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

Diodes Incorporated ZTX690B

Name: ZTX690B
Brand: Diodes Incorporated
SKU: ZTX690B
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: ZTX690B

Manufacturer:: Diodes Incorporated

Category:: Single Bipolar Transistors

Package:: E-Line-3

Datasheet:: ZTX690B.pdf

Description:: TRANS NPN 45V 2A E-LINE

Quantity:: RFQ Add To RFQ list

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Product details

Overview

ZTX690B from Diodes Incorporated is an NPN silicon planar medium-power high-gain transistor designed for switching and linear amplification in low-voltage, moderate-current circuits. It delivers V_CEO = 45 V, h_FE = 400 at I_C = 1 A, V_CE(sat) = 0.5 V (I_C = 1 A, I_B = 5 mA), and f_T = 150 MHz - enabling use in siren drivers, motor control stages, and Darlington pair emitter followers.

For engineers reviewing the ZTX690B datasheet, ZTX690B pinout, ZTX690B application, or ZTX690B equivalent, key selection criteria include saturation voltage under 1 A load, gain stability across 100 mA–2 A, thermal resistance of 116 °C/W on 1-inch² PCB copper, and TO-92 mechanical compatibility with legacy E-Line footprints.

Technical Context

This NPN bipolar junction transistor operates in active, saturation, and cutoff regions with defined breakdown limits: V_(BR)CEO = 45 V at I_C = 10 mA and V_(BR)CBO = 45 V at I_C = 100 µA. Its DC current gain h_FE ranges from 150 (I_C = 2 A) to 500 (I_C = 100 mA), supporting both switching and analog biasing.

Switching performance is characterized by t_on = 33 ns and t_off = 1300 ns under pulsed conditions (I_C = 500 mA, I_B = ±50 mA), while thermal design relies on R_th(j-amb)2 = 116 °C/W when mounted on ≥1 inch² PCB copper - a critical constraint for sustained 1.5 W dissipation.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	45 V - Maximum collector-emitter voltage before avalanche breakdown under open-base condition; defines safe operating voltage headroom in 24–36 V systems.
h_FE @ I_C=1 A	400 - Confirmed DC current gain at 1 A collector current; enables base drive current as low as 2.5 mA for full conduction.
V_CE(sat)	0.5 V @ I_C=1 A, I_B=5 mA - Low saturation voltage minimizes power loss (0.5 W) and self-heating during switching in motor driver H-bridge legs.
f_T	150 MHz @ I_C=50 mA, V_CE=5 V - Transition frequency supports audio-frequency amplification and fast digital switching up to ~10–20 MHz.
R_th(j-amb)	116 °C/W - Thermal resistance on 1-inch² PCB copper; requires ≤1.3 W continuous power to stay below 150 °C junction temperature at 25 °C ambient.
I_C (continuous)	2 A - Absolute maximum DC collector current; usable up to 1.5 A with derating above 25 °C ambient per 5.7 mW/°C.
V_BE(sat)	0.9 V @ I_C=1 A, I_B=10 mA - Base-emitter saturation voltage informs required base drive compliance and series resistor sizing.

Pinout & Package

Package: TO-92 (E-Line compatible, 3-238 outline), through-hole mounting with standard lead spacing and thermal pad requirements (≥1 inch² copper for rated P_tot).

Pin/Terminal	Circuit Role	Design Meaning
E (Emitter)	Current sink terminal	Connected to ground or low-side return path; carries full load current and sets reference for base bias network.
B (Base)	Control input	Receives forward-biased current to enable conduction; requires current-limiting resistor to prevent overdrive beyond I_B(max) ≈ 10 mA.
C (Collector)	Current source terminal	Connected to load and supply rail; must withstand 45 V transient spikes and dissipate heat via PCB copper area.

Key Features

Feature	Design Value
High DC current gain	h_FE = 400 at 1 A enables low-base-drive designs for battery-powered motor control without external pre-driver stages.
Low V_CE(sat)	0.5 V at 1 A reduces conduction losses by >40% versus standard general-purpose transistors (e.g., BC337), improving efficiency in portable siren drivers.
TO-92 mechanical compatibility	E-Line 3-238 footprint allows drop-in replacement of legacy parts like ZTX650/ZTX653 in existing PCBs without layout change.
Wide operating temperature	-55°C to +200°C junction range supports deployment in automotive engine compartments and industrial motor controllers with minimal derating.
Fast switching	t_on/t_off = 33/1300 ns enables PWM operation up to 100 kHz with controlled rise/fall times and reduced switching loss in DC-DC pre-regulators.

Applications

Siren Driver Stage

Battery-Powered Motor Control

Use Scenario: Driving piezoelectric or electromagnetic sirens in security panels and emergency beacons powered by 9–12 V alkaline or Li-ion batteries.

IC Role / Device Role / Timing Role: NPN switch amplifying microcontroller GPIO output to deliver 500–1000 mA peak current into reactive siren loads.

Use Value: V_CE(sat) ≤ 0.5 V ensures >90% power efficiency at 1 A, extending battery life by minimizing resistive loss in the transistor itself.

Use Scenario: Low-cost bidirectional DC motor control in handheld tools, toys, and medical pumps using discrete H-bridge topologies.

IC Role / Device Role / Timing Role: High-side or low-side switching element in half-bridge configurations, driven by logic-level signals with current-limited base resistors.

