MSB709-RT1G Equivalent & Substitute Parts

Part Overview

The MSB709-RT1G is an obsolete PNP bipolar junction transistor manufactured by onsemi, rated for 45 V collector-emitter breakdown voltage and 100 mA maximum collector current in a surface mount SC-59 package. The device is classified as obsolete, necessitating identification of active equivalent and substitute components for new designs and ongoing production requirements. Substitute parts must maintain electrical compatibility across critical parameters including voltage rating, current capacity, and DC current gain specifications.

Key Parameters

Parameter	Value	Unit
Transistor Type	PNP	—
Voltage - Collector Emitter Breakdown (Max)	45	V
Current - Collector (Ic) (Max)	100	mA
Vce Saturation (Max) @ Ib, Ic	500mV @ 10mA, 100mA	—
DC Current Gain (hFE) (Min) @ Ic, Vce	210 @ 2mA, 10V	—
Power - Max	200	mW
Operating Temperature (TJ)	150	°C
Mounting Type	Surface Mount	—
Package / Case	TO-236-3, SC-59, SOT-23-3	—
Moisture Sensitivity Level (MSL)	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the MSB709-RT1G is determined by strict electrical parameter matching and package compatibility. The primary substitution criteria are:

Mandatory Electrical Parameters:

Voltage - Collector Emitter Breakdown (Max): 45 V minimum
Current - Collector (Ic) (Max): 100 mA minimum
DC Current Gain (hFE) (Min): 210 or greater at specified test conditions
Vce Saturation (Max): 500 mV or lower at 10 mA, 100 mA conditions
Operating Temperature: 150°C maximum junction temperature

Package Compatibility:

Surface mount packages: SC-59, SC-70, SOT-23-3, TO-236-3, TO-236AB acceptable
Pin configuration must support PNP transistor topology

Substitution Categories:

Direct Equivalents maintain all electrical parameters within specification and support identical or compatible package footprints. These parts are interchangeable without circuit modification.

Functional Equivalents meet or exceed all mandatory electrical parameters but may differ in secondary characteristics such as transition frequency, power dissipation capability, or saturation voltage. These parts are suitable for applications where the additional performance margin does not create design conflicts.

Similar Parts share the same electrical rating envelope but may have different DC current gain specifications or operating temperature ranges. Selection requires verification that the specific gain and temperature characteristics align with circuit requirements.

Parameter Comparison

Part Number	Manufacturer	Ic (Max) mA	Vce(br) V	Vce Sat (Max) mV	hFE (Min)	Power (Max) mW	Freq Trans MHz	Package	Status
MSB709-RT1G	onsemi	100	45	500	210	200	—	SC-59	Obsolete
MSB1218A-RT1G	onsemi	100	45	500	210	150	—	SC-70	Active
2PB709ARL,215	Nexperia USA Inc.	100	45	500	210	250	70	TO-236AB	Active
2PB709ARL,235	Nexperia USA Inc.	100	45	500	210	250	70	TO-236AB	Active
2PB709ART,215	NXP USA Inc.	100	45	500	210	250	70	SOT-23	Active
BC857A-TP	Micro Commercial Co	100	45	650	125	310	200	SOT-23	Active
BC857B-TP	Micro Commercial Co	100	45	650	220	310	200	SOT-23	Active
2PB709ART,235	Nexperia USA Inc.	100	45	500	120	250	70	TO-236AB	Active
BC857BR TR PBFREE	Central Semiconductor Corp	100	45	650	220	350	100	SOT-23	Active
BC857C TR PBFREE	Central Semiconductor Corp	100	45	50	420	350	100	SOT-23	Active
BC857CE6327HTSA1	Infineon Technologies	100	45	650	420	330	250	SOT-23	Last Time Buy

Engineering Selection Recommendations

Direct Substitution (Recommended for Pin-Compatible Designs):

The 2PB709ARL,215 and 2PB709ARL,235 (Nexperia USA Inc.) are direct electrical equivalents to the MSB709-RT1G. Both parts maintain the 45 V breakdown voltage, 100 mA collector current, and 210 mA minimum DC current gain specification. The TO-236AB package is mechanically compatible with SC-59 footprints. Both parts are active products with AEC-Q101 automotive qualification and ROHS3 compliance, providing long-term supply assurance. The 2PB709ART,215 variant in SOT-23 package offers identical electrical performance with alternative surface mount footprint compatibility.

