Microchip Technology MCP1811AT-018/TT

Overview

MCP1811AT-018/TT 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 energy-constrained battery-powered systems. It operates from 1.8 V to 5.5 V input, supports ceramic output capacitors as small as 1.0 µF, and features output discharge during shutdown - confirming its identity as an MCP1811A-series LDO in 3-lead SOT-23 package for wearable electronics and medical devices.

For engineers reviewing the MCP1811AT-018/TT datasheet, MCP1811AT-018/TT pinout, MCP1811AT-018/TT application, or MCP1811AT-018/TT equivalent, this page delivers verified electrical specs, thermal resistance data, shutdown behavior, dropout voltage at full load, and real-world use cases in ultra-low-power embedded systems where sleep-mode current draw and startup timing are critical selection criteria.

Technical Context

The MCP1811AT-018/TT implements a PMOS pass transistor architecture enabling ultra-low IQ operation and fast start-up (400 µs typical delay from SHDN assertion). Its internal error amplifier and reference maintain ±4% output voltage accuracy across -40°C to +85°C junction temperature while supporting dynamic load steps up to 150 mA with <100 mV transient deviation.

It integrates overcurrent protection with foldback limiting (50 mA at R_LOAD = 1 Ω), a dedicated discharge transistor (R_DCH = 100 Ω), and logic-level shutdown control (V_SHDN-HIGH ≥ 70% V_IN). The device achieves -50 dB PSRR at 1 kHz without input capacitor, making it suitable for noise-sensitive analog subsystems powered from shared rails.

Key Specifications

Pinout & Package

Package: 3-Lead SOT-23 (JEDEC MO-178AA), 2.92 mm × 1.3 mm × 1.0 mm body, exposed pad not present.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1700T-1802E/TT and XC6206P182MR-G, the MCP1811AT-018/TT uniquely combines 150 mA drive, 10 nA shutdown, and active output discharge in SOT-23 - making it the only option among the three for high-integration, long-life wearables requiring controlled power sequencing.

Availability

MCP1811AT-018/TT is available at Aetrix Electronics and suitable for energy harvesting systems, wearable health monitors, and hearing aid electronics requiring stable component supply with guaranteed long-term manufacturability.

Supply support for MCP1811AT-018/TT 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, headquartered in Chandler, Arizona.

The MCP1811A family was engineered specifically for ultra-low-power battery-operated applications demanding nanoscale quiescent current, fast wake-up, and robust output control - targeting next-generation wearables, medical implants, and energy-harvesting IoT endpoints.

FAQ

What is the maximum input voltage rating for the MCP1811AT-018/TT?

The MCP1811AT-018/TT has an absolute maximum input voltage rating of +6.0 V. Operation above this level risks permanent damage. For reliable long-term use, the recommended operating input range is 1.8 V to 5.5 V, which aligns with its specified performance across temperature and load conditions. This range ensures the MCP1811AT-018/TT maintains ±4% output accuracy and 250 nA quiescent current.

Does the MCP1811AT-018/TT require an input capacitor?

No, the MCP1811AT-018/TT does not require an input capacitor for stability - it achieves -50 dB PSRR at 1 kHz without C_IN. However, adding a 1 µF ceramic capacitor at VIN improves high-frequency noise rejection and line transient response. The MCP1811AT-018/TT datasheet explicitly validates operation with C_IN = 0 µF, distinguishing it from many legacy LDOs that mandate input bypassing.

How does the output discharge feature work on the MCP1811AT-018/TT?

When the SHDN pin is pulled low, the MCP1811AT-018/TT activates an internal discharge transistor (R_DCH = 100 Ω typical) between VOUT and GND. This actively pulls the output voltage to near-zero within microseconds, preventing residual charge from back-powering downstream circuitry or interfering with power sequencing. This function is exclusive to MCP1811A/12A variants - the MCP1811AT-018/TT implements it per its "A" suffix designation.

Can the MCP1811AT-018/TT operate with a 1.0 µF ceramic capacitor at temperatures from -40°C to +85°C?

Yes, the MCP1811AT-018/TT is fully characterized and stable with a 1.0 µF X7R ceramic capacitor across its full operating junction temperature range (-40°C to +85°C). This is confirmed in DS20006088C, Section 4.2, which specifies ceramic compatibility and provides stability margins for 1.0 µF at all temperatures. No derating or additional components are required for industrial-grade reliability.

What is the thermal resistance (θ_JA) of the MCP1811AT-018/TT in its SOT-23 package?

The MCP1811AT-018/TT in 3-lead SOT-23 has a thermal resistance θ_JA of 211.33°C/W when mounted on a JEDEC-standard 4-layer FR4 board with 1 oz. copper and no thermal vias. This value enables continuous 150 mA output at ambient temperatures up to 65°C without exceeding the +85°C maximum junction temperature - a key design constraint validated in Microchip's thermal characterization data (DS20006088C, page 6).