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Product details
Overview
QCK3 from Fairchild Semiconductor is a slotted photodarlington optical interrupter switch designed for surface-mount applications exposed to extreme thermal stress during solder reflow. It integrates a GaAs LED emitter and silicon photodarlington sensor across a 4.0 mm slot, operates from −55°C to +100°C, delivers 1.0 mA on-state collector current at 5 mA LED drive, and features infrared-transparent, visible-light-attenuating housing for ambient noise immunity in industrial position sensing.
For engineers reviewing the QCK3 datasheet, pinout, applications, or equivalent options, key selection criteria include its −55°C to +100°C operating temperature range, 1.0 mA minimum IC(ON) under defined bias, 30 V VCEO rating, 4.0 mm slot width, and surface-mount leadform optimized for high-temperature reflow compatibility.
Technical Context
The QCK3 functions as a digital presence/position detector via optical interruption across its fixed 4.0 mm gap. Its photodarlington output provides high current gain (enabling low LED drive), while the electrically conductive housing aids EMI shielding and thermal dissipation.
It is rated for 230°C reflow peak temperature with 5-second dwell and supports continuous operation up to +100°C ambient. The device requires no external biasing-its photodarlington operates in saturation mode with VCE(SAT) ≤ 1.0 V when driven per spec.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Operating Temp Range | −55°C to +100°C: Enables use in automotive engine bays, industrial ovens, and outdoor enclosures without derating. |
| Slot Width | 4.0 mm (0.157"): Fixed mechanical gap defining maximum object thickness detectable without physical contact. |
| IC(ON) Min | 1.0 mA @ IF = 5 mA, VCE = 5 V: Guarantees clean logic-level output swing into typical pull-up loads. |
| VCE(SAT) Max | 1.0 V @ IF = 5 mA, IC = 5 mA: Ensures low power loss and reliable low-side switching in digital interface circuits. |
| VCEO | 30 V: Supports direct interfacing with 24 V industrial control rails without external protection. |
| Reflow Peak Temp | 230°C for 5 sec: Compatible with standard lead-free PCB assembly processes without housing deformation. |
Pinout & Package
QCK3 uses a 4-pin surface-mount package with gull-wing leads formed for flush PCB mounting. Housing is electrically conductive and infrared-transparent with visible-light attenuation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PIN 1 | Cathode | LED cathode connection; must be referenced to ground or negative rail for forward biasing. |
| PIN 2 | Anode | LED anode connection; applies forward voltage to activate infrared emission. |
| PIN 3 | Emitter | Photodarlington emitter output; common terminal for NPN Darlington configuration. |
| PIN 4 | Collector | Photodarlington collector output; provides switched high-current sink path to load. |
Key Features
| Feature | Design Value |
|---|---|
| Single-piece conductive housing | Reduces part count and cost vs. multi-component assemblies while providing EMI shielding and thermal conduction. |
| Infrared-transmissive, visible-light-attenuating lens | Minimizes false triggering from ambient light sources (e.g., fluorescent, LED lighting) in factory environments. |
| 4.0 mm fixed slot geometry | Eliminates alignment sensitivity during assembly and ensures repeatable mechanical detection threshold. |
| Gull-wing SMT leadform | Ensures coplanarity ≤ 0.006" and stable placement on PCBs prior to high-temp reflow soldering. |
Applications
| Industrial Rotary Encoder | High-Temp Conveyor Belt Sensor |
|---|---|
Use Scenario: Detecting gear tooth passage in motor feedback systems inside industrial ovens or near heat-generating machinery. IC Role / Device Role / Timing Role: Digital edge-triggered position sensor providing open-collector-compatible pulse output synchronized to mechanical rotation. Use Value: −55°C to +100°C operation eliminates need for external thermal shielding; 1.0 mA IC(ON) drives standard logic inputs directly without amplification. | Use Scenario: Monitoring belt slippage or jam conditions in food processing lines where steam cleaning and ambient heat exceed 85°C. IC Role / Device Role / Timing Role: Non-contact presence detector verifying object transit across fixed conveyor zones. Use Value: Conductive housing withstands repeated 230°C steam sterilization cycles; IR-filtering prevents misreads from overhead lighting. |
| Automotive Throttle Position Feedback | Heavy-Duty Appliance Door Interlock |
Use Scenario: Sensing throttle plate angle in engine compartments subject to under-hood temperatures up to 95°C. IC Role / Device Role / Timing Role: Analog-approximating digital switch used with calibrated cam profiles to infer angular position. Use Value: Guaranteed operation at +100°C ambient enables direct mounting near intake manifolds; 30 V VCEO tolerates battery transients. | Use Scenario: Verifying oven or washer door closure before initiating high-power heating cycles in commercial appliances. IC Role / Device Role / Timing Role: Safety-critical interlock switch confirming physical barrier integrity prior to energy activation. Use Value: Electrically conductive housing meets IEC 60335 leakage current requirements; 4.0 mm slot accommodates robust mechanical actuator design. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar optical interrupter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Vishay TCST2103 | Smaller 3.2 mm slot; 0.5 mA IC(ON); −40°C to +85°C operating range. | Limited to lower-temperature industrial controls; insufficient for under-hood or oven applications. | Select only if thermal budget allows <85°C ambient and mechanical clearance permits narrower slot. |
| Lite-On L-6320 | 4.2 mm slot; phototransistor (not photodarlington); 0.5 mA IC(ON); −25°C to +85°C. | Lower gain output requires external amplification; not rated for extreme temperature exposure. | Choose only for cost-sensitive, non-extreme-temperature applications where higher LED drive current is acceptable. |
Compared with TCST2103 and L-6320, the QCK3 uniquely supports −55°C to +100°C operation with 1.0 mA guaranteed output current and a 4.0 mm slot-making it the only option qualified for high-reliability, high-temperature industrial and automotive sensing where thermal margin and mechanical robustness are critical.
