Microchip Technology MCP1812AT-025/LB

Overview

MCP1812AT-025/LB from Microchip Technology is a 300 mA ultra-low-quiescent-current LDO regulator with 2.5 V fixed output, 250 nA typical IQ, 400 mV dropout at full load, and output discharge functionality (MCP1812A variant). It operates from 2.4 V to 5.5 V input and stabilizes with only 2.2 µF ceramic output capacitance - ideal for energy harvesting and long-life battery-powered wearable or medical devices.

For engineers reviewing the MCP1812AT-025/LB datasheet, MCP1812AT-025/LB pinout, MCP1812AT-025/LB application, or MCP1812AT-025/LB equivalent, key selection criteria include shutdown current (10 nA typ), output discharge capability, thermal performance in 3-lead SOT-23, and compatibility with Microchip's XLP microcontrollers in ultra-low-power sleep modes.

Technical Context

The MCP1812AT-025/LB implements a PMOS pass transistor architecture enabling ultra-low quiescent current while maintaining fast transient response and high PSRR (–50 dB at 1 kHz). Its integrated discharge transistor (RDCH = 100 Ω) actively pulls VOUT to GND during shutdown (SHDN = GND), eliminating residual voltage hold-up in sensitive low-power systems.

It features overcurrent protection with foldback limiting (100 mA at RLOAD = 1 Ω), stable operation across –40°C to +85°C junction temperature, and supports dynamic load steps up to 300 mA with <100 mV undershoot (typical) under optimized PCB layout with local ceramic decoupling.

Key Specifications

Pinout & Package

Package: 3-Lead SOT-23 (SC-59), JEDEC MO-178AA compliant, thermal resistance θJA = 211.33°C/W on standard 4-layer FR4 board.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1812AT-025/TT and XC6210B252MR-G, the MCP1812AT-025/LB uniquely combines SOT-23 footprint, guaranteed output discharge, and industry-leading 10 nA shutdown current - making it optimal for space- and power-constrained systems requiring deterministic power-off behavior.

Availability

MCP1812AT-025/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.

Supply support for MCP1812AT-025/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 microcontroller, mixed-signal, analog, and Flash-IP solutions, serving automotive, industrial, consumer, and communications markets.

The MCP1812 series belongs to Microchip's ultra-low-power LDO family, designed specifically for battery- and energy-harvesting-powered systems where nanowatt-level quiescent current and fast, controlled power sequencing are mandatory.

FAQ

What is the maximum input voltage rating for the MCP1812AT-025/LB?

The MCP1812AT-025/LB 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 2.4 V to 5.5 V - ensuring proper regulation at 2.5 V output while maintaining specified dropout and thermal performance. Always observe derating guidelines per PCB thermal design.

Does the MCP1812AT-025/LB require an external pull-up resistor on the SHDN pin?

Yes - the MCP1812AT-025/LB SHDN pin is active-low and internally uncommitted. A pull-up resistor (typically 1 MΩ to VIN) is required to maintain normal operation. Without it, the device remains in shutdown mode. The datasheet specifies VSHDN-HIGH ≥70% VIN and VSHDN-LOW ≤20% VIN for valid logic thresholds, confirming the need for robust external biasing.

Can the MCP1812AT-025/LB be used with a 1 µF output capacitor?

No - the MCP1812AT-025/LB requires a minimum of 2.2 µF ceramic (X7R) output capacitance for stability, as confirmed in DS20006088C, Table 1 and Section 4.2. Using only 1 µF may cause oscillation or poor transient response. The MCP1811X variants specify 1 µF; the MCP1812X family (including MCP1812AT-025/LB) mandates 2.2 µF due to higher output current and loop compensation differences.

Is the output discharge feature present in all MCP1812 variants?

Yes - output discharge is exclusive to the "A" suffix variants (e.g., MCP1812A, MCP1812AT-025/LB). The "B" variants (e.g., MCP1812B) omit this function. The "/LB" suffix denotes the 3-lead SOT-23 package and confirms the A-version functionality per Microchip's part numbering convention and Table 1 in DS20006088C.

What is the thermal resistance (θJA) of the MCP1812AT-025/LB in its SOT-23 package?

The MCP1812AT-025/LB in 3-lead SOT-23 has a thermal resistance θJA 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 assumes standard land pattern per Microchip's layout guidelines; adding thermal vias beneath the GND pad can reduce θJA by ~30–50°C/W in production designs.