LMH6646MA Equivalent & Substitute Parts

Part Overview

The LMH6646MA is a voltage feedback amplifier integrated circuit manufactured by Texas Instruments, featuring two circuits with push-pull, rail-to-rail output configuration in an 8-SOIC surface mount package. This device is classified as obsolete product status. The LMH6646MA is no longer in active production, making equivalent substitute parts necessary for new designs and ongoing system support. Active alternatives from Analog Devices Inc. provide enhanced electrical performance while maintaining package and functional compatibility.

Key Parameters

Parameter	Value
Manufacturer Part Number	LMH6646MA
Manufacturer	Texas Instruments
Category	Linear, Amplifiers
Amplifier Type	Voltage Feedback
Number of Circuits	2
Output Type	Push-Pull, Rail-to-Rail
Package / Case	8-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
Operating Temperature	-40°C ~ 85°C
Product Status	Obsolete
RoHS Status	RoHS non-compliant

Substitute Part Grouping Explanation

Substitute parts for the LMH6646MA are selected based on strict electrical and mechanical parameter compatibility. The primary substitution criteria are:

Package Compatibility: All substitute parts use the 8-SOIC surface mount package with identical 0.154" (3.90mm) width, ensuring direct PCB footprint compatibility without layout modifications.

Functional Equivalence: All substitutes provide voltage feedback amplifier topology with two circuits and rail-to-rail output capability, maintaining the core functional requirements of the original design.

Electrical Parameter Alignment: Substitute parts operate within the same supply voltage range (minimum 2.5V to 2.7V, maximum 12V) and temperature range (-40°C to 85°C), ensuring system-level compatibility.

Direct Manufacturer Equivalent: LMH6646MA/NOPB is the direct Texas Instruments equivalent with identical electrical specifications and active product status, differing only in packaging format (Tube vs. standard).

Enhanced Performance Alternatives: AD8032 series parts (AD8032ARZ, AD8032ARZ-REEL, AD8032ARZ-REEL7, AD8032BRZ, AD8032BRZ-REEL, AD8032BRZ-REEL7) from Analog Devices Inc. provide improved slew rate (35V/µs vs. 22V/µs), higher bandwidth (80 MHz vs. 55 MHz), and lower input bias current (450 nA vs. 650 nA) while maintaining package and supply voltage compatibility.

Parameter Comparison

Parameter	LMH6646MA	LMH6646MA/NOPB	AD8032ARZ	AD8032ARZ-REEL	AD8032ARZ-REEL7	AD8032BRZ	AD8032BRZ-REEL	AD8032BRZ-REEL7
Manufacturer	Texas Instruments	Texas Instruments	Analog Devices Inc.	Analog Devices Inc.	Analog Devices Inc.	Analog Devices Inc.	Analog Devices Inc.	Analog Devices Inc.
Amplifier Type	Voltage Feedback	Voltage Feedback	Voltage Feedback	Voltage Feedback	Voltage Feedback	Voltage Feedback	Voltage Feedback	Voltage Feedback
Number of Circuits	2	2	2	2	2	2	2	2
Output Type	Push-Pull, Rail-to-Rail	Push-Pull, Rail-to-Rail	Rail-to-Rail	Rail-to-Rail	Rail-to-Rail	Rail-to-Rail	Rail-to-Rail	Rail-to-Rail
Slew Rate	22 V/µs	22 V/µs	35 V/µs	35 V/µs	35 V/µs	35 V/µs	35 V/µs	35 V/µs
-3dB Bandwidth	55 MHz	55 MHz	80 MHz	80 MHz	80 MHz	80 MHz	80 MHz	80 MHz
Current - Input Bias	650 nA	650 nA	450 nA	450 nA	450 nA	450 nA	450 nA	450 nA
Voltage - Input Offset	1 mV	1 mV	1 mV	1 mV	1 mV	500 µV	500 µV	500 µV
Current - Supply	725 µA (x2 Channels)	725 µA (x2 Channels)	900 µA (x2 Channels)	900 µA (x2 Channels)	900 µA (x2 Channels)	900 µA (x2 Channels)	900 µA (x2 Channels)	900 µA (x2 Channels)
Current - Output / Channel	20 mA	20 mA	15 mA	15 mA	15 mA	15 mA	15 mA	15 mA
Voltage - Supply Span (Min)	2.5 V	2.5 V	2.7 V	2.7 V	2.7 V	2.7 V	2.7 V	2.7 V
Voltage - Supply Span (Max)	12 V	12 V	12 V	12 V	12 V	12 V	12 V	12 V
Operating Temperature	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C
Package / Case	8-SOIC (0.154", 3.90mm Width)	8-SOIC (0.154", 3.90mm Width)	8-SOIC (0.154", 3.90mm Width)	8-SOIC (0.154", 3.90mm Width)	8-SOIC (0.154", 3.90mm Width)	8-SOIC (0.154", 3.90mm Width)	8-SOIC (0.154", 3.90mm Width)	8-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Product Status	Obsolete	Active	Active	Active	Active	Active	Active	Active
RoHS Status	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

For Direct Replacement with Active Product Status: LMH6646MA/NOPB is the recommended direct substitute. This part maintains identical electrical specifications to the obsolete LMH6646MA while providing active product status from Texas Instruments. The primary difference is packaging format (Tube). This selection is appropriate for applications requiring exact electrical parameter matching and Texas Instruments sourcing continuity.

