RN1906,LF Pre-Biased Dual NPN Bipolar Transistor Equivalent & Substitute Parts

Part Overview

The Toshiba RN1906,LF is a pre-biased dual NPN bipolar transistor (BJT) in a 6-TSSOP/SC-88/SOT-363 surface mount package. This component integrates two NPN transistors with internal base and emitter resistors, designed for switching and amplification applications requiring 50V collector-emitter breakdown voltage and 100mA maximum collector current. The main part number RN1906,LF carries an obsolete product status, necessitating identification of functionally equivalent alternatives from active manufacturers. Substitute parts must maintain electrical compatibility across critical parameters including collector current rating, breakdown voltage, internal resistor values, and saturation characteristics to ensure direct circuit replacement without redesign.

Key Parameters

Parameter	Value	Unit
Transistor Type	2 NPN - Pre-Biased (Dual)	—
Current - Collector (Ic) (Max)	100	mA
Voltage - Collector Emitter Breakdown (Max)	50	V
Resistor - Base (R1)	4.7	kOhms
Resistor - Emitter Base (R2)	47	kOhms
DC Current Gain (hFE) (Min) @ Ic, Vce	80 @ 10mA, 5V	—
Vce Saturation (Max) @ Ib, Ic	300	mV
Current - Collector Cutoff (Max)	500	nA
Frequency - Transition	250	MHz
Power - Max	200	mW
Mounting Type	Surface Mount	—
Package / Case	6-TSSOP, SC-88, SOT-363	—
Moisture Sensitivity Level (MSL)	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution compatibility for the RN1906,LF is determined by strict adherence to the following electrical and mechanical parameters:

Primary Substitution Criteria:

Maximum collector current: 100mA
Collector-emitter breakdown voltage: 50V
Internal base resistor (R1): 4.7kOhms
Internal emitter-base resistor (R2): 47kOhms
Surface mount package compatibility: 6-TSSOP, SC-88, SOT-363
Moisture sensitivity level: 1 (Unlimited)

Substitution Categories:

Direct Substitutes (Identical Configuration): Parts maintaining 2 NPN pre-biased transistor configuration with matching electrical specifications and internal resistor values. These include RN1906,LF(CT from Toshiba and DDC143ZU-7-F from Diodes Incorporated.

Functional Equivalents (Compatible Configuration): Parts with 1 NPN + 1 PNP pre-biased transistor configuration or alternative internal resistor specifications that maintain electrical performance within the application envelope. These include DCX143ZU-7-F (Diodes Incorporated), MUN5233DW1T1G and NSVMUN5233DW1T3G (onsemi), and PUMD13,115 and PUMD13,135 (Nexperia USA Inc.).

Compatibility Constraints: Substitutes must support the same maximum collector current (100mA), breakdown voltage (50V), and surface mount package footprint. Variations in transition frequency, saturation voltage, or power dissipation rating do not preclude substitution if the application requirements remain satisfied.

Parameter Comparison

Part Number	Manufacturer	Transistor Type	Ic (Max) mA	Vce(BR) V	R1 kOhms	R2 kOhms	hFE (Min)	Vce Sat (Max) mV	Ic(off) (Max) nA	Ft MHz	P (Max) mW	Package	Status
RN1906,LF	Toshiba	2 NPN	100	50	4.7	47	80	300	500	250	200	SOT-363	Obsolete
RN1906,LF(CT	Toshiba	2 NPN	100	50	4.7	47	80	300	500	250	200	SOT-363	Active
DDC143ZU-7-F	Diodes Inc.	2 NPN	100	50	4.7	47	80	300	500	250	200	SOT-363	Active
DCX143ZU-7-F	Diodes Inc.	1 NPN, 1 PNP	100	50	4.7	47	80	300	500	250	200	SOT-363	Active
MUN5233DW1T1G	onsemi	2 NPN	100	50	4.7	47	80	250	500	—	250	SOT-363	Active
NSVMUN5233DW1T3G	onsemi	2 NPN	100	50	4.7	47	80	250	500	—	250	SOT-363	Active
PUMD13,115	Nexperia	1 NPN, 1 PNP	100	50	4.7	47	100	100	1000	—	300	6-TSSOP	Active
PUMD13,135	Nexperia	1 NPN, 1 PNP	100	50	4.7	47	100	100	1000	—	300	6-TSSOP	Active

Engineering Selection Recommendations

Primary Selection (Direct Replacement):

RN1906,LF(CT from Toshiba Semiconductor and Storage is the direct equivalent substitute. This part maintains identical electrical specifications, internal resistor configuration, and package designation while offering active product status. The transition from cut tape to tape & reel packaging does not affect electrical performance or circuit compatibility.

Secondary Selection (Functional Equivalent with Active Status):

DDC143ZU-7-F from Diodes Incorporated provides a functionally equivalent 2 NPN pre-biased transistor configuration with identical electrical parameters. This part carries active product status and ROHS3 compliance certification, supporting long-term supply chain continuity.

