LTD-2701B Equivalent & Substitute Parts

Part Overview

The LTD-2701B is a blue 7-segment LED display module manufactured by Lite-On Inc., featuring a 2-character common cathode configuration in a 10-DIP package. This component is classified as obsolete, making substitute parts necessary for new designs and production continuity. The display operates at 3.8V forward voltage with a 20mA test current and provides 3mcd brightness output. Finding equivalent alternatives ensures design flexibility and supply chain reliability for applications requiring dual-character numeric or alphanumeric display functionality.

Substiute Parts

LTD-2701B

Lite-On Inc.In Stock: 788LTD-2701B Datasheet

Current PartRFQ

HDSM-293B

Broadcom LimitedIn Stock: 767HDSM-293B Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the LTD-2701B is determined by the following critical parameters:

• Display Configuration: 2-character, 7-segment, common cathode topology
• Color and Wavelength: Blue LED output
• Electrical Compatibility: Forward voltage within acceptable operating range (3.3V–3.8V), test current of 20mA
• Physical Dimensions: Digit size of 0.28" (7.00mm) to maintain form factor compatibility
• Compliance: ROHS3 compliance required for regulatory alignment

The HDSM-293B qualifies as a direct substitute based on matching display configuration, color, character count, common cathode topology, and digit size. While packaging differs (10-SMD vs. 10-DIP), the electrical parameters and functional output remain compatible within the specified operating envelope.

Parameter Comparison

Engineering Selection Recommendations

The HDSM-293B is the qualified substitute for the obsolete LTD-2701B based on the following engineering criteria:

Functional Equivalence: Both components share identical display topology (2-character, 7-segment, common cathode, blue color, 0.28" digit size), ensuring functional compatibility in applications requiring dual-character numeric display output.

Electrical Compatibility: The forward voltage difference of 0.5V (3.8V vs. 3.3V) falls within standard LED operating tolerances and does not preclude substitution. Both components operate at 20mA test current. Circuit designs must accommodate the lower forward voltage of the HDSM-293B through appropriate current-limiting resistor adjustment.

Regulatory Compliance: Both components meet ROHS3 compliance requirements, supporting regulatory alignment for new production and design updates.

Product Status Advantage: The HDSM-293B is actively manufactured by Broadcom Limited, providing long-term supply availability and manufacturing support compared to the obsolete LTD-2701B.

Package Consideration: Substitution requires PCB redesign due to package format change (10-DIP to 10-SMD, No Lead). This is a mechanical constraint, not an electrical one.

Brightness and Dissipation: The HDSM-293B provides higher brightness (6mcd vs. 3mcd) and higher maximum power dissipation (100mW vs. 65mW). Thermal design verification is required for applications with space or heat dissipation constraints.

Frequently Asked Questions (FAQ)

Q: Can the HDSM-293B directly replace the LTD-2701B without circuit modification?

A: Electrical substitution is feasible with resistor adjustment for the 0.5V forward voltage difference. However, PCB redesign is mandatory due to package format change from 10-DIP to 10-SMD, No Lead. Pin-to-pin compatibility does not exist between these package types.

Q: What is the impact of the 0.5V forward voltage difference?

A: The HDSM-293B operates at 3.3V versus the LTD-2701B's 3.8V. This requires recalculation of current-limiting resistor values to maintain 20mA test current. The difference is within standard LED operating parameters and does not affect display functionality.

Q: Does the higher brightness of the HDSM-293B (6mcd vs. 3mcd) create compatibility issues?

A: Higher brightness is generally advantageous for visibility. No compatibility issues arise from increased brightness. Applications with specific brightness requirements should verify that 6mcd output meets design specifications.

Q: What are the storage and handling differences between these components?

A: The LTD-2701B has MSL 1 (unlimited moisture sensitivity), while the HDSM-293B has MSL 3 (168-hour moisture sensitivity). The HDSM-293B requires controlled storage conditions and must be used within 168 hours of package opening under standard humidity conditions.

Q: Are there pin configuration differences between the 10-DIP and 10-SMD packages?

A: Both components use 10-pin configurations with identical functional pin assignments (common cathode, segment connections). Package footprint and soldering method differ significantly, requiring PCB layout redesign.

Q: Is the wavelength difference (428nm vs. 462nm) significant?

A: Both wavelengths fall within the blue spectrum. The 34nm difference represents a slight hue variation from deeper blue (428nm) to brighter blue (462nm). Visual perception differences are minimal in most applications.