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

onsemi BSR18A_D87Z

Name: BSR18A_D87Z
Brand: onsemi
SKU: BSR18A_D87Z
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BSR18A_D87Z

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: BSR18A_D87Z.pdf

Description:: TRANS PNP 40V 0.2A SOT-23-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BSR18A_D87Z from ON Semiconductor is a PNP general-purpose amplifier transistor in SOT-23 package, rated for -40 V V_CEO, -200 mA I_C, and 350 mW power dissipation, optimized for low-to-mid current switching and amplification in consumer and industrial control circuits.

For engineers reviewing the BSR18A_D87Z datasheet, pinout, applications, or equivalent options, this device serves as a cost-effective, high-gain discrete solution for signal inversion, load switching, and interface-level translation where PNP topology and SOT-23 footprint are required.

Technical Context

The BSR18A_D87Z implements a planar epitaxial PNP bipolar junction structure with process 66 heritage, supporting DC current gain (h_FE) from 60 to 300 across I_C = -0.1 mA to -10 mA at V_CE = -1.0 V, and transition frequency f_T of 250 MHz under specified RF conditions.

It features low saturation voltages - V_CE(sat) ≤ -0.25 V at I_C = -10 mA / I_B = -1.0 mA - and fast switching performance with t_d/t_r = 35 ns and t_f = 75 ns, enabling use in pulse-width modulation and digital logic interfacing up to ~10 MHz.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	-40 V - Maximum safe collector-emitter reverse bias before breakdown; defines voltage headroom in high-side switch or level-shifter designs.
I_C (max)	-200 mA - Continuous collector current limit; supports driving LEDs, relays, or small MOSFET gates without external heat sinking.
P_D	350 mW - Total power dissipation at T_A = 25°C; derates linearly at 2.8 mW/°C above ambient.
h_FE	60–300 - DC current gain range across operating currents; enables predictable base drive sizing for saturation in switching applications.
f_T	250 MHz - Transition frequency at I_C = -10 mA, V_CE = -20 V; confirms suitability for RF preamplifier or broadband analog stages up to VHF.
V_CE(sat)	≤ -0.40 V - Collector-emitter saturation voltage at I_C = -50 mA / I_B = -5 mA; ensures low conduction loss in saturated-switch configurations.
C_cb	4.5 pF - Collector-base capacitance at V_CB = -5 V; contributes to Miller effect and bandwidth limitation in high-frequency amplifiers.

Pinout & Package

SOT-23 (TO-236AB) 3-lead surface-mount package with standard JEDEC outline; compact 2.92 mm × 1.30 mm footprint, 1.20 mm max height, and gull-wing leads for reflow compatibility.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Emitter terminal	Current source node in PNP operation; connects to higher potential rail in high-side switch or common-base amplifier.
2 (Base)	Control input	Receives forward-biased current to turn on device; requires current-limiting resistor when driven from logic or microcontroller.
3 (Collector)	Output terminal	Sinks current to load or ground; used as output node in common-emitter amplifier or low-side switch configuration.

Key Features

Feature	Design Value
High DC current gain	h_FE = 100–300 at I_C = -10 mA enables minimal base drive current for efficient switching in battery-powered systems.
Low V_CE(sat)	-0.25 V typical at I_C = -10 mA reduces power loss and self-heating during sustained conduction.
Fast switching speed	t_d/t_r = 35 ns, t_f = 75 ns supports PWM frequencies up to 10 MHz in motor control or LED dimming.
Low noise figure	NF ≈ 2–4 dB at 1 kHz with R_S = 200 Ω makes it suitable for low-level audio preamplification stages.
JEDEC-compliant SOT-23	Standardized footprint ensures drop-in replacement capability and compatibility with automated assembly processes.

