MSD601-RT1 Equivalent & Substitute Parts

Part Overview

The MSD601-RT1 is an NPN bipolar junction transistor manufactured by onsemi, rated for 50 V collector-emitter breakdown voltage and 100 mA maximum collector current in a surface mount SC-59 package. This part is classified as obsolete, which necessitates identification of equivalent and substitute components for ongoing design support and production continuity. The MSD601-RT1 delivers 200 mW maximum power dissipation and is suitable for general-purpose switching and amplification applications in surface mount designs.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Voltage - Collector Emitter Breakdown (Max)	50	V
Current - Collector (Ic) (Max)	100	mA
Power - Max	200	mW
Vce Saturation (Max) @ Ib, Ic	500mV @ 10mA, 100mA	—
Current - Collector Cutoff (Max)	100	nA
DC Current Gain (hFE) (Min) @ Ic, Vce	210 @ 2mA, 10V	—
Mounting Type	Surface Mount	—
Package / Case	TO-236-3, SC-59, SOT-23-3	—
Operating Temperature (Max)	150	°C
RoHS Status	RoHS non-compliant	—

Substitute Part Grouping Explanation

Substitution of the MSD601-RT1 is determined by the following critical electrical and mechanical parameters:

Primary Substitution Criteria:

Transistor Type: NPN
Voltage - Collector Emitter Breakdown (Max): 50 V or greater
Current - Collector (Ic) (Max): 100 mA or greater
Power - Max: 200 mW or greater
Mounting Type: Surface Mount
Package / Case: TO-236-3, SC-59, or SOT-23-3 compatible

Substitution Categories:

Direct Equivalents maintain identical electrical specifications and packaging. The MSD601-RT1G from onsemi is a direct equivalent available in active product status with Tape & Reel packaging and RoHS3 compliance.

Compatible Substitutes meet or exceed all critical electrical parameters but may differ in secondary characteristics such as transition frequency, saturation voltage, or power rating. These parts function identically in the application circuit while offering improved specifications or better availability.

Similar Substitutes satisfy the core electrical requirements (voltage, current, power) and package compatibility but operate within different parameter ranges for gain, saturation voltage, or frequency response. These parts are suitable for applications where the specific parameter variations do not impact circuit performance.

Parameter Comparison

Part Number	Manufacturer	Vce Breakdown (V)	Ic Max (mA)	Power Max (mW)	Vce Sat @ 10mA, 100mA (mV)	hFE Min @ 2mA, 10V	Package	Product Status	RoHS Status
MSD601-RT1	onsemi	50	100	200	500	210	SC-59	Obsolete	RoHS non-compliant
MSD601-RT1G	onsemi	50	100	200	500	210	SC-59	Active	ROHS3 Compliant
2SC1623-L6-TP	Micro Commercial Co	50	100	200	300	—	SOT-23	Active	ROHS3 Compliant
BC847A RFG	Taiwan Semiconductor Corporation	45	100	200	500	110	SOT-23	Active	ROHS3 Compliant
2PD601ART,215	Nexperia USA Inc.	50	100	250	250	210	TO-236AB	Active	ROHS3 Compliant
2PD601ART,235	Nexperia USA Inc.	50	100	250	250	210	TO-236AB	Active	ROHS3 Compliant
BC847B-TP	Micro Commercial Co	45	100	225	500	200	SOT-23	Active	ROHS3 Compliant
BC847BE6327HTSA1	Infineon Technologies	45	100	330	600	200	PG-SOT23	Last Time Buy	ROHS3 Compliant
BC847C,215	Nexperia USA Inc.	45	100	250	400	420	TO-236AB	Active	ROHS3 Compliant
BC847CE6327HTSA1	Infineon Technologies	45	100	200	500	420	PG-SOT23	Last Time Buy	ROHS3 Compliant
BC848BT116	Rohm Semiconductor	30	100	350	600	200	SST3	Active	ROHS3 Compliant

Engineering Selection Recommendations

Primary Recommendation: MSD601-RT1G

The MSD601-RT1G is the direct equivalent replacement for the obsolete MSD601-RT1. This part maintains identical electrical specifications including 50 V breakdown voltage, 100 mA collector current, and 200 mW power rating. The MSD601-RT1G is manufactured by onsemi in active product status with RoHS3 compliance, addressing regulatory requirements for new designs. Packaging is available in Tape & Reel format suitable for automated assembly. This part provides seamless substitution with no circuit redesign required.