Alternative Selections (Compatible Configuration):

MUN5233DW1T1G and NSVMUN5233DW1T3G from onsemi maintain the 2 NPN pre-biased configuration with matching electrical specifications. NSVMUN5233DW1T3G includes AEC-Q101 automotive qualification. Both parts support higher power dissipation (250mW vs. 200mW) and carry active product status.

Compliance-Qualified Alternatives:

DCX143ZU-7-F (Diodes Incorporated) and PUMD13,115 and PUMD13,135 (Nexperia USA Inc.) provide pre-biased transistor functionality with AEC-Q101 automotive qualification and ROHS3 compliance. These parts feature 1 NPN + 1 PNP configuration and support higher power dissipation (200mW to 300mW), suitable for applications requiring automotive-grade components.

Selection Basis:

All recommended substitutes maintain the critical electrical parameters: 100mA maximum collector current, 50V collector-emitter breakdown voltage, 4.7kOhms base resistor, and 47kOhms emitter-base resistor. All parts carry MSL 1 (Unlimited) moisture sensitivity rating and surface mount package compatibility. Selection between alternatives depends on specific application requirements for transistor configuration (2 NPN vs. 1 NPN + 1 PNP), power dissipation margin, and automotive qualification necessity.

Frequently Asked Questions (FAQ)

Q: Can RN1906,LF be directly replaced with RN1906,LF(CT?

A: Yes. RN1906,LF(CT is the direct equivalent with identical electrical specifications and internal resistor values. The packaging difference (cut tape vs. tape & reel) does not affect electrical performance or circuit compatibility. RN1906,LF(CT carries active product status, addressing the obsolescence of the original part.

Q: What is the difference between 2 NPN and 1 NPN + 1 PNP pre-biased transistor configurations?

A: The RN1906,LF contains two independent NPN transistors with shared internal resistor networks. Parts such as DCX143ZU-7-F and PUMD13,115/PUMD13,135 contain one NPN and one PNP transistor. Both configurations support the same maximum collector current (100mA) and breakdown voltage (50V). Selection depends on circuit requirements for complementary transistor pairs versus dual NPN functionality.

Q: Are onsemi MUN5233 parts compatible with the RN1906,LF?

A: Yes. MUN5233DW1T1G and NSVMUN5233DW1T3G maintain the 2 NPN pre-biased configuration with matching internal resistor values (4.7kOhms base, 47kOhms emitter-base). These parts support higher power dissipation (250mW vs. 200mW) and carry active product status. Saturation voltage is lower (250mV vs. 300mV), which does not preclude substitution if application requirements are satisfied.

Q: What is the significance of AEC-Q101 qualification on substitute parts?

A: AEC-Q101 qualification indicates the part meets automotive industry reliability and quality standards. Parts such as NSVMUN5233DW1T3G, DCX143ZU-7-F, and PUMD13,115/PUMD13,135 carry this certification. Selection of AEC-Q101 qualified parts is necessary only if the application requires automotive-grade component compliance.

Q: Do all substitute parts support the same package footprint?

A: All substitute parts support surface mount packages within the 6-TSSOP, SC-88, SOT-363 family. These packages share compatible PCB footprints and land patterns. Verify specific package designation (SOT-363 vs. 6-TSSOP) against PCB design requirements, as some manufacturers designate the same physical package differently.

Q: Can PUMD13,115 or PUMD13,135 be used in place of RN1906,LF?

A: Yes, with circuit design consideration. PUMD13 parts contain 1 NPN + 1 PNP configuration versus the 2 NPN configuration of RN1906,LF. Both maintain identical internal resistor values and maximum electrical ratings. PUMD13 parts offer improved saturation characteristics (100mV vs. 300mV) and higher power dissipation (300mW vs. 200mW). Substitution is valid if the circuit does not require dual NPN functionality.

Q: What is the impact of higher transition frequency on substitution compatibility?

A: The RN1906,LF specifies 250MHz transition frequency. Substitute parts from onsemi (MUN5233 series) do not specify transition frequency in provided data. Diodes Incorporated parts (DDC143ZU-7-F, DCX143ZU-7-F) maintain 250MHz specification. Higher transition frequency supports faster switching applications; lower or unspecified values do not preclude substitution if application bandwidth requirements are satisfied.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All active substitute parts listed carry ROHS3 compliance certification. The original RN1906,LF does not specify ROHS status due to obsolete product classification. ROHS3 compliance is standard for all active pre-biased BJT components from Toshiba, Diodes Incorporated, onsemi, and Nexperia USA Inc.

Q: What inventory considerations apply to substitute part selection?

A: RN1906,LF(CT offers 3,959 pieces in stock. DDC143ZU-7-F provides 7,100 pieces. MUN5233DW1T1G and NSVMUN5233DW1T3G from onsemi offer significantly higher inventory (810,300 and 9,980 pieces respectively). PUMD13,135 from Nexperia provides 10,533 pieces. Inventory levels support long-term supply chain requirements for all recommended substitutes.

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