Applications

LED Driver Circuit	Microcontroller Interface Level Shifter
Use Scenario: Driving multiple indicator or status LEDs from a 3.3 V or 5 V microcontroller GPIO pin. IC Role / Device Role / Timing Role: PNP switch configured in common-emitter mode to sink current from LED anodes tied to V_CC. Use Value: Low V_CE(sat) minimizes voltage drop across the transistor, preserving forward voltage margin for reliable LED turn-on at low supply rails.	Use Scenario: Translating logic-high signals from a 1.8 V MCU to enable a 5 V peripheral or sensor. IC Role / Device Role / Timing Role: Active-low level shifter using emitter-follower or common-collector configuration. Use Value: High h_FE ensures stable output voltage swing within 0.7 V of V_CC, maintaining noise margin for downstream TTL/CMOS inputs.
Relay Driver Stage	Audio Signal Inverter
Use Scenario: Controlling a 12 V relay coil from a low-voltage logic signal in HVAC or industrial control panels. IC Role / Device Role / Timing Role: High-side switch with flyback diode protection, operated in saturation region. Use Value: -40 V V_CEO rating provides sufficient margin against inductive kickback spikes during relay de-energization.	Use Scenario: Inverting low-amplitude audio signals (e.g., microphone bias or line-level feedback) in portable audio devices. IC Role / Device Role / Timing Role: Common-emitter amplifier with fixed bias network and capacitive coupling. Use Value: 250 MHz f_T and low C_cb preserve phase integrity and bandwidth up to 20 kHz, meeting full-audio fidelity requirements.

LED Driver Circuit

Microcontroller Interface Level Shifter

Use Scenario: Driving multiple indicator or status LEDs from a 3.3 V or 5 V microcontroller GPIO pin.

IC Role / Device Role / Timing Role: PNP switch configured in common-emitter mode to sink current from LED anodes tied to V_CC.

Use Value: Low V_CE(sat) minimizes voltage drop across the transistor, preserving forward voltage margin for reliable LED turn-on at low supply rails.

Use Scenario: Translating logic-high signals from a 1.8 V MCU to enable a 5 V peripheral or sensor.

IC Role / Device Role / Timing Role: Active-low level shifter using emitter-follower or common-collector configuration.

Use Value: High h_FE ensures stable output voltage swing within 0.7 V of V_CC, maintaining noise margin for downstream TTL/CMOS inputs.

Relay Driver Stage

Audio Signal Inverter

Use Scenario: Controlling a 12 V relay coil from a low-voltage logic signal in HVAC or industrial control panels.

IC Role / Device Role / Timing Role: High-side switch with flyback diode protection, operated in saturation region.

Use Value: -40 V V_CEO rating provides sufficient margin against inductive kickback spikes during relay de-energization.

Use Scenario: Inverting low-amplitude audio signals (e.g., microphone bias or line-level feedback) in portable audio devices.

IC Role / Device Role / Timing Role: Common-emitter amplifier with fixed bias network and capacitive coupling.

Use Value: 250 MHz f_T and low C_cb preserve phase integrity and bandwidth up to 20 kHz, meeting full-audio fidelity requirements.

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP general-purpose amplifier applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC807-40	Higher h_FE (250–630), same SOT-23 package, identical pinout (E-B-C).	Better suited for ultra-low-base-drive applications; slightly higher V_CE(sat) at high I_C.	Select BC807-40 when higher gain stability over temperature is required, especially below 1 mA I_C.
MMBT4403	Same V_CEO (-40 V) and I_C (-600 mA), but higher P_D (350 mW vs. 225 mW); pinout differs (E-C-B).	Supports higher peak current loads; requires PCB layout revision due to reversed collector/emitter pin assignment.	Choose MMBT4403 only if >200 mA pulsed current capability is needed and board redesign is acceptable.

Compared with BSR18A_D87Z, BC807-40 offers superior gain consistency for precision biasing, while MMBT4403 delivers greater current headroom at the cost of pinout incompatibility - making BSR18A_D87Z the optimal balance of gain, speed, thermal performance, and layout compatibility in space-constrained designs.

Availability

BSR18A_D87Z is available at Aetrix Electronics and suitable for LED driver circuits, microcontroller interface level shifters, relay driver stages, and audio signal inverters requiring stable component supply and consistent parametric performance across production batches.

Supply support for BSR18A_D87Z 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

ON Semiconductor is a global semiconductor manufacturer specializing in energy-efficient power management, analog, sensors, and discrete components for automotive, industrial, cloud power, and IoT applications.

