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Diodes Incorporated BC857AT-7
- Part No.:
- BC857AT-7
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Bipolar Transistors
- Package:
- SOT-523
- Datasheet:
-
BC857AT-7.pdf
- Description:
- TRANS PNP 45V 0.1A SOT-523
- Quantity:
- Payment:
- Shipping:
Inventory:6,758
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Product details
Overview
BC857AT-7 from Diodes Incorporated is a PNP small-signal transistor in SOT523 package, rated for -45V VCEO, -100mA IC, and 150mW power dissipation. It delivers hFE = 125–290 at IC = -2mA, VCE = -5V, and fT = 100MHz, supporting low-power switching and amplification in space-constrained automotive and industrial control circuits.
For engineers reviewing the BC857AT-7 datasheet, BC857AT-7 pinout, BC857AT-7 application, or BC857AT-7 equivalent, key selection criteria include its AEC-Q101 qualification, ultra-small SOT523 footprint, guaranteed VCEO ≥ -45V, hFE binning (A-grade), and thermal resistance of 833°C/W under standard PCB conditions.
Technical Context
This PNP bipolar junction transistor uses epitaxial planar die construction to ensure stable gain and low leakage across temperature. Its complementary NPN counterpart is the BC847AT, enabling matched pair design in differential amplifiers and push-pull stages.
Designed for high-reliability applications, it meets AEC-Q101 stress test requirements and features halogen/antimony-free "Green" molding compound with UL 94V-0 flammability rating. The SOT523 package supports automated placement on fine-pitch PCBs while maintaining JEDEC-compliant ESD robustness (4kV HBM).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | -45 V - Maximum safe collector-emitter voltage before breakdown in common-emitter configuration |
| IC | -100 mA - Continuous DC collector current handling capability without thermal runaway |
| PD | 150 mW - Power dissipation limit on 1 oz copper FR-4 PCB under still-air conditions |
| hFE (A grade) | 125–290 - DC current gain range at -2 mA IC, -5 V VCE, defining base drive sizing |
| fT | 100 MHz - Unity-gain frequency confirming suitability for audio and low-speed digital switching |
| RθJA | 833 °C/W - Junction-to-ambient thermal resistance, critical for ambient temperature derating |
| ESD HBM | 4,000 V - Human Body Model robustness enabling handling without special ESD controls |
Pinout & Package
Package: SOT523 - ultra-small surface-mount plastic package (1.60 × 1.60 × 0.65 mm), molded with halogen-free compound, UL 94V-0 rated, moisture sensitivity level 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Emitter) | Emitter terminal | Current sink node; connects to higher potential in PNP operation; requires proper grounding reference |
| 2 (Base) | Control input | Receives forward-biased current to enable conduction; typical drive ~0.5 mA for 10 mA IC |
| 3 (Collector) | Output terminal | Current source node; connects to load and supply rail; handles full switched load current |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive electronics per stress test requirements including HTOL, TCT, and ESD |
| SOT523 ultra-small footprint | 1.6 mm × 1.6 mm body size enables high-density routing in compact modules and sensor nodes |
| hFE binned (A grade) | Guaranteed 125–290 gain range simplifies bias network design and reduces production calibration |
| Lead-free & RoHS 3 compliant | Fully compliant with EU Directive 2015/863/EU; no intentionally added lead, bromine, chlorine, or antimony |
| Low VCE(SAT) | -300 mV max at IC = -10 mA / IB = -0.5 mA ensures minimal conduction loss in switching apps |
Applications
| Automotive Door Module | Industrial Sensor Interface |
|---|---|
Use Scenario: Driving LED status indicators and small relays in door control units exposed to -40°C to +125°C ambient. IC Role / Device Role / Timing Role: Low-side PNP switch controlling 20 mA indicator loads with fast turn-off via base pull-down. Use Value: AEC-Q101 qualification and -55°C to +150°C operating range ensure reliability over vehicle lifetime. | Use Scenario: Level-shifting and signal inversion between 3.3 V microcontrollers and 5 V analog front-ends in factory sensors. IC Role / Device Role / Timing Role: Active-low logic inverter with defined hFE and low VBE(ON) (-600 to -750 mV) for predictable threshold behavior. Use Value: Tight hFE binning and low noise figure (10 dB @ 0.2 mA) preserve signal integrity in precision analog paths. |
| Portable Medical Monitor | Smart Home Actuator Driver |
Use Scenario: Enabling/disabling low-power analog signal paths in battery-operated patient monitors with strict leakage limits. IC Role / Device Role / Timing Role: High-impedance cutoff switch using low ICBO (-15 nA @ 25°C) to minimize standby current drain. Use Value: Ultra-low leakage and 4 kV HBM ESD rating support safe handling during manual assembly and field service. | Use Scenario: Driving small solenoids and buzzer elements in Wi-Fi-enabled thermostats and lighting controllers. IC Role / Device Role / Timing Role: Medium-current (≤100 mA) saturated switch with VCE(SAT) ≤ -650 mV at full load for efficient actuation. Use Value: 150 mW power rating and 833°C/W thermal resistance allow continuous duty in enclosed plastic enclosures up to 70°C ambient. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PNP small-signal transistor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BC857B-7-F | hFE = 220–520 (B grade); otherwise identical ratings and package | Higher gain range suits low-base-drive designs but increases sensitivity to thermal drift | Select when tighter gain control is needed and circuit tolerates wider hFE spread |
| MMBT3906LT1G | Same SOT-23 package; VCEO = -40 V; hFE = 100–300; not AEC-Q101 qualified | Lacks automotive qualification and has lower breakdown voltage; suitable only for commercial-grade systems | Choose for cost-sensitive non-automotive applications where SOT-23 compatibility is required |
Compared with BC857B-7-F, the BC857AT-7 offers lower and more consistent hFE, easing bias stability in temperature-varying environments; versus MMBT3906LT1G, it provides AEC-Q101 assurance and 5 V higher VCEO, making it preferred for safety-critical automotive subsystems.
