Diodes Incorporated BCW61DTA

Overview

BCW61DTA from Diodes Incorporated is a PNP silicon planar small-signal transistor in SOT-23 package, rated for V_CEO = −32 V, I_C = −200 mA, and P_TOT = 330 mW at T_amb = 25°C. It delivers h_FE = 100–380 (depending on I_C and V_CE), f_T = 180 MHz, and switching times as low as t_d = 35 ns, used in high-speed switching and amplification stages of portable audio and power management circuits.

For engineers reviewing the BCW61DTA datasheet, BCW61DTA pinout, BCW61DTA application, or BCW61DTA equivalent, key selection criteria include verified PNP polarity, SOT-23 terminal mapping (E-B-C), guaranteed h_FE group D performance (min 100 at I_C = −10 µA), V_CE(sat) ≤ −0.25 V at I_C = −10 mA/I_B = −0.25 mA, and thermal stability across −55°C to +150°C operating range.

Technical Context

This transistor operates in active and saturation regions with defined DC current gain groups (A–D); BCW61DTA corresponds to Group D, offering highest h_FE (100–380) across bias conditions including I_C = −10 µA, −2 mA, and −50 mA. Its f_T = 180 MHz and low C_ebo = 11 pF / C_cbo = 6 pF support RF-coupled preamp and fast-switching logic interface roles.

Designed for pulsed operation (300 µs width, low duty cycle), it achieves t_on = 85 ns and t_off = 480 ns with R_L = 990 Ω, R₁ = R₂ = 5 kΩ, and V_BB = −3.6 V. V_BE(sat) ranges from −0.60 V to −1.05 V depending on drive level, enabling precise base bias design in emitter-follower and level-shift configurations.

Key Specifications

Pinout & Package

SOT-23 plastic surface-mount package with gull-wing leads; standardized 3-terminal configuration for automated placement and reflow soldering.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BCW61DTA, BC807-40 offers enhanced voltage headroom and broader gain range but trades off speed; MMBT3906 provides superior f_T yet narrower h_FE spread-making BCW61DTA optimal for cost-sensitive, thermally demanding switching where guaranteed Group D h_FE and −32 V rating are primary constraints.

Availability

BCW61DTA is available at Aetrix Electronics and suitable for portable audio amplifiers, LED driver switches, automotive sensor interfaces, and industrial level shifters requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for BCW61DTA 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 and manufacturing operations across Asia and the Americas.

The BCW61 series belongs to Diodes' general-purpose bipolar transistor product line, engineered for reliability in consumer, industrial, and automotive signal switching and amplification applications where consistent h_FE grouping and SOT-23 footprint compatibility are essential.

FAQ

What is the pin configuration of BCW61DTA in SOT-23?

BCW61DTA uses standard SOT-23 pinout: Pin 1 = Emitter, Pin 2 = Base, Pin 3 = Collector. This matches JEDEC TO-236AB outline and is confirmed by Diodes Incorporated's official package drawings and marking layout (part marking "BD" on top surface). No alternate pinouts exist for this variant.

Does BCW61DTA have a specified junction-to-case thermal resistance?

No, the official datasheet does not list R_θJC. Thermal performance is characterized via P_TOT = 330 mW at T_amb = 25°C with derating curve (2.64 mW/°C above 25°C), implying typical R_θJA ≈ 300°C/W on FR-4 PCB with minimal copper. For thermal design, use P_TOT derating and ambient temperature limits instead of junction-to-case values.

Can BCW61DTA replace BCW61B in existing designs?

Yes, with design verification. BCW61DTA (Group D, h_FE min 100) provides higher and more consistent DC gain than BCW61B (Group B, h_FE min 60), reducing base drive requirements. However, ensure V_CE(sat) and switching timing meet system margins, as higher h_FE may affect transient response in critically damped circuits.

Is BCW61DTA suitable for linear amplifier applications?

Yes, within specified limits. Its f_T = 180 MHz, low noise figure (2 dB), and stable h_FE make it appropriate for low-power audio preamplifiers and sensor signal conditioning. Avoid operation near V_CEO or I_C max ratings in linear mode; maintain V_CE ≥ −5 V and I_C ≤ −100 mA for optimal linearity and thermal safety.