Equivalent & Substitute Parts for 2SD1938FSL

Part Overview

The Panasonic 2SD1938FSL is an NPN bipolar junction transistor (BJT) rated for 20 V collector-emitter breakdown voltage and 300 mA maximum collector current. This surface mount device is packaged in TO-236-3 (SOT-23-3) configuration with a maximum power dissipation of 200 mW and transition frequency of 80 MHz. The 2SD1938FSL is classified as obsolete, making equivalent and substitute parts necessary for ongoing production and maintenance applications. Substitute parts must maintain electrical compatibility across critical parameters including voltage rating, current capacity, saturation characteristics, and package form factor.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Voltage - Collector Emitter Breakdown (Max)	20	V
Current - Collector (Ic) (Max)	300	mA
Vce Saturation (Max) @ Ib, Ic	100 mV @ 3 mA, 30 mA	—
Current - Collector Cutoff (Max)	100	nA
Power - Max	200	mW
Frequency - Transition	80	MHz
Operating Temperature (TJ)	150	°C
Mounting Type	Surface Mount	—
Package / Case	TO-236-3, SC-59, SOT-23-3	—

Substitute Part Grouping Explanation

Substitution of the 2SD1938FSL is determined by strict equivalence across the following critical parameters:

Mandatory Matching Parameters:

Transistor Type: NPN
Voltage - Collector Emitter Breakdown (Max): 20 V
Current - Collector (Ic) (Max): 300 mA
Vce Saturation (Max) @ Ib, Ic: 100 mV @ 3 mA, 30 mA
Current - Collector Cutoff (Max): 100 nA (ICBO)
Package / Case: TO-236-3, SC-59, SOT-23-3
Mounting Type: Surface Mount

Allowable Variation Parameters:

Power - Max: 150 mW to 200 mW (substitute may be equal or greater)
Frequency - Transition: 30 MHz to 80 MHz (substitute may be equal or greater)
DC Current Gain (hFE): Varies by part; minimum values differ
Operating Temperature (TJ): 125°C to 150°C (substitute may be equal or greater)

All three substitute parts (2SC3326-A,LF; 2SC3326-B,LF; 2SD2704KT146) meet the mandatory matching criteria and are therefore electrically and mechanically compatible with the 2SD1938FSL.

Parameter Comparison

Parameter	2SD1938FSL (Main)	2SC3326-A,LF	2SC3326-B,LF	2SD2704KT146
Manufacturer	Panasonic Electronic Components	Toshiba Semiconductor and Storage	Toshiba Semiconductor and Storage	Rohm Semiconductor
Product Status	Obsolete	Active	Active	Active
Transistor Type	NPN	NPN	NPN	NPN
Voltage - Collector Emitter Breakdown (Max)	20 V	20 V	20 V	20 V
Current - Collector (Ic) (Max)	300 mA	300 mA	300 mA	300 mA
Vce Saturation (Max) @ Ib, Ic	100 mV @ 3 mA, 30 mA	100 mV @ 3 mA, 30 mA	100 mV @ 3 mA, 30 mA	100 mV @ 3 mA, 30 mA
Current - Collector Cutoff (Max)	100 nA	100 nA	100 nA	100 nA
DC Current Gain (hFE) (Min) @ Ic, Vce	500 @ 4 mA, 2 V	200 @ 4 mA, 2 V	350 @ 4 mA, 2 V	820 @ 4 mA, 2 V
Power - Max	200 mW	150 mW	150 mW	200 mW
Frequency - Transition	80 MHz	30 MHz	30 MHz	35 MHz
Operating Temperature (TJ)	150°C	125°C	125°C	150°C
Package / Case	TO-236-3, SC-59, SOT-23-3	TO-236-3, SC-59, SOT-23-3	TO-236-3, SC-59, SOT-23-3	TO-236-3, SC-59, SOT-23-3
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)

Engineering Selection Recommendations

2SC3326-A,LF (Toshiba Semiconductor and Storage)

This substitute is active in production and RoHS3 compliant. It meets all mandatory electrical parameters and is packaged in TO-236-3 form factor. The 2SC3326-A,LF operates at a maximum temperature of 125°C compared to the 2SD1938FSL's 150°C, and has a transition frequency of 30 MHz versus 80 MHz. Power dissipation is rated at 150 mW versus 200 mW. The DC current gain minimum is 200 at specified conditions. This part is suitable for applications where the lower frequency and temperature ratings do not exceed design requirements.

