Diodes Incorporated BC857C-7-F

Overview

BC857C-7-F from Diodes Incorporated is a PNP small-signal transistor in SOT23 package, rated for V_CEO = −45 V, I_C = −100 mA, and h_FE = 420–800 at I_C = −2 mA, used in low-power switching and audio-frequency amplification circuits within industrial control and consumer electronics.

For engineers reviewing the BC857C-7-F datasheet, BC857C-7-F pinout, BC857C-7-F application, or BC857C-7-F equivalent, this page delivers verified electrical parameters, SOT23 terminal mapping, real-world use scenarios, and validated alternative transistors with documented gain/voltage trade-offs.

Technical Context

This device operates as a general-purpose PNP bipolar junction transistor optimized for linear amplification and saturated switching. Its high DC current gain (h_FE ≥ 420) enables low-base-drive designs, while its −45 V V_CEO rating supports moderate-voltage rail applications such as level-shifting and discrete logic interfaces.

The BC857C-7-F exhibits V_CE(sat) ≤ −300 mV at I_C = −10 mA / I_B = −0.5 mA and f_T = 100–200 MHz, confirming suitability for AF amplification up to ~100 kHz and fast-switching tasks below 10 MHz with predictable turn-off behavior.

Key Specifications

Pinout & Package

BC857C-7-F is housed in a JEDEC-standard SOT23 plastic surface-mount package with matte tin-plated leads, UL 94V-0 flammability rating, and moisture sensitivity level 1. The device weighs approximately 0.008 g and uses a top-view pin configuration with emitter (E), base (B), and collector (C) assigned to pins 1, 2, and 3 respectively.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP small-signal transistor applications.

Compared with BC857C-7-F, BC857C-13-F offers identical performance in larger reels for cost-efficient high-volume builds, while MMBT3906LT1G trades guaranteed high h_FE for broader V_CEO tolerance-making it viable only where gain variability is acceptable and voltage stress dominates design constraints.

Availability

BC857C-7-F is available at Aetrix Electronics and suitable for industrial control interfaces, consumer audio signal conditioning, and embedded LED driver circuits requiring stable component supply, consistent parametric binning, and long-term manufacturing continuity.

Supply support for BC857C-7-F 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 centers across Asia and manufacturing facilities certified to ISO/TS 16949 and IATF 16949 standards.

The BC856A–BC858C series was developed as a family of complementary PNP/NPN transistors targeting cost-sensitive, high-reliability applications in automotive infotainment, industrial sensors, and consumer power management subsystems.

FAQ

What is the maximum continuous collector current for BC857C-7-F?

The absolute maximum continuous collector current (I_C) is −100 mA at T_A = +25°C. Derating applies above +25°C per the 310 mW power limit and R_θJA = 403°C/W thermal resistance on minimum pad layout. At 85°C ambient, usable I_C drops to approximately −65 mA to maintain junction temperature below 150°C.

Is BC857C-7-F suitable for automotive applications?

Yes-this part meets AEC-Q200 stress test requirements for temperature cycling, humidity, and mechanical shock. Automotive-qualified variants (BC857CQ) exist with additional PPAP documentation, but BC857C-7-F itself is widely deployed in non-safety-critical automotive modules including body control units and HVAC interfaces.

How does the "C" suffix affect BC857C-7-F compared to BC857A-7-F or BC857B-7-F?

The "C" suffix denotes the highest h_FE bin: 420–800 at I_C = −2 mA, versus 125–250 for "A" and 220–475 for "B". This enables lower base current drive, reduced base resistor power dissipation, and improved gain stability in amplifier and precision switch designs.

Can BC857C-7-F replace BC857B-7-F in an existing design?

Yes-pinout, package, and absolute maximum ratings are identical. Substituting BC857C-7-F increases h_FE from 220–475 to 420–800, which may improve gain or reduce base drive requirements. Verify that higher gain does not cause unintended oscillation or saturation delay in high-speed switching applications.