Diodes Incorporated ZMM5248B-7

Overview

ZMM5248B-7 from Diodes Incorporated is a 500mW surface-mount Zener diode with a nominal zener voltage of 18V (17.1–18.9V range at 7.0mA test current), 600Ω maximum zener impedance at 21mA, and +0.085%/°C temperature coefficient. It uses a MiniMELF glass package, supports -65°C to +175°C operation, and is used for precision voltage reference and overvoltage protection in power supply feedback loops.

For engineers reviewing the ZMM5248B-7 datasheet, ZMM5248B-7 pinout, ZMM5248B-7 application, or ZMM5248B-7 equivalent, key selection criteria include its 18V regulation tolerance, low thermal resistance (300°C/W), cathode-band polarity marking, MiniMELF mechanical compatibility, and stable temperature coefficient in industrial sensor biasing and DC-DC converter feedback networks.

Technical Context

This Zener diode operates in reverse breakdown mode to maintain a stable reference voltage under varying load and temperature conditions. Its 18V nominal zener voltage is specified at I_ZT = 7.0mA, with a tight ±0.9V tolerance (17.1–18.9V) and low dynamic impedance (≤600Ω at 21mA).

The device exhibits a positive temperature coefficient of +0.085%/°C, indicating increasing zener voltage with rising junction temperature - a critical factor when designing thermally stable references across wide ambient ranges.

Key Specifications

Pinout & Package

Package: MiniMELF (DO-213AA), hermetically sealed glass case with solderable terminals and cathode band marking. Dimensions: A = 3.30–3.70 mm (length), B = 1.30–1.60 mm (diameter), C = 0.28–0.50 mm (lead diameter). Weight ≈ 0.034 g.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX55C18 and MMSZ5248B, ZMM5248B-7 delivers superior thermal performance (300°C/W vs. 357°C/W), higher power rating (500mW vs. 350mW), and identical voltage tolerance - making it optimal for space-constrained, high-reliability SMT applications demanding robust transient response.

Availability

ZMM5248B-7 is available at Aetrix Electronics and suitable for industrial power supplies, automotive sensor modules, programmable logic controller I/O protection, and medical instrument overvoltage clamping requiring stable component supply and long-term lifecycle continuity.

Supply support for ZMM5248B-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, serving industrial, computing, consumer, and communications markets with high-reliability components.

ZMM52xxB is part of Diodes' MiniMELF Zener diode product line, designed specifically for high-stability voltage reference and transient suppression in compact, thermally demanding SMT applications.

FAQ

What is the maximum reverse current for ZMM5248B-7 at 14V?

The maximum reverse current (I_R) is 0.1 µA at V_R = 14V, measured at T_A = 25°C. This ultra-low leakage ensures minimal loading on high-impedance reference dividers and preserves accuracy in precision analog circuits where bias current errors must be sub-nanoampere.

Can ZMM5248B-7 be used in place of ZMM5247B or ZMM5249B?

No - ZMM5247B (17V) and ZMM5249B (19V) have different nominal zener voltages and non-overlapping tolerance bands. Substituting them would shift regulation points by ≥1V, violating design margins in feedback loops or clamping thresholds. Voltage-specific selection is mandatory per circuit requirements.

Is the MiniMELF package compatible with standard reflow profiles?

Yes - the MiniMELF package meets MIL-STD-202 Method 208 for solderability and is qualified for lead-free reflow per J-STD-020. Peak temperatures up to 260°C for ≤10 seconds are supported, provided thermal mass and board layout allow uniform heating of the glass body without cracking.

How does the +0.085%/°C temperature coefficient affect long-term stability?

This coefficient means V_Z increases by 0.085% per °C rise in junction temperature. Over a 100°C ΔT (e.g., -25°C to +75°C ambient), V_Z shifts ~8.5mV/°C × 100°C = +0.85V - a predictable, linear drift that can be compensated in system calibration or selected for zero-TC reference stacking with negative-TC devices.