Diodes Incorporated ZDT6757TC

Overview

ZDT6757TC from Diodes Incorporated is a complementary medium-power bipolar transistor pair (NPN+PNP) in a single SM-8 (SOT-223-8) package, rated for 300 V V_CEO, 0.5 A continuous I_C, and 2.75 W total power dissipation with both dies active. It serves as a high-voltage switching or linear amplification stage in offline AC/DC auxiliary supplies, relay drivers, and industrial solenoid controls.

For engineers reviewing the ZDT6757TC datasheet, ZDT6757TC pinout, ZDT6757TC application, or ZDT6757TC equivalent, key selection criteria include verified dual-die thermal derating (22 mW/°C), matched h_FE minima (50/40 at 100 mA), and guaranteed 30 MHz f_T under pulsed conditions - critical for synchronous flyback gate drive and bidirectional current sensing circuits.

Technical Context

The ZDT6757TC integrates two discrete silicon planar epitaxial transistors - one NPN (Q1) and one PNP (Q2) - on a shared leadframe within an SM-8 thermally enhanced package. Each die supports independent operation up to 300 V blocking and exhibits symmetrical saturation characteristics: V_CE(sat) ≤ ±0.5 V at ±100 mA/±10 mA drive.

Its thermal design assumes PCB mounting with 2-inch² copper pour, enabling 2.75 W total dissipation when both transistors conduct simultaneously. Electrical parameters are specified under pulsed test conditions (300 µs width, ≤2% duty cycle) to avoid self-heating artifacts during characterization.

Key Specifications

Pinout & Package

Package: SM-8 (8-lead SOT-223 variant), thermally optimized with exposed die pad connected to collector terminals for enhanced heat transfer. Mounting requires 2-inch² copper pour per manufacturer thermal spec.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar complementary high-voltage transistor applications.

Compared with ZDT6757TC, ZXTD6717E6 trades voltage headroom for gain and compactness, while MBT3904DW1T1G serves entirely different low-voltage domains - neither replicates the 300 V/0.5 A dual-die thermal co-location of the ZDT6757TC.

Availability

ZDT6757TC is available at Aetrix Electronics and suitable for industrial relay drivers, offline auxiliary supplies, solenoid current regulators, and bidirectional DC motor control requiring stable component supply across extended temperature ranges and high-voltage reliability.

Supply support for ZDT6757TC 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 semiconductor company specializing in discrete, analog, and mixed-signal devices for power management, signal integrity, and connectivity applications.

ZDT6757TC belongs to Diodes' high-voltage complementary transistor family, engineered specifically for robust switching in industrial power conversion and electromechanical actuation systems operating up to 300 V.

FAQ

What is the maximum safe operating temperature for ZDT6757TC?

The ZDT6757TC has a junction temperature range of –55°C to +150°C. Its thermal resistance (R_θJA) is 45.5°C/W when both dies conduct simultaneously on a 2-inch² copper PCB. To stay within 150°C max T_j, ambient must remain ≤104.5°C at full 2.75 W dissipation - confirming suitability for sealed industrial enclosures with passive cooling.

Can ZDT6757TC replace discrete SOT-223 transistors in existing designs?

Yes, but only if the PCB layout accommodates the 8-lead SM-8 footprint and thermal pad connection. Pin compatibility exists with standard SOT-223-3 devices only for individual dies (C1/E1/B1 ≈ Q1; C2/E2/B2 ≈ Q2), but shared thermal pad and dual-die interaction require revalidation of thermal performance and crosstalk in high-frequency switching.

Is ZDT6757TC suitable for linear amplifier applications?

Yes - its specified h_FE, V_CE(sat), and f_T are characterized under DC and pulsed conditions, and the ±300 V rating supports Class-A operation into reactive loads. However, linear use demands strict attention to SOA limits: at 100 V V_CE, max I_C drops to ~150 mA due to second breakdown constraints outlined in the SOA graph of the FZT657/FZT757 reference datasheets.

Does ZDT6757TC require external base resistors in switching applications?

Yes - base current must be limited to prevent damage during saturation. For 0.5 A I_C, typical h_FE of 50 requires ≥10 mA I_B. With V_BE(on) ≈ 1 V, a 470 Ω resistor from 5 V logic yields ~8.5 mA - sufficient for reliable turn-on while avoiding excessive base charge storage that slows turn-off.