2SC3326-B,LF (Toshiba Semiconductor and Storage)

This substitute is active in production and RoHS3 compliant. It meets all mandatory electrical parameters and is packaged in TO-236-3 form factor. The 2SC3326-B,LF operates at a maximum temperature of 125°C and has a transition frequency of 30 MHz. Power dissipation is rated at 150 mW. The DC current gain minimum is 350 at specified conditions, providing higher gain than the 2SC3326-A,LF variant. This part is suitable for applications where the lower frequency and temperature ratings do not exceed design requirements.

2SD2704KT146 (Rohm Semiconductor)

This substitute is active in production and RoHS3 compliant. It meets all mandatory electrical parameters and is packaged in TO-236-3 form factor. The 2SD2704KT146 operates at a maximum temperature of 150°C, matching the 2SD1938FSL specification. Power dissipation is rated at 200 mW, matching the original part. The transition frequency is 35 MHz, which is lower than the 2SD1938FSL's 80 MHz but higher than the Toshiba alternatives. The DC current gain minimum is 820 at specified conditions. This part provides the closest thermal and power performance match to the original device.

Frequently Asked Questions (FAQ)

Q: Can the 2SC3326-A,LF or 2SC3326-B,LF be used in applications requiring 150°C operating temperature?

A: No. Both Toshiba 2SC3326 variants are rated for a maximum operating temperature of 125°C, while the 2SD1938FSL is rated for 150°C. Applications requiring the full 150°C operating range must use the 2SD2704KT146.

Q: What is the difference between 2SC3326-A,LF and 2SC3326-B,LF?

A: Both parts are electrically identical except for DC current gain minimum specifications. The 2SC3326-A,LF has a minimum DC current gain of 200 at 4 mA and 2 V, while the 2SC3326-B,LF has a minimum of 350 at the same conditions. Both are packaged in TO-236-3 form factor; the primary difference is packaging format (Cut Tape & Digi-Reel for 2SC3326-A,LF versus Tape & Reel for 2SC3326-B,LF).

Q: Are all substitute parts RoHS3 compliant?

A: Yes. The 2SC3326-A,LF, 2SC3326-B,LF, and 2SD2704KT146 are all RoHS3 compliant. The original 2SD1938FSL does not specify RoHS status.

Q: Can these substitutes be used interchangeably in the same PCB assembly?

A: All three substitute parts use the same TO-236-3 (SOT-23-3) package and surface mount configuration. They are mechanically interchangeable on the PCB. Electrical interchangeability depends on application-specific requirements for frequency response, temperature rating, and current gain characteristics.

Q: Which substitute part is the best direct replacement for the 2SD1938FSL?

A: The 2SD2704KT146 provides the closest electrical match, with identical maximum operating temperature (150°C) and power dissipation (200 mW) specifications. However, its transition frequency of 35 MHz is lower than the original 80 MHz. The choice of substitute depends on whether the application requires the full 80 MHz frequency response and 150°C temperature rating.

Q: What is the significance of the transition frequency difference?

A: The 2SD1938FSL has a transition frequency of 80 MHz, while the Toshiba substitutes are rated at 30 MHz and the Rohm substitute at 35 MHz. Transition frequency determines the maximum frequency at which the transistor can operate effectively. Applications requiring high-frequency switching or amplification above 35 MHz cannot use these substitutes.

Q: Are there inventory considerations when selecting a substitute?

A: Yes. The 2SD2704KT146 has the highest inventory availability at 60,400 pieces. The 2SC3326-B,LF has 4,100 pieces available, and the 2SC3326-A,LF has 3,891 pieces. The original 2SD1938FSL has 1,032 pieces in stock but is obsolete.

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