RN1406S,LF(D Equivalent & Substitute Parts

Part Overview

The RN1406S,LF(D is a pre-biased NPN bipolar junction transistor (BJT) manufactured by Toshiba Semiconductor and Storage. This surface mount device operates at 50 V collector-emitter breakdown voltage with a maximum collector current of 100 mA and is housed in a TO-236-3 (SOT-23-3) package. The part is classified as obsolete, necessitating identification of functionally equivalent alternatives from active product lines. Substitute parts maintain identical electrical specifications and mechanical compatibility while offering continued availability and supply chain reliability.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN - Pre-Biased	—
Collector Current (Ic) Maximum	100	mA
Collector-Emitter Breakdown Voltage (Vceo)	50	V
Base Resistor (R1)	4.7	kOhms
Emitter-Base Resistor (R2)	47	kOhms
DC Current Gain (hFE) Minimum	80	—
Vce Saturation Maximum	300	mV
Collector Cutoff Current (Icbo) Maximum	500	nA
Power Dissipation Maximum	200	mW
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 RN1406S,LF(D is determined by strict equivalence across the following critical parameters:

Electrical Equivalence Criteria:

Transistor type: NPN pre-biased configuration
Collector current rating: 100 mA maximum
Collector-emitter breakdown voltage: 50 V
Base resistor (R1): 4.7 kOhms
Emitter-base resistor (R2): 47 kOhms
DC current gain (hFE): minimum 80
Collector cutoff current: 500 nA maximum
Power dissipation: 200 mW or greater

Mechanical Equivalence Criteria:

Surface mount technology
Package compatibility: TO-236-3, SC-59, or SOT-23-3 footprint
Moisture sensitivity level: MSL 1 (Unlimited)

Substitute parts are classified as either direct equivalents (identical part number variants from the same manufacturer) or functionally equivalent alternatives (different manufacturers with identical electrical and mechanical specifications). All listed substitutes maintain active product status and comply with RoHS3 requirements.

Parameter Comparison

Part Number	Manufacturer	Product Status	Ic (Max) mA	Vceo (Max) V	R1 kOhms	R2 kOhms	hFE (Min)	Vce Sat (Max) mV	Icbo (Max) nA	Power (Max) mW	Package	RoHS3
RN1406S,LF(D	Toshiba	Obsolete	100	50	4.7	47	80	300	500	200	SOT-23-3	—
RN1406,LF	Toshiba	Active	100	50	4.7	47	80	300	500	200	SOT-23-3	Yes
DDTC143ZCA-7-F	Diodes Incorporated	Active	100	50	4.7	47	80	300	500	200	SOT-23-3	Yes
DTC143ZCA-TP	Micro Commercial Co	Active	100	50	4.7	47	80	300	500	200	SOT-23-3	Yes
DTC143ZKAT146	Rohm Semiconductor	Active	100	50	4.7	47	80	300	500	200	SOT-23-3	Yes
MMUN2233LT1G	onsemi	Active	100	50	4.7	47	80	250	500	246	SOT-23-3	Yes
MUN2233T1G	onsemi	Active	100	50	4.7	47	80	250	500	230	SC-59	Yes
NSVMUN2233T1G	onsemi	Active	100	50	4.7	47	80	250	500	230	SC-59	Yes
PDTC143ZT,215	Nexperia USA Inc.	Active	100	50	4.7	47	100	100	1000	250	TO-236AB	Yes
PDTC143ZT,235	Nexperia USA Inc.	Active	100	50	4.7	47	100	100	1000	250	TO-236AB	Yes
SMMUN2233LT1G	onsemi	Active	100	50	4.7	47	80	250	500	246	SOT-23-3	Yes

Engineering Selection Recommendations

Direct Equivalent (Preferred for Pin-for-Pin Replacement):

RN1406,LF from Toshiba Semiconductor and Storage is the direct active equivalent of the obsolete RN1406S,LF(D. This part maintains identical electrical specifications and package configuration while offering active product status and RoHS3 compliance. Selection of this part eliminates any design modification requirements.

