FOD250LSD Optoisolator Equivalent & Substitute Parts

Part Overview

The FOD250LSD is an optoisolator transistor with base output manufactured by onsemi, rated for 5000Vrms isolation voltage in a single-channel configuration. This component features a transistor output with base connection, designed for DC input applications with 8-SMD surface mount packaging. The FOD250LSD is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement.

Key Parameters

Parameter	FOD250LSD Value
Manufacturer	onsemi
Voltage - Isolation	5000Vrms
Number of Channels	1
Current Transfer Ratio (Min)	15% @ 16mA
Current Transfer Ratio (Max)	50% @ 16mA
Output Type	Transistor with Base
Voltage - Output (Max)	7V
Current - Output / Channel	8mA
Voltage - Forward (Vf) (Typ)	1.45V
Current - DC Forward (If) (Max)	25mA
Operating Temperature	-40°C ~ 85°C
Mounting Type	Surface Mount
Package / Case	8-SMD, Gull Wing
Moisture Sensitivity Level (MSL)	1 (Unlimited)
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution of the FOD250LSD is determined by the following critical parameters:

Isolation Voltage Compatibility: The FOD250LSD operates at 5000Vrms isolation. Substitute parts must maintain this isolation rating or higher to ensure equivalent electrical safety performance.

Output Configuration: The transistor with base output type is mandatory. All substitute parts must provide identical output topology for circuit compatibility.

Single-Channel Configuration: The FOD250LSD is a single-channel device. Substitute parts must be single-channel optoisolators.

Current Transfer Ratio Range: The CTR range of 15-50% @ 16mA defines the gain characteristics. Substitute parts with overlapping or superior CTR ranges are acceptable.

Input/Output Electrical Characteristics: Forward voltage (Vf), maximum forward current (If), and output current capacity must be compatible with the original design parameters.

Surface Mount Package: The 8-SMD Gull Wing package is the mechanical requirement. Substitute parts must use identical or compatible surface mount packaging.

Substitute parts are grouped into two categories based on isolation voltage:

Category A - 5000Vrms Isolation (Direct Substitutes): 6N135SDM, 6N135SMT&R, 6N136-320E, 6N136-520E

Category B - 3750Vrms Isolation (Reduced Isolation): 6N135-300E, 6N135-500E, 6N136#300, 6N136-300E, 6N136-500E, 6N136-560E

Parameter Comparison

Part Number	Manufacturer	Isolation Voltage	CTR Min @ 16mA	CTR Max @ 16mA	Output Voltage (Max)	Output Current	Vf (Typ)	If (Max)	Operating Temp	Product Status	Package
FOD250LSD	onsemi	5000Vrms	15%	50%	7V	8mA	1.45V	25mA	-40°C ~ 85°C	Obsolete	8-SMD, Gull Wing
6N135SDM	onsemi	5000Vrms	7%	50%	20V	8mA	1.45V	25mA	-40°C ~ 100°C	Active	8-SMD, Gull Wing
6N135SMT&R	Isocom Components 2004 LTD	5000Vrms	7%	50%	20V	8mA	1.45V	25mA	-55°C ~ 100°C	Active	8-SMD, Gull Wing
6N136-320E	Broadcom Limited	5000Vrms	19%	50%	20V	8mA	1.5V	25mA	-55°C ~ 100°C	Active	8-SMD, Gull Wing
6N136-520E	Broadcom Limited	5000Vrms	19%	50%	20V	8mA	1.5V	25mA	-55°C ~ 100°C	Active	8-SMD, Gull Wing
6N135-300E	Broadcom Limited	3750Vrms	7%	50%	20V	8mA	1.5V	25mA	-55°C ~ 100°C	Active	8-SMD, Gull Wing
6N135-500E	Broadcom Limited	3750Vrms	7%	50%	20V	8mA	1.5V	25mA	-55°C ~ 100°C	Active	8-SMD, Gull Wing
6N136#300	Broadcom Limited	3750Vrms	19%	50%	20V	8mA	1.5V	25mA	-55°C ~ 100°C	Active	8-SMD, Gull Wing
6N136-300E	Broadcom Limited	3750Vrms	19%	50%	20V	8mA	1.5V	25mA	-55°C ~ 100°C	Active	8-SMD, Gull Wing
6N136-500E	Broadcom Limited	3750Vrms	19%	50%	20V	8mA	1.5V	25mA	-55°C ~ 100°C	Active	8-SMD, Gull Wing
6N136-560E	Broadcom Limited	3750Vrms	19%	50%	20V	8mA	1.5V	25mA	-55°C ~ 100°C	Active	8-SMD, Gull Wing

