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Home > Products > Discrete Semiconductor Products > Transistors > FETs, MOSFETs > FETs, MOSFETs

NXP Semiconductors BS108/01,126

Name: BS108/01,126
Brand: NXP Semiconductors
SKU: BS108/01,126
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BS108/01,126

Manufacturer:: NXP Semiconductors

Category:: FETs, MOSFETs

Package:: TO-226-3, TO-92-3 (TO-226AA) Formed Leads

Datasheet:: BS108/01,126.pdf

Description:: MOSFET N-CH 200V 300MA TO92-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BS108/01,126 from NXP Semiconductors (formerly Philips) is an N-channel enhancement-mode vertical D-MOS transistor in SOT54 (TO-92) package, rated for 200 V drain-source voltage, 300 mA DC drain current, and 5 Ω typical R_DS(on) at V_GS = 2.8 V. It serves as a low-power switching device in telephone line current interruptors and relay drivers.

For engineers reviewing the BS108/01,126 datasheet, BS108/01,126 pinout, BS108/01,126 application, or BS108/01,126 equivalent, key selection factors include gate-threshold voltage (0.4–1.8 V), fast switching times (6–10 ns turn-on, 49–60 ns turn-off), and direct interface capability with CMOS/TTL logic without level-shifting.

Technical Context

This discrete MOSFET employs vertical D-MOS architecture to achieve high breakdown voltage (200 V) with low on-resistance (2.7–5 Ω) and no secondary breakdown limitation. Its gate threshold voltage range (0.4–1.8 V) enables reliable turn-on from standard logic outputs.

Thermal resistance is 125 K/W junction-to-ambient under PCB-mount conditions (10 × 10 mm drain pad, ≤4 mm lead length), and it delivers 600 mS typical transfer admittance at ID = 300 mA and V_DS = 25 V - supporting robust small-signal gain in driver stages.

Key Specifications

Parameter	Value and Actual Design Meaning
V_DS	200 V - supports operation across telephone line surge transients and relay coil flyback voltages without clamping.
R_DS(on)	2.7–5 Ω at V_GS = 2.8 V, I_D = 100 mA - ensures <150 mW conduction loss at 300 mA, enabling efficient low-power switching.
V_GS(th)	0.4–1.8 V - guarantees turn-on compatibility with 3.3 V and 5 V CMOS/TTL outputs without gate drive circuitry.
t_on/t_off	6–10 ns / 49–60 ns - enables clean digital switching in line transformer and relay driver applications up to ~10 MHz.
C_iss/C_oss	100–120 pF / 20–30 pF - low input/output capacitance minimizes gate drive power and improves high-frequency stability.
P_tot	1 W at T_amb ≤ 25 °C - sufficient for intermittent duty-cycle loads like telephone ring detection and pulse-driven relays.
T_j	150 °C maximum - allows operation in enclosed telecom equipment with moderate airflow or passive heatsinking.

Pinout & Package

SOT54 (TO-92) plastic through-hole package with 3 leads; standardized pinout per JEDEC TO-92 outline and Philips M3D186 handbook. Mounting requires minimum 10 × 10 mm copper pad on drain lead for thermal performance.

Pin/Terminal	Circuit Role	Design Meaning
1	Source	Reference node for gate control; connected to ground or low-side return path in common-source configuration.
2	Gate	Control terminal; accepts logic-level voltage (≥1.8 V) to fully enhance channel; high-impedance input (I_GSS ≤ ±100 nA).
3	Drain	High-voltage output terminal; carries switched load current; requires thermal pad for power dissipation management.

Key Features

Feature	Design Value
No secondary breakdown	Enables safe linear-mode operation during transient overloads - critical for telephone line interruption without destructive failure.
Direct CMOS/TTL interface	Eliminates need for external gate resistors or level shifters when driven by 3.3 V/5 V logic, reducing BOM count and layout area.
High-speed switching	Sub-10 ns turn-on and <60 ns turn-off support precise timing in relay coil energization/de-energization and line signaling.
Low gate leakage	I_GSS ≤ ±100 nA at ±20 V ensures stable gate bias over temperature and time, preventing unintended turn-on in standby modes.
Vertical D-MOS structure	Delivers higher voltage rating and better ruggedness than planar MOSFETs of comparable die size and cost.