Functionally Equivalent Alternatives:

The following parts satisfy all electrical and mechanical substitution criteria and are suitable for direct PCB replacement:

DDTC143ZCA-7-F (Diodes Incorporated): Maintains all core electrical parameters with identical package footprint. Active status with RoHS3 compliance.
DTC143ZCA-TP (Micro Commercial Co): Functionally equivalent with active product status and RoHS3 compliance.
DTC143ZKAT146 (Rohm Semiconductor): Functionally equivalent with active product status and RoHS3 compliance.

Enhanced Performance Alternatives:

The following parts exceed the minimum electrical specifications of the RN1406S,LF(D while maintaining compatibility:

MMUN2233LT1G (onsemi): Provides improved saturation voltage (250 mV vs. 300 mV) and increased power dissipation (246 mW vs. 200 mW). Active status with RoHS3 compliance.
SMMUN2233LT1G (onsemi): Functionally identical to MMUN2233LT1G with active product status and RoHS3 compliance.
PDTC143ZT,215 and PDTC143ZT,235 (Nexperia USA Inc.): Provide enhanced DC current gain (100 vs. 80), improved saturation voltage (100 mV vs. 300 mV), and increased power dissipation (250 mW vs. 200 mW). Both parts carry AEC-Q100 automotive qualification and RoHS3 compliance.

Package-Specific Considerations:

MUN2233T1G and NSVMUN2233T1G (onsemi) utilize SC-59 package variant instead of SOT-23-3. These parts are functionally equivalent but require PCB footprint verification prior to implementation.

All substitute parts maintain MSL 1 (Unlimited) moisture sensitivity classification, ensuring compatibility with standard handling and storage procedures.

Frequently Asked Questions (FAQ)

Q: Can RN1406,LF directly replace RN1406S,LF(D without design modification?

A: Yes. RN1406,LF is the direct active equivalent with identical electrical specifications and package configuration. No design modification is required.

Q: What is the primary difference between the RN1406S,LF(D and its substitutes?

A: The RN1406S,LF(D is classified as obsolete. All listed substitutes are active products with RoHS3 compliance, ensuring continued supply chain availability and regulatory compliance.

Q: Are all substitute parts compatible with the same PCB footprint?

A: Most substitutes utilize SOT-23-3 or TO-236AB packages, which share identical footprints. MUN2233T1G and NSVMUN2233T1G use SC-59 packaging. Verify PCB footprint compatibility before implementation.

Q: What is the significance of the internal resistor values (R1 = 4.7 kOhms, R2 = 47 kOhms)?

A: These internal resistors define the pre-biasing network of the transistor. All listed substitutes maintain identical resistor values, ensuring equivalent switching behavior and circuit performance.

Q: Do the PDTC143ZT,215 and PDTC143ZT,235 parts offer advantages over the base RN1406S,LF(D specification?

A: Yes. These Nexperia parts provide higher DC current gain (100 vs. 80), lower saturation voltage (100 mV vs. 300 mV), and greater power dissipation capability (250 mW vs. 200 mW). Both carry AEC-Q100 automotive qualification.

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

A: MSL 1 indicates the component has unlimited shelf life under standard storage conditions. No special moisture control measures are required during handling or storage.

Q: Can onsemi MMUN2233LT1G and SMMUN2233LT1G be used interchangeably?

A: Yes. Both parts are functionally identical with the same electrical specifications and SOT-23-3 package. Selection between them depends on packaging format availability (Cut Tape vs. Tape & Reel).

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All listed active substitutes comply with RoHS3 requirements. The original RN1406S,LF(D does not specify RoHS3 status due to its obsolete classification.

Q: What is the difference between TO-236-3, SC-59, and SOT-23-3 package designations?

A: These are equivalent package designations for the same 3-pin surface mount form factor. TO-236-3 is the JEDEC designation, SC-59 is the EIAJ designation, and SOT-23-3 is the IEC designation. All are mechanically and electrically compatible.

Q: Which substitute offers the best overall compatibility for direct replacement?

A: RN1406,LF from Toshiba is the recommended first choice as the direct active equivalent. For alternative sources, DDTC143ZCA-7-F (Diodes Incorporated) and DTC143ZKAT146 (Rohm Semiconductor) provide identical specifications with high inventory availability.

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