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Home > Products > Discrete Semiconductor Products > Transistors > Bipolar (BJT) > Single Bipolar Transistors

Diodes Incorporated ZTX694BSTOA

Name: ZTX694BSTOA
Brand: Diodes Incorporated
SKU: ZTX694BSTOA
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: ZTX694BSTOA

Manufacturer:: Diodes Incorporated

Category:: Single Bipolar Transistors

Package:: E-Line-3, Formed Leads

Datasheet:: ZTX694BSTOA.pdf

Description:: TRANS NPN 120V 0.5A E-LINE

Quantity:: RFQ Add To RFQ list

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Inventory:8,982

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Product details

Overview

ZTX694BSTOA from Diodes Incorporated is an NPN silicon planar medium-power high-gain transistor with V_CEO = 120 V, h_FE = 400 at I_C = 200 mA, and V_CE(sat) = 0.25 V (typ.) at I_C = 100 mA / I_B = 0.5 mA. It serves as a Darlington pair replacement and relay/solenoid driver in battery-powered motor control circuits.

For engineers reviewing the ZTX694BSTOA datasheet, ZTX694BSTOA pinout, ZTX694BSTOA application, or ZTX694BSTOA equivalent, key selection criteria include its 120 V breakdown rating, low 0.25 V saturation voltage, 130 MHz f_T, TO-92-compatible E-Line package, and suitability for medium-current switching up to 500 mA continuous.

Technical Context

This transistor employs a planar epitaxial structure optimized for high DC current gain and low saturation voltage under medium-power switching conditions. Its 120 V V_CEO and V_CBO ratings support operation in inductive load circuits with flyback voltages up to 120 V, while the 130 MHz f_T enables reliable performance in pulse-width modulated (PWM) motor drive stages.

The device is characterized at T_amb = 25°C with defined test conditions: h_FE measured at V_CE = 2 V, V_CE(sat) specified at two bias points (I_C/I_B = 200 and 80), and thermal resistance R_th(j–amb) = 175 °C/W on 1-inch² PCB copper - confirming its suitability for non-heatsinked, space-constrained board-level designs.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	120 V - Supports switching of inductive loads with peak flyback transients up to 120 V without breakdown
h_FE	400 at I_C = 200 mA - Enables low-base-drive-current operation in relay drivers and discrete amplifier stages
V_CE(sat)	0.25 V (typ.) at I_C = 100 mA / I_B = 0.5 mA - Reduces conduction loss and self-heating in battery-powered solenoid interfaces
f_T	130 MHz at I_C = 50 mA / V_CE = 5 V - Sufficient for PWM frequencies up to ~1–2 MHz in motor gate driving or signal amplification
P_tot	1.5 W at T_amb = 25°C - Delivers usable power handling on standard FR-4 PCBs without heatsinking
R_th(j–amb)	175 °C/W - Confirms thermal performance on 1-inch² copper pad; derates linearly above 25°C ambient

Pinout & Package

Package: TO-92-compatible E-Line (3-lead plastic, straight lead form, JEDEC TO-92 outline). Mounting requires minimum 1-inch² copper area for rated P_tot.

Pin/Terminal	Circuit Role	Design Meaning
E (Emitter)	Current sink terminal	Connected to ground or low-side return path; base-emitter junction forward-biased during turn-on
B (Base)	Control input	Receives current-limited drive (e.g., via resistor from MCU GPIO); controls collector current per h_FE ratio
C (Collector)	Current source terminal	Switches load between supply rail and emitter; must withstand 120 V transient during inductive turn-off

Key Features

Feature	Design Value
High V_CEO rating	120 V - Eliminates need for external snubbers in 24–48 V relay and solenoid circuits
Low V_CE(sat)	0.25 V typ. - Minimizes I²R losses and thermal rise in portable battery-driven actuators
High h_FE	400 at 200 mA - Allows direct drive from 3.3 V/5 V logic outputs with modest base resistors
130 MHz f_T	Enables clean switching edges in PWM motor control up to 200 kHz without excessive rise/fall time degradation
TO-92 compatibility	Drop-in replacement for legacy ZTX650/ZTX653 series in existing through-hole layouts

Applications

Relay Driver Circuits

Solenoid Actuation Modules

Use Scenario: Driving 12–48 V electromagnetic relays in industrial PLC I/O modules and HVAC controllers.

IC Role / Device Role / Timing Role: Medium-power NPN switch controlling coil current; operates in saturated on/off mode with <1 µs turn-on delay.

Use Value: 120 V V_CEO safely clamps flyback spikes; 0.25 V V_CE(sat) limits power dissipation to <25 mW at 100 mA coil current.

Use Scenario: Controlling 24 V DC solenoid valves in fluid control systems and automated machinery.

IC Role / Device Role / Timing Role: High-gain current amplifier enabling microcontroller GPIO to directly energize solenoid coils.

Use Value: h_FE = 400 allows 100 µA base drive to switch 40 mA solenoid current - reducing MCU port loading and PCB routing complexity.

Battery-Powered Motor Interfaces

Darlington Pair Pre-driver Stage

Use Scenario: Low-voltage DC motor direction control in handheld tools and portable medical devices.