Applications

Telephone Line Current Interruptor	Relay Driver
Use Scenario: Interrupting DC loop current in analog telephone subscriber line interface circuits during call setup or hook-flash detection. IC Role / Device Role / Timing Role: Low-side switch controlling line current path; activated by microcontroller GPIO or logic signal. Use Value: 200 V V_DS withstands ringing voltage surges; 300 mA rating covers standard 20–50 mA loop current with margin.	Use Scenario: Driving electromagnetic relays in PBX systems, modems, or industrial I/O modules requiring isolation and load switching. IC Role / Device Role / Timing Role: High-voltage switch sourcing relay coil current; handles inductive flyback via inherent avalanche ruggedness. Use Value: No secondary breakdown allows safe energy absorption during coil de-energization; fast t_off reduces contact bounce duration.
Line Transformer Driver	High-Speed Signal Switch
Use Scenario: Driving primary windings of line transformers in DSL or ISDN interface circuits for differential signal transmission. IC Role / Device Role / Timing Role: Push-pull or single-ended switch modulating transformer primary current at baseband or low-MHz rates. Use Value: Low C_iss (≤120 pF) and fast switching minimize signal distortion and timing skew in bidirectional line signaling.	Use Scenario: Routing or gating low-power digital or analog signals in test equipment, multiplexers, or programmable logic interfaces. IC Role / Device Role / Timing Role: Voltage-controlled analog/digital switch with minimal on-resistance and charge injection. Use Value: R_DS(on) ≤5 Ω ensures <0.15 V drop at 30 mA; low Crss (≤15 pF) prevents crosstalk between adjacent signal paths.

Telephone Line Current Interruptor

Relay Driver

Use Scenario: Interrupting DC loop current in analog telephone subscriber line interface circuits during call setup or hook-flash detection.

IC Role / Device Role / Timing Role: Low-side switch controlling line current path; activated by microcontroller GPIO or logic signal.

Use Value: 200 V V_DS withstands ringing voltage surges; 300 mA rating covers standard 20–50 mA loop current with margin.

Use Scenario: Driving electromagnetic relays in PBX systems, modems, or industrial I/O modules requiring isolation and load switching.

IC Role / Device Role / Timing Role: High-voltage switch sourcing relay coil current; handles inductive flyback via inherent avalanche ruggedness.

Use Value: No secondary breakdown allows safe energy absorption during coil de-energization; fast t_off reduces contact bounce duration.

Line Transformer Driver

High-Speed Signal Switch

Use Scenario: Driving primary windings of line transformers in DSL or ISDN interface circuits for differential signal transmission.

IC Role / Device Role / Timing Role: Push-pull or single-ended switch modulating transformer primary current at baseband or low-MHz rates.

Use Value: Low C_iss (≤120 pF) and fast switching minimize signal distortion and timing skew in bidirectional line signaling.

Use Scenario: Routing or gating low-power digital or analog signals in test equipment, multiplexers, or programmable logic interfaces.

IC Role / Device Role / Timing Role: Voltage-controlled analog/digital switch with minimal on-resistance and charge injection.

Use Value: R_DS(on) ≤5 Ω ensures <0.15 V drop at 30 mA; low Crss (≤15 pF) prevents crosstalk between adjacent signal paths.

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-voltage, low-current MOSFET switching applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
BS170	Higher V_DS (60 V), lower R_DS(on) (5 Ω typ. at V_GS = 10 V), but V_GS(th) up to 3 V - less compatible with 3.3 V logic.	Not suitable for 200 V telephone line interruption; better for 24–48 V relay coils where gate drive voltage ≥5 V is available.	Select BS170 only if system uses ≥5 V logic and operates below 60 V; BS108/01,126 remains preferred for 200 V telecom use cases.
2N7000	Similar V_DS (60 V), R_DS(on) ≈ 5 Ω at V_GS = 10 V, V_GS(th) 0.8–3.0 V - wider threshold spread increases risk of partial turn-on at marginal drive levels.	Lacks 200 V rating; unsuitable for telephone line surge environments; acceptable only in low-voltage embedded logic-switching roles.	Choose 2N7000 only for cost-sensitive, non-telecom 5 V logic-switching; BS108/01,126 provides guaranteed 200 V operation and tighter V_GS(th) spec.

Compared with BS170 and 2N7000, BS108/01,126 uniquely combines 200 V rating, sub-2 V gate threshold, and no secondary breakdown - making it irreplaceable in telecom line-interrupt applications where voltage margin and logic compatibility are non-negotiable.

Availability

BS108/01,126 is available at Aetrix Electronics and suitable for telephone line interface design, relay driver implementation, and line transformer signal conditioning requiring stable component supply across long-lifecycle telecom and industrial programs.

