Microchip Technology MIC4680-3.3YM-TR

Overview

MIC4680-3.3YM-TR from Micrel is a fixed-output 3.3V, 1.3A synchronous buck regulator in an 8-pin Power SOIC package, operating at 200kHz with 4V–34V input range and internal compensation. It integrates an NPN power switch, thermal shutdown, cycle-by-cycle current limiting, and delivers up to 90% efficiency in high-density DC/DC conversion for industrial power rails.

For engineers reviewing the MIC4680-3.3YM-TR datasheet, MIC4680-3.3YM-TR pinout, MIC4680-3.3YM-TR application, or MIC4680-3.3YM-TR equivalent, key selection criteria include its fixed 3.3V output accuracy (±1%), shutdown current <2µA, saturation voltage ≤1.8V at 1A, thermal shutdown at 160°C, and compatibility with standard 68µH inductors and Schottky diodes in minimal external-component designs.

Technical Context

The MIC4680-3.3YM-TR implements voltage-mode control using a 200kHz oscillator and a 1.23V bandgap reference, comparing feedback against a fixed internal resistor divider tied to the FB pin. Its duty cycle adjusts dynamically to maintain regulation across line (4V–34V) and load (0–1.3A) variations.

Protection architecture includes cycle-by-cycle current limiting (1.3A min), thermal shutdown at 160°C, and logic-level TTL-compatible SHDN input with hysteresis (0.8V–1.6V). The Power SOIC-8 package uses pins 5–8 as a unified ground paddle for low θJA (63°C/W) and enhanced thermal dissipation.

Key Specifications

Pinout & Package

Package: 8-pin Power SOIC (M), with integrated thermal paddle connected to pins 5–8 (GND); rated for –40°C to +125°C junction temperature.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM2675-3.3 and TPS5430DDAR, the MIC4680-3.3YM-TR delivers optimal trade-offs for fixed 3.3V applications: lowest component count, smallest PCB footprint among 1.3A SOIC buck regulators, and proven thermal performance without heatsinks-making it ideal for space-constrained industrial and embedded deployments.

Availability

MIC4680-3.3YM-TR is available at Aetrix Electronics and suitable for industrial power supplies, embedded controller rails, and POS terminal designs requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for MIC4680-3.3YM-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 analog and mixed-signal semiconductor company founded in 1978 and acquired by Microchip Technology in 2015; known for high-reliability power management and interface ICs.

The MIC4680 family was designed as a drop-in replacement for linear regulators and legacy switching solutions in industrial and embedded systems-emphasizing ease of use, minimal external components, and rugged thermal performance in SOIC packaging.

FAQ

What is the maximum continuous output current of the MIC4680-3.3YM-TR?

The MIC4680-3.3YM-TR delivers up to 1.3A continuous output current under proper thermal conditions: ≥6 cm² ground plane connected to pins 5–8, ambient temperature ≤65°C, and 12V input. At higher input voltages (e.g., 24V), output current must be reduced to maintain junction temperature below 125°C-refer to Figure 3 in the datasheet for derating curves. The MIC4680-3.3YM-TR achieves this with internal current limiting and thermal shutdown at 160°C.

Does the MIC4680-3.3YM-TR require external feedback resistors?

No-the MIC4680-3.3YM-TR is a fixed-output variant with an internal resistor divider connected to the FB pin, so the FB pin is directly tied to the 3.3V output. This eliminates external feedback components, simplifies layout, and guarantees ±1% output accuracy across temperature and load. The MIC4680-3.3YM-TR differs from adjustable versions (e.g., MIC4680BM) which require R1/R2 networks to set V_OUT.

What is the recommended input capacitor for the MIC4680-3.3YM-TR?

A 15µF/35V low-ESR tantalum or ceramic capacitor (e.g., AVX TPSE156035R0200) is recommended at the VIN pin, placed as close as possible to pin 2 and pins 5–8. This minimizes high-frequency switching noise and prevents input rail collapse during peak current demand. The MIC4680-3.3YM-TR's internal switch transitions cause rapid dI/dt, making low-inductance placement critical-failure to follow this degrades efficiency and may trigger overcurrent protection.

Can the MIC4680-3.3YM-TR operate with a 5V input?

Yes-the MIC4680-3.3YM-TR supports input voltages from 4V to 34V, so 5V is within specification. However, minimum input is defined as V_OUT + 2.5V = 5.8V for full 1.3A output; at 5V input, maximum continuous output current is reduced due to insufficient headroom for the internal NPN switch's saturation voltage (≤1.8V). Derated current at 5V input is approximately 0.5A-verify with thermal measurements in actual application. The MIC4680-3.3YM-TR remains functional but cannot sustain full-rated load.

How does the shutdown function work on the MIC4680-3.3YM-TR?

The SHDN pin (pin 1) is TTL-compatible: pulling it low (≤0.8V) enables regulation; pulling it high (≥1.6V) disables the internal switch and reduces quiescent current to 30µA typical. Hysteresis between turn-on (0.8V) and turn-off (1.6V) prevents oscillation near threshold. When unused, SHDN must be grounded-leaving it floating may cause erratic behavior. The MIC4680-3.3YM-TR enters true shutdown mode with no switching activity and minimal power draw, ideal for battery-powered sleep states.