Diodes Incorporated ZTX690BQ

Overview

ZTX690BQ from Diodes Incorporated is an NPN silicon planar medium-power high-gain transistor with V_CEO = 45 V, h_FE = 400 at I_C = 1 A, and V_CE(sat) = 0.1 V (typ.) at I_C = 0.1 A / I_B = 0.5 mA - used in siren drivers, battery-powered motor control stages, and Darlington pair emitter followers.

For engineers reviewing the ZTX690BQ datasheet, ZTX690BQ pinout, ZTX690BQ application, or ZTX690BQ equivalent, key selection criteria include saturation voltage under 100 mA drive, DC current gain stability up to 2 A, thermal resistance of 116 °C/W (PCB-mounted), and TO-92 compatibility for legacy board replacements.

Technical Context

This discrete NPN bipolar junction transistor operates in linear amplification and switching modes, supporting continuous collector currents up to 2 A and pulsed peaks to 6 A. Its low V_CE(sat) (0.1–0.5 V) and high h_FE (150–500) enable efficient current amplification in low-voltage battery systems.

The device features f_T = 150 MHz at I_C = 50 mA / V_CE = 5 V, C_ibo = 200 pF, and C_obo = 16 pF - confirming suitability for medium-speed switching (t_on = 33 ns, t_off = 1300 ns) in siren tone generation and brushed DC motor commutation.

Key Specifications

Pinout & Package

Package: TO-92 (E-Line compatible, 3-238 outline), lead-forming option Q indicates straight leads with standard C-B-E pin order (viewed from flat side, leads down).

Key Features

Applications

Equivalent & Alternatives

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

Compared with ZTX653, ZTX690BQ delivers 60% higher DC gain and 39% lower thermal resistance on PCB, enabling smaller footprints and tighter base-drive budgets; versus MJD127, it trades package size for 50× higher f_T, making it preferable for audio-frequency switching where layout density matters.

Availability

ZTX690BQ is available at Aetrix Electronics and suitable for siren drivers, battery-powered motor control circuits, Darlington pair configurations, and low-voltage sensor interfaces requiring stable component supply across industrial and consumer OEM programs.

Supply support for ZTX690BQ 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.

ZTX690BQ belongs to the ZTX series of high-gain silicon transistors engineered for cost-sensitive, medium-power linear and switching applications in battery-operated and industrial control equipment.

FAQ

Is ZTX690BQ RoHS compliant and halogen-free?

Yes. ZTX690BQ meets RoHS Directive 2011/65/EU and is certified halogen-free per IEC 61249-2-21. The TO-92 package uses matte tin-plated leads and epoxy molding compound compliant with JEDEC J-STD-020 moisture sensitivity level 1 (MSL-1).

What is the maximum safe operating area (SOA) for ZTX690BQ at 25°C ambient?

At T_amb = 25°C, the SOA boundary allows 2 A continuous at V_CE ≤ 0.5 V, or 1 A at V_CE ≤ 10 V, or 0.5 A at V_CE ≤ 25 V - defined by the 1.5 W P_tot derating curve and second breakdown limits shown in Figure 3-240 of the datasheet.

Can ZTX690BQ replace BC547 in existing designs?

No - BC547 has V_CEO = 45 V but only h_FE = 110–800 (wide spread) and P_tot = 500 mW. ZTX690BQ offers 3× higher power rating and tighter h_FE consistency (150–500), but requires PCB copper area redesign to handle 1.5 W dissipation.

Does ZTX690BQ support pulse-width modulation (PWM) at 20 kHz?

Yes. With t_on = 33 ns and t_off = 1300 ns, ZTX690BQ supports clean 20 kHz PWM switching in low-side motor drive applications, provided base drive current exceeds 5 mA and gate resistor is ≤1 kΩ to minimize storage time.