Microchip Technology MIC4680-5.0BM

Overview

MIC4680-5.0BM from Micrel is a fixed-output 5.0V, 1.3A continuous current buck regulator in an 8-pin Power SOIC package, operating at 200kHz with 4V–34V input range and internal compensation. It integrates an NPN switch, thermal shutdown, cycle-by-cycle current limiting, and delivers up to 90% efficiency in high-efficiency step-down applications such as industrial power supplies and embedded system pre-regulators.

For engineers reviewing the MIC4680-5.0BM datasheet, MIC4680-5.0BM pinout, MIC4680-5.0BM application, or MIC4680-5.0BM equivalent, key selection considerations include its fixed 5.0V ±1% output accuracy over temperature, 2µA shutdown current, 1.4V saturation voltage at 1A, and compatibility with standard surface-mount inductors and Schottky diodes without external compensation.

Technical Context

The MIC4680-5.0BM employs voltage-mode control architecture with a 1.23V internal bandgap reference and fixed 200kHz oscillator. Its error amplifier compares feedback (tied directly to VOUT in fixed versions) against this reference to generate duty-cycle-modulated gate drive for the integrated NPN switch.

Protection features include cycle-by-cycle current limiting (1.3A typical short-circuit limit), thermal shutdown at 160°C, and logic-level TTL-compatible shutdown input with hysteresis. The device uses a Power SOIC-8 package where pins 5–8 and the die-attach paddle form a unified thermal ground path, enabling θJA = 63°C/W on adequate PCB copper.

Key Specifications

Pinout & Package

Package: 8-pin Power SOIC (M), with integrated thermal paddle connected to pins 5–8 (GND). Designed for enhanced thermal dissipation via PCB ground plane attachment (minimum 6 cm² recommended).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar buck regulator applications.

Compared with LM2678-5.0 and TPS54202D, the MIC4680-5.0BM provides the simplest 5V buck implementation-no feedback resistors, no compensation network, and minimal external parts-making it ideal for cost-sensitive, space-constrained, and time-to-market-critical applications requiring up to 1.3A.

Availability

MIC4680-5.0BM is available at Aetrix Electronics and suitable for industrial power supplies, embedded system pre-regulators, and on-card switching regulators requiring stable component supply, long-lifecycle support, and consistent parametric performance across temperature.

Supply support for MIC4680-5.0BM 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

Micrel Inc. was a U.S.-based analog and mixed-signal semiconductor company specializing in power management, timing, and interface ICs before its acquisition by Microchip Technology in 2015.

The MIC4680 family was designed as easy-to-use, thermally robust buck regulators targeting space- and cost-constrained industrial and embedded applications where reliability and minimal external component count were critical.

FAQ

What is the output voltage tolerance of the MIC4680-5.0BM over temperature?

The MIC4680-5.0BM guarantees ±1% output voltage accuracy at 25°C and ±3% over the full –40°C to +125°C junction temperature range. This is confirmed in the Electrical Characteristics table under "MIC4680-5.0" section, with test conditions specifying 8V ≤ VIN ≤ 34V and 0.1A ≤ ILOAD ≤ 1A. The feedback reference is trimmed to 1.23V with low drift, contributing to stable regulation across temperature.

Can the MIC4680-5.0BM be used with input voltages below 5V?

No - the MIC4680-5.0BM requires a minimum input voltage of 4V, but practical operation at 5V input is marginal due to dropout constraints. Its saturation voltage is 1.4V typical at 1A, so VIN must exceed VOUT + 2.5V (i.e., ≥7.5V) for reliable 1.3A output. At 5V input, maximum usable output current drops significantly and is not characterized; the datasheet specifies VIN(min) = VOUT + 2.5V or 4V, whichever is greater.

Does the MIC4680-5.0BM require external compensation components?

No - the MIC4680-5.0BM features fully internal frequency compensation optimized for stability with standard 68µH inductors and 220µF output capacitors. The datasheet explicitly states "internally compensated with fast transient response" and shows stable Bode plots using only L, COUT, CIN, and D1. No external RC networks or compensation pins are present or needed.

What thermal design guidance applies to the MIC4680-5.0BM's Power SOIC-8 package?

The MIC4680-5.0BM uses a Power SOIC-8 where pins 5–8 and the die-attach paddle are electrically and thermally common. To achieve the rated θJA of 63°C/W, these pins must connect to a minimum 6 cm² PCB ground plane - distributed across layers if needed - with low-impedance vias. Layout Figure 2 and Thermal Considerations section confirm that thermal performance scales directly with copper area attached to pins 5–8.

Is the MIC4680-5.0BM pin-compatible with other MIC4680 variants like the MIC4680-3.3BM or MIC4680BM (adjustable)?

Yes - all MIC4680 variants, including MIC4680-5.0BM, MIC4680-3.3BM, and MIC4680BM, share identical 8-pin Power SOIC (M) pinout and mechanical footprint. Pin functions (SHDN, IN, SW, FB, GND×4) are identical across versions; only internal feedback network differs. This allows direct substitution in layouts where output voltage requirements change, provided input/output capacitor ratings remain appropriate.