2SK3738-TL-E Equivalent & Substitute Parts

Part Overview

The 2SK3738-TL-E is an N-Channel JFET transistor manufactured by onsemi, designed for surface mount applications with a maximum drain current of 1 mA and 40 V drain-to-source voltage rating. The device is housed in an SC-75 (SOT-416) package and dissipates up to 100 mW. This part is classified as obsolete, making identification of functionally equivalent alternatives necessary for ongoing design support and production continuity.

Substiute Parts

2SK3738-TL-E

onsemiIn Stock: 10342SK3738-TL-E Datasheet

Current PartRFQ

2SK545-11D-TB-E

onsemiIn Stock: 7142SK545-11D-TB-E Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 2SK3738-TL-E is determined by the following critical electrical and mechanical parameters:

• FET Channel Type: N-Channel topology must be maintained
• Drain-to-Source Voltage (Vdss): Minimum 40 V rating required
• Maximum Drain Current (Id): 1 mA specification
• Mounting Configuration: Surface mount technology
• Package Compatibility: SC-75 (SOT-416) or equivalent footprint
• Voltage Breakdown (V(BR)GSS): 40 V minimum
• Input Capacitance (Ciss): 1.7 pF maximum at 10 V
• Power Dissipation: 100 mW minimum capability

The substitute part 2SK545-11D-TB-E meets the core electrical requirements for drain voltage, drain current, and channel type. However, package differences exist and must be evaluated for mechanical compatibility in the target application.

Parameter Comparison

Engineering Selection Recommendations

The 2SK545-11D-TB-E provides electrical equivalence to the 2SK3738-TL-E across all critical parameters: identical Vdss (40 V), Id (1 mA), and Ciss (1.7 pF). The substitute offers higher power dissipation capability (125 mW vs. 100 mW), which provides additional thermal margin.

Package differences exist between the main part (SC-75/SOT-416) and the substitute (TO-236-3/SC-59/SOT-23-3). PCB layout modifications are required to accommodate the different footprint. Both parts carry identical MSL ratings (1 - Unlimited) and REACH compliance status, ensuring equivalent environmental handling and regulatory compliance.

The 2SK545-11D-TB-E is classified as obsolete, consistent with the main part status. Both devices are manufactured by onsemi and carry EAR99 ECCN classification.

Frequently Asked Questions (FAQ)

Q: Can the 2SK545-11D-TB-E be used as a direct pin-for-pin replacement for the 2SK3738-TL-E?

A: No. While both are N-Channel JFETs with identical electrical ratings (40 V Vdss, 1 mA Id), the packages differ. The 2SK3738-TL-E uses SC-75 (SOT-416) while the 2SK545-11D-TB-E uses TO-236-3 (SOT-23-3). PCB footprint redesign is required.

Q: What are the key electrical parameters that determine substitution compatibility?

A: Drain-to-source voltage (Vdss), maximum drain current (Id), channel type (N-Channel), voltage breakdown rating (V(BR)GSS), and input capacitance (Ciss) are the primary criteria. Both parts match on all these parameters.

Q: Are there differences in cutoff voltage between these parts?

A: Yes. The 2SK3738-TL-E has a cutoff voltage (VGS off) of 2.3 V @ 1 µA, while the 2SK545-11D-TB-E is specified at 1.5 V @ 1 µA. This difference may affect circuit biasing and should be evaluated in the specific application context.

Q: Do both parts have the same moisture sensitivity rating?

A: Yes. Both the 2SK3738-TL-E and 2SK545-11D-TB-E carry MSL 1 (Unlimited), indicating identical moisture handling requirements and storage conditions.

Q: What is the impact of the higher power rating on the 2SK545-11D-TB-E?

A: The substitute part is rated for 125 mW versus 100 mW for the main part. This provides additional thermal headroom and may allow operation at higher power levels, though the application circuit determines actual power dissipation.