LA-301BB 7-Segment LED Display - Equivalent & Substitute Parts

Part Overview

The LA-301BB is a single-character 7-segment LED display manufactured by Rohm Semiconductor, featuring a blue light-emitting element in a 10-DIP package. This component is classified as Not For New Designs, indicating it has reached end-of-life status. The display operates at 3.6V forward voltage with a 10mA test current and delivers 56mcd brightness output. Due to its discontinued status, identifying functionally compatible alternatives is essential for ongoing maintenance, repair, and legacy system support.

Substiute Parts

LA-301BB

Rohm SemiconductorIn Stock: 1172LA-301BB Datasheet

Current PartRFQ

HDSP-U501

Broadcom LimitedIn Stock: 2070HDSP-U501 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the LA-301BB is determined by the following critical parameters:

• Package Compatibility: 10-DIP (0.209", 5.30mm) form factor ensures mechanical and electrical pin alignment with existing PCB layouts
• Display Configuration: Single-character 7-segment architecture with 0.31" digit size maintains functional equivalence
• Common Anode Pin Configuration: Electrical polarity and control logic compatibility
• Digit/Alpha Size: 0.31" (8.00mm) dimension ensures visual consistency in display applications
• Regulatory Compliance: ROHS3 and REACH compliance status for supply chain and environmental requirements

The HDSP-U501 manufactured by Broadcom Limited meets all mechanical and electrical interface requirements. However, it differs in color (green vs. blue), forward voltage (2.1V vs. 3.6V), brightness output (6.8mcd vs. 56mcd), and power dissipation characteristics. These differences require circuit-level evaluation for specific applications.

Parameter Comparison

Engineering Selection Recommendations

The HDSP-U501 is mechanically and electrically compatible with the LA-301BB at the package and pin-level interface. Both components are ROHS3 compliant and REACH unaffected, meeting current regulatory requirements.

Selection between these parts depends on application-specific requirements:

• Forward Voltage Difference: The HDSP-U501 operates at 2.1V compared to the LA-301BB's 3.6V. This 1.5V reduction affects series resistor calculations and power supply design. Existing current-limiting circuits designed for 3.6V operation require recalculation for the lower forward voltage to maintain proper segment brightness and prevent overcurrent conditions.

• Brightness Output: The LA-301BB delivers 56mcd while the HDSP-U501 delivers 6.8mcd. This 8:1 brightness ratio represents a significant reduction in light output. Applications requiring high visibility or long viewing distances may not achieve equivalent performance with the substitute.

• Power Dissipation: Maximum power dissipation increases from 42mW to 105mW with the HDSP-U501. Thermal management and power budget considerations apply to high-density display arrays.

• Color Specification: The LA-301BB emits blue light (470nm peak wavelength) while the HDSP-U501 emits green light (566nm peak wavelength). Color-critical applications cannot use this substitute without visual impact.

• Product Status: The HDSP-U501 maintains Active status, ensuring continued availability and supply chain support. The LA-301BB's Not For New Designs status limits future sourcing options.

Frequently Asked Questions (FAQ)

Q: Can the HDSP-U501 be used as a direct drop-in replacement for the LA-301BB?

A: The HDSP-U501 is mechanically compatible (same 10-DIP package and 0.31" digit size) and electrically compatible at the pin interface (Common Anode configuration). However, it is not a direct drop-in replacement without circuit modifications. The lower forward voltage (2.1V vs. 3.6V) requires recalculation of series resistor values to maintain proper segment current. The significantly lower brightness (6.8mcd vs. 56mcd) and different color (green vs. blue) may not meet application requirements.

Q: What circuit modifications are necessary to use the HDSP-U501 instead of the LA-301BB?

A: The primary modification involves the series current-limiting resistor. The LA-301BB's 3.6V forward voltage and the HDSP-U501's 2.1V forward voltage create a 1.5V difference. Using the same resistor value will result in excessive current through the HDSP-U501 segments. Recalculate the resistor value using Ohm's Law: R = (Vsupply - Vf) / Iled, where Vf is the new forward voltage and Iled is the desired segment current (typically 10mA for the HDSP-U501).

Q: Are there any compatibility issues with the PCB layout?

A: The physical dimensions are nearly identical (0.433" H x 0.276" W x 0.197" D for LA-301BB vs. 0.433" H x 0.280" W x 0.197" D for HDSP-U501). The 0.004" (0.10mm) width difference is negligible for standard PCB layouts. The 10-DIP package footprint is identical, ensuring mechanical fit without layout modifications.

Q: How does the brightness difference affect display visibility?

A: The LA-301BB delivers 56mcd while the HDSP-U501 delivers 6.8mcd, representing an 8:1 reduction in brightness. In low-ambient-light environments or applications requiring long viewing distances, this reduction may result in noticeably dimmer segment visibility. High-ambient-light environments (direct sunlight, bright indoor lighting) may render the HDSP-U501 segments difficult to read.

Q: Are both parts compliant with current environmental and regulatory standards?

A: Yes. Both the LA-301BB and HDSP-U501 are ROHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements for electronic components in most jurisdictions.

Q: What is the impact of the color difference on system operation?

A: The LA-301BB emits blue light (470nm peak wavelength) while the HDSP-U501 emits green light (566nm peak wavelength). This color difference is visually apparent and cannot be compensated through circuit modifications. Applications where display color is specified or where color consistency across multiple displays is required cannot use the HDSP-U501 as a substitute.