RN1108ACT(TPL3) Equivalent & Substitute Parts

Part Overview

The RN1108ACT(TPL3) is a pre-biased NPN bipolar junction transistor (BJT) manufactured by Toshiba Semiconductor and Storage. This surface mount device is designed for general-purpose switching and amplification applications with a maximum collector current of 80 mA and collector-emitter breakdown voltage of 50 V. The part is classified as obsolete, necessitating identification of active equivalent alternatives that maintain electrical and mechanical compatibility for ongoing production and maintenance requirements.

Substiute Parts

RN1108ACT(TPL3)

Toshiba Semiconductor and StorageIn Stock: 956RN1108ACT(TPL3) Datasheet

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RN1108MFV,L3F

Toshiba Semiconductor and StorageIn Stock: 23437RN1108MFV,L3F Datasheet

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PDTC124TM,315

Nexperia USA Inc.In Stock: 1066PDTC124TM,315 Datasheet

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PDTC124TMB,315

Nexperia USA Inc.In Stock: 873PDTC124TMB,315 Datasheet

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PDTC124XM,315

Nexperia USA Inc.In Stock: 1148PDTC124XM,315 Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the RN1108ACT(TPL3) is determined by strict alignment of the following electrical and mechanical parameters:

Critical Matching Parameters:

• Transistor type: NPN pre-biased configuration
• Collector-emitter breakdown voltage: 50 V maximum
• Base resistor (R1): 22 kOhms
• Emitter-base resistor (R2): 47 kOhms
• Collector current capability: minimum 80 mA
• Surface mount mounting type
• Moisture sensitivity level: 1 (Unlimited)

Acceptable Variation Parameters:

• Collector current (Ic) maximum: may exceed 80 mA
• Power dissipation (P-Max): may exceed 100 mW
• DC current gain (hFE): may differ if minimum specification is met or exceeded
• Vce saturation: may differ within acceptable switching performance ranges
• Collector cutoff current: may be lower (improved leakage performance)
• Package case options: SC-101 or SOT-883 acceptable

All identified substitute parts maintain the core pre-biased NPN topology with identical bias resistor values and voltage ratings, ensuring functional equivalence in circuit applications.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitute: PDTC124XM,315

The PDTC124XM,315 manufactured by Nexperia USA Inc. is the preferred substitute for the obsolete RN1108ACT(TPL3). This part maintains identical bias resistor values (R1 = 22 kOhms, R2 = 47 kOhms), matching collector-emitter breakdown voltage (50 V), and equivalent DC current gain characteristics. The PDTC124XM,315 is actively produced, ROHS3 compliant, AEC-Q100 qualified for automotive applications, and available in SOT-883 package matching the original part specification. The increased collector current rating (100 mA vs. 80 mA) and power dissipation (250 mW vs. 100 mW) provide enhanced performance margins without circuit modification.

Secondary Substitute: PDTC124TM,315

The PDTC124TM,315 is an active alternative offering identical package compatibility (SOT-883) and voltage ratings. This part features improved DC current gain (100 @ 1mA, 5V) and automotive qualification (AEC-Q100). The absence of specified R2 (emitter-base resistor) in the provided data requires circuit validation prior to implementation.

Tertiary Substitute: RN1108MFV,L3F

The RN1108MFV,L3F is an active Toshiba product maintaining the same base product number (RN1108) with identical bias resistor configuration and DC current gain specification. This part is actively produced and ROHS3 compliant. The SOT-723 package differs from the original SC-101/SOT-883 specification and requires PCB layout modification. The increased Vce saturation (300 mV vs. 150 mV) may affect switching performance in current-limited applications.

Tertiary Substitute: PDTC124TMB,315

The PDTC124TMB,315 offers automotive-grade qualification (AEC-Q100) with enhanced frequency performance (230 MHz transition frequency). The 3-XFDFN package (DFN1006B-3) differs from the original specification and requires PCB redesign. This option is suitable for applications requiring higher frequency response.

