OPB877P51 Equivalent & Substitute Parts

Part Overview

The OPB877P51 is an optical sensor through-beam phototransistor module manufactured by TT Electronics/Optek Technology. This component features a 0.125" (3.18mm) sensing distance with pre-wired chassis mount packaging and unamplified phototransistor output configuration. The part is currently obsolete, making equivalent and substitute parts necessary for ongoing system support and new designs requiring this functional specification.

Key Parameters

Parameter	Value
Manufacturer Part Number	OPB877P51
Manufacturer	TT Electronics/Optek Technology
Category	Optical Sensors
Sensing Distance	0.125" (3.18mm)
Sensing Method	Through-Beam
Output Configuration	Phototransistor
Current - DC Forward (If) (Max)	50 mA
Current - Collector (Ic) (Max)	30 mA
Voltage - Collector Emitter Breakdown (Max)	30 V
Operating Temperature	-40°C ~ 85°C
Mounting Type	Chassis Mount
Package / Case	Module, Pre-Wired
Type	Unamplified
Product Status	Obsolete
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution for the OPB877P51 is determined by strict equivalence across the following critical parameters:

Sensing Distance: 0.125" (3.18mm)
Sensing Method: Through-Beam
Output Configuration: Phototransistor
Current - DC Forward (If) (Max): 50 mA
Current - Collector (Ic) (Max): 30 mA
Voltage - Collector Emitter Breakdown (Max): 30 V
Operating Temperature: -40°C ~ 85°C
Type: Unamplified
RoHS Status: ROHS3 Compliant
Moisture Sensitivity Level (MSL): 1 (Unlimited)

All substitute parts listed maintain identical electrical specifications and environmental ratings. Differences exist only in mounting configuration (chassis mount versus through-hole PCB mount) and product status (active versus obsolete).

Parameter Comparison

Part Number	Manufacturer	Sensing Distance	Sensing Method	Output Configuration	If (Max)	Ic (Max)	VCE Breakdown (Max)	Operating Temperature	Mounting Type	Package / Case	Type	Product Status	Inventory
OPB877P51	TT Electronics/Optek Technology	0.125" (3.18mm)	Through-Beam	Phototransistor	50 mA	30 mA	30 V	-40°C ~ 85°C	Chassis Mount	Module, Pre-Wired	Unamplified	Obsolete	1011 Pcs
OPB877T55	TT Electronics/Optek Technology	0.125" (3.18mm)	Through-Beam	Phototransistor	50 mA	30 mA	30 V	-40°C ~ 85°C	Through Hole	PCB Mount	Unamplified	Active	1483 Pcs
OPB360N51	TT Electronics/Optek Technology	0.125" (3.18mm)	Through-Beam	Phototransistor	50 mA	30 mA	30 V	-40°C ~ 85°C	Chassis Mount	Module, Pre-Wired	Unamplified	Active	1394 Pcs
OPB365N11	TT Electronics/Optek Technology	0.125" (3.18mm)	Through-Beam	Phototransistor	50 mA	30 mA	30 V	-40°C ~ 85°C	Chassis Mount	Module, Pre-Wired	Unamplified	Active	658 Pcs
OPB365N51	TT Electronics / Optek Technology	0.125" (3.18mm)	Through-Beam	Phototransistor	50 mA	30 mA	30 V	-40°C ~ 85°C	Chassis Mount	Module, Pre-Wired	Unamplified	Active	1916 Pcs
OPB365P55	TT Electronics/Optek Technology	0.125" (3.18mm)	Through-Beam	Phototransistor	50 mA	30 mA	30 V	-40°C ~ 85°C	Chassis Mount	Module, Pre-Wired	Unamplified	Active	1052 Pcs
OPB370N51	TT Electronics/Optek Technology	0.125" (3.18mm)	Through-Beam	Phototransistor	50 mA	30 mA	30 V	-40°C ~ 85°C	Chassis Mount	Module, Pre-Wired	Unamplified	Active	1250 Pcs
OPB370N55	TT Electronics/Optek Technology	0.125" (3.18mm)	Through-Beam	Phototransistor	50 mA	30 mA	30 V	-40°C ~ 85°C	Chassis Mount	Module, Pre-Wired	Unamplified	Active	90400 Pcs
OPB375N51	TT Electronics/Optek Technology	0.125" (3.18mm)	Through-Beam	Phototransistor	50 mA	30 mA	30 V	-40°C ~ 85°C	Chassis Mount	Module, Pre-Wired	Unamplified	Active	648 Pcs
OPB380N11Z	TT Electronics/Optek Technology	0.125" (3.18mm)	Through-Beam	Phototransistor	50 mA	30 mA	30 V	-40°C ~ 85°C	Chassis Mount	Module, Pre-Wired	Unamplified	Active	1100 Pcs
OPB380P51Z	TT Electronics/Optek Technology	0.125" (3.18mm)	Through-Beam	Phototransistor	50 mA	30 mA	30 V	-40°C ~ 85°C	Chassis Mount	Module, Pre-Wired	Unamplified	Active	651 Pcs

Engineering Selection Recommendations

For applications currently using the obsolete OPB877P51, direct electrical substitution is available through multiple active-status alternatives. Selection between substitute parts depends on mounting configuration requirements and inventory availability.

For Chassis Mount Applications (Pre-Wired Module): OPB360N51, OPB365N11, OPB365N51, OPB365P55, OPB370N51, OPB370N55, OPB375N51, OPB380N11Z, and OPB380P51Z provide identical electrical performance and mechanical compatibility. OPB370N55 offers the highest inventory availability at 90,400 units.

For PCB Mount Applications (Through-Hole): OPB877T55 provides equivalent electrical specifications with through-hole PCB mount configuration, requiring circuit board layout modification from the original chassis mount design.

All substitute parts maintain ROHS3 compliance, MSL 1 rating, and identical electrical parameters (50 mA forward current, 30 mA collector current, 30 V breakdown voltage, -40°C to 85°C operating range).

Frequently Asked Questions (FAQ)

Q: Can OPB877T55 replace OPB877P51 directly in existing assemblies?

A: OPB877T55 provides identical electrical specifications but requires mechanical redesign. The original part uses chassis mount pre-wired configuration, while OPB877T55 is through-hole PCB mount. Physical mounting points and wiring harness connections differ.

Q: What is the difference between the various substitute part numbers (OPB360N51, OPB365N51, OPB370N51, etc.)?

A: All listed substitute parts share identical electrical parameters and chassis mount pre-wired packaging. Differences exist only in internal design variants (indicated by the base product number: OPB360, OPB365, OPB370, OPB375, OPB380). These variants are electrically interchangeable for the specified parameters.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All substitute parts listed maintain ROHS3 compliance and MSL 1 (Unlimited) moisture sensitivity rating, matching the original OPB877P51 specifications.

Q: Which substitute part has the best availability?

A: OPB370N55 has the highest inventory at 90,400 units in stock, providing optimal supply chain reliability for new designs or high-volume replacements.

Q: Can I use OPB877P51 and its substitutes interchangeably in the same circuit?

A: Yes, for applications where the 0.125" (3.18mm) through-beam sensing distance, 50 mA forward current, 30 mA collector current, and 30 V breakdown voltage specifications are met. Mounting configuration must match the mechanical design (chassis mount for pre-wired modules, through-hole for PCB mount variants).

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