MST6911C 7-Segment Display - Equivalent & Substitute Parts

Part Overview

The MST6911C is a 3-character red 7-segment LED display module manufactured by onsemi, featuring a 0.56" digit size in a 12-DIP package configuration. This component is classified as obsolete, making identification of functionally equivalent substitute parts essential for ongoing design support and production continuity. The display operates at 2V forward voltage with 20mA test current and delivers 2.2mcd brightness at a 635nm wavelength peak.

Substiute Parts

MST6911C

onsemiIn Stock: 770MST6911C Datasheet

Current PartRFQ

LTC-561HR

Lite-On Inc.In Stock: 696LTC-561HR Datasheet

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LTC-561P

Lite-On Inc.In Stock: 1092LTC-561P Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the MST6911C is determined by the following critical parameters:

• Number of Characters: Must be 3 characters to maintain display capacity
• Digit/Alpha Size: Must be 0.56" (14.22mm) for mechanical and optical compatibility
• Display Type: Must be 7-Segment for functional equivalence
• Common Pin Configuration: Must be Common Anode to preserve circuit topology
• Color: Must be Red to maintain wavelength consistency
• Voltage - Forward (Vf): Operating range tolerance of ±0.1V acceptable
• Current - Test: Must be 20mA for driver circuit compatibility
• Package / Case: Must be 12-DIP for PCB footprint compatibility

Based on these criteria, the LTC-561P from Lite-On Inc. qualifies as a direct substitute. The LTC-561HR does not qualify due to a 2-character configuration instead of the required 3-character display.

Parameter Comparison

Engineering Selection Recommendations

The LTC-561P from Lite-On Inc. is the qualified substitute for the obsolete MST6911C. Selection rationale is based on the following factors:

• Product Status: LTC-561P maintains active production status, ensuring supply chain continuity and long-term availability compared to the obsolete MST6911C.
• Regulatory Compliance: LTC-561P carries ROHS3 compliance certification, meeting current environmental and material restriction requirements.
• Electrical Compatibility: Forward voltage differential of 0.1V (2.1V vs. 2V) remains within acceptable operating tolerances for standard LED driver circuits. Test current specification of 20mA is identical.
• Mechanical Compatibility: 12-DIP package configuration and 0.56" digit size ensure direct PCB footprint compatibility without layout modifications.
• Functional Equivalence: 3-character display capacity, 7-segment architecture, and common anode configuration preserve circuit topology and software compatibility.

Design considerations: The LTC-561P exhibits lower brightness (0.95mcd vs. 2.2mcd) and operates at a longer wavelength (697nm vs. 635nm), resulting in a more orange-red appearance. Power dissipation is reduced to 40mW maximum. These optical and thermal characteristics should be evaluated against application-specific visibility and thermal management requirements.

Frequently Asked Questions (FAQ)

Q: Can the LTC-561HR be used as a substitute for the MST6911C?

A: No. The LTC-561HR is a 2-character display, while the MST6911C requires 3-character capacity. Character count is a non-negotiable substitution parameter for display modules.

Q: What is the significance of the wavelength difference between MST6911C (635nm) and LTC-561P (697nm)?

A: The 62nm wavelength shift results in a perceptually different red color. The MST6911C produces a pure red appearance, while the LTC-561P appears more orange-red. Visual compatibility depends on application requirements and user perception standards.

Q: Is the forward voltage difference of 0.1V (2V vs. 2.1V) acceptable?

A: Yes. The 0.1V differential is within standard LED operating tolerances and does not require circuit redesign for typical driver configurations using current-limiting resistors or constant-current sources.

Q: Will the reduced brightness of LTC-561P (0.95mcd vs. 2.2mcd) affect display visibility?

A: Brightness reduction is application-dependent. Ambient lighting conditions, viewing distance, and required contrast ratios determine whether the lower millicandela rating is acceptable. Applications requiring high-brightness operation in bright environments may require evaluation.

Q: Are there any PCB layout modifications required when substituting LTC-561P for MST6911C?

A: No. Both components use identical 12-DIP package configuration with 0.56" digit size. Direct footprint compatibility eliminates layout modifications.

Q: What is the advantage of LTC-561P regarding power dissipation?

A: The LTC-561P maximum power dissipation of 40mW is 43% lower than the MST6911C at 70mW. This reduction decreases thermal load on the PCB and driver circuitry, potentially improving system reliability in thermally constrained applications.

Q: Does ROHS3 compliance of LTC-561P affect compatibility with existing designs?

A: No. ROHS3 compliance indicates adherence to material restriction directives and does not alter electrical or mechanical compatibility. It represents an environmental and regulatory advantage for new production runs.