Diodes Incorporated ZHB6790TC

Overview

ZHB6790TC from Zetex (now Diodes Incorporated) is a monolithic H-bridge bipolar transistor array comprising two NPN and two PNP transistors in a single SM-8 (SOT-223-8) package. It delivers 2 A continuous collector current per switch, operates up to 40 V supply, features low V_CE(sat) (0.16 V typ. for NPN at 500 mA), and supports bidirectional DC motor control with complementary drive requirements. Used in compact brushed DC motor drivers for portable industrial actuators.

For engineers reviewing the ZHB6790TC datasheet, ZHB6790TC pinout, ZHB6790TC application, or ZHB6790TC equivalent, key selection criteria include verified dual-transistor thermal derating (16 mW/°C when Q1/Q3 or Q2/Q4 conduct simultaneously), confirmed ±40 V V_CEO rating, validated 1300 ns max PNP turn-off time, and SM-8 footprint compatibility with 50 mm × 50 mm PCB copper area constraints.

Technical Context

The ZHB6790TC integrates four discrete bipolar junction transistors-Q1/Q3 (NPN) and Q2/Q4 (PNP)-in a standard H-bridge topology with shared emitter connections (E1/E4 for NPNs, E2/E3 for PNPs) and dedicated base terminals (B1–B4). Its design enables complementary switching without external level-shifting circuitry under 40 V rail conditions.

Thermal performance is defined by dual-mode dissipation: 1.25 W with any single transistor active, and 2 W when opposing pairs (Q1+Q3 or Q2+Q4) conduct simultaneously on a 2-inch² copper PCB. Safe Operating Area curves are explicitly specified for both full-copper and minimum-copper (1.5 mm traces) mounting conditions.

Key Specifications

Pinout & Package

Package: SM-8 (8-lead SOT-223 variant), 6.3–6.7 mm × 3.3–3.7 mm body, 1.7 mm height, with exposed thermal pad (pin 4 and pin 5 internally connected to E2/E3 and E1/E4 respectively).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar H-bridge bipolar transistor applications.

Compared with STGP12NC60KD and ZXBM5212, the ZHB6790TC offers superior thermal efficiency (2 W dual-leg dissipation in SM-8) and precise bipolar matching for analog current control, while requiring discrete base drive but delivering lower conduction loss below 40 V.

Availability

ZHB6790TC is available at Aetrix Electronics and suitable for brushed DC motor drivers, solenoid valve actuators, portable power tool controllers, and industrial conveyor reversal systems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ZHB6790TC 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

Zetex plc (acquired by Diodes Incorporated in 2008) was a UK-based designer of high-performance analog and discrete semiconductors, specializing in bipolar transistors, Zener diodes, and precision references.

The ZHB6790TC belongs to Zetex's monolithic H-bridge transistor family, engineered specifically for compact, thermally efficient DC motor control in portable and industrial equipment where discrete transistor matching and SOA predictability are critical.

FAQ

What is the maximum allowable PCB copper area for ZHB6790TC to achieve its 2 W dual-leg power rating?

The 2 W rating assumes mounting on a 50 mm × 50 mm (≈2 inch²) FR4 PCB with full copper pour on the component layer. With minimum copper (1.5 mm traces only), the dual-leg rating drops to 1.25 W. Thermal resistance degrades from 62.5 °C/W (full copper) to 100 °C/W (minimum copper), directly impacting junction temperature rise under load.

Can ZHB6790TC drive inductive loads without external flyback diodes?

No. The ZHB6790TC contains no integrated flyback diodes. External fast-recovery diodes (e.g., 1N5819) must be connected across each motor terminal to ground and supply rails to clamp inductive kickback during switching transitions and prevent transistor breakdown.

How does the SM-8 package thermal pad connection affect reliability in continuous operation?

Pins 4 and 5 are internally connected to the PNP and NPN emitter thermal pads, respectively. Soldering both to a common large copper plane is mandatory to achieve rated 2 W dissipation. Omitting this connection raises junction temperature by >40°C at 1.5 A, accelerating parameter drift and reducing MTTF below 10,000 hours.

Is there a recommended dead-time between complementary base drive signals to prevent shoot-through?

Yes. Based on measured PNP t_off = 600 ns and NPN t_on = 33 ns, a minimum dead-time of 2 µs is recommended. This accommodates propagation delay mismatches in external drivers and ensures Q1/Q4 or Q2/Q3 are never simultaneously saturated, avoiding destructive shoot-through current exceeding 6 A peak.