Microchip Technology MCP1811BT-018/LB

Overview

MCP1811BT-018/LB from Microchip Technology is an ultra-low quiescent current (250 nA typical), 150 mA low-dropout linear regulator with fixed 1.8 V output, designed for battery-powered systems requiring multi-year operation. It operates from 1.8 V to 5.5 V input, supports ceramic output capacitors as small as 1.0 µF, and features 5 nA typical shutdown current - ideal for energy harvesting and wearable electronics.

For engineers reviewing the MCP1811BT-018/LB datasheet, MCP1811BT-018/LB pinout, MCP1811BT-018/LB application, or MCP1811BT-018/LB equivalent, this page delivers verified electrical specs, package mapping to 4-lead 1×1 mm UDFN, thermal resistance data (θ_JA = 91.05°C/W), dropout voltage (400–600 mV at 150 mA), and real-world use context for ultra-low-power system design.

Technical Context

The MCP1811BT-018/LB implements a PMOS pass transistor architecture enabling ultra-low IQ while maintaining stable regulation across load (0–150 mA) and temperature (–40°C to +85°C). Its internal error amplifier and reference are optimized for sub-µA bias currents, and the device includes foldback overcurrent protection and thermal shutdown.

Unlike MCP1811A variants, the "B" suffix denotes no output discharge during shutdown - eliminating unintended capacitor discharge paths in precision-sleep applications. The /LB suffix confirms the 4-lead 1×1 mm UDFN package with exposed thermal pad, supporting high-density PCB layouts and improved thermal performance on JEDEC-standard 4-layer boards.

Key Specifications

Pinout & Package

Package: 4-lead 1×1 mm UDFN with exposed thermal pad (EP), optimized for space-constrained PCBs and thermal performance (θ_JA = 91.05°C/W on JEDEC 4-layer board).

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6210B182MR-G and RP114K181D-TR-F, the MCP1811BT-018/LB uniquely combines 5 nA shutdown, 150 mA capability, and 91°C/W thermal resistance in a 1×1 mm UDFN - making it optimal for space- and energy-constrained applications demanding multi-year battery life and robust thermal management.

Availability

MCP1811BT-018/LB is available at Aetrix Electronics and suitable for energy harvesting nodes, wearable medical sensors, hearing aids, smart cards, and ultra-low-power industrial monitoring systems requiring stable component supply and long-term lifecycle support.

Supply support for MCP1811BT-018/LB 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 microcontrollers, analog devices, and Flash-IP solutions, serving automotive, industrial, consumer, and communications markets with high-reliability silicon and development tools.

The MCP1811/1812 family was engineered specifically for ultra-low-power battery and energy-harvesting applications - prioritizing nanoscale quiescent current, minimal external components, and robust operation across wide temperature and load ranges.

FAQ

What is the maximum input voltage rating for the MCP1811BT-018/LB?

The MCP1811BT-018/LB has an absolute maximum input voltage rating of +6.0 V. However, its specified operating input range is 1.8 V to 5.5 V. Exceeding 5.5 V may cause permanent damage or violate reliability specifications, even if below the 6.0 V absolute limit. Always maintain VIN ≤5.5 V in normal operation.

Does the MCP1811BT-018/LB include output discharge functionality during shutdown?

No, the MCP1811BT-018/LB does not include output discharge. As indicated by the "B" suffix in its part number, it belongs to the MCP1811B variant family, which omits the discharge transistor (DT) present in MCP1811A devices. This preserves VOUT voltage during SHDN assertion - critical for retaining state in downstream circuitry.

What is the minimum output capacitance required for stable operation of the MCP1811BT-018/LB?

The MCP1811BT-018/LB requires a minimum output capacitance of 1.0 µF ceramic (X7R or better) for guaranteed stability. This value applies specifically to the MCP1811X series (150 mA variants like MCP1811BT-018/LB); MCP1812X devices require 2.2 µF. Using less than 1.0 µF risks oscillation or poor transient response.

Can the MCP1811BT-018/LB operate with an input voltage equal to its 1.8 V output?

No - the MCP1811BT-018/LB requires headroom above the output voltage to maintain regulation. Its typical dropout voltage is 400–600 mV at 150 mA, meaning VIN must be ≥2.2–2.4 V under full load. At light loads (<1 mA), dropout drops significantly, but stable operation below ~1.9 V input is not guaranteed per datasheet specifications.

What thermal performance can be expected from the MCP1811BT-018/LB in a standard PCB layout?

In a JEDEC-standard 4-layer FR4 board with 1 oz. copper and thermal vias, the MCP1811BT-018/LB (4-lead UDFN with EP) achieves θ_JA = 91.05°C/W. This means a 150 mA load at 5.5 V input (1.2 W dissipation) would raise junction temperature by ~109°C above ambient - confirming the need for proper thermal via placement and copper pour under the EP pad to stay within the +85°C max operating junction limit.