Diodes Incorporated MMBZ5240BT-7-F

Overview

MMBZ5240BT-7-F from Diodes Incorporated is a 10 V, 150 mW surface-mount Zener diode in SOT-523 package, rated for 20 mA test current, 17 Ω zener impedance at 1 kHz, and 3.0 μA reverse leakage at 8.0 V, used for precision voltage regulation and overvoltage protection in space-constrained power management circuits.

For engineers reviewing the MMBZ5240BT-7-F datasheet, MMBZ5240BT-7-F pinout, MMBZ5240BT-7-F application, or MMBZ5240BT-7-F equivalent, key selection criteria include nominal zener voltage tolerance (±5%), thermal resistance (833 °C/W), low capacitance (≈15 pF), RoHS-compliant lead-free plating, and suitability for automated SMT assembly on FR-4 PCBs.

Technical Context

This device operates as a silicon planar Zener diode with controlled reverse breakdown at 10 V ±5% under 20 mA test current. Its low dynamic impedance (17 Ω at 1 kHz) ensures stable regulation across load variations, while its 150 mW power rating and 833 °C/W junction-to-ambient thermal resistance define safe operating limits on standard PCB layouts.

The SOT-523 package enables high-density placement and supports reflow soldering per J-STD-020D Level 1 moisture sensitivity. Polarity is defined by cathode band marking; forward voltage is 0.9 V at 10 mA, confirming standard PN-junction behavior outside breakdown region.

Key Specifications

Pinout & Package

Package: SOT-523 - ultra-small plastic surface-mount case (1.6 × 0.8 × 0.5 mm), UL 94V-0 rated, matte tin-plated Alloy 42 leadframe, polarity indicated by cathode band.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX584C10L-7-F and MMBZ5240BS-7-F, the MMBZ5240BT-7-F offers optimal space efficiency in SOT-523 while maintaining industry-standard 10 V regulation performance-ideal where PCB real estate is constrained but 150 mW dissipation suffices.

Availability

MMBZ5240BT-7-F is available at Aetrix Electronics and suitable for voltage reference, overvoltage protection, reset circuitry, and level-shifting applications requiring stable component supply and consistent parametric performance across production batches.

Supply support for MMBZ5240BT-7-F 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.

The MMBZ52xxBT series belongs to Diodes' general-purpose Zener diode product line, engineered specifically for high-volume, space-constrained consumer and industrial applications demanding reliability, RoHS compliance, and automated assembly compatibility.

FAQ

What is the maximum continuous reverse voltage that can be safely applied to MMBZ5240BT-7-F?

The device is rated for 10 V nominal zener voltage with ±5% tolerance, meaning it maintains regulation between 9.5 V and 10.5 V at 20 mA. Applying reverse voltage beyond 10.5 V risks exceeding power dissipation limits unless current is strictly limited by external series resistance to keep P_D ≤ 150 mW at the given ambient temperature.

Does MMBZ5240BT-7-F require a heatsink for standard PCB mounting?

No heatsink is required. With R_θJA = 833 °C/W and P_D = 150 mW, junction temperature rise is ≈125°C above ambient at full power. On standard FR-4 with recommended pad layout, operation remains within −65°C to +150°C junction range up to +85°C ambient - sufficient for most consumer and industrial applications without added thermal mass.

Can MMBZ5240BT-7-F be used in bidirectional ESD protection circuits?

Yes - its 0.9 V forward voltage at 10 mA enables effective clamping of positive transients to V_CC + 0.9 V and negative transients to GND − 0.9 V. However, total capacitance of ~15 pF limits use to data lines operating below ~10 Mbps; for USB 2.0 or HDMI, dedicated TVS arrays are preferred.

How does the SOT-523 package affect solder joint reliability compared to SOT-23?

SOT-523's smaller pad area (≈0.3 mm² per pad vs. 0.6 mm² for SOT-23) increases thermal stress concentration during reflow. Diodes specifies MIL-STD-202-compliant solderability and J-STD-020D Level 1 moisture sensitivity, but process validation is required for high-reliability automotive or medical assemblies - especially under thermal cycling or mechanical shock conditions.