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Product details
Overview
QCK4 from Fairchild Semiconductor is a surface-mount slotted photodarlington optical interrupter switch with GaAs LED emitter and silicon photodarlington sensor across a 4.0 mm gap, rated for -55°C to +100°C operation, 30 V VCEO, and 3.0–15.0 mA on-state collector current, used in high-temperature industrial position sensing.
For engineers reviewing the QCK4 datasheet, pinout, applications, or equivalent options, key selection criteria include operating temperature range, optical gap tolerance, photodarlington current gain, saturation voltage under defined drive conditions, and lead coplanarity compliance for reflow soldering.
Technical Context
The QCK4 integrates a GaAs infrared LED emitter and a silicon photodarlington detector in a single-piece conductive housing with 4.0 mm optical gap, enabling non-contact object detection via light interruption. Its design supports full-surface-mount assembly with flush PCB seating during reflow.
It operates within -55°C to +100°C ambient, with absolute maximum ratings including 50 mA forward current (emitter), 30 V VCEO (sensor), and linear power derating above 25°C (1.33 mW/°C). The housing is infrared-transparent and visibly tinted to suppress ambient light interference.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Operating Temp Range | -55°C to +100°C - enables use in automotive under-hood, industrial motor control, and aerospace environments without thermal derating penalties. |
| Optical Gap | 4.0 mm (0.157") - defines mechanical clearance for target insertion; fixed physical separation ensures consistent switching threshold. |
| IC(ON) | 3.0–15.0 mA at IF = 5.0 mA, VCE = 5 V - provides reliable digital output current margin for TTL/CMOS interface without external amplification. |
| VCE(SAT) | ≤1.0 V at IF = 5 mA, IC = 5.0 mA - ensures low-voltage drop in saturated switching state, minimizing power loss in logic-level interfacing. |
| VCEO | 30 V - supports direct connection to 24 V industrial control rails with safety margin against transients. |
| Lead Coplanarity | ≤0.006" - guarantees uniform solder joint formation during automated reflow, critical for high-yield SMT manufacturing. |
Pinout & Package
Package: 4-pin surface-mount slotted interrupter in conductive thermoplastic housing, dimensions 0.527" × 0.370" × 0.185", lead pitch 0.100", with infrared-transparent tinted window.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PIN 1 | Cathode | LED cathode - connects to ground or current sink; polarity-sensitive for proper emitter biasing. |
| PIN 2 | Anode | LED anode - accepts forward drive current up to 50 mA; requires series resistor for IF control. |
| PIN 3 | Emitter | Photodarlington emitter - tied internally to sensor substrate; common reference for collector output. |
| PIN 4 | Collector | Photodarlington collector - open-collector output node delivering IC(ON); requires pull-up for logic-high assertion. |
Key Features
| Feature | Design Value |
|---|---|
| Single-piece conductive housing | Reduces part count and assembly cost while providing EMI shielding and mechanical rigidity for harsh environments. |
| Infrared-transparent, visible-light-tinted window | Blocks ambient visible light interference while transmitting 940 nm LED emission, improving signal-to-noise ratio in daylight-exposed applications. |
| 4.0 mm fixed optical gap | Eliminates alignment variability during PCB placement; ensures repeatable actuation distance without field calibration. |
| Flush-mount lead form | Enables coplanar reflow soldering on standard SMT lines without tombstoning or skew, supporting high-volume automated assembly. |
Applications
| Industrial Motor Commutation | Automotive Throttle Position Sensing |
|---|---|
Use Scenario: Detecting rotor slot passage in brushless DC motor controllers operating near engine blocks. IC Role / Device Role / Timing Role: Optical interrupter providing edge-triggered commutation timing signals synchronized to motor rotation. Use Value: -55°C to +100°C rating ensures stable switching performance inside hot engine compartments without thermal drift or failure. | Use Scenario: Monitoring throttle plate angular position in drive-by-wire systems exposed to under-hood thermal cycling. IC Role / Device Role / Timing Role: Non-contact position detector generating discrete ON/OFF states corresponding to throttle open/closed thresholds. Use Value: Fixed 4.0 mm gap and IR-filtered window prevent false triggering from heat-induced air shimmer or sunlight ingress. |