The BSR18A_D87Z belongs to ON Semiconductor's legacy general-purpose bipolar transistor product line, originally developed by Fairchild Semiconductor to deliver reliable, low-cost amplification and switching in high-volume consumer and industrial electronics.

FAQ

What is the maximum continuous collector current rating for BSR18A_D87Z?

The BSR18A_D87Z has a maximum continuous collector current (I_C) rating of -200 mA at T_A = 25°C. This value decreases with rising ambient temperature due to thermal derating at 2.8 mW/°C. The device remains functional up to its absolute maximum junction temperature of 150°C, but sustained operation near I_C = -200 mA requires careful thermal design. Always verify actual current draw and junction temperature in the final BSR18A_D87Z application.

Does BSR18A_D87Z support high-frequency amplification?

Yes, the BSR18A_D87Z achieves a transition frequency (f_T) of 250 MHz under test conditions of I_C = -10 mA and V_CE = -20 V, confirming usability in VHF-range amplification and RF front-end stages. Its low C_cb (4.5 pF) and C_eb (10 pF) further support broadband response. However, gain and stability must be validated per circuit layout and biasing in the target BSR18A_D87Z application.

What is the pin configuration of BSR18A_D87Z in the SOT-23 package?

The BSR18A_D87Z uses standard SOT-23 pinout: Pin 1 = Emitter, Pin 2 = Base, Pin 3 = Collector (E-B-C). This matches JEDEC TO-236AB and is compatible with common pick-and-place tooling and PCB land patterns. The marking "T92" appears on the top surface for visual identification. Confirm orientation during layout using the official ON Semiconductor package drawing MA03D.

Can BSR18A_D87Z replace BC857 in existing designs?

BSR18A_D87Z and BC857 share similar PNP functionality and SOT-23 packaging, but differ in key parameters: BC857 has lower V_CEO (-45 V vs. -40 V), higher h_FE (110–800), and different pinout (E-C-B). Direct substitution is not recommended without verifying voltage margin, gain dependency, and PCB trace routing. For new BSR18A_D87Z designs, always validate switching timing and saturation behavior under actual load conditions.

Is BSR18A_D87Z suitable for automotive applications?

The BSR18A_D87Z is not AEC-Q101 qualified and lacks automotive-grade screening or extended temperature validation beyond its specified -55°C to +150°C junction range. While it may function in non-safety-critical automotive subsystems (e.g., cabin lighting or infotainment peripherals), ON Semiconductor does not guarantee reliability under automotive stress profiles. For qualified alternatives, consult ON Semiconductor's AEC-Q101 PNP portfolio - do not assume BSR18A_D87Z meets automotive requirements without independent qualification testing.

BSR18A_D87Z 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:: PNP

Current - Collector (Ic) (Max):: 200 mA

Voltage - Collector Emitter Breakdown (Max):: 40 V

Vce Saturation (Max) @ Ib, Ic:: 400mV @ 5mA, 50mA

Current - Collector Cutoff (Max):: 50nA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 100 @ 10mA, 1V

Power - Max:: 350 mW

Frequency - Transition:: 250MHz

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-3

BSR18A_D87Z FAQ

1.How can I place an order for BSR18A_D87Z through Aetrix?

Please submit a Request for Quotation (RFQ) for BSR18A_D87Z 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 BSR18A_D87Z reliable?

The price and inventory of BSR18A_D87Z are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BSR18A_D87Z is usually 5 days.

3.What payment methods are accepted for BSR18A_D87Z?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BSR18A_D87Z transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BSR18A_D87Z?

BSR18A_D87Z orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BSR18A_D87Z 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 BSR18A_D87Z?

For technical support, including BSR18A_D87Z datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BSR18A_D87Z requirements.

6.How does Aetrix verify that BSR18A_D87Z is sourced from the original manufacturer or authorized distributors?

All BSR18A_D87Z 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 BSR18A_D87Z meets industry standards.

7.What is the process for return or replacement of BSR18A_D87Z?

All BSR18A_D87Z units undergo pre-shipment inspection (PSI). If there is an issue with BSR18A_D87Z, 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 BSR18A_D87Z part is unused and in its original packaging.

Return procedure for BSR18A_D87Z:

1.Submit a request within 90 days.

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

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