OP705A Equivalent & Substitute Parts

Part Overview

The OP705A is a phototransistor optical sensor manufactured by TT Electronics / Optek Technology, designed for 935nm infrared detection applications. This component features a top-view T-1 package configuration with a maximum collector current of 30 mA and operates across an extended temperature range of -40°C to 100°C. The OP705A is classified as obsolete, making identification of functionally equivalent substitute components essential for ongoing system support and new design implementations.

Substiute Parts

OP705A

TT Electronics / Optek TechnologyIn Stock: 1030OP705A Datasheet

Current PartRFQ

PT204-6C

Everlight Electronics Co LtdIn Stock: 357904PT204-6C Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the OP705A is determined by alignment across the following critical parameters:

• Wavelength Compatibility: The OP705A operates at 935nm. Substitute components must function within the near-infrared spectrum at wavelengths compatible with 935nm detection circuits, specifically 940nm phototransistors which operate within the same application band.
• Electrical Ratings: Collector-emitter breakdown voltage (30 V maximum), collector current capacity (20-30 mA range), and dark current (100 nA maximum) must be maintained or exceeded.
• Package and Mounting: Through-hole T-1 package configuration with top-view orientation ensures mechanical and electrical compatibility with existing PCB layouts.
• Environmental Compliance: RoHS3 compliance and MSL Level 1 rating are required for regulatory and manufacturing process compatibility.
• Operating Temperature Range: The substitute must support the application's thermal requirements; narrower ranges may be acceptable depending on system deployment conditions.

The PT204-6C from Everlight Electronics Co Ltd qualifies as a direct substitute based on these parameters.

Parameter Comparison

Engineering Selection Recommendations

The PT204-6C is an active, in-stock substitute for the obsolete OP705A. Both components maintain identical collector-emitter breakdown voltage (30 V) and dark current specifications (100 nA maximum). The PT204-6C operates at 940nm, which is within the near-infrared detection band and compatible with 935nm-based optical systems.

The PT204-6C exhibits a reduced maximum collector current rating of 20 mA compared to the OP705A's 30 mA. Applications requiring the full 30 mA collector current capacity must evaluate circuit design margins to confirm compatibility.

The PT204-6C operating temperature range (-25°C to 85°C) is narrower than the OP705A (-40°C to 100°C). Systems deployed in extended temperature environments must confirm that the PT204-6C range meets application requirements.

Both components are ROHS3 compliant and carry MSL Level 1 ratings, ensuring regulatory and manufacturing process compatibility. The PT204-6C is available in high inventory volume (357,835 pieces), supporting both immediate replacement and long-term supply continuity.

Frequently Asked Questions (FAQ)

Q: Can the PT204-6C directly replace the OP705A in existing designs?

A: The PT204-6C is mechanically and electrically compatible for through-hole T-1 package applications. Circuit designs must account for the reduced maximum collector current (20 mA vs. 30 mA) and narrower operating temperature range (-25°C to 85°C vs. -40°C to 100°C).

Q: What is the wavelength difference between 935nm and 940nm?

A: Both wavelengths operate within the near-infrared spectrum used for optical sensing applications. The 5nm difference is within the typical spectral response overlap of phototransistor designs and does not prevent functional substitution in standard detection circuits.

Q: Are there any compliance or certification differences?

A: Both the OP705A and PT204-6C are ROHS3 compliant with MSL Level 1 ratings. No compliance barriers exist for substitution.

Q: What is the significance of the "Radial, T-1 Lens" package designation for the PT204-6C?

A: The PT204-6C maintains the T-1 through-hole package form factor compatible with OP705A PCB layouts. The radial lead configuration and integrated lens are standard for T-1 phototransistor designs and do not affect mechanical compatibility.

Q: Is the PT204-6C suitable for high-temperature applications?

A: The PT204-6C operates to a maximum of 85°C. Applications requiring operation above 85°C or below -25°C must evaluate alternative components or confirm that the narrower range meets system requirements.