QBSS391CB 7-Segment LED Display - Equivalent & Substitute Parts

Part Overview

The QBSS391CB is a single-character, 7-segment LED display module manufactured by QT Brightek (QTB). This blue display operates at 3.2V forward voltage with a 10mA test current and features a 0.39-inch digit size in a compact 10-SMD surface-mount package. The device is classified as obsolete, making identification of functionally equivalent substitute parts essential for ongoing design support and production continuity.

Substiute Parts

QBSS391CB

QT Brightek (QTB)In Stock: 1055QBSS391CB Datasheet

Current PartRFQ

SMC391LB G/W

American Opto Plus LEDIn Stock: 856SMC391LB G/W Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the QBSS391CB is determined by strict alignment of the following critical parameters:

Primary Compatibility Criteria:

• Display type must be 7-segment
• Single character configuration
• 0.39-inch digit size (10.00mm)
• Blue color emission
• Common cathode pin configuration
• 3.2V forward voltage operation
• 10-SMD surface-mount package with no leads
• Compliance with ROHS3 and equivalent environmental standards

Secondary Considerations:

• Test current may vary within acceptable operating ranges
• Physical dimensions may have minor tolerance variations
• Millicandela rating must remain at or above 40mcd for equivalent brightness performance

The SMC391LB G/W manufactured by American Opto Plus LED meets all primary compatibility criteria and is therefore classified as a direct functional equivalent.

Parameter Comparison

Engineering Selection Recommendations

The SMC391LB G/W is a direct functional equivalent for the obsolete QBSS391CB based on the following engineering criteria:

Electrical Compatibility: Both devices operate at identical 3.2V forward voltage and 40mcd brightness rating. The SMC391LB G/W operates at 20mA test current compared to the QBSS391CB's 10mA; however, both share the same 120mW maximum power dissipation specification, indicating the substitute is designed for equivalent thermal performance within standard circuit implementations.

Mechanical Compatibility: Both parts utilize identical 10-SMD surface-mount packages with no leads. Physical dimensions are within acceptable manufacturing tolerances for PCB footprint compatibility. The SMC391LB G/W height is 0.512" versus 0.591" for the QBSS391CB, representing a 0.079" reduction that does not impact assembly or clearance requirements in standard applications.

Regulatory Compliance: Both devices maintain ROHS3 compliance and identical moisture sensitivity ratings (2A, 4 weeks), ensuring equivalent handling and storage requirements throughout the supply chain.

Production Status: The SMC391LB G/W is currently in active production with confirmed inventory availability (795 pcs), providing reliable long-term sourcing compared to the obsolete QBSS391CB status.

Frequently Asked Questions (FAQ)

Q: Can the SMC391LB G/W be used as a direct replacement for the QBSS391CB without circuit modifications?

A: Yes. Both devices share identical electrical specifications (3.2V forward voltage, 40mcd brightness, common cathode configuration) and package type (10-SMD, no lead). The higher test current (20mA vs. 10mA) reflects the substitute's design characteristics but does not require circuit redesign, as both operate within the same 120mW power dissipation envelope.

Q: Are there physical mounting differences between these two parts?

A: Both parts use identical 10-SMD surface-mount packages. The SMC391LB G/W is slightly shorter (0.512" vs. 0.591" height) and marginally thicker (0.159" vs. 0.157" depth), but these variations are within standard PCB assembly tolerances and do not affect footprint compatibility or clearance requirements.

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

A: Test current specifications indicate the current level at which brightness and forward voltage are measured. The SMC391LB G/W's 20mA test current reflects its design operating point but does not mandate operation at this level. Circuit designers should apply standard current-limiting resistor calculations based on their specific supply voltage and brightness requirements.

Q: Are storage and handling requirements identical for both parts?

A: Yes. Both devices carry identical Moisture Sensitivity Level ratings (2A, 4 weeks), requiring equivalent storage conditions and handling procedures. No additional precautions are necessary when transitioning from QBSS391CB to SMC391LB G/W inventory.

Q: Is the SMC391LB G/W available for immediate production use?

A: Yes. The SMC391LB G/W is classified as active product status with confirmed inventory of 795 pieces in stock, providing immediate availability for design implementation and production deployment.

Q: Do both parts meet the same environmental and regulatory standards?

A: Yes. Both the QBSS391CB and SMC391LB G/W are ROHS3 compliant and carry identical REACH and ECCN classifications (EAR99), ensuring equivalent regulatory acceptance across all markets and applications.