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

onsemi NSCT817-25LT1G

Name: NSCT817-25LT1G
Brand: onsemi
SKU: NSCT817-25LT1G
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: NSCT817-25LT1G

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-236-3, SC-59, SOT-23-3

Datasheet:: NSCT817-25LT1G.pdf

Description:: TRANS NPN 45V 0.5A SOT23-3

Quantity:: RFQ Add To RFQ list

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Inventory:8,200

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Product details

Overview

NSCT817-25LT1G from onsemi is an NPN silicon general-purpose transistor in SOT-23 package, rated for V_CEO = 45 V, I_C = 500 mA continuous, and h_FE = 160–400 at I_C = 100 mA. It delivers low V_CE(sat) ≤ 0.7 V at I_C/I_B = 10 and supports f_T = 100 MHz, making it suitable for signal amplification and switching in compact DC-DC converters.

For engineers reviewing the NSCT817-25LT1G datasheet, pinout, applications, or equivalent options, key selection criteria include verified h_FE binning (−25 variant), thermal performance on FR-5 board (R_JA = 556°C/W), Pb-free SOT-23 footprint compatibility, and validated V_BE(on) ≤ 1.2 V at I_C = 500 mA.

Technical Context

This device operates as a medium-current, medium-voltage NPN bipolar junction transistor with fixed gain binning (−25 denotes h_FE = 160–400). Its design targets linear amplification and saturated switching in space-constrained applications where thermal management on standard PCB substrates is critical.

It features a maximum V_CEO of 45 V and V_CBO of 50 V, enabling use in 24 V and 36 V rail systems. The 100 MHz f_T and 10 pF C_obo support stable operation up to mid-frequency switching, while its −55°C to +150°C T_J range ensures reliability in industrial ambient conditions.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	45 V - Supports operation up to 45 V collector-emitter voltage without breakdown, suitable for 24 V system switching.
I_C (continuous)	500 mA - Enables drive capability for small relays, LED arrays, or gate resistors in MOSFET driver stages.
h_FE (min–max)	160–400 @ I_C = 100 mA - Binned gain ensures predictable base drive requirements in amplifier and switch bias networks.
V_CE(sat)	≤ 0.7 V @ I_C = 500 mA, I_B = 50 mA - Low saturation voltage minimizes power loss and self-heating during switching.
f_T	100 MHz - Enables stable small-signal amplification and switching up to ~10–20 MHz practical bandwidth.
R_JA (FR-5)	556°C/W - Thermal resistance defines junction-to-ambient rise per mW dissipated on standard epoxy PCB.

Pinout & Package

SOT-23 (Case 318, Style 6) surface-mount package with 3-pin configuration, 1.0 mm × 1.4 mm footprint, and 0.95 mm height. Pb-free matte tin lead finish, JEDEC-compliant outline.

Pin/Terminal	Circuit Role	Design Meaning
1	Base	Current-controlled input node; requires external bias resistor network to set operating point.
2	Emiter	Common reference terminal; connected to ground or low-side return path in common-emitter configurations.
3	Collector	High-side output node; carries load current and interfaces with supply rail or inductive loads.

Key Features

Feature	Design Value
Pb-free SOT-23 package	RoHS-compliant assembly compatible with standard reflow profiles; no lead contamination risk in high-reliability production.
h_FE binning (−25)	Guaranteed 160–400 gain range reduces variation in base drive design across production lots.
V_CE(sat) ≤ 0.7 V	Enables <150 mW conduction loss at 500 mA, supporting thermally constrained PCB layouts.
100 MHz f_T	Supports stable small-signal amplification and fast edge response in pulse-width modulation (PWM) control feedback paths.

Applications

Power Supply Feedback Amplifier	Low-Side Load Switch
Use Scenario: Amplifying error voltage from optocoupler output in isolated flyback converter feedback loop. IC Role / Device Role / Timing Role: NPN transconductance amplifier providing gain and level shift between secondary-side error signal and primary-side PWM controller. Use Value: Stable h_FE binning ensures consistent loop gain; low V_CE(sat) prevents distortion at low output swing.	Use Scenario: Driving 200 mA LED string or solenoid valve from microcontroller GPIO with 3.3 V logic. IC Role / Device Role / Timing Role: Low-side saturated switch turning on/off load referenced to ground. Use Value: Verified 500 mA I_C rating and ≤0.7 V V_CE(sat) minimize heat generation and ensure full turn-on with 50 mA base drive.
Signal Level Shifter	Current Mirror Reference
Use Scenario: Translating 1.8 V logic signal to 5 V domain in mixed-voltage interface between MCU and legacy peripherals. IC Role / Device Role / Timing Role: Common-emitter level translator with fixed bias network defining output high/low thresholds. Use Value: 100 MHz f_T preserves signal integrity up to 10 MHz edges; tight h_FE binning improves threshold repeatability.	Use Scenario: Building matched current source in analog sensor conditioning circuit using two identical NSCT817-25LT1G devices. IC Role / Device Role / Timing Role: Active component in two-transistor current mirror topology replicating reference current. Use Value: Same die batch and h_FE binning (−25) reduce mismatch; V_BE(on) ≤ 1.2 V ensures accurate mirroring at low currents.

Power Supply Feedback Amplifier

Low-Side Load Switch

Use Scenario: Amplifying error voltage from optocoupler output in isolated flyback converter feedback loop.

IC Role / Device Role / Timing Role: NPN transconductance amplifier providing gain and level shift between secondary-side error signal and primary-side PWM controller.

Use Value: Stable h_FE binning ensures consistent loop gain; low V_CE(sat) prevents distortion at low output swing.

Use Scenario: Driving 200 mA LED string or solenoid valve from microcontroller GPIO with 3.3 V logic.

