Microchip Technology MIC79050-4.2BM-TR

Overview

MIC79050-4.2BM-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 Power SOIC-8 package - used in compact portable Li-ion systems requiring precise end-of-charge termination.

For engineers reviewing the MIC79050-4.2BM-TR datasheet, MIC79050-4.2BM-TR pinout, MIC79050-4.2BM-TR application, or MIC79050-4.2BM-TR equivalent, key selection criteria include battery voltage tolerance, dropout performance under load, enable logic compatibility, reverse leakage (<10 µA), and thermal resistance (θ_JA = 63°C/W) for sustained 500 mA operation.

Technical Context

The MIC79050-4.2BM-TR implements a high-precision linear charging architecture using an internal PNP pass transistor and bandgap-referenced error amplifier. Its feedback loop regulates BAT output to exactly 4.2 V by comparing FB node voltage against 1.225 V internal reference, enabling accurate constant-voltage charge termination critical for Li-ion cell longevity.

It features dual-stage protection: foldback current limiting (750–1000 mA) and thermal shutdown triggered above +125°C junction temperature. The EN pin (TTL/CMOS-compatible) allows external control of charging state, reducing quiescent ground current to ≤0.1 µA in shutdown mode while maintaining <12 µA reverse battery leakage.

Key Specifications

Pinout & Package

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

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS650230RSLR and MCP73831T-2DCI/OT, the MIC79050-4.2BM-TR offers superior thermal resistance (63°C/W), integrated enable functionality, and tighter voltage accuracy over the Li-ion charging temperature range - making it optimal for thermally constrained, high-reliability portable designs requiring simple, robust charging.

Availability

MIC79050-4.2BM-TR is available at Aetrix Electronics and suitable for smartphone battery management, wearable health monitors, industrial handheld scanners, and medical point-of-care devices requiring stable component supply and long-term production continuity.

Supply support for MIC79050-4.2BM-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 is a U.S.-based semiconductor manufacturer specializing in microcontrollers, analog, and mixed-signal ICs for embedded control, power management, and timing applications.

The MIC79050 product line delivers highly accurate, thermally robust linear Li-ion chargers optimized for portable electronics where simplicity, safety, and precision charge termination are critical - targeting space- and power-constrained battery-powered systems.

FAQ

What is the maximum continuous output current of the MIC79050-4.2BM-TR?

The MIC79050-4.2BM-TR is rated for 500 mA continuous output current at 4.2 V with proper PCB thermal design. Its current-limit threshold is 750–1000 mA, but sustained operation above 500 mA requires careful thermal management due to power dissipation (e.g., 5 V input → 4.2 V @ 500 mA yields 400 mW loss). The MIC79050-4.2BM-TR datasheet specifies 500 mA as the guaranteed operational limit under standard SOIC-8 thermal conditions.

Does the MIC79050-4.2BM-TR support adjustable output voltage?

No, the MIC79050-4.2BM-TR is a fixed 4.2 V output device. While the FB pin allows external manipulation (e.g., pulling low to disable output), it does not support programmable voltage adjustment via resistor dividers like adjustable regulators. The "-4.2" suffix explicitly denotes its factory-trimmed 4.2 V output. For variable-output Li-ion charging, Microchip offers the MIC79051 family, but the MIC79050-4.2BM-TR itself provides only fixed 4.2 V regulation.

How does the MIC79050-4.2BM-TR handle reverse battery connection?

The MIC79050-4.2BM-TR includes inherent reversed-battery protection: when IN is disconnected or grounded, reverse current from BAT to IN is limited to <12 µA. This prevents battery discharge and protects internal circuitry during incorrect installation or field servicing. This behavior is confirmed in the datasheet's General Description and Figure 2-14/2-15 reverse leakage curves - a key safety feature distinguishing it from basic LDOs.

What is the thermal shutdown trigger temperature for the MIC79050-4.2BM-TR?

The MIC79050-4.2BM-TR activates thermal shutdown at a junction temperature of +125°C, as specified in the Temperature Specifications table (DS20005771B-page 5). Once triggered, the device halts charging until junction temperature falls below the hysteresis threshold (~15°C below trip point). This protects both the MIC79050-4.2BM-TR and connected Li-ion cell from thermal runaway during overload or inadequate heatsinking.

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

No - the MIC79050-4.2BM-TR requires a minimum input voltage of 2.5 V, but to regulate 4.2 V output, VIN must exceed V_BAT by at least the dropout voltage. At 500 mA, dropout is 380 mV; thus, 3.3 V input is insufficient (3.3 V − 4.2 V = −0.9 V). Valid operation requires VIN ≥ 4.58 V (4.2 V + 380 mV) for full-load regulation. The MIC79050-4.2BM-TR is intended for 5 V+ adapters or higher-input industrial rails.