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Home > Products > Discrete Semiconductor Products > Transistors > Bipolar (BJT) > Single Bipolar Transistors

onsemi 2SD1685F

Name: 2SD1685F
Brand: onsemi
SKU: 2SD1685F
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 2SD1685F

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-225AA, TO-126-3

Datasheet:: 2SD1685F.pdf

Description:: TRANS NPN 20V 5A TO-126ML

Quantity:: RFQ Add To RFQ list

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Product details

Overview

2SD1685F from onsemi is an NPN bipolar junction transistor (BJT) in TO-126ML package, rated for 20 V V_CEO, 5 A continuous collector current, and low 220–500 mV V_CE(sat) at I_C = 3 A / I_B = 60 mA. It delivers fast switching (t_on = 30 ns, t_f = 40 ns) and high DC current gain (h_FE = 95–560), suited for lamp drivers and relay interface circuits in industrial control modules.

For engineers reviewing the 2SD1685F datasheet, pinout, applications, or equivalent options, key selection criteria include verified V_CE(sat) performance at 3 A, h_FE rank F classification (160–320 at 500 mA), thermal dissipation capability (10 W at T_c = 25°C), and insulator-free mounting enabled by plastic-covered leadframe.

Technical Context

This NPN BJT operates as a medium-power switching device with fixed three-terminal topology (Emitter–Collector–Base). Its design emphasizes low saturation voltage and robust pulse handling (I_CP = 8 A), enabling efficient drive of inductive loads without external heat sinking under controlled case temperature conditions.

The device features a gain-bandwidth product of 120 MHz and output capacitance of 45 pF at V_CB = 10 V, supporting reliable operation in strobe and regulator feedback paths where moderate RF content and stable gain are required across –25°C to +75°C ambient range.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	20 V - Maximum safe collector-emitter voltage before breakdown; defines use in ≤20 V rail applications like 12 V lamp/relay drivers.
I_C (cont.)	5 A - Continuous DC collector current rating; supports sustained load switching without derating at T_c = 25°C.
V_CE(sat)	220–500 mV @ I_C=3 A/I_B=60 mA - Low conduction loss enables high-efficiency switching with minimal power dissipation in saturated state.
h_FE Rank F	160–320 @ I_C=500 mA/V_CE=2 V - Guaranteed DC current gain range ensures predictable base drive sizing for consistent turn-on behavior.
t_on/t_f	30 ns / 40 ns - Fast switching transitions reduce switching losses and support strobe timing up to ~10 MHz repetition rates.
P_C (T_c=25°C)	10 W - Thermal power limit at case temperature 25°C; requires heatsinking or airflow for sustained >1 W dissipation.
f_T	120 MHz - Gain-bandwidth product confirms suitability for signal amplification or feedback loop compensation up to mid-VHF range.

Pinout & Package

Package: TO-126ML - Plastic-encapsulated, insulator-free power package with exposed collector tab for direct heatsink mounting; JEITA/JEDEC compliant TO-126 outline; mass = 0.97 g.

Pin/Terminal	Circuit Role	Design Meaning
1	Emitter	Current exit path; connected to ground or low-side return in common-emitter switch configurations.
2	Collector	Current entry path; electrically tied to exposed metal tab for thermal conduction and mechanical mounting to heatsink.
3	Base	Control terminal; requires current-limited drive (e.g., 60 mA for 3 A I_C) to achieve specified V_CE(sat).

Key Features

Feature	Design Value
Low V_CE(sat)	220–500 mV at full 3 A load - reduces conduction loss and self-heating during extended on-state operation.
Insulator-free mounting	Plastic-covered leadframe eliminates need for mica washer or insulating pad when bolting to heatsink - simplifies assembly and improves thermal contact.
High pulse current	8 A peak (I_CP) - supports short-duration surge loads such as solenoid pull-in or flash capacitor discharge.
Wide h_FE range	160–320 (Rank F) - enables consistent biasing across production lots without individual gain binning in cost-sensitive designs.

