Diodes Incorporated ZDT605TC

Overview

ZDT605TC from Diodes Incorporated is a dual NPN medium-power Darlington transistor in SM-8 (SOT-223-8) package, designed for high-current switching and amplification in industrial control and power management circuits. It features V_CEO = 120 V, I_C = 1 A per die, h_FE = 2000–100,000 at I_C = 50 mA–2 A, V_CE(sat) ≤ 1.5 V at I_C = 1 A / I_B = 1 mA, and operates from –55°C to +150°C.

For engineers reviewing the ZDT605TC datasheet, ZDT605TC pinout, ZDT605TC application, or ZDT605TC equivalent, key selection considerations include dual-die thermal derating (22 mW/°C when both transistors active), guaranteed V_(BR)CBO ≥ 140 V, pulsed switching performance (t_on = 0.5 µs, t_off = 1.6 µs), and validated Darlington gain linearity across 0.01–2 A collector current range.

Technical Context

The ZDT605TC integrates two independent NPN Darlington pairs in a single SM-8 thermally enhanced package, each with built-in base-emitter resistors omitted-requiring external base drive control. Its structure supports parallel operation or complementary half-bridge configurations with matched V_BE(sat) (1.7 V typical at I_C = 1 A) and tightly coupled thermal response due to shared die substrate.

Electrical behavior is characterized under pulsed conditions (300 µs width, ≤2% duty cycle) to maintain junction temperature stability. Key AC parameters-including f_T = 150 MHz at I_C = 100 mA and C_ibo = 90 pF-confirm suitability for medium-speed switching above audio frequencies while retaining DC gain integrity up to 2 A.

Key Specifications

Pinout & Package

Package: SM-8 (8-lead SOT-223 variant), thermally optimized with exposed drain pad connected to Collector 1 and Collector 2 for enhanced heat transfer. Mounting requires minimum 2 inch² copper area on PCB for rated power dissipation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ZXTDA6712E6TA and MBT3904DW1T1G, the ZDT605TC uniquely delivers dual 120 V/1 A Darlington channels in one thermally efficient SM-8 package-enabling compact, high-reliability designs in industrial power interfaces where voltage margin, gain, and thermal coupling matter.

Availability

ZDT605TC is available at Aetrix Electronics and suitable for industrial relay drivers, DC motor direction controllers, linear regulator pass elements, and high-voltage sensor interface amplifiers requiring stable component supply across extended temperature and long-life production cycles.

Supply support for ZDT605TC 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, specializing in high-reliability components for industrial, automotive, and computing applications.

The ZDT605TC belongs to Diodes' high-voltage Darlington transistor product line, engineered specifically for ruggedized switching and amplification in harsh-environment control systems where thermal coupling, voltage margin, and gain consistency are critical.

FAQ

What is the maximum safe operating voltage for ZDT605TC in continuous DC applications?

The ZDT605TC is rated for V_CEO = 120 V under open-base conditions and V_CBO = 140 V. For reliable long-term operation, design should limit steady-state collector-emitter voltage to ≤100 V to maintain margin against transients and temperature-induced degradation. Derating to 80 V is recommended for 150°C ambient operation.

Can both Darlington pairs be operated simultaneously at full current without thermal runaway?

Yes-when mounted on ≥2 inch² copper area, both dies can operate continuously at 1 A each (2.75 W total) with 45.5 °C/W thermal resistance. The shared substrate ensures matched thermal drift, and h_FE uniformity across current range prevents current hogging. No external balancing resistors are required.

Is ZDT605TC suitable for PWM motor control at 20 kHz?

Yes-measured t_on = 0.5 µs and t_off = 1.6 µs at I_C = 0.5 A confirm clean switching at 20 kHz (50 µs period). However, V_CE(sat) rise at high duty cycles requires attention to average power dissipation; thermal design must accommodate 2.75 W max with appropriate copper area.

Does ZDT605TC include integrated base-emitter resistors or require external biasing?

ZDT605TC has no internal base-emitter resistors-it is a bare Darlington pair requiring externally controlled base current. This provides full flexibility in drive design: users may implement current-limited GPIO drive, dedicated base resistors, or active current sources depending on switching speed and gain requirements.