For Enhanced Performance with RoHS3 Compliance: The AD8032 series (AD8032ARZ, AD8032ARZ-REEL, AD8032ARZ-REEL7, AD8032BRZ, AD8032BRZ-REEL, AD8032BRZ-REEL7) from Analog Devices Inc. provides superior electrical performance characteristics including 59% higher slew rate (35V/µs vs. 22V/µs), 45% higher bandwidth (80 MHz vs. 55 MHz), and 31% lower input bias current (450 nA vs. 650 nA). All AD8032 variants are ROHS3 compliant and carry active product status. These parts are suitable for new designs and applications where improved dynamic performance and regulatory compliance are required.

Packaging Format Selection: AD8032ARZ and AD8032BRZ are supplied in Tube packaging. AD8032ARZ-REEL, AD8032ARZ-REEL7, AD8032BRZ-REEL, and AD8032BRZ-REEL7 are supplied in Cut Tape (CT) & Digi-Reel® format. Selection between these variants depends on procurement and assembly process requirements.

Input Offset Voltage Consideration: AD8032BRZ and AD8032BRZ-REEL variants feature 500 µV input offset voltage compared to 1 mV in AD8032ARZ variants and the original LMH6646MA. Applications requiring lower input offset voltage should specify the AD8032B grade.

Frequently Asked Questions (FAQ)

Q: Can AD8032 series parts directly replace LMH6646MA in existing designs?

A: AD8032 series parts are pin-compatible and functionally equivalent in 8-SOIC package configuration. However, the AD8032 series provides enhanced electrical performance (higher slew rate, bandwidth, and lower input bias current). Designs must accommodate the 0.2V higher minimum supply voltage (2.7V vs. 2.5V) and 5 mA lower output current per channel (15 mA vs. 20 mA). Circuit validation is required to confirm performance improvements do not introduce stability issues in existing feedback networks.

Q: What is the difference between AD8032ARZ and AD8032BRZ variants?

A: Both variants share identical slew rate (35V/µs), bandwidth (80 MHz), input bias current (450 nA), and supply current specifications. The primary difference is input offset voltage: AD8032ARZ specifies 1 mV maximum, while AD8032BRZ specifies 500 µV maximum. AD8032BRZ is the precision grade suitable for applications requiring lower DC offset performance.

Q: What packaging formats are available for AD8032 parts?

A: AD8032ARZ and AD8032BRZ are supplied in Tube packaging. AD8032ARZ-REEL, AD8032BRZ-REEL, AD8032ARZ-REEL7, and AD8032BRZ-REEL7 are supplied in Cut Tape (CT) & Digi-Reel® format. The -REEL7 designation indicates 7-inch reel format. Selection depends on assembly equipment compatibility and procurement volume requirements.

Q: Is LMH6646MA/NOPB a suitable substitute for new product designs?

A: LMH6646MA/NOPB maintains identical electrical specifications to the obsolete LMH6646MA and carries active product status from Texas Instruments. However, this part is ROHS3 compliant only in the /NOPB variant. For new designs requiring maximum performance and regulatory compliance, AD8032 series parts from Analog Devices Inc. are preferred due to superior electrical characteristics and established long-term availability.

Q: What are the supply voltage compatibility considerations?

A: LMH6646MA and LMH6646MA/NOPB operate with minimum supply voltage of 2.5V. AD8032 series parts require minimum 2.7V supply voltage. Designs operating at 2.5V to 2.6V supply voltage must use LMH6646MA/NOPB. Designs operating at 2.7V or higher can use either part family.

Q: Are all substitute parts RoHS compliant?

A: LMH6646MA is RoHS non-compliant. LMH6646MA/NOPB is ROHS3 compliant. All AD8032 series variants (AD8032ARZ, AD8032ARZ-REEL, AD8032ARZ-REEL7, AD8032BRZ, AD8032BRZ-REEL, AD8032BRZ-REEL7) are ROHS3 compliant. For applications requiring RoHS compliance, LMH6646MA/NOPB or any AD8032 variant is suitable.

Q: What is the inventory status of substitute parts?

A: LMH6646MA/NOPB has 1482 pieces in stock. AD8032ARZ has 12665 pieces in stock. AD8032ARZ-REEL has 100516 pieces in stock. AD8032ARZ-REEL7 has 46608 pieces in stock. AD8032BRZ has 7812 pieces in stock. AD8032BRZ-REEL has 2200 pieces in stock. AD8032BRZ-REEL7 has 100200 pieces in stock. AD8032ARZ-REEL and AD8032BRZ-REEL7 offer the highest inventory availability.

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