OP555A Phototransistor 935nm Side View Radial Equivalent & Substitute Parts

Part Overview

The OP555A is an active phototransistor optical sensor manufactured by TT Electronics/Optek Technology, designed for 935nm wavelength detection in side view radial configuration. This component is a through-hole mounted photodetector suitable for infrared sensing applications requiring side-view orientation. The part is in active production status with ROHS3 compliance and unlimited moisture sensitivity rating (MSL 1). Substitute parts may be required due to inventory constraints, supply chain discontinuities, or application-specific wavelength requirements within compatible parameter ranges.

Substiute Parts

OP555A

TT Electronics/Optek TechnologyIn Stock: 914OP555A Datasheet

Current PartRFQ

QSE122

onsemiIn Stock: 1812QSE122 Datasheet

MFR RecommendedRFQ

QSE122

onsemiIn Stock: 1812QSE122 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the OP555A is determined by strict alignment of the following critical parameters:

• Mounting Type: Through Hole (required match)
• Orientation: Side View (required match)
• Package / Case: Radial (required match)
• Voltage - Collector Emitter Breakdown (Max): 30 V (required match)
• Current - Dark (Id) (Max): 100 nA (required match)
• Power - Max: 100 mW (required match)
• Operating Temperature Range: -40°C ~ 100°C (required match)
• RoHS Status: ROHS3 Compliant (required match)

The QSE122 phototransistor from onsemi meets all mandatory mechanical and electrical compatibility criteria. The wavelength difference (880nm vs. 935nm) represents a near-infrared spectrum variation within the phototransistor operational range. The viewing angle variance (50° vs. 56°) and maximum collector current specification differences are secondary parameters that do not preclude functional substitution in applications where the primary detection wavelength tolerance permits 880nm operation.

Parameter Comparison

Engineering Selection Recommendations

Both the OP555A and QSE122 maintain active production status with ROHS3 compliance and REACH unaffected regulatory standing. Selection between these components should be based on application-specific wavelength requirements. The OP555A operates at 935nm, while the QSE122 operates at 880nm. Both components share identical maximum voltage ratings (30 V), dark current specifications (100 nA maximum), power dissipation limits (100 mW), and operating temperature ranges (-40°C to 100°C). The mechanical compatibility is confirmed through matching through-hole mounting, side-view orientation, and radial packaging. Component selection should prioritize wavelength alignment with the infrared source or detection target in the end application.

Frequently Asked Questions (FAQ)

Q: Can QSE122 directly replace OP555A in existing PCB designs?

A: Yes, from a mechanical and electrical standpoint. The QSE122 shares identical through-hole mounting, side-view orientation, and radial package configuration. However, the wavelength difference (880nm vs. 935nm) requires verification that the application's infrared source or detection target is compatible with 880nm operation.

Q: What is the significance of the wavelength difference between 935nm and 880nm?

A: Both wavelengths fall within the near-infrared spectrum used in phototransistor applications. The 55nm difference may affect detection efficiency depending on the specific infrared source. Applications using 935nm LEDs or sources optimized for that wavelength should use the OP555A. Applications with 880nm sources or wavelength-agnostic designs may use the QSE122.

Q: Are the viewing angles interchangeable?

A: The OP555A has a 56° viewing angle while the QSE122 has a 50° viewing angle. The 6° difference represents a minor reduction in angular sensitivity. For applications requiring maximum angular coverage, the OP555A is preferred. For applications with tightly controlled optical geometry, the QSE122 is acceptable.

Q: Do both parts meet the same compliance standards?

A: Yes. Both the OP555A and QSE122 are ROHS3 compliant, REACH unaffected, and carry EAR99 ECCN classification. Both are rated for identical operating temperature ranges (-40°C to 100°C) and share the same maximum voltage (30 V) and power dissipation (100 mW) specifications.

Q: What is the maximum collector current difference between these parts?

A: The OP555A specifies a maximum collector current (Ic) of 4.7 mA. The QSE122 datasheet does not provide this parameter in the available specifications. Circuit designs relying on specific collector current characteristics should reference the QSE122 manufacturer datasheet for this value before substitution.