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Nexperia USA Inc. BC817K-40HR
- Part No.:
- BC817K-40HR
- Manufacturer:
- Nexperia USA Inc.
- Category:
- Single Bipolar Transistors
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
BC817K-40HR.pdf
- Description:
- TRANS NPN 45V 0.5A TO-236AB
- Quantity:
- Payment:
- Shipping:
Inventory:2,268
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Product details
Overview
BC817K-40HR from Nexperia is a 45 V, 500 mA NPN general-purpose transistor in SOT23 package, optimized for switching and linear amplification in industrial control logic, power supply feedback loops, and LED driver stages. It delivers hFE = 250–600 at VCE = 1 V, IC = 100 mA, operates up to 175 °C junction temperature, and features VCE(sat) ≤ 700 mV at IC = 500 mA / IB = 50 mA.
For engineers reviewing the BC817K-40HR datasheet, BC817K-40HR pinout, BC817K-40HR application, or BC817K-40HR equivalent, this page provides verified pin functions, thermal derating curves, safe operating area (SOA) boundaries, and validated alternatives for high-reliability discrete switching designs requiring stable DC current gain across wide temperature ranges.
Technical Context
This NPN bipolar junction transistor uses epitaxial planar technology with emitter ballasting for improved current sharing and thermal stability. Its base-emitter junction supports continuous operation up to 175 °C, and its collector-base breakdown voltage (VCBO = 50 V) exceeds rated VCEO (45 V), enabling margin in transient overvoltage conditions.
The device exhibits pulsed peak collector current capability of 1 A (tp ≤ 1 ms), low output capacitance (Cc = 3 pF at VCB = 10 V), and transition frequency fT ≥ 100 MHz - confirming suitability for medium-speed digital switching and analog signal buffering up to ~10 MHz.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | 45 V - Maximum sustainable collector-emitter voltage with open base; defines upper rail limit in switch-mode applications. |
| IC | 500 mA continuous - Rated DC collector current at Tamb = 25 °C on standard FR4 PCB; sets load-driving capacity in relay drivers or fan controllers. |
| hFE | 250–600 at VCE = 1 V, IC = 100 mA - High and tightly binned DC current gain enables low-base-drive designs and stable biasing in amplifier stages. |
| VCE(sat) | ≤ 700 mV at IC = 500 mA, IB = 50 mA - Low saturation voltage minimizes conduction loss and self-heating in high-duty-cycle switching. |
| Ptot | 950 mW on 4-layer FR4 PCB with 1 cm² collector pad - Thermal performance enables compact layout without forced air cooling in ambient ≤ 75 °C. |
| Tj(max) | 175 °C - Extended junction temperature rating supports operation in automotive under-hood, industrial motor drives, and sealed enclosure environments. |
| fT | ≥ 100 MHz - Confirms usable bandwidth for pulse-width modulation (PWM) signal amplification and fast edge-rate digital interfacing. |
Pinout & Package
SOT23 (TO-236AB) plastic surface-mount package with gull-wing leads; 3-terminal configuration optimized for automated placement and reflow soldering on standard FR4 PCBs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (B) | Base | Current-controlled input node; requires series resistor to limit IB ≤ 200 mA peak and ensure hFE-based saturation. |
| 2 (E) | Emitter | Reference terminal for bias network; connected to ground or low-side return path in common-emitter configurations. |
| 3 (C) | Collector | High-current output node; thermally coupled to PCB copper pour to sustain Ptot derating per Figure 1. |
Key Features
| Feature | Design Value |
|---|---|
| Three hFE bins (16H/25H/40H) | Enables precise gain matching in parallel transistor arrays or feedback loop compensation networks without external trimming. |
| 175 °C maximum junction temperature | Supports uninterrupted operation in sealed enclosures, motor control modules, and industrial PLC I/O cards without thermal shutdown. |
| Low VCE(sat) and Cc | Reduces switching losses and improves rise/fall time in 10–100 kHz PWM circuits such as DC-DC converter gate drivers and solenoid controls. |
| FR4 PCB thermal derating curves | Provides validated power dissipation limits for 1-layer vs. 4-layer boards, enabling accurate thermal margining during layout phase. |
| IEC 60134 Absolute Maximum Ratings | Guarantees robustness against short-term overloads, including 1 A pulsed current and 50 V collector-base transients. |
Applications
| Industrial Relay Driver | LED Constant-Current Sink |
|---|---|
Use Scenario: Driving 24 V DC electromechanical relays in programmable logic controller (PLC) output modules. IC Role / Device Role / Timing Role: NPN switch in common-emitter configuration, sinking relay coil current through collector to ground. Use Value: VCE(sat) ≤ 700 mV ensures <170 mW dissipation at 500 mA, eliminating need for heatsinking in dense I/O card layouts. |
Use Scenario: Precision current sink for high-brightness white LEDs in signage and machine vision lighting. IC Role / Device Role / Timing Role: Linear pass element controlled by op-amp feedback to regulate LED current independent of forward voltage drift. Use Value: hFE = 250–600 enables stable 100–500 mA regulation with <±3% error over –40 to +125 °C ambient. |
| Power Supply Feedback Transistor | Microcontroller GPIO Expander |
Use Scenario: Isolating and amplifying optocoupler output signals in isolated flyback converter feedback paths. IC Role / Device Role / Timing Role: Small-signal amplifier stage converting phototransistor current into clean voltage for UC384x-type PWM controller reference input. Use Value: fT ≥ 100 MHz and Cc = 3 pF preserve loop stability margins while supporting >50 kHz compensation bandwidth. |
Use Scenario: Level-shifting and current boosting for 3.3 V microcontroller GPIO pins driving 5 V logic inputs or small solenoids. IC Role / Device Role / Timing Role: Digital buffer transistor configured as emitter-follower or common-emitter switch to extend drive capability beyond MCU pin limits. Use Value: IC = 500 mA and Tj = 175 °C allow sustained 100 mA loads at elevated board temperatures without gain collapse. |
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 |
|---|---|---|---|
| BC817-40,215 (Nexperia) | Same die, but in legacy SOT23 marking format without 'K' suffix; identical electrical specs and thermal behavior. | No functional difference; used interchangeably in new designs where legacy BOM compatibility is required. | Select when sourcing from distributors holding older stock or aligning with pre-2022 reference designs. |
| MMBT4401LT1G (onsemi) | Higher VCEO = 40 V (vs. 45 V), lower hFE = 100–300, and higher VCE(sat) = 0.75 V at same IC/IB. | Marginally reduced voltage headroom and gain stability; acceptable in non-critical 24 V systems with relaxed thermal constraints. | Choose only if BC817K-40HR is unavailable and design tolerates 5 V lower breakdown and 20% higher saturation loss. |
Compared with BC817K-40HR, BC817-40,215 offers identical performance with legacy marking, while MMBT4401LT1G trades 5 V VCEO margin and 250–600 hFE consistency for broader distributor availability - making the original part optimal for high-reliability, thermally constrained, or precision-gain applications.
