Diodes Incorporated BCV27TA

Overview

BCV27TA from Diodes Incorporated is an NPN silicon planar Darlington transistor in SOT-23 package, featuring V_CEO = 30 V, I_C = 500 mA, V_CE(sat) = 1.0 V at I_C = 100 mA/I_B = 0.1 mA, h_FE ≥ 4000 at I_C = 100 µA, and f_T = 170 MHz - used for high-gain low-saturation switching in compact power management circuits.

For engineers reviewing the BCV27TA datasheet, BCV27TA pinout, BCV27TA application, or BCV27TA equivalent, key selection criteria include Darlington current gain linearity at low base drive, thermal derating above 25°C, SOT-23 thermal resistance (R_θJA ≈ 370°C/W), and safe operating area under pulsed I_C conditions.

Technical Context

This Darlington pair integrates two NPN transistors monolithically to deliver high DC current gain (h_FE up to 10,000) with single-base control. It operates with V_CB ≤ 30 V and supports pulsed I_C up to 800 mA at ≤2% duty cycle.

The device exhibits low V_CE(sat) (1.0 V) and V_BE(sat) (1.5 V) under rated switching conditions, enabling efficient low-voltage load driving. Its f_T of 170 MHz confirms usable bandwidth beyond typical switching frequencies.

Key Specifications

Pinout & Package

SOT-23 plastic surface-mount package with standard 3-pin configuration: emitter, base, collector arranged in linear order (pin 1 = emitter, pin 2 = base, pin 3 = collector) per JEDEC TO-236AB outline; thermal pad not present.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BCV27TA, BCV28TA provides polarity complementarity without performance trade-offs, while FMMT38A extends voltage capability at the cost of higher conduction loss and reduced thermal efficiency in SOT-23.

Availability

BCV27TA is available at Aetrix Electronics and suitable for LED driver circuits, relay driver modules, thermal sensor interfaces, and small-signal amplifier stages requiring stable component supply and consistent parametric performance across production batches.

Supply support for BCV27TA 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 in Taiwan and China.

The BCV27TA belongs to Diodes' general-purpose bipolar transistor product line, engineered for space-constrained, high-gain switching applications in industrial automation, consumer electronics, and automotive body control modules.

FAQ

What is the maximum pulsed collector current for BCV27TA?

The absolute maximum pulsed collector current is 800 mA, measured under pulsed conditions with pulse width = 300 µs and duty cycle ≤2%. Exceeding this limit risks thermal runaway even with short duration, as SOT-23 lacks thermal mass to absorb transient energy.

Does BCV27TA include an integrated base resistor?

No, BCV27TA is a bare Darlington pair without built-in base resistors. External base current limiting is required to prevent overdrive and ensure reliable saturation; typical designs use 10 kΩ–100 kΩ series resistors from MCU GPIO pins.

Can BCV27TA replace BCV47 in existing designs?

No - BCV47 has V_CEO = 60 V and V_CBO = 80 V versus BCV27TA's 30 V/40 V ratings. Substituting BCV27TA into BCV47 circuits risks premature breakdown in 48 V or higher systems, even if pinout and h_FE match.

What is the recommended PCB layout practice for thermal management?

Use minimum 2 mm² copper pour connected directly to the collector pad (Pin 3), avoid thermal relief on that pad, and place the device away from other heat sources. Derate P_tot by 3.3 mW/°C above 25°C ambient per the 370°C/W R_θJA specification.