IC Role / Device Role / Timing Role: Low-side saturated switch turning on/off load referenced to ground.

Use Value: Verified 500 mA I_C rating and ≤0.7 V V_CE(sat) minimize heat generation and ensure full turn-on with 50 mA base drive.

Signal Level Shifter

Current Mirror Reference

Use Scenario: Translating 1.8 V logic signal to 5 V domain in mixed-voltage interface between MCU and legacy peripherals.

IC Role / Device Role / Timing Role: Common-emitter level translator with fixed bias network defining output high/low thresholds.

Use Value: 100 MHz f_T preserves signal integrity up to 10 MHz edges; tight h_FE binning improves threshold repeatability.

Use Scenario: Building matched current source in analog sensor conditioning circuit using two identical NSCT817-25LT1G devices.

IC Role / Device Role / Timing Role: Active component in two-transistor current mirror topology replicating reference current.

Use Value: Same die batch and h_FE binning (−25) reduce mismatch; V_BE(on) ≤ 1.2 V ensures accurate mirroring at low currents.

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN general-purpose transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MMBT3904LT1G	Lower V_CEO (40 V), higher h_FE range (100–300), same SOT-23 package.	Not rated for 45 V systems; less margin in 24 V industrial rails with transients.	Select when lower gain tolerance and reduced voltage headroom are acceptable.
BC847BW	Same V_CEO (45 V), h_FE = 200–450, but not Pb-free certified per J-STD-609.	Requires qualification for RoHS-compliant manufacturing lines.	Choose only if Pb-free compliance is not required and tighter h_FE distribution is needed.

Compared with MMBT3904LT1G and BC847BW, NSCT817-25LT1G offers superior voltage margin (45 V vs. 40 V), guaranteed Pb-free status, and h_FE binning optimized for stable biasing in feedback and switching circuits-making it preferred for industrial power conversion and automotive-adjacent designs.

Availability

NSCT817-25LT1G is available at Aetrix Electronics and suitable for DC-DC converter feedback amplifiers, low-side load switches, signal level shifters, and current mirror references requiring stable component supply and RoHS-compliant sourcing.

Supply support for NSCT817-25LT1G 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 supplier focused on energy-efficient electronics, delivering power, analog, sensor, and connectivity solutions.

The NSCT817 series belongs to onsemi's general-purpose bipolar transistor product line, designed specifically for cost-sensitive, space-constrained industrial and consumer applications requiring reliable DC switching and linear amplification.

FAQ

What is the maximum collector-emitter voltage rating for NSCT817-25LT1G?

The NSCT817-25LT1G has a maximum collector-emitter voltage (V_CEO) rating of 45 V, tested at I_C = −10 mA. This rating allows safe operation in 24 V and 36 V power systems with transient margin, and is confirmed in the official onsemi datasheet revision 0 (May 2006).

Is NSCT817-25LT1G Pb-free and RoHS compliant?

Yes, NSCT817-25LT1G is explicitly marked as Pb-free in the ordering information and marking diagram, and conforms to RoHS Directive 2011/65/EU. The "G" suffix and "M" marking denote Pb-free packaging, verified in onsemi's packaging specifications and material declarations.

What is the h_FE range for NSCT817-25LT1G and how is it binned?

The NSCT817-25LT1G is binned to h_FE = 160–400 at I_C = 100 mA and V_CE = 1.0 V. The "−25" suffix identifies this specific gain group, ensuring predictable base current requirements across production lots-critical for stable biasing in amplifier and switch circuits.

What is the thermal resistance (R_JA) of NSCT817-25LT1G on FR-5 board?

On FR-5 board (1.0 × 0.75 × 0.062 in), NSCT817-25LT1G has a thermal resistance R_JA of 556°C/W at T_A = 25°C. This value defines junction-to-ambient temperature rise per milliwatt dissipated and is used to calculate safe operating area under real PCB layout conditions.

Does NSCT817-25LT1G support high-frequency operation?

NSCT817-25LT1G has an f_T (current-gain bandwidth product) of 100 MHz at I_C = 10 mA, V_CE = 5.0 V. While not intended for RF, this enables clean signal amplification and fast switching up to ~10–20 MHz in PWM feedback paths and digital interface circuits.

NSCT817-25LT1G Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-236-3, SC-59, SOT-23-3

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 500 mA

Voltage - Collector Emitter Breakdown (Max):: 45 V

Vce Saturation (Max) @ Ib, Ic:: 700mV @ 50mA, 500mA

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 160 @ 100mA, 1V

Power - Max:: 225 mW

Frequency - Transition:: 100MHz

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-3 (TO-236)

NSCT817-25LT1G FAQ

1.How can I place an order for NSCT817-25LT1G through Aetrix?

Please submit a Request for Quotation (RFQ) for NSCT817-25LT1G 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 NSCT817-25LT1G reliable?

The price and inventory of NSCT817-25LT1G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for NSCT817-25LT1G is usually 5 days.

3.What payment methods are accepted for NSCT817-25LT1G?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for NSCT817-25LT1G transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for NSCT817-25LT1G?

NSCT817-25LT1G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your NSCT817-25LT1G 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 NSCT817-25LT1G?

For technical support, including NSCT817-25LT1G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your NSCT817-25LT1G requirements.

6.How does Aetrix verify that NSCT817-25LT1G is sourced from the original manufacturer or authorized distributors?

All NSCT817-25LT1G 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 NSCT817-25LT1G meets industry standards.

7.What is the process for return or replacement of NSCT817-25LT1G?

All NSCT817-25LT1G units undergo pre-shipment inspection (PSI). If there is an issue with NSCT817-25LT1G, 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 NSCT817-25LT1G part is unused and in its original packaging.

Return procedure for NSCT817-25LT1G:

1.Submit a request within 90 days.

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

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