Engineering Selection Recommendations

Primary Substitutes (5000Vrms Isolation):

The 6N135SDM, 6N135SMT&R, 6N136-320E, and 6N136-520E maintain the 5000Vrms isolation voltage specification of the FOD250LSD. These parts are all classified as Active products, ensuring long-term availability and supply chain stability. The 6N136-320E and 6N136-520E offer improved minimum CTR (19% vs. 15%), higher maximum output voltage (20V vs. 7V), and extended operating temperature range (-55°C to 100°C vs. -40°C to 85°C). The 6N135SDM and 6N135SMT&R provide equivalent electrical performance with onsemi and Isocom manufacturing respectively, both maintaining the 1.45V forward voltage specification.

Secondary Substitutes (3750Vrms Isolation):

The 6N135-300E, 6N135-500E, 6N136#300, 6N136-300E, 6N136-500E, and 6N136-560E operate at 3750Vrms isolation voltage, which is 25% lower than the FOD250LSD specification. These parts are suitable only for applications where the reduced isolation voltage meets system requirements. All secondary substitutes are Active products with RoHS3 compliance (except 6N136#300, which is RoHS non-compliant). The Broadcom 6N136 series variants offer higher minimum CTR (19%) and extended temperature range (-55°C to 100°C).

Compliance Considerations:

All substitute parts maintain MSL 1 (Unlimited) moisture sensitivity rating and REACH Unaffected status, matching the FOD250LSD environmental specifications. RoHS3 compliance is available across most active substitutes, supporting modern manufacturing requirements.

Frequently Asked Questions (FAQ)

Q: Can I use a 3750Vrms substitute in place of the FOD250LSD 5000Vrms specification?

A: Substitution with reduced isolation voltage is only permissible if your circuit design and safety requirements allow for 3750Vrms isolation. The isolation voltage rating must meet or exceed your application's electrical safety standards. If your design requires 5000Vrms isolation, use only Category A substitutes (6N135SDM, 6N135SMT&R, 6N136-320E, 6N136-520E).

Q: What is the difference between the onsemi 6N135SDM and the Broadcom 6N136-320E?

A: Both maintain 5000Vrms isolation and 8-SMD Gull Wing packaging. The 6N136-320E offers higher minimum CTR (19% vs. 7%), higher maximum output voltage (20V vs. 20V), and extended operating temperature range (-55°C to 100°C vs. -40°C to 100°C). The 6N135SDM uses onsemi manufacturing with 1.45V forward voltage, while the 6N136-320E uses Broadcom manufacturing with 1.5V forward voltage.

Q: Are all substitute parts available in the same packaging?

A: All substitute parts use 8-SMD Gull Wing surface mount packaging, matching the FOD250LSD mechanical footprint. Packaging variants (Tube, Tape & Reel, Cut Tape) differ by supplier but do not affect the electrical or mechanical compatibility of the component itself.

Q: What is the significance of the Current Transfer Ratio (CTR) range?

A: CTR determines the gain of the optoisolator. The FOD250LSD specifies 15-50% CTR @ 16mA. Substitute parts with overlapping or higher minimum CTR values (such as 19% in the 6N136 series) provide equivalent or improved performance. Lower minimum CTR values (7% in some 6N135 variants) may require circuit design verification to ensure adequate signal transfer.

Q: Which substitute offers the best temperature performance?

A: All active substitute parts operate across -55°C to 100°C, extending the FOD250LSD's -40°C to 85°C range. This wider temperature specification is available across the 6N135 and 6N136 series, providing improved thermal margin for demanding applications.

Q: Is RoHS compliance important for my selection?

A: RoHS3 compliance is available across most active substitutes (6N135SDM, 6N135-300E, 6N135-500E, 6N135SMT&R, 6N136-300E, 6N136-320E, 6N136-500E, 6N136-520E, 6N136-560E). The 6N136#300 is RoHS non-compliant. Select RoHS3-compliant parts if your manufacturing or end-use requirements mandate environmental compliance.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message