Microchip Technology MIC79050-4.2YMM-TR

Overview

MIC79050-4.2YMM-TR from Microchip Technology is a fixed-output 4.2 V linear lithium-ion battery charger IC with ±0.75% voltage accuracy over –5°C to +60°C, 380 mV dropout at 500 mA, and integrated thermal shutdown/current-limit protection. It operates from 2.5 V to 16 V input and delivers up to 500 mA charging current in thermally enhanced MSOP-8 package - used in compact portable Li-ion power systems including cellular phones and palmtop computers.

For engineers reviewing the MIC79050-4.2YMM-TR datasheet, MIC79050-4.2YMM-TR pinout, MIC79050-4.2YMM-TR application, or MIC79050-4.2YMM-TR equivalent, this page provides verified functional identity, validated 8-pin MSOP package mapping, confirmed Li-ion termination accuracy and dropout performance, real-world pulse-charging capability, and two manufacturer-validated alternative parts for design flexibility.

Technical Context

The MIC79050-4.2YMM-TR implements a high-precision linear charging architecture using an internal PNP pass transistor controlled by a bandgap-referenced error amplifier. Its feedback (FB) and enable (EN) pins support external regulation and system-level charge control - enabling constant-current/constant-voltage (CC/CV) charging without external op-amps in basic configurations.

It features dual-stage protection: foldback current limiting (750–1000 mA) and thermal shutdown triggered above +125°C junction temperature. Reverse leakage is limited to ≤10 µA when input is floating or grounded, preserving battery standby life. The device maintains 0.05%/W thermal regulation and 75 dB ripple rejection at 120 Hz.

Key Specifications

Pinout & Package

Package: 8-lead thermally enhanced MSOP (YMM), with exposed thermal pad connected to GND. Pin 1 = EN, Pin 2 = IN, Pin 3 = BAT, Pin 4 = FB, Pins 5–8 = GND (internally tied).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar lithium-ion linear charger applications.

Compared with MCP73831T-2DCI/OT and BQ24075RGTR, the MIC79050-4.2YMM-TR uniquely balances precision (±0.75%), ultra-low dropout (380 mV), and programmability (EN/FB) in a thermally optimized MSOP-8 - making it optimal for mid-power, thermally sensitive, or pulse-charged Li-ion systems where accuracy and control flexibility outweigh raw current capability.

Availability

MIC79050-4.2YMM-TR is available at Aetrix Electronics and suitable for cellular phone charging, palmtop computer power management, and self-charging battery packs requiring stable component supply, long-lifecycle support, and consistent parametric performance across production batches.

Supply support for MIC79050-4.2YMM-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

Microchip Technology Inc. is a U.S.-based semiconductor company specializing in microcontrollers, analog devices, and power management ICs, with broad industrial and consumer market reach.

The MIC79050 product line delivers highly accurate, thermally robust linear Li-ion chargers targeting cost-sensitive, space-constrained portable electronics where ±0.75% voltage accuracy and zero-off current are essential.

FAQ

What is the exact output voltage tolerance of the MIC79050-4.2YMM-TR over temperature?

The MIC79050-4.2YMM-TR guarantees ±0.75% battery voltage accuracy over the Li-ion charging temperature range of –5°C to +60°C. This specification is measured at the BAT pin with VIN = VBAT + 1.0 V and IOUT = 100 µA to 500 mA. At 25°C, typical drift is ±0.25%, and worst-case variation remains within ±0.75% across the full –40°C to +125°C operating junction range.

Does the MIC79050-4.2YMM-TR support external current limiting or only fixed internal current limit?

The MIC79050-4.2YMM-TR features a fixed internal current limit of 750–1000 mA (typical 900 mA) that activates when VBAT ≈ 0 V. It does not support externally adjustable current limiting. However, the FB pin enables external PWM modulation to effectively control average charge current - allowing designers to implement programmable current profiles without modifying the IC's internal limit threshold.

Can the MIC79050-4.2YMM-TR be used with a 3.3 V input supply?

No - the MIC79050-4.2YMM-TR requires a minimum input voltage of 2.5 V, but its 4.2 V output and 380 mV dropout require VIN ≥ 4.58 V to sustain full 500 mA output. At 3.3 V input, the device enters dropout and cannot regulate 4.2 V; output follows VIN minus saturation voltage (~0.6–0.8 V), delivering ~2.5–2.7 V. For 3.3 V input systems, a boost converter or different charger IC is required.

How does the EN pin behavior differ between MIC79050-4.2YMM-TR and the 3-lead SOT-223 version?

The EN pin is exclusive to the 8-lead versions (MIC79050-4.2YMM-TR and MIC79050-4.2YM). The 3-lead SOT-223 variant (MIC79050-4.2YS) has no EN pin and remains permanently enabled. When EN ≤ 0.18 V on the MIC79050-4.2YMM-TR, ground current drops to ≤0.1 µA and BAT floats to battery voltage - enabling true zero-power shutdown not available in the 3-lead variant.

Is the MIC79050-4.2YMM-TR RoHS compliant and lead-free?

Yes - the MIC79050-4.2YMM-TR is RoHS compliant and lead-free per Microchip's standard packaging. The "YMM" suffix denotes the thermally enhanced MSOP-8 package with lead-free matte tin finish, qualified to JEDEC J-STD-020 moisture sensitivity level 1 (MSL1), and compatible with standard Pb-free reflow profiles.