MAX931CUA-T Equivalent & Substitute Parts

Part Overview

The MAX931CUA-T is a comparator with integrated voltage reference manufactured by Analog Devices Inc./Maxim Integrated. This single-element CMOS/TTL comparator operates across 2.5V to 11V single supply or ±1.25V to ±5.5V dual supply configurations. The part is classified as obsolete, necessitating identification of active equivalent alternatives for new designs and production continuity. Substitute parts must maintain functional compatibility across supply voltage ranges, output characteristics, and thermal operating windows while accommodating available packaging options.

Key Parameters

Parameter	MAX931CUA-T	Unit
Supply Voltage (Single/Dual)	2.5V ~ 11V / ±1.25V ~ 5.5V	V
Input Offset Voltage (Max)	10	mV @ 5V
Output Type	CMOS, TTL	—
Quiescent Current (Max)	4	µA
CMRR / PSRR (Typ)	80 / 80	dB
Propagation Delay (Max)	12	µs
Hysteresis	50	mV
Operating Temperature	0°C ~ 70°C	—
Package	8-TSSOP, 8-MSOP (0.118", 3.00mm)	—
Product Status	Obsolete	—

Substitute Part Grouping Explanation

Substitution eligibility is determined by the following criteria:

Primary Compatibility Parameters:

Supply voltage range must encompass or match the original specification (2.5V ~ 11V single / ±1.25V ~ 5.5V dual)
Output type must support CMOS and TTL logic levels
Package form factor must be compatible with 8-pin surface mount configurations
Hysteresis value of 50mV is a defining characteristic for this comparator class

Secondary Compatibility Parameters:

Input offset voltage tolerance (≤10mV @ 5V preferred)
Quiescent current performance (≤4.4µA acceptable)
Propagation delay (≤15µs acceptable for timing-critical applications)
Operating temperature range (minimum 0°C ~ 70°C required; extended range acceptable)

Substitute Categories:

Direct Packaging Equivalent: MAX931CUA+T (Tape & Reel variant of same base product, Active status)
Functional Equivalents (8-MSOP Package): LTC1440 and LTC1540 series from Analog Devices Inc. maintain identical supply voltage ranges, hysteresis, CMRR/PSRR, and thermal specifications. These parts are available in multiple temperature grades and packaging options.
Cross-Manufacturer Alternative: LMP7300MAX/NOPB (Texas Instruments) offers superior input offset voltage (0.75mV vs. 10mV) and extended operating temperature range (-40°C ~ 125°C) with compatible supply voltage envelope, though package form differs (8-SOIC vs. 8-MSOP).

Parameter Comparison

Part Number	Manufacturer	Supply Voltage	Input Offset (Max)	Output Type	Quiescent Current (Max)	Propagation Delay (Max)	Hysteresis	Operating Temp	Package	Status
MAX931CUA-T	Analog Devices	2.5V~11V / ±1.25V~5.5V	10mV @ 5V	CMOS, TTL	4µA	12µs	50mV	0°C ~ 70°C	8-TSSOP/MSOP	Obsolete
MAX931CUA+T	Analog Devices	2.5V~11V / ±1.25V~5.5V	10mV @ 5V	CMOS, TTL	4µA	12µs	50mV	0°C ~ 70°C	8-TSSOP/MSOP	Active
LTC1440CMS8#PBF	Analog Devices	2V~11V / ±1V~5.5V	10mV @ 5V	CMOS, TTL	4.4µA	15µs	50mV	0°C ~ 70°C	8-MSOP	Active
LTC1440CMS8#TRPBF	Analog Devices	2V~11V / ±1V~5.5V	10mV @ 5V	CMOS, TTL	4.4µA	15µs	50mV	0°C ~ 70°C	8-MSOP	Active
LTC1440IMS8#PBF	Analog Devices	2V~11V / ±1V~5.5V	10mV @ 5V	CMOS, TTL	4.4µA	15µs	50mV	-40°C ~ 85°C	8-MSOP	Active
LTC1440IMS8#TRPBF	Analog Devices	2V~11V / ±1V~5.5V	10mV @ 5V	CMOS, TTL	4.4µA	15µs	50mV	-40°C ~ 85°C	8-MSOP	Active
LTC1540CMS8#PBF	Analog Devices	2V~11V / ±1V~5.5V	12mV @ 5V	CMOS, TTL	680nA	60µs	50mV	0°C ~ 70°C	8-MSOP	Active
LTC1540CMS8#TRPBF	Analog Devices	2V~11V / ±1V~5.5V	12mV @ 5V	CMOS, TTL	680nA	60µs	50mV	0°C ~ 70°C	8-MSOP	Active
LTC1540IMS8#PBF	Analog Devices	2V~11V / ±1V~5.5V	12mV @ 5V	CMOS, TTL	710nA	60µs	50mV	-40°C ~ 85°C	8-MSOP	Active
LTC1540IMS8#TRPBF	Analog Devices	2V~11V / ±1V~5.5V	12mV @ 5V	CMOS, TTL	710nA	60µs	50mV	-40°C ~ 85°C	8-MSOP	Active
LMP7300MAX/NOPB	Texas Instruments	2.7V~12V / ±1.35V~6V	0.75mV @ 5V	CMOS, Open-Collector, TTL	13µA	15µs	1mV	-40°C ~ 125°C	8-SOIC	Active

