MCP661-E/SN Equivalent & Substitute Parts

Part Overview

The MCP661-E/SN is a general-purpose operational amplifier manufactured by Microchip Technology, configured as a single-circuit rail-to-rail amplifier in an 8-SOIC surface-mount package. This device is classified as Active product status and is ROHS3 compliant. The MCP661-E/SN operates across a supply voltage range of 2.5 V to 5.5 V with an operating temperature range of -40°C to 125°C, making it suitable for low-voltage analog signal processing applications. Equivalent and substitute parts are identified based on matching electrical performance parameters, mechanical compatibility, and package specifications to ensure direct functional replacement in circuit designs.

Key Parameters

Parameter	MCP661-E/SN	Unit
Amplifier Type	General Purpose	—
Number of Circuits	1	—
Output Type	Rail-to-Rail	—
Package / Case	8-SOIC (0.154", 3.90mm Width)	—
Mounting Type	Surface Mount	—
Slew Rate	32	V/µs
Gain Bandwidth Product	60	MHz
Current - Input Bias	6	pA
Voltage - Input Offset	1.8	mV
Current - Supply	6	mA
Voltage - Supply Span (Min)	2.5	V
Voltage - Supply Span (Max)	5.5	V
Operating Temperature	-40 to 125	°C
RoHS Status	ROHS3 Compliant	—
Moisture Sensitivity Level	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitute parts for the MCP661-E/SN are identified based on the following critical parameters that determine functional compatibility:

Primary Compatibility Criteria:

Package / Case: 8-SOIC (0.154", 3.90mm Width) — mechanical and pin compatibility
Output Type: Rail-to-Rail — output swing capability
Number of Circuits: 1 — single amplifier configuration
Mounting Type: Surface Mount — assembly compatibility

Secondary Performance Criteria:

Voltage - Supply Span (Min/Max): Must encompass or match the 2.5 V to 5.5 V range
Operating Temperature: Must support -40°C to 125°C or equivalent industrial range
Slew Rate, Gain Bandwidth Product, Input Bias Current, Input Offset Voltage: Performance parameters that determine signal fidelity and application suitability

Substitute parts are grouped into two categories:

Category 1: Direct Electrical Equivalents — Parts with comparable or superior electrical performance within the same supply voltage and temperature operating ranges.

Category 2: Functional Alternatives — Parts with different electrical characteristics but compatible package, output type, and circuit configuration that may require application-level verification.

Parameter Comparison

Part Number	Manufacturer	Amplifier Type	Slew Rate (V/µs)	Gain Bandwidth Product (MHz)	Input Bias Current (pA/µA)	Input Offset Voltage (mV/µV)	Supply Current (mA/µA)	Supply Voltage Min (V)	Supply Voltage Max (V)	Operating Temp (°C)	Package
MCP661-E/SN	Microchip Technology	General Purpose	32	60	6 pA	1.8 mV	6 mA	2.5	5.5	-40 to 125	8-SOIC
AD8061ARZ	Analog Devices Inc.	Voltage Feedback	650	320	3.5 µA	1 mV	6.8 mA	2.7	8	-40 to 85	8-SOIC
AD8061ARZ-REEL	Analog Devices Inc.	Voltage Feedback	650	320	3.5 µA	1 mV	6.8 mA	2.7	8	-40 to 85	8-SOIC
AD8061ARZ-REEL7	Analog Devices Inc.	Voltage Feedback	650	320	3.5 µA	1 mV	6.8 mA	2.7	8	-40 to 85	8-SOIC
AD8063ARZ	Analog Devices Inc.	Voltage Feedback	650	320	3.5 µA	1 mV	6.8 mA	2.7	8	-40 to 85	8-SOIC
AD8063ARZ-REEL7	Analog Devices Inc.	Voltage Feedback	650	320	3.5 µA	1 mV	6.8 mA	2.7	8	-40 to 85	8-SOIC
MAX4289ESA+	Analog Devices Inc./Maxim Integrated	General Purpose	0.006	0.017	5 nA	200 µV	18 µA	1	5.5	-40 to 85	8-SOIC
OPA338UA	Burr Brown	General Purpose	4.6	12.5	0.2 pA	500 µV	525 µA	2.7	5.5	-40 to 85	8-SOIC
OPA340UA	Texas Instruments	General Purpose	6	5.5	0.2 pA	150 µV	750 µA	2.5	5.5	-40 to 85	8-SOIC
OPA340UA/2K5	Texas Instruments	General Purpose	6	5.5	0.2 pA	150 µV	750 µA	2.5	5.5	-40 to 85	8-SOIC
OPA347UA	Burr Brown	General Purpose	0.17	0.35	0.5 pA	2 mV	20 µA	2.3	5.5	-55 to 125	8-SOIC

Engineering Selection Recommendations

Compliance and Certification Basis:

All substitute parts listed are ROHS3 compliant and REACH unaffected, matching the regulatory status of the MCP661-E/SN. Moisture Sensitivity Level (MSL) ratings are provided for each part; the MCP661-E/SN carries MSL 1 (Unlimited), while some substitutes carry MSL 2 (1 Year), which affects storage and handling requirements.

