MCP1811AT-033/LB Equivalent & Substitute Parts

Part Overview

The MCP1811AT-033/LB is a linear voltage regulator IC from Microchip Technology designed for positive fixed 3.3V output applications with 150mA current capacity. This device is packaged in SC-70-3 (SOT-323) surface mount configuration and features integrated enable control and over-current protection. The part is classified as obsolete, making identification of active equivalent alternatives essential for new designs and ongoing production support.

Substiute Parts

MCP1811AT-033/LB

Microchip TechnologyIn Stock: 736MCP1811AT-033/LB Datasheet

Current PartRFQ

MCP1711T-33I/OT

Microchip TechnologyIn Stock: 10126MCP1711T-33I/OT Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the MCP1811AT-033/LB is determined by the following critical parameters:

• Output voltage specification: 3.3V fixed
• Output current capability: 150mA minimum
• Input voltage tolerance: maximum 5.5V or higher
• Voltage dropout performance: 0.6V or lower at rated current
• Control features: Enable function required
• Operating temperature range: -40°C to 85°C minimum
• Mounting type: Surface mount
• Manufacturer: Microchip Technology (same family preferred)

The MCP1711T-33I/OT qualifies as a direct substitute based on matching all critical electrical parameters while offering improved product status (active) and enhanced quiescent current performance.

Parameter Comparison

Engineering Selection Recommendations

The MCP1711T-33I/OT is the qualified substitute for the obsolete MCP1811AT-033/LB based on the following engineering criteria:

All critical electrical parameters match or exceed the original specification. The MCP1711T-33I/OT maintains identical output voltage (3.3V), output current (150mA), control features (Enable), and operating temperature range (-40°C to 85°C). Input voltage rating is improved to 6V, and voltage dropout performance remains within acceptable tolerance at 0.67V versus 0.6V.

The substitute part carries active product status with full manufacturing support, ensuring long-term availability and supply chain stability. RoHS3 compliance and REACH unaffected status provide regulatory alignment for current manufacturing standards.

Package transition from SC-70-3 (3-pin) to SOT-23-5 (5-pin) requires PCB layout modification. The SOT-23-5 package provides additional pins for enhanced circuit flexibility and improved thermal performance compared to the SC-70-3 footprint.

Frequently Asked Questions (FAQ)

Q: Can the MCP1711T-33I/OT directly replace the MCP1811AT-033/LB without circuit modifications?

A: Electrical substitution is direct. However, the package change from SC-70-3 to SOT-23-5 requires PCB footprint redesign. Pin configuration differs between the two packages, necessitating layout updates before implementation.

Q: What is the impact of the package change on circuit performance?

A: The SOT-23-5 package offers improved thermal characteristics and additional pins compared to SC-70-3. This change does not degrade performance; it provides enhanced design flexibility. Verify pin assignments in the respective datasheets before PCB layout.

Q: Are there electrical performance differences between these parts?

A: Voltage dropout increases marginally from 0.6V to 0.67V at 150mA. Quiescent current increases from 0.5 µA to 1.27 µA. Both differences are within acceptable engineering tolerance for 3.3V regulator applications and do not impact functional compatibility.

Q: Why is the MCP1811AT-033/LB classified as obsolete?

A: The MCP1811 series has been superseded by the MCP1711 series within Microchip Technology's product portfolio. The MCP1711T-33I/OT represents the current active equivalent with improved specifications and ongoing manufacturing support.

Q: What certifications apply to the substitute part?

A: The MCP1711T-33I/OT is RoHS3 compliant and REACH unaffected, meeting current regulatory requirements for electronic component manufacturing and distribution.