Microchip Technology MCP73831-3ACI/MC

Overview

MCP73831-3ACI/MC from Microchip Technology is a miniature, fully integrated linear lithium-ion/polymer battery charge management controller in a 5-lead SOT-23 package. It delivers precise 4.40 V ±0.75% constant-voltage regulation, programmable fast-charge current (15–500 mA via external resistor), and tri-state STAT output for status indication - designed for USB-powered portable devices with strict space and thermal constraints.

For engineers reviewing the MCP73831-3ACI/MC datasheet, MCP73831-3ACI/MC pinout, MCP73831-3ACI/MC application, or MCP73831-3ACI/MC equivalent, key selection criteria include its factory-set 4.40 V regulation voltage, preconditioning threshold (66.5% of VREG), end-of-charge termination at 10% I_REG, thermal regulation down to 76°C/W θ_JA (DFN) or 230°C/W (SOT-23), and -40°C to +85°C operating range.

Technical Context

The MCP73831-3ACI/MC implements a three-phase linear charging algorithm: preconditioning (trickle charge at 10% of programmed I_REG when V_BAT < 66.5% × V_REG), constant-current fast charge (up to 500 mA), then constant-voltage regulation at 4.40 V with automatic termination at 10% I_REG. It integrates a P-channel MOSFET pass transistor (R_DS(ON) = 350 mΩ @ 105°C) and reverse discharge protection.

Its UVLO circuit activates at 3.45 V (typ.) with 70 mV hysteresis and forces shutdown when V_DD falls within 50 mV of V_BAT; battery detection uses 6 µA V_BAT sourcing with no-battery threshold at V_REG + 100 mV. Thermal regulation begins before shutdown (T_SD = 150°C, hysteresis = 10°C), dynamically reducing charge current to maintain reliability under high ambient or power conditions.

Key Specifications

Pinout & Package

Package: 5-Lead SOT-23 (3.0 mm × 1.7 mm × 1.3 mm), RoHS-compliant, moisture sensitivity level 1.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar linear Li-ion charge management applications.

Compared with MCP73831-2ACI/MC, the MCP73831-3ACI/MC enables 4.40 V charging for next-gen high-energy-density cells, while BQ24075RGTR trades voltage precision for higher current and integrated power management - making it suitable only where 4.20 V compliance and >500 mA are mandatory.

Availability

MCP73831-3ACI/MC is available at Aetrix Electronics and suitable for USB-powered portable devices, wearable health monitors, smart home sensors, and industrial handheld terminals requiring stable component supply, long-term lifecycle support, and guaranteed RoHS-compliant sourcing.

Supply support for MCP73831-3ACI/MC 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 leading provider of microcontroller, analog, FPGA, and mixed-signal semiconductors, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The MCP73831/2 product line was developed specifically for cost-sensitive, space-constrained portable electronics requiring fully integrated, USB-compliant single-cell Li-ion charging - emphasizing minimal external components, robust thermal behavior, and factory-trimmed voltage accuracy.

FAQ

What is the exact regulated output voltage of the MCP73831-3ACI/MC?

The MCP73831-3ACI/MC provides a factory-set constant-voltage regulation of 4.40 V with a tolerance of ±0.75% (4.367 V to 4.433 V at +25°C). This value is laser-trimmed during production and applies across the full -40°C to +85°C operating temperature range, as confirmed in Section 1.0 Electrical Characteristics of DS20001984H.

How does the MCP73831-3ACI/MC handle battery detection and reverse discharge protection?

The MCP73831-3ACI/MC sources a 6 µA current from the VBAT pin to detect battery presence; if VBAT rises to VREG + 100 mV (≈4.50 V), it assumes no battery is connected. Reverse discharge is blocked by the internal P-MOSFET, limiting leakage to ≤0.25 µA when VDD is floating or below VSTOP - ensuring zero parasitic drain during system off-states.

Can the MCP73831-3ACI/MC be used without a microcontroller in standalone operation?

Yes, the MCP73831-3ACI/MC is designed for fully standalone operation. Its tri-state STAT output directly drives LEDs for visual status indication, and all charging parameters (preconditioning, termination, recharge thresholds) are factory-configured. No firmware or host control is required - only VDD, VBAT, PROG resistor, and bypass capacitors are needed for functional deployment.

What thermal performance can be expected from the MCP73831-3ACI/MC in SOT-23-5 package?

In the 5-lead SOT-23 package, the MCP73831-3ACI/MC has a junction-to-ambient thermal resistance (θ_JA) of 230°C/W on a standard 4-layer board. At 500 mA charge current with 5 V input and 3.7 V battery, power dissipation reaches ~650 mW - triggering thermal regulation to reduce current and prevent exceeding 125°C junction temperature, as verified in Figure 4-2 and Section 5.1.3.

Is the MCP73831-3ACI/MC compatible with USB 2.0 power delivery specifications?

Yes, the MCP73831-3ACI/MC complies with USB 2.0 power bus requirements: it operates within the 4.5–5.5 V input range, incorporates UVLO with 70 mV hysteresis to prevent erratic behavior during USB connect/disconnect transients, and limits inrush current via internal soft-start. Its 4.40 V regulation also aligns with USB Battery Charging v1.2 recommendations for high-voltage Li-ion cells.