Availability
BC857AT-7 is available at Aetrix Electronics and suitable for automotive door modules, industrial sensor interfaces, portable medical monitors, and smart home actuator drivers requiring stable component supply and long-term lifecycle support.
Supply support for BC857AT-7 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
Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design, manufacturing, and sales operations across Asia, Europe, and North America.
The BC857 series belongs to Diodes' AEC-Q101-qualified small-signal transistor product line, engineered specifically for automotive body electronics, industrial controls, and consumer devices demanding high reliability in miniature packages.
FAQ
What is the maximum operating temperature for BC857AT-7?
The BC857AT-7 has an operating junction temperature range of -55°C to +150°C, verified per AEC-Q101 testing. Its storage temperature matches this range. Derating begins above +25°C ambient, with power dissipation linearly reduced to zero at +150°C based on RθJA = 833°C/W.
Is BC857AT-7 pin-compatible with BC857B-7-F or BC857C-7-F?
Yes - all BC857x-7-F variants share identical SOT523 pinout (Emitter-Base-Collector on pins 1-2-3) and mechanical dimensions. Only hFE binning differs: A (125–290), B (220–520), C (420–800). No layout change is needed when substituting within the same package.
Does BC857AT-7 support reflow soldering per J-STD-020?
Yes - the device is qualified for standard lead-free reflow profiles per J-STD-020, with Moisture Sensitivity Level 1 (unlimited floor life at ≤30°C/60% RH). Matte tin-plated terminals ensure reliable wetting and joint formation without pre-baking.
How does BC857AT-7 differ from the NPN BC847AT-7-F?
The BC847AT-7-F is the complementary NPN transistor: same SOT523 package, AEC-Q101 qualification, and voltage/current ratings, but with opposite polarity (VCEO = +45 V, IC = +100 mA). They are designed for paired use in differential amplifiers, mirror circuits, and push-pull output stages.
BC857AT-7 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- SOT-523
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- Transistor Type:
- PNP
- Current - Collector (Ic) (Max):
- 100 mA
- Voltage - Collector Emitter Breakdown (Max):
- 45 V
- Vce Saturation (Max) @ Ib, Ic:
- 650mV @ 5mA, 100mA
- Current - Collector Cutoff (Max):
- 15nA (ICBO)
- DC Current Gain (hFE) (Min) @ Ic, Vce:
- 125 @ 2mA, 5V
- Power - Max:
- 150 mW
- Frequency - Transition:
- 100MHz
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-523
BC857AT-7 FAQ
1.How can I place an order for BC857AT-7 through Aetrix?
Please submit a Request for Quotation (RFQ) for BC857AT-7 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 BC857AT-7 reliable?
The price and inventory of BC857AT-7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC857AT-7 is usually 5 days.
3.What payment methods are accepted for BC857AT-7?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC857AT-7 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BC857AT-7?
BC857AT-7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BC857AT-7 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 BC857AT-7?
For technical support, including BC857AT-7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC857AT-7 requirements.
6.How does Aetrix verify that BC857AT-7 is sourced from the original manufacturer or authorized distributors?
All BC857AT-7 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 BC857AT-7 meets industry standards.
7.What is the process for return or replacement of BC857AT-7?
All BC857AT-7 units undergo pre-shipment inspection (PSI). If there is an issue with BC857AT-7, 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 BC857AT-7 part is unused and in its original packaging.
Return procedure for BC857AT-7:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BC857AT-7 Tags
-
MMBT3906LT1G
onsemi
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MMBT3904-7-F
Diodes Incorporated
-
MMBT3904LT1G
onsemi
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MMBT3906-7-F
Diodes Incorporated
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MMBT3904-TP
Micro Commercial Co
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MMBT2222A-7-F
Diodes Incorporated
-
BC846BLT1G
onsemi
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BC847B,215
Nexperia USA Inc.
-
SMMBT3904LT1G
onsemi
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MMBT2222A-TP
Micro Commercial Co
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MMBTA06LT1G
onsemi
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MMBT2222ALT1G
onsemi
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