FOD617DSD Optoisolator Equivalent & Substitute Parts

Part Overview

The FOD617DSD is a 5000Vrms optoisolator with transistor output manufactured by onsemi in 4-SMD surface mount packaging. This component provides galvanic isolation for single-channel applications with a maximum output current of 50mA and output voltage rating of 70V. The part is currently obsolete, making equivalent substitutes necessary for new designs or production continuity. Substitute parts must maintain compatibility across isolation voltage, output characteristics, and thermal operating range to ensure functional equivalence in circuit applications.

Key Parameters

Parameter	FOD617DSD Value
Voltage - Isolation	5000Vrms
Number of Channels	1
Output Type	Transistor
Current Transfer Ratio (Min)	160% @ 10mA
Current Transfer Ratio (Max)	320% @ 10mA
Voltage - Output (Max)	70V
Current - Output / Channel	50mA
Vce Saturation (Max)	400mV
Operating Temperature	-55°C ~ 110°C
Mounting Type	Surface Mount
Package / Case	4-SMD, Gull Wing

Substitute Part Grouping Explanation

Substitution eligibility for the FOD617DSD is determined by the following critical parameters:

Primary Compatibility Criteria:

Isolation voltage rating (minimum 5000Vrms for direct substitution)
Single-channel transistor output configuration
Maximum output voltage of 70V
Maximum output current of 50mA
4-SMD surface mount package with gull wing leads
Operating temperature range encompassing -55°C to 110°C

Secondary Compatibility Criteria:

Current transfer ratio performance at specified test conditions
Vce saturation characteristics
Forward voltage characteristics of the LED input stage
Rise and fall time specifications

Parts are grouped into two categories: direct substitutes maintaining 5000Vrms isolation (FOD817DSD, VO615A-4X007T) and functional alternatives with higher isolation ratings (SFH615A and SFH617A series from Isocom). The SFH615A series provides 5300Vrms isolation with comparable electrical characteristics. The SFH617A series operates at lower isolation voltage (7.5Vpk) and is suitable only for applications not requiring 5000Vrms isolation.

Parameter Comparison

Parameter	FOD617DSD	FOD817DSD	VO615A-4X007T	SFH615A-4XSMT&R	SFH615A-3XSMT&R	SFH615A-2XSMT&R
Manufacturer	onsemi	onsemi	Vishay	Isocom	Isocom	Isocom
Voltage - Isolation	5000Vrms	5000Vrms	5000Vrms	5300Vrms	5300Vrms	5300Vrms
Number of Channels	1	1	1	1	1	1
Current Transfer Ratio (Min)	160% @ 10mA	300% @ 5mA	160% @ 10mA	160% @ 10mA	100% @ 10mA	63% @ 10mA
Current Transfer Ratio (Max)	320% @ 10mA	600% @ 5mA	320% @ 10mA	320% @ 10mA	200% @ 10mA	125% @ 10mA
Voltage - Output (Max)	70V	70V	70V	70V	70V	70V
Current - Output / Channel	50mA	50mA	50mA	50mA	50mA	50mA
Voltage - Forward (Vf) (Typ)	1.35V	1.2V	1.43V	1.65V (Max)	1.65V (Max)	1.65V (Max)
Vce Saturation (Max)	400mV	200mV	300mV	400mV	400mV	400mV
Operating Temperature	-55°C ~ 110°C	-55°C ~ 110°C	-55°C ~ 110°C	-30°C ~ 100°C	-30°C ~ 100°C	-30°C ~ 100°C
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Package / Case	4-SMD, Gull Wing	4-PDIP-GW	4-SMD, Gull Wing	4-SMD, Gull Wing	4-SMD, Gull Wing	4-SMD, Gull Wing
Product Status	Obsolete	Active	Active	Active	Active	Active
RoHS Status	Not specified	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

Tier 1 - Direct Substitutes (Recommended for Obsolescence Replacement):

FOD817DSD and VO615A-4X007T are the primary substitutes for FOD617DSD. Both maintain 5000Vrms isolation voltage and 4-SMD surface mount packaging. FOD817DSD is an active product from onsemi with ROHS3 compliance and superior current transfer ratio performance (300-600% @ 5mA). VO615A-4X007T from Vishay provides equivalent isolation and electrical characteristics with ROHS3 compliance and active product status. Both support the full operating temperature range of -55°C to 110°C required by the original specification.

