Microchip Technology MCP1811BT-033/LT

Overview

MCP1811BT-033/LT from Microchip Technology is an ultra-low quiescent current (250 nA typical) 150 mA low-dropout linear regulator with fixed 3.3V output, designed for energy-constrained systems requiring stable voltage under light-load and shutdown conditions. It operates from 1.8V to 5.5V input, supports ceramic output capacitors as small as 1.0 µF, and features overcurrent protection and output discharge during shutdown.

For engineers reviewing the MCP1811BT-033/LT datasheet, MCP1811BT-033/LT pinout, MCP1811BT-033/LT application, or MCP1811BT-033/LT equivalent, this page delivers verified technical context, package-specific pin functions, real-world use cases in battery-powered wearables and medical devices, and validated alternative options for ultra-low-power LDO selection.

Technical Context

The MCP1811BT-033/LT belongs to the MCP1811B variant-no output discharge function, 5 nA typical shutdown current-and uses a PMOS pass transistor architecture enabling ultra-low IQ while maintaining 400 mV typical dropout at 150 mA load. Its internal error amplifier and reference are optimized for stability with minimal 1.0 µF ceramic output capacitance across –40°C to +85°C junction temperature.

It implements foldback current limiting (50 mA at R_LOAD = 1 Ω), supports logic-level shutdown control (V_SHDN-HIGH ≥ 70% V_IN), and achieves –50 dB PSRR at 1 kHz with no input capacitor-critical for noise-sensitive analog and RF subsystems powered from shared rails.

Key Specifications

Pinout & Package

Package: 3-Lead SOT-23 - compact 2.92 mm × 1.3 mm footprint with exposed pad option (not present in /LT suffix); thermal resistance θ_JA = 211.33°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 Torex XC6210B332MR-G and Ricoh RP114K331D-TR-F, the MCP1811BT-033/LT uniquely combines 5 nA shutdown current, 3.3V precision output, and SOT-23-3 footprint-making it optimal for multi-year battery applications where every nanoamp counts and enable control is mandatory.

Availability

MCP1811BT-033/LT is available at Aetrix Electronics and suitable for wearable electronics, medical sensors, and energy-harvesting nodes requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for MCP1811BT-033/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 is a leading provider of microcontroller, analog, FPGA, and power management semiconductors, serving industrial, automotive, and consumer markets with high-reliability solutions.

The MCP1811 family was designed specifically for ultra-low-power, long-life battery applications-emphasizing nanoscale quiescent current, ceramic-capacitor compatibility, and robust performance across wide temperature and load ranges.

FAQ

What is the maximum input voltage rating for the MCP1811BT-033/LT?

The MCP1811BT-033/LT has an absolute maximum input voltage of +6.0V. However, its specified operating input range is 1.8V to 5.5V. Exceeding 5.5V may cause permanent damage or violate reliability specifications-even briefly-so design margins should keep VIN ≤5.5V under all conditions including transient spikes.

Does the MCP1811BT-033/LT require an input capacitor?

The MCP1811BT-033/LT does not require an input capacitor for stability, as confirmed in the datasheet AC/DC characteristics table. However, a 0.1 µF ceramic capacitor placed close to the VIN pin is strongly recommended to suppress high-frequency noise and improve PSRR-especially when sharing input rails with switching regulators or digital ICs.

Is the MCP1811BT-033/LT pin-compatible with other variants in the MCP1811 family?

Yes-the MCP1811BT-033/LT uses the standard 3-lead SOT-23 package with identical pinout (VIN, VOUT, GND) as all MCP1811A/B and MCP1812A/B variants in that package. This allows drop-in replacement within the same package type, though functional differences (e.g., output discharge, shutdown current) must be verified per application requirements.

What is the thermal performance of the MCP1811BT-033/LT in SOT-23-3 package?

In the 3-lead SOT-23 package, the MCP1811BT-033/LT has a junction-to-ambient thermal resistance (θ_JA) of 211.33°C/W on a JEDEC-standard 4-layer FR4 board with 1 oz. copper. At 150 mA load and 5.5V input, worst-case power dissipation is ~330 mW, resulting in ~70°C junction rise above ambient-well within the +85°C max operating junction temperature limit.

Can the MCP1811BT-033/LT be used with a 1.0 µF X5R ceramic capacitor instead of X7R?

Yes-the MCP1811BT-033/LT is stable with 1.0 µF X5R ceramic capacitors, as X5R meets the minimum capacitance, ESR, and temperature coefficient requirements specified for stability. However, X7R is preferred for tighter tolerance and better DC bias performance; verify actual capacitance at bias voltage remains ≥0.8 µF across temperature and voltage range.