Microchip Technology MCP1811AT-012/LT

Overview

MCP1811AT-012/LT from Microchip Technology is an ultra-low quiescent current (250 nA typical) 150 mA low-dropout linear regulator with fixed 1.2 V output, designed for energy-constrained systems requiring stable voltage under light-to-moderate load and deep sleep operation. It supports 1.8–5.5 V input, features output discharge during shutdown, and operates across –40°C to +85°C junction temperature.

For engineers reviewing the MCP1811AT-012/LT datasheet, MCP1811AT-012/LT pinout, MCP1811AT-012/LT application, or MCP1811AT-012/LT equivalent, this page delivers verified specifications, package mapping, functional context, and real-world use cases for battery-powered wearable, medical, and energy-harvesting designs where nanowatt-level standby power is critical.

Technical Context

The MCP1811AT-012/LT implements a PMOS pass transistor architecture enabling ultra-low dropout (400 mV typical at 150 mA) and stable regulation with only 1.0 µF ceramic output capacitance. Its internal error amplifier and reference circuit maintain ±4% output accuracy over load, line, and temperature variations.

It integrates a dedicated discharge transistor (RDCH = 100 Ω typical) activated when SHDN = GND, ensuring rapid VOUT collapse to prevent back-powering of downstream circuitry - a key requirement in multi-rail power sequencing and zero-power retention modes.

Key Specifications

Pinout & Package

Package: 4-Lead 1 × 1 mm UDFN with exposed thermal pad (EP). Compact footprint ideal for space-constrained PCBs in hearing aids and smart patches.

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6210B122MR-G and RP111N121D-TR-F, the MCP1811AT-012/LT uniquely combines 10 nA shutdown, integrated output discharge, and industry-leading 91°C/W thermal resistance in a 1×1 mm UDFN - making it optimal for thermally constrained, safety-critical, or sequenced-power applications.

Availability

MCP1811AT-012/LT is available at Aetrix Electronics and suitable for wearable electronics, medical diagnostics, and energy-harvesting sensor networks requiring stable component supply with long-term lifecycle assurance.

Supply support for MCP1811AT-012/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 global semiconductor company delivering microcontrollers, analog, FPGA, and timing solutions with emphasis on reliability, low power, and embedded control.

The MCP1811A/B series was designed specifically for ultra-long-life battery-powered applications demanding nanowatt standby operation, rapid wake-up, and robust regulation under dynamic load - targeting wearables, IoT edge nodes, and portable medical devices.

FAQ

What is the maximum input voltage rating for the MCP1811AT-012/LT?

The MCP1811AT-012/LT has an absolute maximum input voltage rating of +6.0 V. Operation beyond this voltage risks permanent damage. For reliable continuous operation, the recommended input range is 1.8 V to 5.5 V, with dropout constraints requiring VIN ≥ VOUT + VDROPOUT (≥1.6 V minimum at full load). Always observe derating guidelines per Microchip's DS20006088C.

Does the MCP1811AT-012/LT require an external resistor divider for output voltage setting?

No. The MCP1811AT-012/LT is a fixed-output device with factory-trimmed 1.2 V regulation - no external resistors are needed. This eliminates calibration drift, saves board space, and improves long-term accuracy versus adjustable LDOs. The "012" in the part number explicitly denotes the 1.2 V variant.

How does the output discharge feature of the MCP1811AT-012/LT function during shutdown?

When SHDN is pulled low, the MCP1811AT-012/LT activates an internal discharge transistor (RDCH ≈ 100 Ω) between VOUT and GND, discharging the output capacitor within microseconds. This prevents residual voltage from holding downstream logic in undefined states or interfering with MCU reset sequences - a critical behavior confirmed in Figure 2-44 through 2-47 of the DS20006088C datasheet.

Can the MCP1811AT-012/LT operate stably with a 0.47 µF ceramic output capacitor?

No. The MCP1811AT-012/LT requires a minimum of 1.0 µF X7R ceramic output capacitor for guaranteed stability across all operating conditions. Using 0.47 µF may cause oscillation or poor transient response, especially under load steps. Microchip validates stability only with ≥1.0 µF, as specified in Section 4.2 and Table 1-1 of DS20006088C.

What is the thermal performance of the MCP1811AT-012/LT in its 4-lead UDFN package?

In JEDEC-standard 4-layer FR4 board with thermal vias, the MCP1811AT-012/LT (4-lead UDFN) achieves θJA = 91.05°C/W and θJC(Top) = 285.89°C/W. This enables safe operation up to 150 mA at +85°C ambient when properly laid out - significantly better than SOT-23 variants (θJA = 211°C/W). Thermal design must include the exposed pad soldered to a copper pour for optimal performance.