Secondary Recommendations for Active Designs:

The 2PD601ART,215 and 2PD601ART,235 from Nexperia USA Inc. are active products with 50 V breakdown voltage matching the original specification. Both parts offer improved saturation voltage (250 mV versus 500 mV) and increased power rating (250 mW versus 200 mW). These parts carry AEC-Q101 automotive qualification and RoHS3 compliance. The TO-236AB package is mechanically compatible with SC-59 footprints.

The 2SC1623-L6-TP from Micro Commercial Co maintains 50 V breakdown voltage and 100 mA current rating with improved saturation voltage (300 mV). This part is in active status with RoHS3 compliance and offers higher transition frequency (250 MHz) for applications requiring enhanced switching performance.

Alternative Options for Reduced Voltage Applications:

The BC847A RFG, BC847B-TP, BC847C,215, and BC847CE6327HTSA1 are suitable for applications where 45 V breakdown voltage is acceptable. These parts are in active product status or Last Time Buy status with RoHS3 compliance. The BC847 series offers varied gain characteristics (hFE ranging from 110 to 420) and improved saturation voltage performance.

Not Recommended:

The BC848BT116 from Rohm Semiconductor has a maximum breakdown voltage of 30 V, which is below the 50 V specification of the MSD601-RT1. This part is unsuitable for direct substitution in circuits requiring 50 V operation.

The BC847BE6327HTSA1 and BC847CE6327HTSA1 from Infineon Technologies are in Last Time Buy status, indicating discontinued product lines. These parts should not be selected for new designs requiring long-term supply continuity.

Frequently Asked Questions (FAQ)

Q: Can the MSD601-RT1G be used as a direct replacement for the MSD601-RT1?

A: Yes. The MSD601-RT1G is the direct equivalent with identical electrical specifications. The primary difference is product status (active versus obsolete) and RoHS compliance. No circuit modifications are required.

Q: What is the difference between SC-59 and SOT-23 packages?

A: SC-59 and SOT-23 are equivalent package designations for the same three-lead surface mount transistor form factor (TO-236-3). Both packages are mechanically and electrically compatible. The terms are used interchangeably by different manufacturers.

Q: Can I use a 45 V rated transistor in a circuit designed for 50 V?

A: No. The 45 V breakdown voltage rating is below the 50 V specification of the MSD601-RT1. Using a lower-rated part creates risk of transistor failure if the circuit experiences voltage transients or design margin variations. Parts with 50 V or greater ratings must be selected.

Q: What does RoHS3 compliance mean?

A: RoHS3 compliance indicates the part meets Restriction of Hazardous Substances Directive requirements, restricting lead, cadmium, mercury, and other hazardous materials. The original MSD601-RT1 is RoHS non-compliant. RoHS3-compliant alternatives are required for new designs and many regulated applications.

Q: Why do some substitute parts have higher power ratings?

A: Higher power ratings (250 mW or 330 mW versus 200 mW) indicate improved thermal performance and greater design margin. These parts can dissipate more heat without exceeding maximum junction temperature. Higher power ratings do not change circuit operation but provide additional safety margin.

Q: What is the significance of saturation voltage differences?

A: Saturation voltage (Vce Sat) determines the voltage drop across the transistor when fully conducting. Lower saturation voltage (250 mV versus 500 mV) reduces power dissipation and heat generation. For switching applications, lower saturation voltage improves efficiency. For linear amplification, saturation voltage may be less critical depending on circuit design.

Q: Can I substitute BC848BT116 for the MSD601-RT1?

A: No. The BC848BT116 has a maximum breakdown voltage of 30 V, which is insufficient for circuits designed for 50 V operation. This part is not suitable for direct substitution.

Q: What does "Last Time Buy" product status mean?

A: Last Time Buy indicates the manufacturer has announced end-of-life for the product. Existing inventory may be available for purchase, but no future production is planned. Parts in Last Time Buy status should not be selected for new designs requiring long-term supply continuity.

Q: Are there any differences in operating temperature range between substitute parts?

A: Yes. The MSD601-RT1 specifies 150°C maximum junction temperature. Some substitute parts specify extended temperature ranges (−55°C to 150°C or −65°C to 150°C), providing improved performance in extreme temperature environments. The MSD601-RT1 does not specify a minimum operating temperature, so extended low-temperature ratings do not impact substitution suitability.

Q: What is DC Current Gain (hFE) and why does it vary between parts?

A: DC Current Gain (hFE) is the ratio of collector current to base current at specified operating conditions. The MSD601-RT1 specifies hFE minimum of 210 at 2 mA collector current and 10 V Vce. Substitute parts may have different hFE values (ranging from 110 to 420 in the available options). Higher hFE requires less base current to achieve the same collector current. For switching applications, hFE variations typically do not impact circuit performance if the base drive is sufficient. For linear amplification, hFE variations may require circuit adjustment.

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