NXP Semiconductors BC857AT,115

Overview

BC857AT,115 from Nexperia is a PNP general purpose transistor in SC-75 (SOT416) package, rated for −45 V V_CEO, −50 V V_CBO, and −100 mA I_C, with h_FE of 125–250 at −2 mA I_C, used for low-power switching and amplification in portable battery-powered equipment.

For engineers reviewing the BC857AT,115 datasheet, BC857AT,115 pinout, BC857AT,115 application, or BC857AT,115 equivalent, key selection criteria include its PNP polarity, SC-75 thermal resistance (833 K/W), guaranteed h_FE range, V_CEsat ≤ −200 mV at −10 mA/−0.5 mA, and −5 V V_EBO rating for emitter-base reverse tolerance.

Technical Context

This device operates as a silicon PNP bipolar junction transistor optimized for linear amplification and saturated switching in low-voltage, low-current circuits. Its design supports stable DC current gain across −55 °C to +150 °C ambient, with V_BE = −580 to −700 mV at −2 mA I_C and f_T = 100 MHz enabling audio-frequency signal handling.

Thermal performance is defined for FR4 PCB mounting (R_{th j-a} = 833 K/W), and electrical limits comply with IEC 60134 absolute maximum ratings. The SC-75 package enables high-density placement while maintaining sufficient power dissipation (P_tot = 150 mW at T_amb ≤ 25 °C).

Key Specifications

Pinout & Package

BC857AT,115 is housed in a plastic surface-mounted SC-75 (SOT416) package with 3 leads, measuring 1.75 × 1.45 × 0.9 mm (L × W × H), optimized for space-constrained portable designs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BC857B,115 and MMBT3906LT1G, BC857AT,115 delivers optimal balance of gain predictability, SC-75 space efficiency, and thermal resistance for portable and space-constrained industrial designs-without requiring layout changes or gain recalibration.

Availability

BC857AT,115 is available at Aetrix Electronics and suitable for portable audio amplifiers, low-voltage logic-level switching, and automotive body control modules requiring stable component supply and long-term manufacturability.

Supply support for BC857AT,115 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 leader in discrete, logic, and PowerMOS semiconductors, formed in 2017 from the former NXP Standard Products division, serving automotive, industrial, computing, consumer, and wearable markets.

The BC857AT,115 belongs to Nexperia's BC856T/BC857T series of PNP general purpose transistors, designed specifically for reliable low-power switching and amplification in space- and power-constrained portable and automotive electronics.

FAQ

What is the maximum collector-emitter voltage rating for BC857AT,115?

The BC857AT,115 has a maximum collector-emitter voltage (V_CEO) rating of −45 V under open-base conditions, as specified in the Absolute Maximum Ratings table. This rating defines the upper limit of reverse bias the transistor can withstand between collector and emitter without breakdown, and must not be exceeded in circuit design to ensure reliability and prevent permanent damage to the BC857AT,115.

What is the DC current gain (h_FE) range of BC857AT,115 and at what conditions is it measured?

The BC857AT,115 exhibits a DC current gain (h_FE) range of 125 to 250 when tested at V_CE = −5 V and I_C = −2 mA, per the manufacturer's characterization data. This gain window is guaranteed across production lots and reflects the device's small-signal amplification capability under standard bias conditions, directly influencing base resistor selection in both amplifier and switch configurations using the BC857AT,115.

Is BC857AT,115 pin-compatible with BC857B,115 or BC857C,115?

Yes, BC857AT,115 shares identical pinout (base-emitter-collector on pins 1–2–3), package (SC-75/SOT416), and absolute maximum ratings with BC857B,115 and BC857C,115. The only functional difference lies in the h_FE range: BC857AT,115 is binned to 125–250, BC857B,115 to 220–475, and BC857C,115 to 420–800. No PCB change is needed when substituting within the BC857T series, provided gain requirements align with the BC857AT,115 specification.

What is the thermal resistance (R_{th j-a}) of BC857AT,115 and how does it affect PCB layout?

The BC857AT,115 has a junction-to-ambient thermal resistance (R_{th j-a}) of 833 K/W when mounted on a standard FR4 printed-circuit board with no copper pour. This relatively high value means even modest power dissipation (e.g., 50 mW) causes significant junction temperature rise-requiring careful attention to trace width, local copper area, and airflow. Designers should avoid routing heat-sensitive components near the BC857AT,115 and consider thermal relief patterns if higher continuous current is expected, as the BC857AT,115's thermal behavior directly impacts long-term reliability.

Does BC857AT,115 support operation at elevated temperatures, and what is its maximum junction temperature?

Yes, BC857AT,115 is rated for junction temperatures up to 150 °C and ambient operating temperatures from −65 °C to +150 °C, making it suitable for under-hood automotive or industrial environments. Its h_FE, V_BE, and V_CEsat parameters are characterized across this full range, with graphical data showing stable gain down to −55 °C and up to +150 °C. To maintain performance, designers must ensure the BC857AT,115's actual junction temperature stays within this limit via appropriate power derating and thermal management.