LMH6646MMX Equivalent & Substitute Parts

Part Overview

The LMH6646MMX is a voltage feedback operational amplifier manufactured by Texas Instruments, featuring dual-channel push-pull, rail-to-rail output configuration in an 8-VSSOP surface mount package. This device is classified as obsolete product status. Due to its obsolete classification, direct equivalents and active substitutes are necessary for new designs and ongoing production requirements. Substitute parts maintain functional compatibility through equivalent amplifier topology, circuit count, and electrical performance within specified operating parameters.

Key Parameters

Parameter	Value	Unit
Amplifier Type	Voltage Feedback	—
Number of Circuits	2	Channels
Output Type	Push-Pull, Rail-to-Rail	—
Slew Rate	22	V/µs
-3dB Bandwidth	55	MHz
Current - Input Bias	650	nA
Voltage - Input Offset	1	mV
Current - Supply (x2 Channels)	725	µA
Current - Output / Channel	20	mA
Voltage - Supply Span (Min)	2.5	V
Voltage - Supply Span (Max)	12	V
Operating Temperature	-40 to 85	°C
Package / Case	8-TSSOP, 8-MSOP (0.118", 3.00mm Width)	—
Mounting Type	Surface Mount	—
RoHS Status	RoHS non-compliant	—

Substitute Part Grouping Explanation

Substitution compatibility for the LMH6646MMX is determined by the following critical parameters:

Primary Compatibility Criteria:

Amplifier Type: Voltage Feedback topology
Number of Circuits: Dual-channel (2 circuits)
Output Type: Rail-to-Rail configuration
Package / Case: 8-TSSOP or 8-MSOP form factor
Mounting Type: Surface Mount
Operating Temperature Range: Minimum -40°C to 85°C coverage
Supply Voltage Range: Minimum 2.5V to 12V span compatibility

Substitution Categories:

Category 1: Direct Equivalent (Same Manufacturer) LMH6646MMX/NOPB is the direct equivalent from Texas Instruments with identical electrical specifications and packaging. This part differs only in product status (Active vs. Obsolete) and RoHS compliance (ROHS3 Compliant vs. non-compliant).

Category 2: Functional Substitutes (Enhanced Performance) AD8032ARMZ, AD8032ARMZ-REEL, and AD8032ARMZ-REEL7 from Analog Devices Inc. provide enhanced performance characteristics including higher slew rate (35V/µs vs. 22V/µs), increased bandwidth (80 MHz vs. 55 MHz), and lower input bias current (450 nA vs. 650 nA). These parts maintain dual-channel voltage feedback topology and rail-to-rail output in compatible 8-MSOP packaging.

Category 3: High-Performance Substitutes ADA4807-2ARMZ and ADA4807-2ARMZ-R7 from Analog Devices Inc. represent high-performance alternatives with significantly enhanced specifications: slew rate of 250V/µs, bandwidth of 180 MHz, and extended operating temperature to 125°C. These parts maintain dual-channel voltage feedback topology and rail-to-rail output in 8-MSOP packaging with higher output current capability (80 mA vs. 20 mA).

Parameter Comparison

Parameter	LMH6646MMX	LMH6646MMX/NOPB	AD8032ARMZ	AD8032ARMZ-REEL	AD8032ARMZ-REEL7	ADA4807-2ARMZ	ADA4807-2ARMZ-R7
Manufacturer	Texas Instruments	Texas Instruments	Analog Devices Inc.	Analog Devices Inc.	Analog Devices Inc.	Analog Devices Inc.	Analog Devices Inc.
Product Status	Obsolete	Active	Active	Active	Active	Active	Active
Amplifier Type	Voltage Feedback	Voltage Feedback	Voltage Feedback	Voltage Feedback	Voltage Feedback	Voltage Feedback	Voltage Feedback
Number of Circuits	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
Slew Rate (V/µs)	22	22	35	35	35	250	250
-3dB Bandwidth (MHz)	55	55	80	80	80	180	180
Current - Input Bias (nA)	650	650	450	450	450	1200	1200
Voltage - Input Offset (mV)	1	1	1	1	1	0.14	0.14
Current - Supply (µA, x2 Channels)	725	725	900	900	900	1000	1000
Current - Output / Channel (mA)	20	20	15	15	15	80	80
Voltage - Supply Span Min (V)	2.5	2.5	2.7	2.7	2.7	2.7	2.7
Voltage - Supply Span Max (V)	12	12	12	12	12	11	11
Operating Temperature (°C)	-40 to 85	-40 to 85	-40 to 85	-40 to 85	-40 to 85	-40 to 125	-40 to 125
Package / Case	8-TSSOP, 8-MSOP	8-TSSOP, 8-MSOP	8-TSSOP, 8-MSOP	8-TSSOP, 8-MSOP	8-TSSOP, 8-MSOP	8-TSSOP, 8-MSOP	8-TSSOP, 8-MSOP
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
RoHS Status	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Packaging Type	—	Tape & Reel (TR)	Tube	Tape & Reel (TR)	Cut Tape (CT) & Digi-Reel®	Tube	Cut Tape (CT) & Digi-Reel®
Inventory (Pcs)	1598	2172	2100	3100	20388	3300	17405

Engineering Selection Recommendations

For Direct Replacement (Obsolete to Active Transition): LMH6646MMX/NOPB is the primary selection for direct replacement. This part maintains identical electrical specifications and mechanical compatibility while transitioning from obsolete to active product status. The part is ROHS3 compliant, addressing regulatory requirements for new production. Inventory availability of 2172 pieces supports production continuity.