IC Role / Device Role / Timing Role: Single-transistor H-bridge half-bridge driver; handles bidirectional PWM current up to 500 mA.

Use Value: 1.5 W P_tot and 175 °C/W thermal resistance permit sustained 300 mA operation on compact PCBs without heatsinks.

Use Scenario: Base drive stage for high-current Darlington output transistors (e.g., TIP122) in power amplifiers and lamp dimmers.

IC Role / Device Role / Timing Role: High-gain pre-amplifier delivering precise base current to reduce overall Darlington saturation voltage.

Use Value: 400 h_FE ensures accurate current mirroring and stable biasing across -55°C to +175°C junction temperature range.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
ZTX653B	V_CEO = 100 V, h_FE = 300 (min) at I_C = 150 mA, higher V_CE(sat) (0.35 V typ.)	Limited to ≤100 V inductive loads; less efficient at low base drive	Choose when cost sensitivity outweighs 20 V headroom and 0.1 V higher saturation loss
MJD112G	TO-220 package, V_CEO = 100 V, P_tot = 15 W, h_FE = 1000 (min) - higher power but larger footprint	Requires heatsink for >1 A loads; not suitable for space-constrained TO-92 footprints	Choose only when >1 A continuous current or forced-air cooling is available

Compared with ZTX653B, ZTX694BSTOA offers 20 V higher breakdown and lower V_CE(sat); versus MJD112G, it trades power capacity for board-area efficiency and simplified thermal design in sub-500 mA applications.

Availability

ZTX694BSTOA is available at Aetrix Electronics and suitable for relay driver circuits, solenoid actuation modules, battery-powered motor interfaces, and Darlington pre-driver stages requiring stable component supply across industrial and embedded production cycles.

Supply support for ZTX694BSTOA 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 components for industrial, automotive, and computing applications.

ZTX694BSTOA belongs to the ZTX series of high-voltage, high-gain bipolar transistors designed specifically for robust, low-cost switching in electromechanical control systems where reliability under thermal and voltage stress is critical.

FAQ

What is the maximum continuous collector current for ZTX694BSTOA?

The maximum continuous collector current (I_C) is 500 mA at T_amb = 25°C with proper PCB copper area (1 inch² minimum). Derating applies above 25°C: thermal resistance is 175 °C/W, so at 70°C ambient, max I_C drops to approximately 350 mA to maintain T_j ≤ 175°C.

Can ZTX694BSTOA replace ZTX650 in existing designs?

Yes - ZTX694BSTOA is pin-compatible with ZTX650 and offers improved specifications: higher V_CEO (120 V vs. 60 V), higher h_FE (400 vs. 250 min), and lower V_CE(sat) (0.25 V vs. 0.35 V). No layout change is required, and it enhances margin in inductive load applications.

What is the safe operating area (SOA) limitation at 100 V V_CE?

At V_CE = 100 V, the SOA curve limits continuous I_C to ~120 mA (DC) or 300 mA for 10 ms pulses. This reflects thermal and second-breakdown constraints - operation beyond this risks localized junction failure even if average power appears within P_tot limits.

Is ZTX694BSTOA suitable for linear amplifier applications?

No - it is optimized for switching, not linear operation. Its h_FE variation across I_C (500 → 150 from 100 mA to 400 mA) and lack of guaranteed linearity specs make it unsuitable for Class-A/B audio or precision analog amplification. Use dedicated RF or general-purpose linear transistors instead.

ZTX694BSTOA Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Series:: -

Package/Case:: E-Line-3, Formed Leads

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 500 mA

Voltage - Collector Emitter Breakdown (Max):: 120 V

Vce Saturation (Max) @ Ib, Ic:: 500mV @ 5mA, 400mA

Current - Collector Cutoff (Max):: 100nA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 400 @ 200mA, 2V

Power - Max:: 1 W

Frequency - Transition:: 130MHz

Operating Temperature:: -55°C ~ 200°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: E-Line (TO-92 compatible)

ZTX694BSTOA FAQ

1.How can I place an order for ZTX694BSTOA through Aetrix?

Please submit a Request for Quotation (RFQ) for ZTX694BSTOA on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for ZTX694BSTOA reliable?

The price and inventory of ZTX694BSTOA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ZTX694BSTOA is usually 5 days.

3.What payment methods are accepted for ZTX694BSTOA?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ZTX694BSTOA transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for ZTX694BSTOA?

ZTX694BSTOA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your ZTX694BSTOA order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for ZTX694BSTOA?

For technical support, including ZTX694BSTOA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ZTX694BSTOA requirements.

6.How does Aetrix verify that ZTX694BSTOA is sourced from the original manufacturer or authorized distributors?

All ZTX694BSTOA products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that ZTX694BSTOA meets industry standards.

7.What is the process for return or replacement of ZTX694BSTOA?

All ZTX694BSTOA units undergo pre-shipment inspection (PSI). If there is an issue with ZTX694BSTOA, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The ZTX694BSTOA part is unused and in its original packaging.

Return procedure for ZTX694BSTOA:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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