Applications

Lamp Driver	Relay Driver
Use Scenario: Driving incandescent or LED arrays in industrial status panels requiring 3–5 A pulsed or continuous current. IC Role / Device Role / Timing Role: NPN switch controlling current path between 12–20 V supply and lamp cathode/anode. Use Value: Low V_CE(sat) minimizes voltage drop and heat generation, extending lamp life and reducing heatsink size.	Use Scenario: Activating 12 V or 24 V electromagnetic relays in PLC output modules and motor starters. IC Role / Device Role / Timing Role: High-current interface between microcontroller GPIO and relay coil, providing galvanic isolation via optocoupler or transformer driver stage. Use Value: 8 A pulse rating handles relay inrush current; fast t_on/t_f prevents contact chatter during rapid cycling.
Voltage Regulator Pass Element	Strobe Flash Circuit
Use Scenario: Series pass transistor in linear regulators delivering up to 5 A at ≤20 V output, e.g., test equipment power supplies. IC Role / Device Role / Timing Role: Adjustable current source operating in active region; base driven by error amplifier to maintain constant output voltage. Use Value: 10 W dissipation capability at T_c = 25°C supports stable regulation under full load without forced cooling.	Use Scenario: High-speed flash discharge switch in camera strobes or emergency lighting systems requiring sub-100 ns turn-off. IC Role / Device Role / Timing Role: Saturated switch discharging high-voltage capacitor (≥300 V) through xenon tube via triggered gate pulse. Use Value: 40 ns fall time ensures clean flash termination; low Cob (45 pF) limits capacitive feedthrough into trigger circuitry.

Lamp Driver

Relay Driver

Use Scenario: Driving incandescent or LED arrays in industrial status panels requiring 3–5 A pulsed or continuous current.

IC Role / Device Role / Timing Role: NPN switch controlling current path between 12–20 V supply and lamp cathode/anode.

Use Value: Low V_CE(sat) minimizes voltage drop and heat generation, extending lamp life and reducing heatsink size.

Use Scenario: Activating 12 V or 24 V electromagnetic relays in PLC output modules and motor starters.

IC Role / Device Role / Timing Role: High-current interface between microcontroller GPIO and relay coil, providing galvanic isolation via optocoupler or transformer driver stage.

Use Value: 8 A pulse rating handles relay inrush current; fast t_on/t_f prevents contact chatter during rapid cycling.

Voltage Regulator Pass Element

Strobe Flash Circuit

Use Scenario: Series pass transistor in linear regulators delivering up to 5 A at ≤20 V output, e.g., test equipment power supplies.

IC Role / Device Role / Timing Role: Adjustable current source operating in active region; base driven by error amplifier to maintain constant output voltage.

Use Value: 10 W dissipation capability at T_c = 25°C supports stable regulation under full load without forced cooling.

Use Scenario: High-speed flash discharge switch in camera strobes or emergency lighting systems requiring sub-100 ns turn-off.

IC Role / Device Role / Timing Role: Saturated switch discharging high-voltage capacitor (≥300 V) through xenon tube via triggered gate pulse.

Use Value: 40 ns fall time ensures clean flash termination; low Cob (45 pF) limits capacitive feedthrough into trigger circuitry.

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN medium-power switching transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
2SD1733	V_CEO = 25 V, I_C = 3 A, V_CE(sat) = 300–700 mV @ 2 A - lower current rating, higher saturation voltage.	Less suitable for 5 A continuous loads; better fit for 2–3 A relay/lamp drivers where higher V_CEO margin is needed.	Select 2SD1733 only if system requires ≥25 V breakdown margin and can accept reduced current capacity and higher conduction loss.
MJD127G	V_CEO = 100 V, I_C = 2 A, V_CE(sat) = 1.5 V @ 1.5 A - much higher voltage rating but significantly lower current and higher saturation voltage.	Targeted at high-voltage, low-current switching (e.g., flyback snubbers); not interchangeable for 5 A lamp/relay loads.	Choose MJD127G only for applications demanding >60 V V_CEO with <2 A load current; avoid where low V_CE(sat) or high I_C is critical.

Compared with 2SD1685F, 2SD1733 offers higher voltage headroom but sacrifices current capacity and efficiency, while MJD127G trades all key 2SD1685F advantages (5 A, low V_CE(sat)) for extreme voltage tolerance-neither is pin-compatible, and both require PCB layout revision.

Availability

2SD1685F is available at Aetrix Electronics and suitable for lamp drivers, relay interfaces, and voltage regulator pass elements requiring stable component supply, consistent h_FE binning (Rank F), and insulator-free thermal mounting.

