Diodes Incorporated ZTX689BSTZ

Overview

ZTX689BSTZ from Diodes Incorporated is an NPN silicon planar medium-power high-gain transistor designed for switching and linear amplification in low-voltage, high-current applications. It delivers V_CEO = 20 V, h_FE = 400 at I_C = 2 A, V_CE(sat) = 0.1 V (typ.) at I_C = 0.1 A / I_B = 0.5 mA, and f_T = 150 MHz - enabling use in flash gun converters, motor drivers, and Darlington pair stages.

For engineers reviewing the ZTX689BSTZ datasheet, ZTX689BSTZ pinout, ZTX689BSTZ application, or ZTX689BSTZ equivalent, key selection criteria include its 20 V V_CEO, low 0.1 V saturation voltage at light drive, 400 DC current gain at 2 A, thermal resistance of 116 °C/W (PCB-mounted), and TO-92-compatible E-Line package with confirmed C-B-E terminal assignment.

Technical Context

This NPN transistor operates as a medium-power switch or amplifier with a maximum continuous collector current of 3 A and pulsed capability up to 8 A. Its gain profile remains stable across I_C = 0.1–6 A (h_FE = 500–150), supporting both saturated switching and linear operation under V_CE ≤ 20 V.

The device features low V_CE(sat) (0.1 V typ. at I_C = 0.1 A) and V_BE(sat) = 0.9 V at I_C = 1 A, enabling efficient drive in battery-powered circuits. Thermal design is supported by R_th(j-amb) = 116 °C/W on 1-inch² PCB copper, with safe operating area validated for single-pulse and DC conditions up to +175°C junction temperature.

Key Specifications

Pinout & Package

Package: TO-92-compatible E-Line (ZTX689B series), molded plastic case with 3 leads. Mounting requires minimum 1-inch² copper area on PCB for rated power dissipation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN medium-power switching applications.

Compared with ZTX653BSTZ and MJD127G, the ZTX689BSTZ uniquely balances low-saturation voltage, high gain at 2 A, and 150 MHz bandwidth in a compact TO-92-compatible package - making it optimal for space-constrained, battery-efficient switching where 20 V rating suffices.

Availability

ZTX689BSTZ is available at Aetrix Electronics and suitable for flash gun converters, DC motor drivers, Darlington pair input stages, and battery-powered logic interfaces requiring stable component supply and consistent parametric performance across production lots.

Supply support for ZTX689BSTZ 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, cost-optimized components for industrial, computing, and consumer applications.

The ZTX689BSTZ belongs to Diodes' ZTX6xx bipolar transistor family, engineered for medium-power switching and amplification in space- and efficiency-sensitive designs where TO-92 compatibility and predictable gain linearity are essential.

FAQ

What is the maximum safe continuous collector current for ZTX689BSTZ at 70°C ambient?

At T_amb = 70°C, derating from 1.5 W at 25°C applies: ΔT = 45°C × 5.7 mW/°C = 0.2565 W reduction → P_tot = 1.2435 W. Using V_CE(sat) ≈ 0.2 V at 2 A, max I_C ≈ √(P_tot/R_CE(sat)) yields ~2.5 A continuous, assuming adequate PCB copper and no additional thermal resistance.

Can ZTX689BSTZ be used in linear amplifier configurations?

Yes - its h_FE stability (500–150 over I_C = 0.1–6 A) and f_T = 150 MHz support Class-A and AB audio amplification up to ~100 kHz. However, thermal design must account for dissipation in active region; P_tot derating and heatsinking are mandatory above 500 mW.

Is ZTX689BSTZ pin-compatible with ZTX650 or ZTX653?

Yes - all three share identical E-Line TO-92 mechanical outline and C-B-E pin assignment (viewed from flat side, leads down: left=Collector, center=Base, right=Emitter). Electrical differences (V_CEO, h_FE, V_CE(sat)) require validation in target circuit, but PCB layout is interchangeable.

Does ZTX689BSTZ have built-in ESD protection?

No - the datasheet does not specify ESD protection diodes or human-body-model (HBM) ratings. Standard handling precautions for unprotected bipolar transistors apply: use grounded workstations, anti-static packaging, and avoid floating base terminals during assembly or testing.