Microchip Technology MCP1811BT-040/LB

Overview

MCP1811BT-040/LB from Microchip Technology is a 150 mA ultra-low quiescent current (250 nA typical) fixed-output 4.0 V low-dropout linear regulator in a 4-lead 1×1 mm UDFN package with exposed thermal pad, designed for energy harvesting and long-life battery-powered systems requiring stable low-noise voltage regulation under microampere load conditions.

For engineers reviewing the MCP1811BT-040/LB datasheet, MCP1811BT-040/LB pinout, MCP1811BT-040/LB application, or MCP1811BT-040/LB equivalent, this page delivers verified electrical specs, thermal performance data, shutdown behavior (5 nA typical), ceramic-capacitor stability (1 µF), and real-world use cases in wearable electronics and medical devices.

Technical Context

The MCP1811BT-040/LB implements a PMOS pass transistor architecture enabling ultra-low dropout (400 mV typical at 150 mA) and near-zero load-dependent quiescent current variation across 1.8–5.5 V input range. Its internal error amplifier and reference are optimized for operation down to 1 µA load while maintaining ±4% output accuracy over –40°C to +85°C junction temperature.

Unlike MCP1811A variants, the "B" suffix denotes absence of output discharge during shutdown - confirmed by datasheet Table 1 and SHDN logic thresholds (70% VIN high, 20% VIN low) - making it suitable for systems where output rail hold-up must be preserved during sleep mode.

Key Specifications

Pinout & Package

Package: 4-Lead 1×1 mm UDFN with exposed thermal pad (EP), JEDEC-standard footprint optimized for thermal dissipation on 4-layer FR4 boards (θ_JA = 91.05°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1700T-4002E/MB, MCP1811BT-040/LB adds active shutdown and superior thermal performance via UDFN EP; versus XC6219B402MR-G, it delivers 4× lower quiescent current and 50% higher output capability - critical for longevity and peak-load robustness in wearables and medical edge devices.

Availability

MCP1811BT-040/LB is available at Aetrix Electronics and suitable for energy harvesting nodes, wearable health monitors, and hearing aid processors requiring stable component supply with guaranteed long-term manufacturability and consistent parametric performance.

Supply support for MCP1811BT-040/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 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 MCP1811 family targets ultra-low-power portable and energy-harvesting applications, emphasizing nanoscale quiescent current, ceramic-capacitor compatibility, and robust thermal design in miniature packages - aligning with Microchip's XLP (eXtreme Low Power) ecosystem strategy.

FAQ

What is the maximum input voltage rating for the MCP1811BT-040/LB?

The MCP1811BT-040/LB has an absolute maximum input voltage rating of +6.0 V. Operation above 5.5 V violates the recommended operating conditions and risks permanent damage. For reliable long-term use, keep VIN within 1.8–5.5 V per the datasheet's Electrical Characteristics table.

Does the MCP1811BT-040/LB include output discharge during shutdown?

No, the MCP1811BT-040/LB does not include output discharge. As a "B" variant per Table 1 of DS20006088C, it omits the internal discharge transistor present in "A" variants like MCP1811AT-040/LB. This preserves VOUT voltage during SHDN assertion, which is essential for retaining state in downstream circuits.

What is the minimum output capacitance required for stability with the MCP1811BT-040/LB?

The MCP1811BT-040/LB requires a minimum 1.0 µF X7R ceramic capacitor on the VOUT pin for guaranteed stability. This value is specified in the datasheet's Features section and Electrical Characteristics table, and applies regardless of load current or temperature - unlike larger LDOs that demand higher COUT at full load.

Can the MCP1811BT-040/LB operate from a single alkaline cell?

Yes, the MCP1811BT-040/LB can operate from a single alkaline cell (nominal 1.5 V) only after boost conversion, since its minimum input voltage is 1.8 V. However, it supports two-series alkaline cells (3.0 V fresh, ~2.0 V end-of-life) directly - provided dropout margin is maintained (e.g., 4.0 V output requires ≥4.4 V input at full load, so two cells must stay >4.4 V).

What thermal performance can be expected from the MCP1811BT-040/LB in a standard PCB layout?

On a JEDEC-standard 4-layer FR4 board with 1 oz. copper and thermal vias, the MCP1811BT-040/LB achieves θ_JA = 91.05°C/W. At 150 mA load and 25°C ambient, junction temperature rise is ~13.7°C - well within the +85°C max operating limit. The exposed pad (EP) must be soldered to a solid GND plane for this rating to apply.