Microchip Technology MCP1812AT-018/7QX

Overview

MCP1812AT-018/7QX from Microchip Technology is a 300 mA ultra-low-quiescent-current LDO regulator with 1.8 V fixed output, 250 nA typical IQ, and output discharge functionality (MCP1812A variant). It operates from 1.8 V to 5.5 V input, supports ceramic output capacitors ≥2.2 µF, and delivers stable low-noise power for energy-constrained systems such as hearing aids and smart wearables.

For engineers reviewing the MCP1812AT-018/7QX datasheet, MCP1812AT-018/7QX pinout, MCP1812AT-018/7QX application, or MCP1812AT-018/7QX equivalent, key selection criteria include its 10 nA shutdown current, 400 mV dropout at 300 mA, ±4% output voltage accuracy over –40°C to +85°C, and compatibility with 1×1 mm UDFN-4 packaging for space-constrained PCB layouts.

Technical Context

The MCP1812AT-018/7QX implements a PMOS pass transistor architecture enabling ultra-low quiescent current and fast start-up (400 µs delay from SHDN), while maintaining stability with minimal 2.2 µF ceramic output capacitance. Its internal discharge transistor (RDCH = 100 Ω) actively pulls VOUT to GND during shutdown, preventing residual voltage hold-up in battery-sensitive systems.

Designed for micro-power operation, it features foldback current limiting (100 mA at RLOAD = 1 Ω), 5 nA typical shutdown supply current (MCP1812B variant excluded - this part is MCP1812A), and PSRR of –50 dB at 1 kHz under no-input-capacitor conditions. Thermal resistance is 91.05°C/W (θJA, JEDEC 4-layer board) in its 4-lead UDFN package.

Key Specifications

Pinout & Package

Package: 4-Lead 1 × 1 mm UDFN with exposed thermal pad (EP) - optimized for thermal performance and ultra-dense PCB layouts in wearable and implantable devices.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1812AT-018/OT and XC6210B182MR-G, the MCP1812AT-018/7QX uniquely combines 250 nA IQ, integrated output discharge, and 1×1 mm UDFN packaging - making it the only option capable of enabling >5-year battery life in space-constrained, shutdown-aware designs like ingestible sensors or sealed environmental monitors.

Availability

MCP1812AT-018/7QX is available at Aetrix Electronics and suitable for energy harvesting, wearable electronics, and medical device applications requiring stable component supply, long-lifecycle support, and guaranteed traceability for regulated markets.

Supply support for MCP1812AT-018/7QX 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 microcontrollers, analog devices, and Flash-IP solutions, serving automotive, industrial, consumer, and communications markets with vertically integrated silicon and software platforms.

The MCP1811/12 family was designed specifically for ultra-low-power, battery-critical applications - emphasizing nanoscale IQ, minimal external components, and robust performance across temperature and load extremes in portable and implantable systems.

FAQ

What is the maximum input voltage rating for the MCP1812AT-018/7QX?

The MCP1812AT-018/7QX has an absolute maximum input voltage rating of +6.0 V. However, its operational input range is specified from 1.8 V to 5.5 V. Exceeding 5.5 V may cause permanent damage or violate safety margins defined in DS20006088C. For reliable long-term operation, keep VIN ≤5.5 V and ensure transient spikes remain within the ±0.3 V margin relative to GND or VIN.

Does the MCP1812AT-018/7QX require an input capacitor?

While the MCP1812AT-018/7QX is stable without an input capacitor, Microchip recommends a 1 µF X7R ceramic capacitor placed as close as possible to the VIN and GND pins. This reduces high-frequency noise coupling and improves PSRR performance - especially critical when powered from noisy sources like switching regulators or shared battery rails. The absence of CIN degrades PSRR by up to 20 dB at 100 kHz.

How does the output discharge function operate in the MCP1812AT-018/7QX?

The MCP1812AT-018/7QX integrates an NMOS discharge transistor (RDCH = 100 Ω typical) between VOUT and GND, activated only when SHDN is driven low. This discharges the output capacitor rapidly - typically within tens of microseconds - eliminating residual voltage that could interfere with system reset, cause latch-up in downstream logic, or violate safety isolation requirements in medical devices.

Is the MCP1812AT-018/7QX compatible with 0201-size 2.2 µF ceramic capacitors?

Yes - the MCP1812AT-018/7QX is explicitly characterized and guaranteed stable with 2.2 µF X7R ceramic output capacitors, including industry-standard 0201 (0603 metric) case sizes. Microchip's DS20006088C confirms stability across temperature and aging effects when using 2.2 µF ±20% X7R dielectrics, enabling highly miniaturized designs without compromising transient response or noise performance.

What is the thermal resistance (θJA) of the MCP1812AT-018/7QX in its 4-lead UDFN package?

The MCP1812AT-018/7QX in the 4-lead 1×1 mm UDFN package has a measured θJA of 91.05°C/W when mounted on a JEDEC-standard 4-layer FR4 board with 1 oz. copper and thermal vias under the exposed pad. This value assumes proper soldering of the EP pad to an internal ground plane - omitting thermal vias increases θJA by >30%, risking thermal shutdown above 150 mA continuous load at +85°C ambient.