Availability
BC817K-40HR is available at Aetrix Electronics and suitable for industrial relay drivers, LED constant-current sinks, power supply feedback amplifiers, and microcontroller GPIO expanders requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for BC817K-40HR 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
Nexperia is a global semiconductor expert focused on high-volume, high-reliability essential semiconductors - delivering discrete, logic, and MOSFET solutions optimized for efficiency, miniaturization, and thermal resilience.
The BC817KH series belongs to Nexperia's general-purpose bipolar transistor product line, engineered specifically for cost-sensitive yet thermally demanding industrial, consumer, and computing applications where consistent DC gain and rugged SOA are critical.
FAQ
What is the maximum allowable base current for continuous operation?
The absolute maximum peak base current is 200 mA (single pulse, tp ≤ 1 ms). For continuous DC operation, IB must be limited to ensure IC ≤ 500 mA and junction temperature remains ≤ 175 °C. At IC = 500 mA and hFE = 250 (minimum), IB ≈ 2 mA is sufficient for saturation - typical designs use 5–10 mA for margin. Exceeding 20 mA DC risks thermal runaway on standard FR4.
Does BC817K-40HR support wave soldering?
Yes - Nexperia provides dedicated wave soldering footprint data (Figure 45) specifying 2.8 mm × 4.5 mm pad dimensions, 1.4 mm dual-side solder resist openings, and preferred transport direction. The SOT23 package is qualified for both reflow and wave processes per J-STD-020 and IPC-A-610 standards, with peak temperature ≤ 260 °C for ≤ 5 seconds.
How does thermal resistance vary with PCB construction?
Rth(j-a) ranges from 158 K/W (4-layer FR4, 1 cm² collector pad) to 353 K/W (single-sided FR4, standard footprint). This 2.2× variation directly impacts allowable power: at Tamb = 75 °C, max Ptot drops from 760 mW to 340 mW. Designers must select layout per Figure 1 derating curves - not datasheet headline values - for reliable operation.
Is BC817K-40HR qualified for automotive applications?
No - Revision 2 (2025) explicitly states "Product(s) changed to non-automotive qualification." Automotive-grade equivalents include BC817B-40Q (AEC-Q101 qualified) or PBSS4041T (higher VCEO, Q-grade). BC817K-40HR is intended for industrial, consumer, and computing applications where ASIL or zero-defect requirements do not apply.
BC817K-40HR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Nexperia USA Inc.
- Series:
- -
- Package/Case:
- TO-236-3, SC-59, SOT-23-3
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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:
- 250 @ 100mA, 1V
- Power - Max:
- 350 mW
- Frequency - Transition:
- 100MHz
- Operating Temperature:
- 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TO-236AB
BC817K-40HR FAQ
1.How can I place an order for BC817K-40HR through Aetrix?
Please submit a Request for Quotation (RFQ) for BC817K-40HR 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 BC817K-40HR reliable?
The price and inventory of BC817K-40HR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC817K-40HR is usually 5 days.
3.What payment methods are accepted for BC817K-40HR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC817K-40HR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BC817K-40HR?
BC817K-40HR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BC817K-40HR 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 BC817K-40HR?
For technical support, including BC817K-40HR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC817K-40HR requirements.
6.How does Aetrix verify that BC817K-40HR is sourced from the original manufacturer or authorized distributors?
All BC817K-40HR 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 BC817K-40HR meets industry standards.
7.What is the process for return or replacement of BC817K-40HR?
All BC817K-40HR units undergo pre-shipment inspection (PSI). If there is an issue with BC817K-40HR, 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 BC817K-40HR part is unused and in its original packaging.
Return procedure for BC817K-40HR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BC817K-40HR Tags
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MMBT3906LT1G
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MMBT3904-7-F
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MMBT3904LT1G
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MMBT3906-7-F
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BC846BLT1G
onsemi
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BC847B,215
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