Availability
QCK3 is available at Aetrix Electronics and suitable for industrial rotary encoders, high-temperature conveyor belt sensors, and automotive throttle position feedback systems requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for QCK3 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
Fairchild Semiconductor was a U.S.-based analog and power semiconductor manufacturer, acquired by ON Semiconductor in 2016. Known for rugged optoelectronic and power devices with strong industrial reliability heritage.
The QCK3 belongs to Fairchild's photodarlington optical interrupter product line, engineered specifically for non-contact position and presence detection in thermally demanding surface-mount applications.
FAQ
What is the maximum operating temperature of the QCK3?
The QCK3 has a specified operating temperature range of −55°C to +100°C. This rating is validated per Fairchild's absolute maximum ratings table and enables deployment in high-heat environments such as engine compartments, industrial ovens, and sterilization equipment. The QCK3 maintains functional performance within this full range without derating, unlike many competing optical switches limited to +85°C.
Does the QCK3 require external current-limiting resistors for the LED?
Yes, the QCK3 requires an external series resistor on the LED anode (PIN 2) to limit forward current to ≤50 mA. At typical 5 mA drive for nominal IC(ON) output, a resistor value is calculated using VF ≈ 1.4 V and supply voltage. The QCK3 itself does not integrate current regulation, so proper resistor selection is essential to ensure longevity and consistent optical coupling in the QCK3.
Is the QCK3 compatible with lead-free reflow soldering processes?
Yes, the QCK3 is explicitly qualified for lead-free reflow with a peak temperature of 230°C for 5 seconds, as documented in the Fairchild datasheet. Its housing material and lead finish are engineered to withstand this thermal profile without delamination or warping, making the QCK3 suitable for modern RoHS-compliant manufacturing lines without process modification.
What is the function of the conductive housing in the QCK3?
The QCK3 housing is electrically conductive and serves dual purposes: it acts as an EMI shield to reduce optical crosstalk and electrical noise coupling into the photodarlington sensor, and it enhances thermal conduction away from the die during high-ambient operation. This feature is explicitly noted in the datasheet notes and contributes to the QCK3's stability in electrically noisy industrial settings.
How does the QCK3 differ from the QCK4 variant?
The QCK4 shares identical packaging, pinout, and thermal specifications with the QCK3 but delivers higher optical coupling: 3.0–15.0 mA IC(ON) vs. QCK3's 1.0 mA minimum. Both are slotted photodarlington interrupters, but the QCK3 is selected where lower sensitivity and tighter output consistency are preferred-such as in safety-critical interlocks where over-sensitivity could cause nuisance trips. The QCK3 remains functionally distinct and not interchangeable with QCK4 without circuit validation.
QCK3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- 4-SMD, Gull Wing
- Packaging:
- Tube
- Product Status:
- Obsolete
- Sensing Distance:
- 0.157" (4mm)
- Sensing Method:
- Through-Beam
- Output Configuration:
- Photodarlington
- Current - DC Forward (If) (Max):
- 50 mA
- Current - Collector (Ic) (Max):
- 40 mA
- Voltage - Collector Emitter Breakdown (Max):
- 30 V
- Response Time:
- -
- Operating Temperature:
- -40°C ~ 100°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
QCK3 FAQ
1.How can I place an order for QCK3 through Aetrix?
Please submit a Request for Quotation (RFQ) for QCK3 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 QCK3 reliable?
The price and inventory of QCK3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for QCK3 is usually 5 days.
3.What payment methods are accepted for QCK3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for QCK3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for QCK3?
QCK3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your QCK3 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 QCK3?
For technical support, including QCK3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your QCK3 requirements.
6.How does Aetrix verify that QCK3 is sourced from the original manufacturer or authorized distributors?
All QCK3 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 QCK3 meets industry standards.
7.What is the process for return or replacement of QCK3?
All QCK3 units undergo pre-shipment inspection (PSI). If there is an issue with QCK3, 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 QCK3 part is unused and in its original packaging.
Return procedure for QCK3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
QCK3 Tags
-
GP1S094HCZ0F
SHARP/Socle Technology
-
GP1S092HCPIF
SHARP/Socle Technology
-
GP1S396HCPSF
SHARP/Socle Technology
-
LTH-301-07
Lite-On Inc.
-
RPI-352
Rohm Semiconductor
-
RPI-0226
Rohm Semiconductor
-
TCPT1300X01
Vishay Semiconductor Opto Division
-
EE-SX1320
Omron Electronics Inc-EMC Div
-
TCUT1300X01
Vishay Semiconductor Opto Division
-
EE-SX1103
Omron Electronics Inc-EMC Div
-
H22A1
Isocom Components 2004 LTD
-
EE-SX1041
Omron Electronics Inc-EMC Div
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