Selection Criteria:

• For direct PCB compatibility: PDTC124XM,315 or PDTC124TM,315 (SOT-883 package)
• For Toshiba product continuity: RN1108MFV,L3F (requires layout modification)
• For automotive applications: PDTC124XM,315, PDTC124TM,315, or PDTC124TMB,315 (all AEC-Q100 qualified)
• For high-frequency applications: PDTC124TMB,315 (230 MHz transition frequency)

Frequently Asked Questions (FAQ)

Q: Can PDTC124XM,315 be used as a direct replacement for RN1108ACT(TPL3)?

A: Yes. The PDTC124XM,315 maintains identical bias resistor values (R1 = 22 kOhms, R2 = 47 kOhms), collector-emitter breakdown voltage (50 V), and is available in the same SOT-883 package. The increased collector current rating (100 mA vs. 80 mA) and power dissipation (250 mW vs. 100 mW) provide enhanced performance margins. No circuit modification is required for standard switching applications.

Q: What is the difference between the Nexperia PDTC124 variants?

A: PDTC124XM,315 includes both R1 and R2 bias resistors (22 kOhms and 47 kOhms respectively) and is available in SOT-883 package. PDTC124TM,315 is also SOT-883 packaged but does not specify R2 value in the provided data. PDTC124TMB,315 is packaged in 3-XFDFN (DFN1006B-3) and includes transition frequency specification (230 MHz). All three are AEC-Q100 qualified automotive-grade parts.

Q: Why is RN1108MFV,L3F not the primary recommendation despite being from the same manufacturer?

A: While RN1108MFV,L3F maintains identical bias resistor configuration and is actively produced, it uses the SOT-723 package rather than the original SC-101/SOT-883 specification. This requires PCB layout modification. Additionally, the Vce saturation specification (300 mV vs. 150 mV) indicates different switching characteristics that may affect performance in current-limited applications. PDTC124XM,315 provides superior compatibility with no layout changes required.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All identified substitute parts (RN1108MFV,L3F, PDTC124TM,315, PDTC124TMB,315, and PDTC124XM,315) are ROHS3 compliant. The original RN1108ACT(TPL3) does not specify RoHS status in the provided data.

Q: What is the significance of AEC-Q100 qualification?

A: AEC-Q100 qualification indicates the part meets automotive industry reliability and quality standards established by the Automotive Electronics Council. The Nexperia PDTC124 variants (PDTC124TM,315, PDTC124TMB,315, PDTC124XM,315) are all AEC-Q100 qualified, making them suitable for automotive applications. The original RN1108ACT(TPL3) and RN1108MFV,L3F do not specify automotive qualification.

Q: Can PDTC124TMB,315 be used in place of PDTC124XM,315?

A: PDTC124TMB,315 is electrically compatible but uses a different package (3-XFDFN vs. SOT-883). Direct substitution requires PCB redesign. The 230 MHz transition frequency specification of PDTC124TMB,315 indicates enhanced high-frequency performance suitable for applications requiring faster switching speeds.

Q: What is the moisture sensitivity level (MSL) and why is it important?

A: MSL 1 (Unlimited) indicates the component has unlimited shelf life and does not require special moisture control during storage or handling. All identified substitute parts maintain MSL 1 specification, ensuring compatibility with existing supply chain and storage procedures.

Q: Are there any electrical performance differences between PDTC124XM,315 and the original RN1108ACT(TPL3)?

A: The primary differences are enhanced performance margins: PDTC124XM,315 provides 100 mA collector current (vs. 80 mA) and 250 mW power dissipation (vs. 100 mW). DC current gain at 5 mA, 5V is 80 (matching the original specification at 10 mA, 5V). Vce saturation is identical at 150 mV. These differences represent improved capability without degradation of original specifications.

Q: What package options are available for substitutes?

A: SOT-883 package is available for PDTC124XM,315 and PDTC124TM,315 (direct PCB compatibility with original). SOT-723 is available for RN1108MFV,L3F (requires layout modification). 3-XFDFN (DFN1006B-3) is available for PDTC124TMB,315 (requires PCB redesign). Selection depends on PCB layout constraints and design flexibility.