MCP1811AT-033/TT Equivalent & Substitute Parts

Part Overview

The MCP1811AT-033/TT is a linear voltage regulator IC from Microchip Technology designed to deliver a fixed 3.3V output at 150mA in a compact SOT-23-3 surface mount package. This device is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production requirements. The part provides positive fixed output regulation with enable control and over-current protection across an operating temperature range of -40°C to 85°C.

Key Parameters

Parameter	Value
Output Voltage (Fixed)	3.3V
Output Current	150mA
Input Voltage (Max)	5.5V
Voltage Dropout (Max)	0.6V @ 150mA
Quiescent Current	0.5 µA
Package Type	SOT-23-3
Control Features	Enable
Protection Features	Over Current
Operating Temperature	-40°C to 85°C
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitute parts for the MCP1811AT-033/TT are selected based on the following critical parameters:

Fixed output voltage of 3.3V
Output current capability of 150mA minimum
Maximum input voltage compatibility (5.5V or higher)
Surface mount packaging suitable for SOT-23 form factors
Operating temperature range of -40°C to 85°C
RoHS3 compliance and REACH unaffected status

Two active substitute parts meet these criteria: the MCP1711T-33I/OT (Microchip Technology) and the AP2120N-3.3TRG1 (Diodes Incorporated). Both devices maintain the same output voltage and current specifications while offering active product status and improved availability.

Parameter Comparison

Parameter	MCP1811AT-033/TT (Original)	MCP1711T-33I/OT (Substitute)	AP2120N-3.3TRG1 (Substitute)
Manufacturer	Microchip Technology	Microchip Technology	Diodes Incorporated
Output Voltage	3.3V	3.3V	3.3V
Output Current	150mA	150mA	150mA
Input Voltage (Max)	5.5V	6V	6V
Voltage Dropout (Max)	0.6V @ 150mA	0.67V @ 150mA	0.5V @ 150mA
Quiescent Current	0.5 µA	1.27 µA	50 µA
Package Type	SOT-23-3	SOT-23-5	SOT-23-3
Control Features	Enable	Enable	None
Protection Features	Over Current	None	Over Current
Operating Temperature	-40°C to 85°C	-40°C to 85°C	-40°C to 85°C
Product Status	Obsolete	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
REACH Status	REACH Unaffected	REACH Unaffected	REACH Unaffected

Engineering Selection Recommendations

Both substitute parts are active products with full RoHS3 compliance and REACH unaffected status, providing long-term availability and regulatory compliance advantages over the obsolete MCP1811AT-033/TT.

The MCP1711T-33I/OT maintains Microchip Technology manufacturer continuity and preserves the enable control feature. However, it uses a SOT-23-5 package requiring PCB layout modification from the original SOT-23-3 footprint. This substitute is suitable for designs where control features are required and package redesign is feasible.

The AP2120N-3.3TRG1 from Diodes Incorporated maintains the original SOT-23-3 package footprint, enabling direct PCB substitution without layout changes. It provides superior voltage dropout performance (0.5V versus 0.6V) and retains over-current protection. The absence of enable control should be evaluated against circuit requirements. This substitute is optimal for designs prioritizing minimal PCB modification and improved dropout characteristics.

Frequently Asked Questions (FAQ)

Q: Can the MCP1711T-33I/OT be used as a direct replacement without PCB modifications?

A: No. The MCP1711T-33I/OT uses a SOT-23-5 package with five pins, while the original MCP1811AT-033/TT uses SOT-23-3 with three pins. PCB layout and footprint changes are required.

Q: Is the AP2120N-3.3TRG1 a pin-for-pin compatible substitute?

A: Yes. The AP2120N-3.3TRG1 uses the same SOT-23-3 package as the original part, allowing direct PCB substitution without layout modifications.

Q: What is the significance of the enable control feature difference?

A: The MCP1811AT-033/TT and MCP1711T-33I/OT include enable control for power management. The AP2120N-3.3TRG1 lacks this feature. If your circuit requires the ability to disable the regulator output, the MCP1711T-33I/OT is the appropriate choice despite package differences.

Q: How do the quiescent current specifications affect substitute selection?

A: The MCP1811AT-033/TT has 0.5 µA quiescent current, the MCP1711T-33I/OT has 1.27 µA, and the AP2120N-3.3TRG1 has 50 µA. For battery-powered or ultra-low-power applications, the MCP1711T-33I/OT provides the lowest quiescent current among active substitutes.

Q: Are both substitutes suitable for the full -40°C to 85°C operating temperature range?

A: Yes. Both the MCP1711T-33I/OT and AP2120N-3.3TRG1 support the complete -40°C to 85°C operating temperature range specified for the original part.

Q: What are the compliance implications of using these substitutes?

A: Both substitutes are RoHS3 compliant and REACH unaffected, matching the regulatory status of the original obsolete part and ensuring compliance with current environmental standards.

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