive drift with rising temperature, requiring compensation in high-accuracy references; its 500mW power rating and 300°C/W thermal resistance define maximum ambient operating limits per derating curves.

Key Specifications

Pinout & Package

Package: MiniMELF (DO-213AA), hermetically sealed glass case with cathode band marking; dimensions A = 3.30–3.70 mm, B = 1.30–1.60 mm, C = 0.28–0.50 mm; weight ≈ 0.034 g.

Key Features

Applications

Availability

ZMM5238B-7 is available at Aetrix Electronics and suitable for industrial sensor signal conditioning, microcontroller reset circuitry, and low-power analog power rail clamp applications requiring stable component supply and traceable sourcing.

Supply support for ZMM5238B-7 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design and manufacturing operations across Asia and the Americas.

ZMM52xxB is part of Diodes' standard Zener diode product line, engineered for cost-effective, high-reliability voltage regulation in consumer, industrial, and automotive power management subsystems.

FAQ

What is the maximum reverse voltage this diode can withstand before breakdown?

The ZMM5238B-7 has a nominal zener voltage of 8.7V with a guaranteed range of 8.27V to 9.14V at 20mA test current. Breakdown occurs within this specified range under controlled DC or pulsed conditions per JEDEC standards; it is not rated for sustained operation above 9.14V.

Can this diode be used in place of a 9.1V Zener like ZMM5239B?

No - ZMM5238B-7 (8.7V) and ZMM5239B (9.1V) have non-overlapping zener voltage ranges (8.27–9.14V vs. 8.65–9.56V). Substitution requires verification of circuit margin, especially in precision references where 0.4V offset affects trip points or regulation accuracy.

Is the MiniMELF package compatible with standard reflow soldering profiles?

Yes - the MiniMELF (DO-213AA) package is qualified for lead-free reflow per IPC/JEDEC J-STD-020, with peak temperatures up to 260°C. Its glass body and solderable terminals meet MIL-STD-202 Method 208 requirements for thermal cycling reliability.

Does this part have a specified junction capacitance value?

No specific junction capacitance is listed for ZMM5238B-7 in the datasheet. Figure 2 shows typical C_j vs. V_Z for the series, estimating ~12–15 pF at 2.0V reverse bias, but no guaranteed min/max is provided for this variant - design margins should assume worst-case values from adjacent types if critical.