4N33 Optoisolator Darlington - Equivalent & Substitute Parts

Part Overview

The 4N33 is an optoisolator with Darlington output configuration, designed for single-channel isolation applications requiring 5300Vrms isolation voltage. This component is manufactured by Isocom Components 2004 LTD and is currently in active production status. The 4N33 operates as a DC input device with Darlington output featuring base access, suitable for applications requiring galvanic isolation in industrial and consumer electronics. Substitute parts are identified when equivalent electrical and mechanical parameters align with the original specification, enabling component interchangeability in design and procurement scenarios.

Substiute Parts

4N33

Isocom Components 2004 LTDIn Stock: 46644N33 Datasheet

Current PartRFQ

4N33M

Fairchild SemiconductorIn Stock: 138074N33M Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 4N33 are identified based on the following critical parameters that determine functional equivalence:

• Single-channel optoisolator configuration
• Darlington output with base access
• DC input type
• 6-DIP through-hole package format
• Operating temperature range of -55°C to 100°C
• Isolation voltage capability (minimum 5000Vrms acceptable)
• Forward voltage and saturation characteristics compatible with 1.2V Vf and 1V Vce(sat)

The 4N33M from Fairchild Semiconductor meets these substitution criteria, with the exception of isolation voltage (5000Vrms versus 5300Vrms) and maximum output voltage (55V versus 30V), which represent relaxed constraints suitable for applications not requiring the full specification of the original part.

Parameter Comparison

Engineering Selection Recommendations

Both the 4N33 and 4N33M are active production components with established compliance certifications. The 4N33 maintains ROHS3 compliance and REACH unaffected status. Selection between these parts depends on application-specific isolation voltage requirements and PCB layout constraints related to package dimensions. The 4N33M offers higher maximum output voltage capability (55V versus 30V), which may provide additional design margin in applications with elevated output voltage demands. The 4N33M package dimension (0.400" versus 0.300") represents a physical difference that must be evaluated against PCB layout specifications. Both components share identical operating temperature ranges, saturation characteristics, and switching time parameters, ensuring functional compatibility in most isolation circuit topologies.

Frequently Asked Questions (FAQ)

Q: Can the 4N33M directly replace the 4N33 in existing designs?

A: Direct replacement is possible with consideration of two factors: the 4N33M has a lower isolation voltage rating (5000Vrms versus 5300Vrms), which is acceptable only if the application does not require the full 5300Vrms isolation specification. The 4N33M package is physically larger (0.400" versus 0.300"), requiring verification that PCB footprint and layout accommodate the larger DIP spacing.

Q: What are the key electrical differences between these parts?

A: The primary electrical differences are isolation voltage (5300Vrms for 4N33 versus 5000Vrms for 4N33M) and maximum output voltage (30V for 4N33 versus 55V for 4N33M). Forward voltage, saturation voltage, and switching characteristics are identical. Maximum DC forward current differs slightly (80mA for 4N33 versus 60mA for 4N33M).

Q: Are there package compatibility concerns?

A: Yes. The 4N33 uses a 6-DIP package with 0.300" (7.62mm) spacing, while the 4N33M uses 0.400" (10.16mm) spacing. Both are through-hole mount types, but PCB footprints are not interchangeable without layout modification.

Q: Which part should be selected for new designs?

A: Selection depends on isolation voltage requirements and available PCB space. If 5300Vrms isolation is mandatory, the 4N33 is required. If 5000Vrms isolation is sufficient and higher output voltage capability is beneficial, the 4N33M is suitable. Both parts are in active production with established supply chains.

Q: Do both parts meet the same compliance standards?

A: The 4N33 is specified as ROHS3 compliant and REACH unaffected. The 4N33M compliance information is not provided in the available specification data. Compliance verification should be confirmed with the respective manufacturer before final part selection.