Supply support for 2SD1685F 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

onsemi (formerly ON Semiconductor) is a global semiconductor manufacturer specializing in energy-efficient power, analog, sensor, and connectivity solutions for automotive, industrial, cloud, and IoT applications.

The 2SD1685F belongs to onsemi's general-purpose bipolar transistor product line, engineered for cost-effective, high-reliability switching in industrial controls, power management, and lighting systems where low saturation voltage and robust pulse handling are essential.

FAQ

What is the h_FE range for 2SD1685F and how is it binned?

The 2SD1685F is binned to Rank F, specifying a DC current gain (h_FE) range of 160 to 320 when measured at V_CE = 2 V and I_C = 500 mA. This binning ensures predictable base drive requirements across production lots. The 2SD1685F datasheet confirms this range is guaranteed per unit, and no additional test data or lot-specific h_FE spreads beyond Rank F apply to the 2SD1685F ordering variant.

Does 2SD1685F require an insulating washer when mounted to a heatsink?

No, the 2SD1685F does not require an insulating washer because its leadframe is fully covered with plastic, electrically isolating the collector (pin 2 and metal tab) from the mounting surface. This feature is explicitly stated in the "Features" section of the 2SD1685F datasheet and validated by the TO-126ML package construction. Mounting the 2SD1685F directly to a grounded heatsink is safe and thermally optimal.

What are the absolute maximum ratings for 2SD1685F at T_a = 25°C?

At ambient temperature 25°C, the 2SD1685F has absolute maximum ratings of V_CBO = 60 V, V_CEO = 20 V, V_EBO = 6 V, I_C = 5 A, I_CP = 8 A (pulse), P_C = 1.5 W (free-air), and T_j = 150°C. These stress limits are defined in the official 2SD1685F datasheet (Document No. EN2042B) and must not be exceeded to ensure device reliability.

How does the switching performance of 2SD1685F compare to standard general-purpose transistors?

The 2SD1685F delivers t_on = 30 ns, t_stg = 300 ns, and t_f = 40 ns under standardized test conditions (V_CC = 10 V, R_L = 5 Ω, I_C = 2 A), outperforming typical general-purpose BJTs (e.g., 2N2222: t_f > 250 ns). This speed enables clean switching in strobe and PWM-driven lamp applications. The 2SD1685F datasheet confirms these values are measured and guaranteed across the Rank F population.

Is 2SD1685F RoHS-compliant and what is its packaging format?

Yes, the 2SD1685F is RoHS-compliant and marked "Pb Free" in the Ordering Information table of its datasheet. It ships in moisture-sensitive bag packaging with a minimum quantity of 200 pcs./bag. The "VR" suffix in the 2SD1685F ordering code indicates compliance with onsemi's standard environmental specifications, including lead-free terminations and halogen-free molding compound.

2SD1685F Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-225AA, TO-126-3

Packaging:: Bulk

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 5 A

Voltage - Collector Emitter Breakdown (Max):: 20 V

Vce Saturation (Max) @ Ib, Ic:: 500mV @ 60mA, 3A

Current - Collector Cutoff (Max):: 100nA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 160 @ 500mA, 2V

Power - Max:: 1.5 W

Frequency - Transition:: 120MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-126ML

2SD1685F FAQ

1.How can I place an order for 2SD1685F through Aetrix?

Please submit a Request for Quotation (RFQ) for 2SD1685F 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 2SD1685F reliable?

The price and inventory of 2SD1685F are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 2SD1685F is usually 5 days.

3.What payment methods are accepted for 2SD1685F?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 2SD1685F transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 2SD1685F?

2SD1685F orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 2SD1685F 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 2SD1685F?

For technical support, including 2SD1685F datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 2SD1685F requirements.

6.How does Aetrix verify that 2SD1685F is sourced from the original manufacturer or authorized distributors?

All 2SD1685F 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 2SD1685F meets industry standards.

7.What is the process for return or replacement of 2SD1685F?

All 2SD1685F units undergo pre-shipment inspection (PSI). If there is an issue with 2SD1685F, 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 2SD1685F part is unused and in its original packaging.

Return procedure for 2SD1685F:

1.Submit a request within 90 days.

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

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