Supply support for BS108/01,126 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

NXP Semiconductors, formerly Philips Semiconductors, is a global leader in high-reliability analog and discrete semiconductor solutions, with deep heritage in telecom and industrial power devices.

The BS108/01,126 belongs to Philips' legacy vertical D-MOS transistor family designed specifically for robust, low-cost switching in analog telephony, relay control, and line interface equipment.

FAQ

What is the maximum continuous drain current for BS108/01,126?

The BS108/01,126 supports a maximum continuous drain current (I_D) of 300 mA at T_amb ≤ 25 °C with proper PCB thermal management (10 × 10 mm drain pad). At elevated ambient temperatures or without thermal relief, derating applies per the 125 K/W junction-to-ambient thermal resistance specification. The BS108/01,126 must not exceed this limit to maintain reliability and avoid thermal runaway.

Can BS108/01,126 be driven directly by a 3.3 V microcontroller GPIO?

Yes - the BS108/01,126 has a gate-source threshold voltage (V_GS(th)) ranging from 0.4 V to 1.8 V, and its R_DS(on) is fully specified at V_GS = 2.8 V. A 3.3 V GPIO will fully enhance the channel, delivering ≤5 Ω on-resistance and ensuring low conduction loss. The BS108/01,126 thus eliminates need for gate drivers in 3.3 V logic systems.

Does BS108/01,126 support avalanche energy handling?

The BS108/01,126 datasheet does not specify single-pulse avalanche energy (E_AS) or repetitive avalanche ratings. However, its "no secondary breakdown" feature and vertical D-MOS construction provide inherent ruggedness against inductive flyback in relay and transformer applications - confirmed by its use in telephone line interruptors and relay drivers per official Philips application guidance.

What is the recommended PCB layout for thermal performance of BS108/01,126?

For optimal thermal performance, the BS108/01,126 drain lead must be soldered to a minimum 10 × 10 mm copper pad on the PCB, with maximum lead length of 4 mm. This achieves the specified 125 K/W junction-to-ambient thermal resistance. Smaller pads or longer leads significantly degrade power handling - the BS108/01,126 will exceed 150 °C junction temperature under full 1 W dissipation without this layout.

Is BS108/01,126 RoHS compliant?

The BS108/01,126 was originally released in 2001, predating RoHS legislation. NXP's current product change notifications confirm legacy versions such as BS108/01,126 are manufactured in RoHS-compliant processes and meet lead-free soldering requirements. Full compliance documentation for BS108/01,126 is available upon request from Aetrix Electronics' technical support team.

BS108/01,126 Specifications

Product attributes: Attribute value

Manufacturer:: NXP Semiconductors

Series:: -

Package/Case:: TO-226-3, TO-92-3 (TO-226AA) Formed Leads

Packaging:: Tape & Box (TB)

Product Status:: Obsolete

FET Type:: N-Channel

Technology:: MOSFET (Metal Oxide)

Drain to Source Voltage (Vdss):: 200 V

Current - Continuous Drain (Id) @ 25°C:: 300mA (Ta)

Drive Voltage (Max Rds On, Min Rds On):: 2.8V

Rds On (Max) @ Id, Vgs:: 5Ohm @ 100mA, 2.8V

Vgs(th) (Max) @ Id:: 1.8V @ 1mA

Gate Charge (Qg) (Max) @ Vgs:: -

Vgs (Max):: ±20V

Input Capacitance (Ciss) (Max) @ Vds:: 120 pF @ 25 V

FET Feature:: -

Power Dissipation (Max):: 1W (Ta)

Operating Temperature:: -55°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

BS108/01,126 FAQ

1.How can I place an order for BS108/01,126 through Aetrix?

Please submit a Request for Quotation (RFQ) for BS108/01,126 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for BS108/01,126 reliable?

The price and inventory of BS108/01,126 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BS108/01,126 is usually 5 days.

3.What payment methods are accepted for BS108/01,126?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BS108/01,126 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BS108/01,126?

BS108/01,126 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BS108/01,126 order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for BS108/01,126?

For technical support, including BS108/01,126 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BS108/01,126 requirements.

6.How does Aetrix verify that BS108/01,126 is sourced from the original manufacturer or authorized distributors?

All BS108/01,126 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that BS108/01,126 meets industry standards.

7.What is the process for return or replacement of BS108/01,126?

All BS108/01,126 units undergo pre-shipment inspection (PSI). If there is an issue with BS108/01,126, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The BS108/01,126 part is unused and in its original packaging.

Return procedure for BS108/01,126:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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