J109 N-Channel JFET 25V TO-92-3 Equivalent & Substitute Parts

Part Overview

The J109 is an N-Channel JFET transistor rated for 25V operation in a TO-92-3 through-hole package. Manufactured by NXP Semiconductors, this component is classified as obsolete. Due to its obsolete status and limited availability from original sources, equivalent substitute parts are necessary for ongoing design support and production continuity. Substitute parts must maintain electrical compatibility within the specified parameter ranges while meeting the same packaging and environmental requirements.

Substiute Parts

J109,126

NXP SemiconductorsIn Stock: 982J109,126 Datasheet

Current PartRFQ

BF256B

onsemiIn Stock: 39931BF256B Datasheet

MFR RecommendedRFQ

J109-D26Z

onsemiIn Stock: 40106J109-D26Z Datasheet

MFR RecommendedRFQ

J211-D74Z

onsemiIn Stock: 4793J211-D74Z Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the J109 are selected based on the following critical parameters that determine functional equivalence:

Primary Substitution Criteria:

• FET Type: N-Channel configuration
• Package: TO-92-3 through-hole form factor
• Drain to Source Voltage (Vdss): 25V or higher
• Voltage - Breakdown (V(BR)GSS): 25V or higher
• Resistance - RDS(On): 12 Ohms or lower
• Operating Temperature: Support for 150°C or higher
• Mounting Type: Through Hole

The substitute parts listed maintain these electrical and mechanical parameters within acceptable ranges for direct replacement in applications designed for the J109. All substitutes are available in the same TO-92-3 package and support equivalent voltage and current specifications.

Parameter Comparison

Engineering Selection Recommendations

J109-D26Z (Primary Substitute)

The J109-D26Z is the direct equivalent from onsemi, sharing the same base product number (J109) and electrical specifications. This part maintains 25V Vdss, 12 Ohms RDS(On), and supports the full operating temperature range (-55°C to 150°C). Product status is active with high inventory availability (40,055 pcs). RoHS3 compliance and REACH unaffected status match the original part. This is the preferred substitute for direct replacement applications.

J211-D74Z (Alternative Substitute)

The J211-D74Z provides N-Channel JFET operation at 25V in the same TO-92-3 package. Current rating is 20 mA, which is lower than the J109 but suitable for applications with reduced current requirements. Product status is active with adequate inventory (4,693 pcs). RoHS3 compliance and REACH unaffected status are maintained. This substitute is applicable where lower drain current specifications are acceptable.

BF256B (Higher Voltage Alternative)

The BF256B operates at 30V Vdss, providing higher voltage margin than the J109. This part is manufactured by onsemi and available in the same TO-92-3 package. Product status is active with substantial inventory (39,915 pcs). RoHS3 compliance and REACH unaffected status are confirmed. The BF256B is suitable for applications where higher voltage headroom is beneficial, though it is not a direct electrical equivalent due to different current and resistance specifications.

Frequently Asked Questions (FAQ)

Q: Can the J109-D26Z directly replace the J109 in all applications?

A: Yes. The J109-D26Z maintains identical electrical specifications (25V Vdss, 12 Ohms RDS(On), 25V V(BR)GSS) and operates across the same temperature range. Both parts use the TO-92-3 through-hole package. The J109-D26Z is the direct equivalent and primary substitute.

Q: What is the difference between J109-D26Z and J211-D74Z?

A: Both are N-Channel JFETs in TO-92-3 packages rated for 25V operation. The J211-D74Z has a lower drain current rating (20 mA) compared to the J109-D26Z (40 mA @ 15V). The J211-D74Z is suitable for lower-current applications. Both are active products from onsemi.

Q: Why is BF256B rated for 30V instead of 25V?

A: The BF256B is designed for higher voltage applications and provides 30V Vdss rating. This higher voltage rating does not prevent its use in 25V circuits but represents a different product line. The BF256B has different current and resistance characteristics and should be selected based on specific circuit requirements rather than as a direct pin-for-pin replacement.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. The J109-D26Z, J211-D74Z, and BF256B are all RoHS3 compliant and REACH unaffected, matching the environmental compliance of the original J109.

Q: What is the package compatibility between the J109 and its substitutes?

A: All substitute parts use the TO-92-3 (TO-226-3, TO-226AA) through-hole package with formed leads. Pin configuration and physical dimensions are identical, allowing direct board-level replacement without layout modifications.

Q: Which substitute has the best inventory availability?

A: The BF256B has the highest inventory (39,915 pcs), followed by J109-D26Z (40,055 pcs) and J211-D74Z (4,693 pcs). All three substitutes maintain active product status with adequate stock for production requirements.