For Enhanced Performance Requirements: AD8032ARMZ, AD8032ARMZ-REEL, or AD8032ARMZ-REEL7 are suitable when improved performance characteristics are acceptable within the application design. These parts provide 59% higher slew rate (35V/µs vs. 22V/µs) and 45% increased bandwidth (80 MHz vs. 55 MHz) while maintaining dual-channel voltage feedback topology and rail-to-rail output. All variants are ROHS3 compliant and active products. AD8032ARMZ-REEL7 offers the highest inventory availability (20388 pieces) in Cut Tape & Digi-Reel packaging format.

For High-Performance Applications: ADA4807-2ARMZ or ADA4807-2ARMZ-R7 are applicable when significantly enhanced performance is required. These parts deliver 11.4x higher slew rate (250V/µs vs. 22V/µs), 3.3x increased bandwidth (180 MHz vs. 55 MHz), and 4x higher output current capability (80 mA vs. 20 mA). Extended operating temperature range to 125°C supports high-temperature environments. Both variants are ROHS3 compliant and active products. ADA4807-2ARMZ-R7 provides superior inventory availability (17405 pieces) in Cut Tape & Digi-Reel packaging.

Compliance Considerations: All substitute parts are ROHS3 compliant, addressing environmental and regulatory requirements. The original LMH6646MMX is RoHS non-compliant; transition to compliant alternatives is necessary for new designs and production batches subject to RoHS directives.

Frequently Asked Questions (FAQ)

Q1: Can LMH6646MMX/NOPB be used as a direct replacement for LMH6646MMX?

A: Yes. LMH6646MMX/NOPB is the direct equivalent with identical electrical specifications, circuit configuration, and mechanical packaging. The primary differences are product status (Active vs. Obsolete) and RoHS compliance (ROHS3 Compliant vs. non-compliant). No circuit redesign is required.

Q2: What are the key differences between AD8032ARMZ and the original LMH6646MMX?

A: AD8032ARMZ maintains dual-channel voltage feedback topology and rail-to-rail output in compatible 8-MSOP packaging. Performance enhancements include higher slew rate (35V/µs vs. 22V/µs), increased bandwidth (80 MHz vs. 55 MHz), and lower input bias current (450 nA vs. 650 nA). Supply voltage range shifts from 2.5V minimum to 2.7V minimum. Output current per channel decreases from 20 mA to 15 mA.

Q3: When should ADA4807-2ARMZ be selected over AD8032ARMZ?

A: ADA4807-2ARMZ is selected when high-speed, high-current applications require significantly enhanced performance. This part provides 250V/µs slew rate (vs. 35V/µs for AD8032ARMZ), 180 MHz bandwidth (vs. 80 MHz), and 80 mA output current per channel (vs. 15 mA). Extended operating temperature to 125°C supports thermal-demanding environments. Trade-offs include higher supply current (1 mA vs. 900 µA per dual channels) and higher input bias current (1.2 µA vs. 450 nA).

Q4: Are all substitute parts compatible with the 8-VSSOP package specification?

A: All substitute parts are specified for 8-TSSOP and 8-MSOP (0.118", 3.00mm Width) packages. The original LMH6646MMX uses 8-VSSOP supplier device package designation. The 8-MSOP and 8-TSSOP packages are mechanically and electrically compatible for surface mount applications with identical pin configurations and spacing.

Q5: What packaging options are available for the AD8032 series?

A: Three packaging variants are available: AD8032ARMZ (Tube), AD8032ARMZ-REEL (Tape & Reel), and AD8032ARMZ-REEL7 (Cut Tape & Digi-Reel). Selection depends on production volume and assembly process requirements. AD8032ARMZ-REEL7 offers the highest inventory availability (20388 pieces) and is suitable for high-volume automated assembly.

Q6: What is the minimum supply voltage requirement for substitute parts?

A: LMH6646MMX and LMH6646MMX/NOPB support 2.5V minimum supply voltage. AD8032 series and ADA4807-2 series require 2.7V minimum supply voltage. Applications operating below 2.7V must use the original LMH6646MMX or LMH6646MMX/NOPB.

Q7: Do all substitute parts meet RoHS compliance requirements?

A: Yes. All substitute parts listed (LMH6646MMX/NOPB, AD8032ARMZ variants, and ADA4807-2ARMZ variants) are ROHS3 compliant. The original LMH6646MMX is RoHS non-compliant and should be replaced with compliant alternatives for new production.

Q8: How does input offset voltage compare across substitute options?

A: LMH6646MMX, LMH6646MMX/NOPB, and AD8032 series specify 1 mV input offset voltage. ADA4807-2ARMZ and ADA4807-2ARMZ-R7 provide superior offset voltage specification of 140 µV, offering 7.1x better precision for precision analog applications.

Q9: What is the maximum operating temperature for each substitute?

A: LMH6646MMX, LMH6646MMX/NOPB, and AD8032 series support -40°C to 85°C operating range. ADA4807-2ARMZ and ADA4807-2ARMZ-R7 extend the maximum operating temperature to 125°C, supporting high-temperature industrial and automotive applications.

Q10: Are there inventory considerations for part selection?

A: Current inventory levels vary: LMH6646MMX/NOPB (2172 pcs), AD8032ARMZ (2100 pcs), AD8032ARMZ-REEL (3100 pcs), AD8032ARMZ-REEL7 (20388 pcs), ADA4807-2ARMZ (3300 pcs), and ADA4807-2ARMZ-R7 (17405 pcs). AD8032ARMZ-REEL7 and ADA4807-2ARMZ-R7 offer the highest availability for high-volume production requirements.

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