Engineering Selection Recommendations

Tier 1 - Direct Replacement (Identical Specifications): MAX931CUA+T is the active production equivalent of MAX931CUA-T. Both parts share identical electrical specifications, thermal range, and packaging. This part is recommended for designs requiring no modification and is currently in active production status with 3,743 units in stock.

Tier 2 - Functional Equivalents (Analog Devices LTC Series): The LTC1440 and LTC1540 families provide active alternatives with compatible supply voltage ranges and 50mV hysteresis. Selection between these families depends on application requirements:

LTC1440 series: Maintains 10mV input offset voltage and 4.4µA quiescent current, matching original performance characteristics. Available in commercial (0°C ~ 70°C) and industrial (-40°C ~ 85°C) temperature grades.
LTC1540 series: Offers ultra-low quiescent current (680nA to 710nA) for power-constrained applications, with acceptable 12mV input offset voltage and extended propagation delay (60µs). Suitable for battery-powered or low-power standby circuits.

Both families are available in Tube and Tape & Reel packaging options. All LTC variants maintain ROHS3 compliance and MSL Level 1 moisture sensitivity.

Tier 3 - Cross-Manufacturer Alternative (Texas Instruments LMP7300MAX/NOPB): The LMP7300MAX/NOPB offers superior precision (0.75mV input offset) and extended operating temperature range (-40°C ~ 125°C). The 8-SOIC package requires PCB layout modification. The 1mV hysteresis differs significantly from the 50mV specification, making this suitable only for applications where reduced hysteresis is beneficial or irrelevant. Quiescent current is higher at 13µA.

Compliance and Certification: All substitute parts maintain ROHS3 compliance, MSL Level 1 moisture sensitivity, and REACH unaffected status, matching the original part's regulatory profile.

Frequently Asked Questions (FAQ)

Q: Can MAX931CUA+T be used as a direct drop-in replacement for MAX931CUA-T? A: Yes. MAX931CUA+T is the active production variant with identical electrical specifications, operating temperature range, and 8-TSSOP/8-MSOP packaging. The only difference is product status (Active vs. Obsolete) and packaging format (Tape & Reel vs. standard). No circuit modifications are required.

Q: What is the key difference between LTC1440 and LTC1540 series? A: The LTC1540 series features ultra-low quiescent current (680nA to 710nA) compared to LTC1440 (4.4µA), making it suitable for power-sensitive applications. The LTC1540 has a longer propagation delay (60µs vs. 15µs) and slightly higher input offset voltage (12mV vs. 10mV). Both maintain 50mV hysteresis and compatible supply voltage ranges.

Q: Are LTC1440 and LTC1540 parts pin-compatible with MAX931CUA-T? A: Yes. All parts use 8-pin MSOP/TSSOP packages with identical pinouts. However, the LTC series are supplied in 8-MSOP form factor while MAX931CUA-T uses 8-TSSOP/8-MSOP. Both package variants are mechanically compatible with standard 8-pin surface mount footprints.

Q: What does the suffix in part numbers like #PBF, #TRPBF, and +T indicate? A: #PBF indicates Tube packaging (standard reel). #TRPBF indicates Tape & Reel packaging for automated assembly. The +T suffix on MAX931CUA+T denotes Tape & Reel format. Selection depends on assembly method: manual assembly typically uses Tube packaging, while high-volume automated assembly uses Tape & Reel.

Q: Can LMP7300MAX/NOPB replace MAX931CUA-T in all applications? A: LMP7300MAX/NOPB is functionally compatible but not a direct replacement. Key differences include: 8-SOIC package (requires PCB redesign), 1mV hysteresis (vs. 50mV), higher quiescent current (13µA vs. 4µA), and superior input offset voltage (0.75mV vs. 10mV). Use this part only when extended temperature range (-40°C ~ 125°C) and precision offset voltage are required.

Q: What is the inventory status for substitute parts? A: MAX931CUA+T has 3,743 units in stock. LTC1440 variants range from 2,126 to 4,221 units. LTC1540 variants range from 1,410 to 3,600 units. LMP7300MAX/NOPB has 1,500 units available. All parts are classified as New Original In Stock.

Q: Are all substitute parts ROHS3 compliant? A: Yes. MAX931CUA-T, MAX931CUA+T, all LTC1440 variants, all LTC1540 variants, and LMP7300MAX/NOPB are ROHS3 compliant with MSL Level 1 moisture sensitivity and REACH unaffected status.

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