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

onsemi 2SA1705T-AN

Name: 2SA1705T-AN
Brand: onsemi
SKU: 2SA1705T-AN
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 2SA1705T-AN

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: SC-71

Datasheet:: 2SA1705T-AN.pdf

Description:: TRANS PNP 50V 1A 3-NMP

Quantity:: RFQ Add To RFQ list

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Product details

Overview

2SA1705T-AN from onsemi is a PNP bipolar junction transistor (BJT) rated for -50 V V_CEO, -1 A I_C, and 0.9 W P_C, optimized for low V_CE(sat) (-500 mV at I_C = -500 mA, I_B = -50 mA) and fast switching in relay and lamp driver circuits.

For engineers reviewing the 2SA1705T-AN datasheet, pinout, applications, or equivalent options, key selection factors include its SC-71 (NMP) package, h_FE rank T (200–400 at I_C = -100 mA), f_T = 150 MHz, and guaranteed V_(BR)CEO = -50 V with t_on/t_f ≤ 40 ns/30 ns.

Technical Context

This PNP BJT uses onsemi's FBET (Flat Base Epitaxial Transistor) process to achieve low saturation voltage and high-speed switching performance. Its design targets discrete power control in DC-DC feedback paths and load switching where low base drive loss and tight V_CE(sat) tolerance are critical.

The device operates within a -55°C to +150°C storage range and 150°C maximum junction temperature, with absolute maximum ratings including V_CBO = -60 V, V_EBO = -5 V, and I_CP = -2 A (pulse). It is not rated for automotive safety-critical or medical implant applications.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	-50 V - Maximum collector-emitter blocking voltage under open-base conditions; defines safe operating voltage in linear and switching modes.
I_C	-1 A - Continuous DC collector current rating; sets upper limit for steady-state load switching capability.
V_CE(sat)	-500 mV max @ I_C = -500 mA, I_B = -50 mA - Low saturation voltage reduces conduction loss and heat generation in saturated-switch applications.
f_T	150 MHz - Gain-bandwidth product indicating usable frequency range for small-signal amplification or high-speed switching.
h_FE Rank	T (200–400) @ V_CE = -2 V, I_C = -100 mA - Tighter DC current gain binning enables predictable base drive sizing in production designs.
t_on/t_f	40 ns / 30 ns - Fast turn-on and fall times support efficient operation in PWM-driven loads up to ~5 MHz.

Pinout & Package

Package: SC-71 (JEITA/JEDEC), also designated NMP(Taping) - surface-mount, 3-pin, plastic molded case with 2.54 mm lead pitch and 0.275 g mass.

Pin/Terminal	Circuit Role	Design Meaning
1	Emitter	Current exit terminal for PNP operation; connects to higher potential node (e.g., V_CC) in common-emitter switch configurations.
2	Collector	Current entry terminal; ties to load return path (e.g., ground side of relay coil) in standard switching layouts.
3	Base	Control input; requires negative bias relative to emitter to forward-bias base-emitter junction and enable conduction.

Key Features

Feature	Design Value
FBET process technology	Enables precise doping profile control for consistent V_CE(sat) and h_FE across production lots.
Low V_CE(sat)	Reduces power dissipation by >30% vs. legacy PNP transistors at I_C = -500 mA, improving thermal margin in compact PCB layouts.
Fast switching (t_on/t_f)	Minimizes transition losses during PWM operation, supporting efficient duty-cycle control in lamp and solenoid drivers.
SC-71 (NMP) package	Provides standardized SMT footprint compatible with automated assembly and reflow profiles per J-STD-020.

Applications

Lamp Driver	Relay Driver
Use Scenario: Driving incandescent or LED indicator lamps in industrial HMIs and instrumentation panels. IC Role / Device Role / Timing Role: PNP switch controlling lamp current path between V_CC and ground via emitter-follower or common-emitter topology. Use Value: Low V_CE(sat) ensures minimal voltage drop across the transistor, preserving lamp brightness and reducing self-heating at 500 mA loads.	Use Scenario: Activating electromagnetic relays in PLC output modules and motor control interfaces. IC Role / Device Role / Timing Role: High-current PNP switch sourcing relay coil current from a microcontroller GPIO or logic-level driver. Use Value: Guaranteed h_FE ≥200 allows reliable saturation with ≤50 mA base drive, simplifying level-shifting circuitry.
Voltage Regulator Pass Element	DC-DC Feedback Switch
Use Scenario: Serving as the series pass transistor in linear voltage regulators delivering up to 1 A output. IC Role / Device Role / Timing Role: Linear-mode PNP regulating output voltage by adjusting conduction between input and output rails. Use Value: 150°C T_j rating and 0.9 W P_C support stable operation under thermal stress when paired with modest heatsinking.	Use Scenario: Implementing error amplifier output stage in buck converter feedback loops requiring fast response. IC Role / Device Role / Timing Role: Discrete PNP switch enabling rapid pull-up of compensation node or reference adjust line. Use Value: 150 MHz f_T and sub-100 ns switching ensure minimal phase lag in closed-loop regulation dynamics.

Lamp Driver

Relay Driver

Use Scenario: Driving incandescent or LED indicator lamps in industrial HMIs and instrumentation panels.

IC Role / Device Role / Timing Role: PNP switch controlling lamp current path between V_CC and ground via emitter-follower or common-emitter topology.

Use Value: Low V_CE(sat) ensures minimal voltage drop across the transistor, preserving lamp brightness and reducing self-heating at 500 mA loads.

Use Scenario: Activating electromagnetic relays in PLC output modules and motor control interfaces.

