Microchip Technology MCP1812AT-018/LT

Overview

MCP1812AT-018/LT from Microchip Technology is an ultra-low quiescent current (250 nA typical), 300 mA output, fixed 1.8 V low-dropout linear regulator in a 3-lead SOT-23 package, designed for energy harvesting and long-life battery-powered systems where sleep-mode power budget is critical.

For engineers reviewing the MCP1812AT-018/LT datasheet, MCP1812AT-018/LT pinout, MCP1812AT-018/LT application, or MCP1812AT-018/LT equivalent, this page delivers verified electrical specs, thermal performance, shutdown behavior, ceramic capacitor stability requirements, and real-world use cases in wearable and medical edge devices.

Technical Context

The MCP1812AT-018/LT implements a PMOS pass transistor architecture enabling ultra-low IQ operation and fast transient response. It features integrated output discharge (DT switch) during shutdown, active overcurrent protection with foldback, and stable regulation across –40°C to +85°C junction temperature.

Its 1.8 V output is factory-trimmed to ±4% tolerance at 1 mA load, with dropout voltage ≤600 mV at 300 mA output. Input voltage range is 2.4 V to 5.5 V under full-load conditions, and it requires only 2.2 µF ceramic output capacitance for stability.

Key Specifications

Pinout & Package

Package: 3-Lead SOT-23 (SC-59), JEDEC MO-178AA, 2.92 mm × 1.3 mm × 1.0 mm body, thermally enhanced with exposed pad (not electrically connected in this variant).

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6219B182MR-G and RP114K181D-TR-F, the MCP1812AT-018/LT uniquely combines 300 mA capability, 10 nA shutdown, and integrated output discharge-making it the only choice for high-current, zero-leakage, actively discharged 1.8 V rails in space- and power-constrained designs.

Availability

MCP1812AT-018/LT is available at Aetrix Electronics and suitable for energy harvesting nodes, wearable medical sensors, and hearing aids requiring stable component supply with guaranteed long-term manufacturability and traceable sourcing.

Supply support for MCP1812AT-018/LT 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 timing solutions, serving automotive, industrial, communications, and consumer markets with vertically integrated silicon and software platforms.

The MCP1812AT-018/LT belongs to Microchip's ultra-low-power LDO family, engineered specifically for battery longevity in intermittent-operation edge devices-prioritizing nanoscale quiescent current, ceramic capacitor compatibility, and robust shutdown behavior over raw speed or high-voltage tolerance.

FAQ

What is the minimum input voltage required for the MCP1812AT-018/LT to deliver full 300 mA output?

The MCP1812AT-018/LT requires a minimum input voltage of 2.4 V to sustain 300 mA output while maintaining regulation. This is derived from its maximum dropout voltage of 600 mV at 300 mA plus the 1.8 V nominal output, ensuring stable operation down to end-of-life battery voltages in single-cell Li-ion or dual-alkaline systems. Below 2.4 V, output current capability degrades progressively.

Does the MCP1812AT-018/LT require an external shutdown control signal, and what logic levels trigger it?

Yes-the MCP1812AT-018/LT includes a dedicated SHDN pin (not present in the 3-lead SOT-23 package). However, the /LT suffix indicates this variant is the *non-shutdown* version: it lacks the SHDN pin entirely and operates continuously when powered. For shutdown functionality, engineers must select variants like MCP1812AT-018/OT (5-lead SOT-23) instead. The MCP1812AT-018/LT is always-on.

Can the MCP1812AT-018/LT be used with a 1 µF output capacitor, or is 2.2 µF mandatory?

A 2.2 µF ceramic (X7R) output capacitor is mandatory for stability across all operating conditions of the MCP1812AT-018/LT. While the MCP1811X series supports 1.0 µF, the MCP1812X family-including the MCP1812AT-018/LT-requires 2.2 µF minimum to ensure phase margin >45° and prevent oscillation under dynamic load steps up to 300 mA. Using 1 µF risks instability and output overshoot.

What is the thermal resistance (θJA) of the MCP1812AT-018/LT in its SOT-23 package, and how does it affect power dissipation?

The MCP1812AT-018/LT in 3-lead SOT-23 has a θJA of 211.33°C/W on a JEDEC-standard 4-layer FR4 board with 1 oz. copper. At 300 mA output and 2.4 V input (0.6 V dropout), power dissipation is 180 mW, resulting in a junction-to-ambient rise of ~38°C. With 25°C ambient, junction temperature reaches ~63°C-well below the +85°C max rating, confirming safe continuous operation without heatsinking.

How does the output discharge feature behave in the MCP1812AT-018/LT, and is it enabled by default?

The MCP1812AT-018/LT does not include output discharge functionality. That feature is exclusive to the "A" suffix variants (e.g., MCP1812A), which have a 5-lead package with SHDN pin. The "T" suffix in MCP1812AT denotes the A-version, but the "/LT" package code confirms it is the 3-lead SOT-23 variant-lacking both SHDN and discharge transistor. Therefore, the MCP1812AT-018/LT has no output discharge capability; VOUT floats after input removal.