Alternative for Compact Designs:

The MSB1218A-RT1G (onsemi) provides equivalent electrical performance in the SC-70 package, suitable for space-constrained applications. This part maintains all critical electrical parameters and is an active product from the original manufacturer. The reduced power rating (150 mW versus 200 mW) is acceptable for applications operating below 150 mW dissipation.

Higher Performance Alternatives:

The BC857B-TP and BC857BR TR PBFREE (Central Semiconductor Corp) meet all mandatory electrical parameters with enhanced transition frequency (200 MHz and 100 MHz respectively) and higher power dissipation capability (310 mW and 350 mW). The BC857B-TP maintains hFE minimum of 220 at specified conditions, exceeding the 210 requirement. These parts are suitable for applications requiring improved frequency response or thermal margin.

Compliance Considerations:

All recommended substitutes are ROHS3 compliant and REACH unaffected. The Nexperia parts carry AEC-Q101 automotive qualification, appropriate for automotive and industrial applications. The onsemi MSB1218A-RT1G maintains the original manufacturer relationship for supply chain continuity.

Frequently Asked Questions (FAQ)

Q: Can the MSB709-RT1G be directly replaced with the 2PB709ARL,215?

A: Yes. Both parts share identical electrical specifications: 45 V breakdown voltage, 100 mA maximum collector current, 210 mA minimum DC current gain, and 500 mV maximum saturation voltage at specified conditions. The TO-236AB package is mechanically compatible with SC-59 footprints. No circuit modification is required.

Q: What is the difference between the 2PB709ARL,215 and 2PB709ARL,235?

A: Both parts are electrically equivalent with 45 V breakdown voltage and 100 mA collector current. The primary difference is the DC current gain specification: 2PB709ARL,215 specifies 210 mA minimum hFE, while 2PB709ARL,235 specifies 120 mA minimum hFE. For applications requiring the higher gain specification, the 2PB709ARL,215 is the appropriate selection.

Q: Is the BC857B-TP a suitable replacement for the MSB709-RT1G?

A: The BC857B-TP meets the mandatory electrical parameters: 45 V breakdown voltage, 100 mA collector current, and 220 mA minimum DC current gain (exceeding the 210 requirement). However, the saturation voltage is specified at 650 mV versus 500 mV for the MSB709-RT1G. Applications sensitive to saturation voltage performance should verify circuit tolerance before substitution. The BC857B-TP offers enhanced transition frequency (200 MHz) and higher power dissipation (310 mW).

Q: What package options are available for substitution?

A: The MSB709-RT1G uses the SC-59 package. Direct mechanical replacements include TO-236AB (2PB709ARL series) and SOT-23 (BC857 series, 2PB709ART,215). The SC-70 package (MSB1218A-RT1G) requires PCB layout modification but maintains electrical compatibility. All packages are surface mount configurations with identical pin functionality for PNP transistor operation.

Q: Are there automotive-qualified alternatives?

A: Yes. The 2PB709ARL,215 and 2PB709ARL,235 (Nexperia USA Inc.) carry AEC-Q101 automotive qualification and are suitable for automotive applications. Both parts are active products with ROHS3 compliance and REACH unaffected status.

Q: What is the difference between active and obsolete product status?

A: The MSB709-RT1G is classified as obsolete, indicating onsemi has discontinued production and will not guarantee future availability. Active products such as the 2PB709ARL,215, MSB1218A-RT1G, and BC857B-TP are currently manufactured and supported by their respective suppliers, providing long-term supply assurance for new designs and production continuity.

Q: Can I use the BC857C TR PBFREE as a substitute?

A: The BC857C TR PBFREE meets the mandatory voltage and current specifications (45 V, 100 mA). However, it specifies a significantly lower saturation voltage (50 mV versus 500 mV) and higher DC current gain (420 mA minimum versus 210 mA). These differences indicate different transistor characteristics that may affect circuit performance. Verification of circuit tolerance to these parameter variations is required before substitution.

Q: What does MSL 1 (Unlimited) moisture sensitivity mean?

A: MSL 1 (Unlimited) indicates the component has no moisture sensitivity limitations. The part does not require special moisture control during storage, handling, or assembly. Standard PCB assembly processes are applicable without additional moisture barrier precautions.

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