Microchip Technology MIC4680YM-TR

Overview

MIC4680YM-TR from Micrel is a fixed-frequency, internally compensated 200 kHz buck regulator with integrated 1.3A NPN switch, operating from 4V to 34V input and delivering adjustable output down to 1.25V (typical feedback voltage 1.23V). It features thermal shutdown, cycle-by-cycle current limiting, <2 µA shutdown quiescent current, and SOIC-8 power package for high-efficiency step-down conversion in industrial power supplies.

For engineers reviewing the MIC4680YM-TR datasheet, MIC4680YM-TR pinout, MIC4680YM-TR application, or MIC4680YM-TR equivalent, key selection criteria include its 200 kHz fixed switching frequency, internal compensation eliminating external compensation components, 1.23V feedback reference accuracy (±1%), wide 4–34V input range, and thermal/overcurrent protection architecture - all validated for use in on-card regulators and pre-regulators requiring stable 1A output.

Technical Context

The MIC4680YM-TR implements voltage-mode control using a 1.23V bandgap reference and error amplifier comparing FB voltage against that reference; the resulting error signal modulates duty cycle via comparison with a 200 kHz sawtooth oscillator waveform. It integrates an NPN power switch with 1.4–1.8V saturation voltage at 1A load.

Protection functions include cycle-by-cycle current limiting (1.3–2.5A short-circuit limit), thermal shutdown at 160°C, and TTL-compatible SHDN input with 0.8V/1.6V logic thresholds and hysteresis. Frequency foldback (30–100 kHz) activates under hard short-circuit conditions to reduce per-cycle energy dissipation.

Key Specifications

Pinout & Package

Package: 8-pin Power-SOIC (SOIC-8 with enhanced thermal pad structure; pins 5–8 and die paddle form single low-θ_JA ground path; θ_JA = 63°C/W on 1"² FR4 board).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM2678-5.0/NOPB and TPS5430DR, the MIC4680YM-TR offers unique integration of adjustable output, internal compensation, and robust 1.3A capability in SOIC-8 - making it optimal for cost-sensitive, space-constrained industrial buck designs where simplicity and proven stability are prioritized over maximum current or ultra-high frequency.

Availability

MIC4680YM-TR is available at Aetrix Electronics and suitable for industrial power supplies, on-card DC-DC converters, and battery charger circuits requiring stable component supply with long-term lifecycle visibility.

Supply support for MIC4680YM-TR 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 semiconductor company specializing in power management, analog, and timing ICs, acquired by Microchip Technology in 2015.

The MIC4680YM-TR belongs to Micrel's SuperSwitcher™ family of integrated buck regulators, designed specifically for simple, high-efficiency, low-component-count step-down conversion in industrial and embedded systems.

FAQ

What is the feedback reference voltage of the MIC4680YM-TR and how does it affect output adjustment?

The MIC4680YM-TR has a precision 1.23 V ±1% internal feedback reference voltage. This value determines output voltage via the external resistor divider on the FB pin: V_OUT = 1.23 × (1 + R1/R2). Its tight tolerance ensures accurate output regulation across temperature and load, enabling reliable 3.3V or 5V generation or custom voltages down to 1.25V without trimming. The MIC4680YM-TR's reference stability directly defines system accuracy in adjustable configurations.

Can the MIC4680YM-TR operate with input voltages below 4V?

No - the MIC4680YM-TR specifies a minimum operating input voltage of 4V per its Absolute Maximum and Operating Ratings. Below this, the internal regulator cannot sustain bias, leading to erratic switching or dropout. For sub-4V applications, such as single-cell Li-ion (2.7–4.2V), the MIC4680YM-TR is not suitable; alternative low-V_IN buck regulators like the TPS62130 should be considered. The MIC4680YM-TR is engineered for industrial 12V/24V/32V rails.

How does the MIC4680YM-TR handle thermal overload, and what is the shutdown threshold?

The MIC4680YM-TR incorporates thermal shutdown that activates at 160°C junction temperature, protecting the die during sustained overload or inadequate PCB cooling. Once triggered, regulation halts and the device remains off until junction temperature falls below the hysteresis threshold (~145°C). This behavior is confirmed in Electrical Characteristics and Functional Description sections. The MIC4680YM-TR's Power-SOIC-8 package relies on pins 5–8 connected to a ≥6 cm² ground plane to maintain safe operation at full 1.3A load.

Is the MIC4680YM-TR pin-compatible with other versions like MIC4680-3.3YM or MIC4680-5.0YM?

Yes - the MIC4680YM-TR is functionally and physically pin-compatible with MIC4680-3.3YM and MIC4680-5.0YM. All share identical SOIC-8 Power-SOIC packaging, pinout (SHDN, VIN, SW, FB, GND×4), and electrical interface. The only difference is internal feedback divider configuration: MIC4680YM-TR is adjustable (FB open), while -3.3YM and -5.0YM have fixed internal dividers. No PCB changes are needed when substituting between these variants.

What external components are mandatory for basic operation of the MIC4680YM-TR?

Four external components are mandatory: input capacitor (≥15 µF, 35V), output capacitor (≥220 µF, 16V), power inductor (68 µH, 1.5A), and Schottky catch diode (e.g., B260A or SS26). These are specified in Typical Application circuits and confirmed in Applications Information. The MIC4680YM-TR requires no additional compensation or timing components due to internal compensation and fixed 200 kHz oscillator - enabling minimal BOM count and rapid prototyping.