Microchip Technology MCP1811BT-025/OT

Overview

MCP1811BT-025/OT from Microchip Technology is a 2.5V fixed-output, 150 mA ultra-low quiescent current LDO regulator in SOT-23-3 package, featuring 250 nA typical IQ, 5 nA shutdown current (MCP1811B variant), and stable operation with 1.0 µF ceramic output capacitor - designed for energy harvesting and long-life battery-powered wearable electronics.

For engineers reviewing the MCP1811BT-025/OT datasheet, MCP1811BT-025/OT pinout, MCP1811BT-025/OT application, or MCP1811BT-025/OT equivalent, this page delivers verified electrical specs, thermal performance data, functional role in low-power subsystems, and validated alternative options for ultra-low-I_Q LDO selection.

Technical Context

The MCP1811BT-025/OT implements a CMOS-based LDO architecture optimized for sub-µA static current, with internal error amplifier, overcurrent protection, and integrated discharge transistor disabled (MCP1811B series). It operates across 1.8V–5.5V input range while maintaining ±4% output voltage accuracy over –40°C to +85°C junction temperature.

Its 400 mV typical dropout at 150 mA enables regulation from low-voltage sources such as single-cell Li-ion or coin cells. The device requires no external compensation and achieves PSRR of –50 dB at 1 kHz with zero input capacitor, supporting noise-sensitive analog and RF subsystems.

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 ultra-low-quiescent-current LDO applications.

Compared with XC6210B252MR-G and RP114K251D-TR-F, the MCP1811BT-025/OT offers the lowest shutdown current (5 nA) in a 3-pin SOT-23, simplifying layout and maximizing battery longevity in intermittently powered systems - but lacks enable control and thermal foldback.

Availability

MCP1811BT-025/OT is available at Aetrix Electronics and suitable for energy harvesting nodes, wearable medical sensors, and secure smart cards requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for MCP1811BT-025/OT 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 specializing in microcontrollers, analog devices, and timing solutions, with a strong focus on low-power and embedded control markets.

The MCP1811 family was engineered specifically for ultra-long-life battery-powered applications - delivering industry-leading quiescent current while maintaining robust regulation, thermal safety, and ease of use in space-constrained designs.

FAQ

What is the maximum input voltage rating for the MCP1811BT-025/OT?

The MCP1811BT-025/OT has an absolute maximum input voltage rating of +6.0 V. Its recommended operating input range is 1.8 V to 5.5 V. Exceeding 6.0 V risks permanent damage; sustained operation above 5.5 V is outside specification and may degrade reliability or cause functional failure. Always include input overvoltage protection if upstream sources can exceed 5.5 V.

Does the MCP1811BT-025/OT include output discharge functionality during shutdown?

No, the MCP1811BT-025/OT does not include output discharge. Its part number suffix "B" identifies it as the MCP1811B variant, which omits the discharge transistor present in MCP1811A devices. When SHDN is pulled low, VOUT floats - preserving charge on downstream capacitors or backup supplies. This behavior is confirmed in Table 1 and Figure 2-3 of DS20006088C.

What output capacitor value and type are required for stable operation of the MCP1811BT-025/OT?

The MCP1811BT-025/OT requires a minimum 1.0 µF X7R ceramic capacitor at the VOUT pin for guaranteed stability. TDK, Murata, and Samsung X7R MLCCs rated ≥6.3 V DC are recommended. Larger values (e.g., 2.2 µF) improve transient response but are not required. Tantalum or aluminum electrolytic capacitors are not supported and may cause oscillation.

Can the MCP1811BT-025/OT operate from a single alkaline AA cell?

Yes - the MCP1811BT-025/OT supports input voltages as low as 1.8 V, matching the end-of-life voltage of a fresh alkaline AA cell (~1.6 V nominal, ~1.0 V under load). With its 400 mV typical dropout at 150 mA, it regulates 2.5 V output down to ~2.9 V input; thus, it functions reliably across the full usable discharge curve of two-series AA cells (up to ~3.2 V), but not from a single AA cell alone.

What is the thermal resistance (θ_JA) of the MCP1811BT-025/OT in its SOT-23-3 package?

The MCP1811BT-025/OT in 3-Lead SOT-23 has a typical junction-to-ambient thermal resistance (θ_JA) of 211.33 °C/W on a JEDEC-standard 4-layer FR4 board with 1 oz. copper. This value assumes standard PCB layout - no thermal vias or copper pour. For continuous 150 mA operation at 2.5 V output, power dissipation is ≤150 mW, resulting in <32 °C junction rise above ambient, well within the –40°C to +85°C operating range.