IC Role / Device Role / Timing Role: High-current PNP switch sourcing relay coil current from a microcontroller GPIO or logic-level driver.

Use Value: Guaranteed h_FE ≥200 allows reliable saturation with ≤50 mA base drive, simplifying level-shifting circuitry.

Voltage Regulator Pass Element

DC-DC Feedback Switch

Use Scenario: Serving as the series pass transistor in linear voltage regulators delivering up to 1 A output.

IC Role / Device Role / Timing Role: Linear-mode PNP regulating output voltage by adjusting conduction between input and output rails.

Use Value: 150°C T_j rating and 0.9 W P_C support stable operation under thermal stress when paired with modest heatsinking.

Use Scenario: Implementing error amplifier output stage in buck converter feedback loops requiring fast response.

IC Role / Device Role / Timing Role: Discrete PNP switch enabling rapid pull-up of compensation node or reference adjust line.

Use Value: 150 MHz f_T and sub-100 ns switching ensure minimal phase lag in closed-loop regulation dynamics.

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP switching transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
2SA1037AK-TL-E	V_CEO = -50 V, I_C = -150 mA, h_FE = 120–270, SC-70 package	Lower current rating limits use to signal-level or low-power switching only	Select when board space is constrained and load current stays below 150 mA.
MMBT2907ALT1G	V_CEO = -60 V, I_C = -600 mA, h_FE = 100–300, SOT-23 package	Lower P_C (350 mW) and reduced I_C require derating above 400 mA continuous	Choose for cost-sensitive, medium-current applications where 0.9 W dissipation is not required.

Compared with 2SA1705T-AN, the 2SA1037AK-TL-E offers smaller footprint but insufficient current handling for relay coils, while MMBT2907ALT1G provides higher V_CBO but lower thermal capacity-neither is pin-compatible, and both require layout revision for replacement.

Availability

2SA1705T-AN is available at Aetrix Electronics and suitable for voltage regulators, relay drivers, and lamp drivers requiring stable component supply, consistent h_FE binning, and industrial-grade thermal reliability.

Supply support for 2SA1705T-AN 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, with leadership in power management, analog, sensors, and discrete devices.

The 2SA1705T-AN belongs to onsemi's general-purpose PNP BJT product line, engineered for robust, low-cost switching in industrial controls, power supplies, and interface circuits where reliability and parametric consistency are essential.

FAQ

What is the h_FE range for 2SA1705T-AN?

The 2SA1705T-AN is binned to Rank T, with DC current gain h_FE specified from 200 to 400 at V_CE = -2 V and I_C = -100 mA. This tighter range than Rank S (140–280) supports more predictable base drive design in production systems using the 2SA1705T-AN.

Does 2SA1705T-AN support pulse operation beyond its DC current rating?

Yes-the 2SA1705T-AN supports pulsed collector current I_CP up to -2 A with 1 ms pulse width and ≤10% duty cycle. This capability enables short-duration surge handling in relay coil energization or lamp inrush limiting, provided thermal limits are observed per the 2SA1705T-AN derating curve.

What is the package type and marking format for 2SA1705T-AN?

The 2SA1705T-AN uses the SC-71 package (JEITA/JEDEC), also labeled NMP(Taping) in onsemi documentation. Marking includes "A1705", lot number, and "T" rank identifier on the top surface; pin 1 is emitter, pin 2 is collector, and pin 3 is base per the 2SA1705T-AN outline drawing.

How does V_CE(sat) of 2SA1705T-AN compare to similar PNP transistors?

The 2SA1705T-AN guarantees V_CE(sat) ≤ -500 mV at I_C = -500 mA and I_B = -50 mA, which is 15–25% lower than typical values for legacy PNP devices like the 2SA1013 or BC807 in comparable packages-directly reducing conduction loss and thermal load in the 2SA1705T-AN.

Is 2SA1705T-AN RoHS compliant and halogen-free?

Yes-the 2SA1705T-AN is Pb-free and RoHS-compliant per its ordering information ("Pb Free" noted for 2SA1705S-AN and VR-marked 2SA1705T-AN variants), and meets JEDEC JS709B halogen-free requirements as confirmed in onsemi's material declarations for the NMP package family.

2SA1705T-AN Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: SC-71

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: PNP

Current - Collector (Ic) (Max):: 1 A

Voltage - Collector Emitter Breakdown (Max):: 50 V

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

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 200 @ 100mA, 2V

Power - Max:: 900 mW

Frequency - Transition:: 150MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: 3-NMP

2SA1705T-AN FAQ

1.How can I place an order for 2SA1705T-AN through Aetrix?

Please submit a Request for Quotation (RFQ) for 2SA1705T-AN 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 2SA1705T-AN reliable?

The price and inventory of 2SA1705T-AN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 2SA1705T-AN is usually 5 days.

3.What payment methods are accepted for 2SA1705T-AN?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 2SA1705T-AN transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 2SA1705T-AN?

2SA1705T-AN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 2SA1705T-AN 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 2SA1705T-AN?

For technical support, including 2SA1705T-AN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 2SA1705T-AN requirements.

6.How does Aetrix verify that 2SA1705T-AN is sourced from the original manufacturer or authorized distributors?

All 2SA1705T-AN 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 2SA1705T-AN meets industry standards.

7.What is the process for return or replacement of 2SA1705T-AN?

All 2SA1705T-AN units undergo pre-shipment inspection (PSI). If there is an issue with 2SA1705T-AN, 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 2SA1705T-AN part is unused and in its original packaging.

Return procedure for 2SA1705T-AN:

1.Submit a request within 90 days.

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

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