Use Value: h_FE ≥ 400 at 1 A permits direct MCU GPIO drive (3.3 V/5 V) without buffer transistors, reducing BOM count and board space.

Darlington Pair Emitter Follower

Industrial Sensor Interface Amplifier

Use Scenario: Boosting current drive capability in analog sensor signal conditioning circuits where op-amp outputs require >100 mA sourcing/sinking.

IC Role / Device Role / Timing Role: Emitter follower configured with fixed base bias to provide unity-gain, low-output-impedance buffering for precision DAC outputs or thermistor bridges.

Use Value: Low V_BE(sat) = 0.9 V and tight h_FE tolerance ensure stable quiescent current and minimal offset error across temperature.

Use Scenario: Linear amplification stage for millivolt-level signals from RTDs, strain gauges, or thermocouples in programmable logic controller (PLC) input modules.

IC Role / Device Role / Timing Role: Discrete NPN configured in common-emitter topology with emitter degeneration resistor for stable DC gain and bandwidth control.

Use Value: f_T = 150 MHz and low C_obo = 16 pF support clean amplification up to 100 kHz without phase shift or instability in feedback networks.

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
ZTX653	V_CEO = 60 V, h_FE = 250 @ 1 A, V_CE(sat) = 0.7 V - higher voltage rating but lower gain and higher saturation loss.	Better suited for 48 V industrial bus interfaces; less efficient at 1 A due to +0.2 V V_CE(sat).	Select when system voltage exceeds 45 V; avoid if base drive current budget is constrained.
BCX56-16	V_CEO = 80 V, h_FE = 160 @ 500 mA, R_th(j-amb) = 200 °C/W - higher voltage, lower gain, significantly worse thermal performance.	Acceptable for low-duty-cycle switching; unsuitable for continuous 1 A operation without heatsinking.	Choose only for cost-sensitive, low-power applications where thermal margin is not critical.

Compared with ZTX690B, ZTX653 trades gain and efficiency for higher voltage headroom, while BCX56-16 sacrifices thermal capability and gain for broader voltage range - making ZTX690B optimal for 24–36 V, 1 A continuous, thermally constrained designs.

Availability

ZTX690B is available at Aetrix Electronics and suitable for siren drivers, battery-powered motor controllers, Darlington pair emitter followers, and industrial sensor interface amplifiers requiring stable component supply and long-term obsolescence management.

Supply support for ZTX690B 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, industry-qualified components for automotive, industrial, and consumer markets.

The ZTX series targets medium-power bipolar transistors optimized for robust switching and linear operation in cost-sensitive, thermally demanding applications - emphasizing gain consistency, low saturation, and TO-92 manufacturability.

FAQ

Is ZTX690B RoHS compliant and halogen-free?

Yes, ZTX690B meets RoHS Directive 2011/65/EU and is certified halogen-free per IEC 61249-2-21. The device uses lead-free matte tin plating on leads and complies with JEDEC J-STD-020 moisture sensitivity level 1 (unlimited floor life at ≤30 °C/85% RH).

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

At T_amb = 70°C, derating applies at 5.7 mW/°C above 25°C. With 45°C rise, allowable power drops by 257 mW, limiting I_C to approximately 1.3 A (using V_CE(sat) ≈ 0.45 V), assuming no additional heatsinking beyond the specified 1-inch² copper.

Can ZTX690B replace BC337 in existing designs?

Yes, with verification: ZTX690B shares TO-92 package and pinout (E-B-C), but offers higher V_CEO (45 V vs. 45 V), higher h_FE (400 vs. 100–630), and lower V_CE(sat) (0.5 V vs. 0.7 V). Confirm base resistor values accommodate higher gain to avoid overdrive and thermal runaway.

Does ZTX690B support pulse operation beyond its DC ratings?

Yes - absolute maximum I_CM = 6 A is specified for short pulses (≤300 µs, duty cycle ≤2%). This supports surge current handling in motor startup or solenoid actuation, provided average power remains within P_tot = 1.5 W and junction temperature stays below 200 °C.

ZTX690B Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Series:: -

Package/Case:: E-Line-3

Packaging:: Bulk

Product Status:: Active

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 2 A

Voltage - Collector Emitter Breakdown (Max):: 45 V

Vce Saturation (Max) @ Ib, Ic:: 500mV @ 5mA, 1A

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 400 @ 1A, 2V

Power - Max:: 1 W

Frequency - Transition:: 150MHz

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

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

ZTX690B FAQ

1.How can I place an order for ZTX690B through Aetrix?

Please submit a Request for Quotation (RFQ) for ZTX690B 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 ZTX690B reliable?

The price and inventory of ZTX690B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ZTX690B is usually 5 days.

3.What payment methods are accepted for ZTX690B?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ZTX690B transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for ZTX690B?

ZTX690B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your ZTX690B 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 ZTX690B?

For technical support, including ZTX690B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ZTX690B requirements.

6.How does Aetrix verify that ZTX690B is sourced from the original manufacturer or authorized distributors?

All ZTX690B 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 ZTX690B meets industry standards.

7.What is the process for return or replacement of ZTX690B?

All ZTX690B units undergo pre-shipment inspection (PSI). If there is an issue with ZTX690B, 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 ZTX690B part is unused and in its original packaging.

Return procedure for ZTX690B:

1.Submit a request within 90 days.

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

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