LM77CIMX-5 Temperature Sensor Equivalent & Substitute Parts

Part Overview

The LM77CIMX-5 is a digital temperature sensor manufactured by Texas Instruments, designed for local temperature measurement across the -55°C to 125°C range with 9-bit resolution and I2C output interface. The device operates on supply voltages between 3V and 5.5V and features programmable limit thresholds, output switch capability, and shutdown mode functionality. This part is classified as obsolete, making equivalent substitute components necessary for new designs and ongoing production requirements.

Key Parameters

Parameter	Value
Sensor Type	Digital, Local
Sensing Temperature Range	-55°C ~ 125°C
Resolution	9 bits
Output Type	I2C
Supply Voltage	3V ~ 5.5V
Accuracy	±1.5°C (±3°C)
Operating Temperature	-55°C ~ 125°C
Package	8-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
Features	Output Switch, Programmable Limit, Shutdown Mode

Substitute Part Grouping Explanation

Substitution for the LM77CIMX-5 is determined by the following critical parameters: I2C serial communication interface, local temperature sensing capability, operating temperature range of -55°C to 125°C, 9-bit resolution, and 8-pin surface mount packaging. The substitute parts are grouped into two categories based on these electrical and mechanical compatibility criteria.

Category 1: Direct Texas Instruments Equivalent The LM77CIMX-5/NOPB maintains identical electrical specifications and packaging to the main part, with the primary distinction being product status (active versus obsolete) and RoHS compliance level.

Category 2: Microchip MCP9844 Series The MCP9844T-BE/MNY, MCP9844T-BE/MNYAA, and MCP9844T-BE/MNYAB variants provide functional equivalence through I2C interface compatibility and overlapping temperature sensing range (-40°C to 125°C). These parts differ in packaging format (Cut Tape, Tape & Reel configurations) and supply voltage range (1.7V ~ 3.6V versus 3V ~ 5.5V), requiring circuit-level evaluation for voltage compatibility.

Parameter Comparison

Parameter	LM77CIMX-5	LM77CIMX-5/NOPB	MCP9844T-BE/MNY	MCP9844T-BE/MNYAA	MCP9844T-BE/MNYAB
Manufacturer	Texas Instruments	Texas Instruments	Microchip Technology	Microchip Technology	Microchip Technology
Product Status	Obsolete	Active	Active	Active	Active
Output Type	I2C	I2C	2-Wire Serial, I2C	2-Wire Serial, I2C	2-Wire Serial, I2C
Operating Temperature	-55°C ~ 125°C	-55°C ~ 125°C	-40°C ~ 125°C	-40°C ~ 125°C	-40°C ~ 125°C
Supply Voltage	3V ~ 5.5V	3V ~ 5.5V	1.7V ~ 3.6V	1.7V ~ 3.6V	1.7V ~ 3.6V
Accuracy	±1.5°C (±3°C)	±1.5°C (±3°C)	±3°C (Max)	±3°C (Max)	±3°C (Max)
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
RoHS Status	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)

Engineering Selection Recommendations

For Direct Replacement: The LM77CIMX-5/NOPB is the primary substitute, offering identical electrical and thermal specifications while providing active product status and ROHS3 compliance. This part is suitable for applications requiring no circuit modification.

For New Designs: The Microchip MCP9844T-BE series (MNY, MNYAA, MNYAB variants) provides functional equivalence with active product status and full RoHS3 compliance. Selection among these variants depends on packaging requirements (Cut Tape versus Tape & Reel). Circuit design must account for the reduced supply voltage range (1.7V ~ 3.6V) compared to the original part's 3V ~ 5.5V specification.

Compliance Considerations: All substitute parts maintain REACH unaffected status and EAR99 export classification. The transition from RoHS non-compliant to ROHS3 compliant alternatives aligns with current regulatory requirements for electronic component procurement.

Frequently Asked Questions (FAQ)

Q: Can the MCP9844T-BE series directly replace the LM77CIMX-5 without circuit modification? A: The MCP9844T-BE series provides I2C interface compatibility and overlapping temperature sensing capability. However, the reduced supply voltage range (1.7V ~ 3.6V versus 3V ~ 5.5V) requires verification of circuit power supply specifications. Pin-to-pin compatibility must be confirmed through datasheet review before implementation.

Q: What is the primary difference between LM77CIMX-5 and LM77CIMX-5/NOPB? A: The LM77CIMX-5/NOPB is the active production variant with ROHS3 compliance, while the original LM77CIMX-5 is obsolete and RoHS non-compliant. Electrical and thermal specifications are identical.

Q: How do the MCP9844T-BE packaging variants differ? A: MCP9844T-BE/MNY is supplied in Cut Tape format, MCP9844T-BE/MNYAA in Tape & Reel format, and MCP9844T-BE/MNYAB in unspecified packaging. Selection depends on procurement and assembly requirements.

Q: Is the accuracy difference between LM77CIMX-5 (±1.5°C) and MCP9844T-BE (±3°C) significant for substitution? A: The MCP9844T-BE series exhibits lower accuracy specification. Applications requiring ±1.5°C accuracy must evaluate whether ±3°C maximum accuracy is acceptable for the intended function.

Q: What is the minimum operating temperature difference between the original part and Microchip substitutes? A: The LM77CIMX-5 operates to -55°C, while MCP9844T-BE variants operate to -40°C minimum. Applications requiring operation below -40°C must use the LM77CIMX-5/NOPB or original part.

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