LMH6646MM Equivalent & Substitute Parts

Part Overview

The LMH6646MM is a voltage feedback operational amplifier featuring dual circuits with push-pull, rail-to-rail output configuration in an 8-VSSOP surface mount package. Manufactured by Texas Instruments, this component is classified as Last Time Buy, indicating discontinued production with limited inventory availability. The LMH6646MM operates across a 2.5V to 12V supply range with a slew rate of 22V/µs and -3dB bandwidth of 55 MHz, suitable for general-purpose analog signal conditioning and amplification applications.

Due to Last Time Buy status, identification of equivalent and substitute parts is necessary to ensure design continuity and long-term component availability for production and maintenance applications.

Key Parameters

Parameter	Value	Unit
Amplifier Type	Voltage Feedback	—
Number of Circuits	2	—
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 (per Channel)	725	µA
Current - Output / Channel	20	mA
Voltage - Supply Span (Min)	2.5	V
Voltage - Supply Span (Max)	12	V
Operating Temperature Range	-40 to 85	°C
Package / Case	8-TSSOP, 8-MSOP (0.118", 3.00mm Width)	—
Mounting Type	Surface Mount	—
RoHS Status	ROHS3 Compliant	—
Moisture Sensitivity Level	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitute parts for the LMH6646MM are grouped into two categories based on electrical and mechanical compatibility:

Category 1: Direct Texas Instruments Equivalents

LMH6646MM/NOPB
LMH6646MMX/NOPB

These parts share identical electrical specifications with the main part number, including slew rate (22V/µs), bandwidth (55 MHz), input bias current (650 nA), and output current (20 mA). Differences exist only in packaging configuration (Tape & Reel versus bulk) and product status (Active versus Last Time Buy). Both maintain the same 8-VSSOP supplier device package and surface mount configuration.

Category 2: Analog Devices Substitutes with Enhanced Performance

AD8032ARMZ
AD8032ARMZ-REEL
AD8032ARMZ-REEL7
ADA4807-2ARMZ
ADA4807-2ARMZ-R7

These parts provide voltage feedback amplifier functionality with dual circuits and rail-to-rail output in compatible 8-MSOP surface mount packages. The AD8032 series offers improved slew rate (35V/µs) and bandwidth (80 MHz) compared to the LMH6646MM. The ADA4807-2 series provides significantly enhanced performance with 250V/µs slew rate and 180 MHz bandwidth, suitable for applications requiring higher-speed signal processing.

All substitute parts maintain compatibility with the 2.5V minimum supply voltage requirement and operate within the -40°C to 85°C temperature range (ADA4807-2 extends to 125°C). Package footprints are mechanically compatible with 8-TSSOP and 8-MSOP configurations.

Parameter Comparison

Part Number	Manufacturer	Slew Rate (V/µs)	-3dB Bandwidth (MHz)	Input Bias Current (nA)	Output Current / Channel (mA)	Supply Current / Channel (µA)	Supply Voltage Min (V)	Supply Voltage Max (V)	Temp Range (°C)	Package	Product Status
LMH6646MM	Texas Instruments	22	55	650	20	725	2.5	12	-40 to 85	8-VSSOP	Last Time Buy
LMH6646MM/NOPB	Texas Instruments	22	55	650	20	725	2.5	12	-40 to 85	8-VSSOP	Active
LMH6646MMX/NOPB	Texas Instruments	22	55	650	20	725	2.5	12	-40 to 85	8-VSSOP	Active
AD8032ARMZ	Analog Devices Inc.	35	80	450	15	900	2.7	12	-40 to 85	8-MSOP	Active
AD8032ARMZ-REEL	Analog Devices Inc.	35	80	450	15	900	2.7	12	-40 to 85	8-MSOP	Active
AD8032ARMZ-REEL7	Analog Devices Inc.	35	80	450	15	900	2.7	12	-40 to 85	8-MSOP	Active
ADA4807-2ARMZ	Analog Devices Inc.	250	180	1200	80	1000	2.7	11	-40 to 125	8-MSOP	Active
ADA4807-2ARMZ-R7	Analog Devices Inc.	250	180	1200	80	1000	2.7	11	-40 to 125	8-MSOP	Active

Engineering Selection Recommendations

For Direct Replacement (Identical Electrical Performance):

Select LMH6646MM/NOPB or LMH6646MMX/NOPB when exact electrical specifications and performance characteristics must be maintained. Both parts are Active status products with current manufacturing support, ensuring long-term availability. These options are appropriate for designs where the 22V/µs slew rate and 55 MHz bandwidth are specified requirements and cannot be altered. Both maintain ROHS3 compliance and MSL Level 1 rating identical to the original part.

