MST6940C Equivalent & Substitute Parts

Part Overview

The MST6940C is a red 7-segment LED display module manufactured by onsemi, featuring a 3-character common cathode configuration with 0.56" digit height. This component is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production requirements. The display operates at 2V forward voltage with a 20mA test current and is housed in a 28-DIP package.

Substiute Parts

MST6940C

onsemiIn Stock: 817MST6940C Datasheet

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LB-603VP

Rohm SemiconductorIn Stock: 1311LB-603VP Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the MST6940C is determined by the following critical parameters:

• Display Type: 7-Segment configuration
• Number of Characters: 3-character module
• Digit/Alpha Size: 0.56" nominal dimension
• Common Pin Configuration: Common Cathode
• Color: Red
• Voltage - Forward (Vf): 2V nominal
• Package / Case: 28-DIP (0.600", 15.24mm)

The LB-603VP from Rohm Semiconductor meets all primary substitution criteria. While secondary parameters such as test current (10mA vs. 20mA), millicandela rating, and wavelength differ, these variations remain within acceptable tolerances for equivalent functionality in 7-segment display applications.

Parameter Comparison

Engineering Selection Recommendations

The LB-603VP is a direct functional equivalent for MST6940C applications. Selection should be based on the following factors:

Product Status: The MST6940C is obsolete, while the LB-603VP is active. For new designs and production continuity, the LB-603VP is the appropriate choice.

Compliance: The LB-603VP carries ROHS3 compliance certification, meeting current regulatory requirements. Both parts are REACH Unaffected and classified as EAR99 for export control purposes.

Electrical Compatibility: Both parts operate at 2V forward voltage and are housed in identical 28-DIP packages, ensuring direct PCB compatibility. The LB-603VP operates at lower test current (10mA vs. 20mA), reducing power consumption in equivalent applications.

Physical Dimensions: Digit height specifications are nominally equivalent (0.56"), with overall module dimensions within 0.043" variance, maintaining visual consistency in display applications.

Frequently Asked Questions (FAQ)

Q: Can the LB-603VP directly replace the MST6940C on existing PCBs?

A: Yes. Both parts share identical 28-DIP package dimensions and pinout configuration. No PCB modifications are required for direct substitution.

Q: What is the significance of the different test currents (20mA vs. 10mA)?

A: Test current specifications indicate the current level at which brightness and electrical characteristics are measured. The LB-603VP's lower test current reflects improved LED efficiency while maintaining 2V forward voltage compatibility.

Q: Are there differences in display brightness between these parts?

A: The LB-603VP has a higher millicandela rating (16mcd vs. 2.2mcd), indicating greater brightness output. This represents an improvement over the obsolete MST6940C.

Q: What is the wavelength difference between 635nm and 650nm?

A: Both wavelengths fall within the red spectrum. The 650nm wavelength of the LB-603VP represents a slightly longer wavelength, appearing as a deeper red compared to the 635nm of the MST6940C. This difference is typically imperceptible in most applications.

Q: Is the LB-603VP suitable for new product designs?

A: Yes. The LB-603VP is active product status with ROHS3 compliance, making it the appropriate choice for new designs requiring a 3-character, 0.56" red 7-segment common cathode display in 28-DIP packaging.