Microchip Technology MCP1811AT-020/LT

Overview

MCP1811AT-020/LT from Microchip Technology is a 150 mA ultra-low-quiescent-current LDO regulator with fixed 2.0 V output, 250 nA typical IQ, and output discharge functionality (MCP1811A variant), housed in a 4-lead 1×1 mm UDFN package. It operates from 1.8 V to 5.5 V input, supports ceramic output capacitors as low as 1.0 µF, and delivers stable voltage for energy-constrained systems such as wearable sensors and medical hearing aids.

For engineers reviewing the MCP1811AT-020/LT datasheet, MCP1811AT-020/LT pinout, MCP1811AT-020/LT application, or MCP1811AT-020/LT equivalent, this page provides verified technical context, package-specific pin functions, real-world use cases in battery longevity-critical designs, and validated alternative options for ultra-low-power LDO selection.

Technical Context

The MCP1811AT-020/LT implements a PMOS pass transistor architecture enabling ultra-low dropout voltage (400 mV typical at 150 mA) and minimal ground current (90–110 µA across load). Its internal error amplifier and reference maintain ±4% output accuracy over –40°C to +85°C junction temperature while supporting fast start-up (400 µs delay from SHDN) and dynamic load response.

It integrates an active discharge transistor (RDCH = 100 Ω typical) that pulls VOUT to GND during shutdown (SHDN = GND), preventing residual voltage hold-up in power-gated subsystems. The device is optimized for stability with 1 µF X7R ceramic output capacitance and exhibits –50 dB PSRR at 1 kHz without input capacitor.

Key Specifications

Pinout & Package

Package: 4-Lead 1×1 mm UDFN with exposed thermal pad (EP). Optimized for high thermal efficiency on compact PCBs with thermal vias.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1811AT-020/OT, the MCP1811AT-020/LT adds active shutdown and output discharge in a smaller UDFN package-enabling tighter power control in space-constrained, battery-sensitive designs. Versus XC6210B202MR-G, it provides guaranteed discharge functionality and tighter input voltage lower limit (1.8 V vs. 1.7 V), making it more robust for weak-energy sources.

Availability

MCP1811AT-020/LT is available at Aetrix Electronics and suitable for energy harvesting, wearable electronics, and medical device applications requiring stable component supply with long-term lifecycle assurance.

Supply support for MCP1811AT-020/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, mixed-signal, analog, and Flash-IP solutions, serving automotive, industrial, consumer, and communications markets with high-reliability semiconductor products.

The MCP1811/12 family targets ultra-low-power portable and energy-harvesting systems, delivering regulated voltage with nanoscale quiescent current and minimal external components-designed specifically for multi-year battery life in sensing and edge-compute endpoints.

FAQ

What is the maximum continuous output current of the MCP1811AT-020/LT?

The MCP1811AT-020/LT delivers a maximum continuous output current of 150 mA under specified thermal conditions. This rating assumes adequate PCB copper area and thermal vias beneath the exposed pad to maintain junction temperature ≤+85°C. At higher ambient temperatures or reduced copper, derating applies per the 91.05°C/W θJA value for the 1×1 mm UDFN package.

Does the MCP1811AT-020/LT require an input capacitor?

The MCP1811AT-020/LT does not require an input capacitor for stability, though a 1 µF ceramic capacitor placed close to the VIN pin improves PSRR and transient response. The datasheet confirms stable operation with CIN = 0 µF in PSRR testing, making it suitable for space-constrained or ultra-low-leakage designs where input capacitance must be minimized.

How does the output discharge function operate in the MCP1811AT-020/LT?

In the MCP1811AT-020/LT, pulling SHDN low activates an internal NMOS discharge switch (RDCH = 100 Ω typical) between VOUT and GND. This discharges the output capacitor rapidly-typically reducing VOUT from 2.0 V to <100 mV in under 1 ms with a 1 µF load-eliminating residual voltage that could interfere with downstream power sequencing or cause latch-up in connected ICs.

Can the MCP1811AT-020/LT be used with a 1.5 V input supply?

No-the MCP1811AT-020/LT has a minimum input voltage specification of 1.8 V. At 1.5 V input, the device will not regulate and VOUT will follow VIN minus dropout (which itself increases sharply below 1.8 V). For sub-1.8 V sources, consider energy harvesting boost regulators followed by the MCP1811AT-020/LT, or alternate LDOs rated for lower VIN such as the TPS780xx series.

What is the thermal resistance (θJA) of the MCP1811AT-020/LT package?

The MCP1811AT-020/LT in its 4-lead 1×1 mm UDFN package has a JEDEC-standard θJA of 91.05°C/W when mounted on a 4-layer FR4 board with 1 oz. copper and thermal vias under the exposed pad. This value assumes optimal layout; omitting vias or reducing copper area increases θJA significantly-potentially limiting max output current in high-ambient environments.