For Performance Enhancement with Compatibility:

The AD8032ARMZ series (AD8032ARMZ, AD8032ARMZ-REEL, AD8032ARMZ-REEL7) provides improved performance margins while maintaining mechanical and functional compatibility. These parts offer 59% higher slew rate (35V/µs versus 22V/µs) and 45% greater bandwidth (80 MHz versus 55 MHz). Input bias current is reduced to 450 nA, and all variants are Active status with robust inventory levels. The minimum supply voltage increases to 2.7V, which remains compatible with most 2.5V-specified designs operating at nominal or higher supply levels. Selection among AD8032ARMZ variants depends on packaging requirements: tube packaging for AD8032ARMZ, standard Tape & Reel for AD8032ARMZ-REEL, and Cut Tape with Digi-Reel for AD8032ARMZ-REEL7.

For High-Speed Applications:

The ADA4807-2ARMZ and ADA4807-2ARMZ-R7 are suitable only when application requirements demand significantly higher performance specifications. These parts feature 250V/µs slew rate and 180 MHz bandwidth, representing 11.4x and 3.3x improvements respectively over the LMH6646MM. Output current capability increases to 80 mA per channel. Operating temperature range extends to 125°C. However, input bias current increases to 1.2 µA and supply current to 1 mA per channel. Maximum supply voltage is limited to 11V. These parts are appropriate only when circuit design has been verified to accommodate the higher performance characteristics and modified electrical parameters.

All substitute options maintain ROHS3 compliance, MSL Level 1 rating, and surface mount configuration compatible with existing PCB layouts designed for 8-pin TSSOP/MSOP packages.

Frequently Asked Questions (FAQ)

Q: Can LMH6646MM/NOPB be used as a direct replacement for LMH6646MM?

A: Yes. LMH6646MM/NOPB provides identical electrical specifications, including slew rate (22V/µs), bandwidth (55 MHz), input bias current (650 nA), and output current (20 mA). The only difference is packaging configuration (Tape & Reel) and product status (Active versus Last Time Buy). Both use the same 8-VSSOP package and surface mount configuration.

Q: What are the key differences between the AD8032ARMZ and LMH6646MM?

A: The AD8032ARMZ offers improved performance with 35V/µs slew rate (versus 22V/µs), 80 MHz bandwidth (versus 55 MHz), and lower input bias current of 450 nA (versus 650 nA). Supply current increases to 900 µA per channel. The minimum supply voltage is 2.7V instead of 2.5V. Both maintain dual-circuit, rail-to-rail configuration in compatible 8-MSOP packages. The AD8032ARMZ is Active status with higher inventory availability.

Q: Can the ADA4807-2ARMZ replace the LMH6646MM in any application?

A: The ADA4807-2ARMZ provides significantly enhanced performance but introduces different electrical characteristics that may require circuit redesign. Input bias current increases to 1.2 µA, supply current to 1 mA per channel, and maximum supply voltage is limited to 11V. The ADA4807-2ARMZ is appropriate only when application requirements specifically demand 250V/µs slew rate and 180 MHz bandwidth, and circuit design has been verified to accommodate these parameters.

Q: What is the difference between AD8032ARMZ-REEL and AD8032ARMZ-REEL7?

A: Both parts have identical electrical specifications. The difference is packaging format: AD8032ARMZ-REEL uses standard Tape & Reel packaging, while AD8032ARMZ-REEL7 uses Cut Tape with Digi-Reel format. AD8032ARMZ-REEL7 has significantly higher inventory (20,388 pcs versus 3,100 pcs). Selection depends on assembly equipment compatibility and procurement requirements.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All listed substitute parts—LMH6646MM/NOPB, LMH6646MMX/NOPB, AD8032ARMZ series, and ADA4807-2ARMZ series—are ROHS3 compliant with MSL Level 1 (Unlimited) moisture sensitivity rating, matching the original LMH6646MM specifications.

Q: What is the minimum supply voltage compatibility for substitutes?

A: The LMH6646MM operates at 2.5V minimum. Direct equivalents (LMH6646MM/NOPB, LMH6646MMX/NOPB) maintain this specification. The AD8032ARMZ series requires 2.7V minimum, and the ADA4807-2ARMZ series also requires 2.7V minimum. Designs operating at 2.5V supply must use direct Texas Instruments equivalents or verify that actual operating supply voltage is 2.7V or higher.

Q: Can these parts be used interchangeably on the same PCB?

A: LMH6646MM, LMH6646MM/NOPB, and LMH6646MMX/NOPB are mechanically and electrically interchangeable. The AD8032ARMZ series and ADA4807-2ARMZ series use 8-MSOP packages compatible with 8-TSSOP/8-MSOP footprints, but electrical parameter differences require circuit verification before substitution. Footprint compatibility does not guarantee functional equivalence.

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