Microchip Technology MCP1812BT-033/LB

Overview

MCP1812BT-033/LB from Microchip Technology is a 300 mA ultra-low quiescent current (250 nA typical) fixed 3.3V low-dropout linear regulator in a 3-lead SOT-23 package, featuring shutdown mode with 5 nA typical supply current and stable operation with only 2.2 µF ceramic output capacitance. It targets energy-constrained systems requiring long battery life and precise low-noise voltage regulation, such as wearable medical sensors and wireless sensor nodes.

For engineers reviewing the MCP1812BT-033/LB datasheet, MCP1812BT-033/LB pinout, MCP1812BT-033/LB application, or MCP1812BT-033/LB equivalent, key selection criteria include its 400 mV dropout at 300 mA, ±4% output voltage accuracy over -40°C to +85°C, output discharge capability (MCP1812A variant), and compatibility with micro-power MCUs like PIC XLP series.

Technical Context

The MCP1812BT-033/LB implements a CMOS-based LDO architecture optimized for ultra-low static power, with internal error amplifier, current-limit protection, and thermal shutdown. Its feedback loop is internally compensated for stability with minimal 2.2 µF ceramic output capacitance, eliminating need for ESR-tuned tantalum capacitors.

It features active output discharge during shutdown (SHDN = GND), enabling rapid VOUT ramp-down to prevent back-powering of downstream circuitry. The device operates across 2.4V–5.5V input range while maintaining regulation at 3.3V output up to full 300 mA load, with dropout voltage tightly specified at 400 mV (typical) at maximum current.

Key Specifications

Pinout & Package

Package: 3-Lead SOT-23 (SC-59), 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 XC6210B332MR-G and ADP160ACBZ-3.3-R7, the MCP1812BT-033/LB uniquely delivers 300 mA output with 5 nA shutdown current and integrated output discharge - critical for systems requiring both high peak current and aggressive power gating.

Availability

MCP1812BT-033/LB is available at Aetrix Electronics and suitable for wearable electronics, medical devices, and energy-harvesting systems requiring stable component supply with guaranteed long-term manufacturability and consistent parametric performance.

Supply support for MCP1812BT-033/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 is a leading provider of microcontrollers, analog, 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 - delivering industry-leading 250 nA quiescent current while maintaining robust 300 mA output capability and ceramic-capacitor stability.

FAQ

What is the minimum input voltage required for MCP1812BT-033/LB to regulate 3.3V at 300 mA?

The MCP1812BT-033/LB requires a minimum input voltage of 3.7V to maintain regulation at 300 mA load, based on its typical 400 mV dropout voltage (VDROPOUT = V_IN – V_OUT). At higher temperatures or worst-case process corners, the maximum dropout may reach 600 mV, so 3.9V is recommended for margin. This enables use with partially discharged single-cell Li-ion (3.7–4.2V) and LiFePO₄ (3.2–3.6V) sources.

Does MCP1812BT-033/LB include output discharge functionality?

Yes, MCP1812BT-033/LB includes active output discharge: when SHDN is pulled low, an internal NMOS transistor (RDCH = 100 Ω typical) connects VOUT to GND, discharging the output capacitor rapidly. This prevents back-powering of upstream circuitry and ensures clean power sequencing - a feature confirmed for the MCP1812A variant, which the /LB suffix denotes per Microchip's packaging and variant coding.

Which output capacitor value and type are required for stable operation of MCP1812BT-033/LB?

The MCP1812BT-033/LB requires a minimum 2.2 µF X7R ceramic capacitor between VOUT and GND for guaranteed stability across temperature and load. TDK C3216X7R1E225K or Murata GRM188R71E225KA01D are validated equivalents. Electrolytic or tantalum capacitors are unnecessary and discouraged due to ESR sensitivity; the regulator's internal compensation is optimized exclusively for low-ESR ceramic types.

How does the quiescent current of MCP1812BT-033/LB vary with input voltage and temperature?

Per Figure 2-57 and 2-58 in DS20006088C, MCP1812BT-033/LB quiescent current remains tightly bounded: 220–320 nA over 3.5–5.5V input range at +25°C, with <10% increase at +85°C and <5% decrease at –40°C. This flat, temperature-invariant IQ profile ensures predictable battery lifetime calculations across industrial and medical operating environments.

Is MCP1812BT-033/LB pin-compatible with other devices in the MCP1811/12 family?

Yes - MCP1812BT-033/LB uses the standard 3-lead SOT-23 pinout (VIN–VOUT–GND) shared across all MCP1811A/B and MCP1812A/B variants in that package. No PCB redesign is needed when migrating between output voltages (e.g., 2.8V, 3.0V, 3.3V) or current grades (150 mA vs. 300 mA), provided the same package and variant type (A/B) are selected.