Diodes Incorporated FZT694BTA

Overview

FZT694BTA from Diodes Incorporated is a 120V NPN medium-power high-gain transistor in SOT223 package, rated for 1A continuous collector current, with hFE > 400 at 0.2A and V_CE(sat) ≤ 500 mV at I_C = 400 mA / I_B = 5 mA. It serves as a high-voltage switching element in relay drivers and Darlington pair stages.

For engineers reviewing the FZT694BTA datasheet, FZT694BTA pinout, FZT694BTA application, or FZT694BTA equivalent, key selection criteria include breakdown voltage margin (BV_CEO = 120 V), saturation performance under 400 mA load, thermal resistance to ambient (R_θJA = 41.7 °C/W on 50 mm × 50 mm 2 oz copper), and RoHS-compliant green packaging.

Technical Context

This NPN bipolar junction transistor operates in linear or saturated switching modes with guaranteed BV_CEO and BV_CBO ≥ 120 V, enabling use in 100 V-class industrial control rails. Its f_T = 130 MHz supports moderate-speed switching up to ~100 kHz with low storage time.

The device features low V_CE(sat) (250 mV typical at I_C = 100 mA / I_B = 0.5 mA) and high DC current gain (h_FE = 500 min at I_C = 100 mA), making it suitable for base-driven high-side loads where drive current efficiency matters.

Key Specifications

Pinout & Package

Package: SOT223 (Type DN), surface-mount, 4-pin configuration with emitter-connected tab for thermal conduction and mechanical anchoring.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN high-voltage switching applications.

Compared with ZXTN2012E6TA and FZT651TA, FZT694BTA uniquely balances 120 V breakdown, 1 A current, and SOT223 thermal capability-making it the only option among the three qualified for sustained operation on 100 V industrial buses with >100 ms ON-time duty.

Availability

FZT694BTA is available at Aetrix Electronics and suitable for relay drivers, solenoid controllers, and Darlington pair stages requiring stable component supply across automotive qualification programs, industrial PLC designs, and long-lifecycle embedded systems.

Supply support for FZT694BTA 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, manufacturing, and sales operations across Asia, Europe, and North America.

FZT694BTA belongs to Diodes' high-voltage bipolar transistor product line, engineered specifically for industrial and automotive power interface applications demanding ruggedness, thermal reliability, and AEC-Q101 readiness.

FAQ

What is the maximum safe operating temperature for FZT694BTA?

The FZT694BTA has a junction temperature range of –55 °C to +150 °C. For reliable long-term operation, keep T_J ≤ 125 °C under continuous load. With R_θJA = 41.7 °C/W on 50 mm × 50 mm 2 oz copper, this limits usable power dissipation to ~2.2 W at 25 °C ambient. Derating curves in DS33158 show allowable power drops linearly above 25 °C.

Is FZT694BTA qualified for automotive use?

FZT694BTA is not pre-qualified to AEC-Q101 but is manufactured in IATF 16949-certified facilities and supports PPAP documentation upon request. Diodes offers the pin-compatible FZT694BTQ variant (with Q suffix) for full AEC-Q101 Grade 1 qualification. Customers requiring automotive-grade assurance should specify the Q-suffix part or contact Diodes directly for change-controlled release.

How does the SOT223 thermal tab affect PCB layout?

The SOT223 tab is electrically connected to the collector and must be soldered to a dedicated copper pour for thermal conduction. Minimum recommended pad layout dimensions are provided in DS33158: C = 2.30 mm, C1 = 6.40 mm, Y2 = 8.00 mm. Isolation from other nets is required due to collector potential; thermal relief is discouraged as it degrades R_θJL from 12.9 °C/W to >30 °C/W.

Can FZT694BTA replace a Darlington transistor directly?

No-FZT694BTA is a single NPN transistor, not a Darlington pair. However, it is explicitly designed as a Darlington *replacement* in applications where gain requirements allow h_FE ≥ 400 instead of >10,000. It reduces propagation delay, improves bandwidth, and eliminates second-transistor saturation voltage drop-but requires higher base drive current than a Darlington would for the same collector current.