Supply Voltage Compatibility:

The MCP661-E/SN operates within 2.5 V to 5.5 V. Substitute parts must support this range or a compatible subset:

AD8061ARZ, AD8061ARZ-REEL, AD8061ARZ-REEL7, AD8063ARZ, AD8063ARZ-REEL7: Support 2.7 V to 8 V (compatible with MCP661-E/SN supply range)
OPA340UA, OPA340UA/2K5: Support 2.5 V to 5.5 V (exact match)
OPA338UA: Support 2.7 V to 5.5 V (compatible)
MAX4289ESA+: Support 1 V to 5.5 V (compatible)
OPA347UA: Support 2.3 V to 5.5 V (compatible)

Operating Temperature Range:

The MCP661-E/SN operates from -40°C to 125°C. Most substitute parts operate from -40°C to 85°C, which is a narrower range. OPA347UA extends to -55°C to 125°C, matching the upper temperature limit of the MCP661-E/SN.

Package and Mechanical Compatibility:

All listed substitute parts use the 8-SOIC (0.154", 3.90mm Width) package with surface-mount configuration, ensuring direct mechanical compatibility and PCB layout compatibility with the MCP661-E/SN.

Product Status:

All substitute parts carry Active product status, indicating ongoing manufacturer support and availability.

Frequently Asked Questions (FAQ)

Q1: Can I directly replace MCP661-E/SN with AD8061ARZ in my circuit?

A: AD8061ARZ is mechanically compatible (8-SOIC package) and electrically compatible within the 2.5 V to 5.5 V supply range. However, AD8061ARZ has a maximum operating temperature of 85°C, while MCP661-E/SN supports 125°C. If your application requires operation above 85°C, AD8061ARZ is not suitable. Additionally, AD8061ARZ is a voltage feedback amplifier with significantly higher slew rate (650 V/µs vs. 32 V/µs) and bandwidth (320 MHz vs. 60 MHz), which may affect circuit behavior in bandwidth-limited applications.

Q2: What is the difference between AD8061ARZ, AD8061ARZ-REEL, and AD8061ARZ-REEL7?

A: These three part numbers are electrically and functionally identical. The differences are in packaging format: AD8061ARZ is supplied in Tube packaging, AD8061ARZ-REEL is supplied in Tape & Reel (TR) format, and AD8061ARZ-REEL7 is supplied in Cut Tape (CT) & Digi-Reel® format. Selection depends on assembly process requirements and order quantities. All three carry the same electrical specifications and ROHS3 compliance.

Q3: Why does OPA347UA have a wider operating temperature range (-55°C to 125°C) than the MCP661-E/SN (-40°C to 125°C)?

A: OPA347UA is designed for extended temperature operation and is rated for -55°C minimum, exceeding the MCP661-E/SN specification. This does not affect substitution compatibility; it indicates OPA347UA can operate in more extreme cold environments. However, OPA347UA has significantly lower bandwidth (350 kHz vs. 60 MHz) and slew rate (0.17 V/µs vs. 32 V/µs), making it unsuitable for high-speed signal processing applications.

Q4: What does Moisture Sensitivity Level (MSL) mean for part selection?

A: MSL indicates the maximum time a component can be exposed to ambient moisture before soldering. MCP661-E/SN carries MSL 1 (Unlimited), meaning no moisture sensitivity restrictions. Substitute parts with MSL 2 (1 Year) must be stored in dry conditions and used within one year of opening the package. If your supply chain or storage practices cannot accommodate MSL 2 requirements, select parts with MSL 1 rating.

Q5: Can I use MAX4289ESA+ as a substitute if my circuit operates at 1 V supply voltage?

A: MAX4289ESA+ supports a minimum supply voltage of 1 V, while MCP661-E/SN requires minimum 2.5 V. If your circuit operates at 1 V, MAX4289ESA+ is compatible with that voltage, but it is not a direct substitute for MCP661-E/SN in circuits designed for 2.5 V to 5.5 V operation. Additionally, MAX4289ESA+ has extremely low bandwidth (17 kHz) and slew rate (0.006 V/µs), suitable only for DC and very low-frequency applications.

Q6: Which substitute part has the lowest input bias current?

A: OPA338UA and OPA340UA both have input bias current of 0.2 pA, which is lower than MCP661-E/SN (6 pA). OPA347UA has 0.5 pA input bias current. Lower input bias current reduces errors in high-impedance signal conditioning circuits. However, this advantage must be weighed against other performance parameters such as bandwidth and slew rate for your specific application.

Q7: Are all substitute parts ROHS3 compliant?

A: Yes, all listed substitute parts carry ROHS3 compliance status, matching the MCP661-E/SN. This ensures compatibility with environmental regulations and procurement requirements for ROHS3-compliant assemblies.

Q8: What is the significance of "Voltage Feedback" vs. "General Purpose" amplifier type?

A: Amplifier type describes the internal architecture. General Purpose amplifiers (MCP661-E/SN, OPA338UA, OPA340UA, OPA347UA, MAX4289ESA+) are optimized for versatile applications with moderate bandwidth and slew rate. Voltage Feedback amplifiers (AD8061ARZ, AD8063ARZ series) are optimized for high-speed applications with significantly higher bandwidth and slew rate. Selection depends on your circuit's frequency response requirements.

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