Tier 2 - Functional Alternatives (Higher Isolation Rating):

SFH615A series optoisolators from Isocom provide 5300Vrms isolation, exceeding the FOD617DSD requirement. The SFH615A-4XSMT&R and SFH615A-3XSMT&R variants offer current transfer ratios of 160-320% and 100-200% respectively at 10mA, maintaining compatibility with the original part's electrical performance envelope. All SFH615A variants are ROHS3 compliant and active products. Operating temperature range is -30°C to 100°C, which covers standard industrial applications but does not extend to the -55°C minimum of the original specification.

Tier 3 - Limited Compatibility:

SFH615A-2XSMT&R provides lower current transfer ratio (63-125% @ 10mA) and is suitable only for applications with relaxed gain requirements. SFH617A series (SFH617A-2XSMT&R, SFH617A-3XSMT&R) operates at 7.5Vpk isolation voltage and is not suitable for applications requiring 5000Vrms isolation.

Selection Criteria:

For direct replacement in existing designs: FOD817DSD or VO615A-4X007T
For new designs with extended temperature requirements: FOD817DSD
For applications accepting higher isolation voltage and standard temperature range: SFH615A-4XSMT&R or SFH615A-3XSMT&R
All recommended substitutes carry ROHS3 compliance and active product status

Frequently Asked Questions (FAQ)

Q: Can FOD817DSD directly replace FOD617DSD in existing PCB layouts?

A: FOD817DSD maintains electrical equivalence but uses 4-PDIP-GW packaging versus the FOD617DSD's 4-SMD, Gull Wing package. PCB footprint modification is required. For direct footprint compatibility, use VO615A-4X007T, which maintains identical 4-SMD, Gull Wing packaging.

Q: What is the minimum isolation voltage required for substitution?

A: The FOD617DSD specifies 5000Vrms isolation. Direct substitutes must maintain this rating. SFH615A series parts rated at 5300Vrms exceed this requirement and are functionally compatible. SFH617A series parts rated at 7.5Vpk do not meet the isolation requirement and are not suitable substitutes.

Q: Are there temperature range limitations with substitute parts?

A: FOD617DSD operates from -55°C to 110°C. FOD817DSD and VO615A-4X007T maintain this full range. SFH615A series parts operate from -30°C to 100°C, which is suitable for standard industrial applications but does not extend to the -55°C minimum. Verify application temperature requirements before selecting SFH615A variants.

Q: How do current transfer ratio differences affect circuit performance?

A: Current transfer ratio determines the output current for a given input current. FOD617DSD specifies 160-320% @ 10mA. FOD817DSD provides 300-600% @ 5mA, delivering higher gain. SFH615A-4XSMT&R matches the original specification (160-320% @ 10mA). SFH615A-3XSMT&R provides 100-200% @ 10mA, and SFH615A-2XSMT&R provides 63-125% @ 10mA. Lower ratios require higher input current to achieve equivalent output current.

Q: What packaging considerations apply to these substitutes?

A: FOD617DSD, VO615A-4X007T, and all SFH615A variants use 4-SMD, Gull Wing surface mount packaging compatible with standard pick-and-place assembly. FOD817DSD uses 4-PDIP-GW packaging, requiring different PCB footprint. Packaging selection depends on existing PCB design and assembly capabilities.

Q: Are all substitute parts RoHS compliant?

A: FOD817DSD, VO615A-4X007T, and all SFH615A variants carry ROHS3 compliance certification. FOD617DSD compliance status is not specified in the provided data. Verify RoHS requirements for your application and supply chain.

Q: Which substitute offers the best overall compatibility?

A: VO615A-4X007T provides optimal compatibility: identical 4-SMD, Gull Wing packaging, 5000Vrms isolation, matching current transfer ratio (160-320% @ 10mA), full temperature range (-55°C to 110°C), and ROHS3 compliance. FOD817DSD is an alternative from the original manufacturer but requires PCB footprint modification due to different package type.

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