| Factory Automation Limit Switching | High-Temp Conveyor Belt Object Detection |
Use Scenario: End-of-travel detection for robotic arms in foundry or glass-manufacturing cells where ambient exceeds 85°C. IC Role / Device Role / Timing Role: Slotted switch confirming mechanical actuator reach by beam interruption, feeding PLC input modules. Use Value: Conductive housing and lead coplanarity ensure long-term reliability and solder joint integrity during repeated thermal shock cycles. | Use Scenario: Detecting metal or plastic parts on conveyor belts passing through ovens or curing zones. IC Role / Device Role / Timing Role: Photodarlington-based presence sensor delivering robust digital output despite ambient IR radiation from heated surfaces. Use Value: 30 V VCEO and 15 mA IC(ON) allow direct interfacing with 24 V industrial IO modules without level-shifting circuitry. |
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 optical gap; 50°C to +100°C operating range; lower IC(ON) (0.5–3.0 mA); TO-5 package with leads. | Better suited for compact enclosures with tighter mechanical tolerances; not rated for -55°C cold start. | Select when space-constrained but thermal extremes are less severe; verify mechanical fit and cold-start functionality. |
| Lite-On LTH-1550-01 | 4.2 mm optical gap; -40°C to +85°C rating; higher VCEO (70 V); DIP-4 package with gull-wing leads. | Higher voltage tolerance supports 48 V systems; wider gap eases mechanical integration but reduces positional resolution. | Choose for 48 V industrial controls requiring extended voltage headroom; confirm PCB footprint compatibility. |
Compared with TCST2103 and LTH-1550-01, the QCK4 uniquely combines -55°C cold-start capability, 4.0 mm precision gap, and surface-mount flush-lead geometry-making it optimal for high-reliability SMT deployments in thermally aggressive environments where both low-temperature startup and reflow compatibility are mandatory.
Availability
QCK4 is available at Aetrix Electronics and suitable for industrial motor control, automotive throttle sensing, factory automation limit switching, and high-temp conveyor belt detection requiring stable component supply across extended temperature ranges.
Supply support for QCK4 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 IC manufacturer acquired by ON Semiconductor in 2016; known for high-reliability optoelectronics and ruggedized discrete components.
The QCK3/QCK4 series belongs to Fairchild's photointerrupter product line, engineered specifically for surface-mount optical sensing in extreme-temperature industrial and automotive applications where traditional through-hole devices fail.
FAQ
What is the maximum operating temperature for the QCK4?
The QCK4 has a specified operating temperature range of -55°C to +100°C, verified per its Absolute Maximum Ratings table. This allows deployment in under-hood automotive locations and industrial equipment near motors or furnaces. The QCK4 maintains stable photodarlington gain and LED efficiency across this full span without derating until ambient exceeds 25°C, where linear power derating of 1.33 mW/°C applies.
Does the QCK4 require external current limiting for the LED emitter?
Yes, the QCK4 LED emitter requires an external series current-limiting resistor. With a forward voltage ≤1.4 V at 20 mA and absolute maximum forward current of 50 mA, the resistor value must be selected based on the drive voltage and desired IF (typically 5–20 mA). For example, at 5 V supply and 10 mA target, a 360 Ω resistor ensures safe operation. The QCK4 itself contains no internal current regulation.
Is the QCK4 pin-compatible with the QCK3?
No, the QCK4 is not pin-compatible with the QCK3 in functional terms despite identical pinout numbering. While both share the same 4-pin configuration and mechanical footprint, their coupled electrical characteristics differ significantly: QCK3 delivers 1.0–? mA IC(ON), whereas QCK4 delivers 3.0–15.0 mA. Substituting one for the other without circuit review risks insufficient output drive or excessive loading on downstream logic.
What does the "tinted" housing of the QCK4 achieve?
The QCK4 housing is tinted to attenuate visible light while remaining transparent to near-infrared (940 nm) emitted by its GaAs LED. This spectral selectivity prevents false triggering from ambient daylight, fluorescent lighting, or indicator LEDs in the same enclosure. The tinting directly improves noise immunity in mixed-light industrial settings-confirmed by its inclusion in Fairchild's official features list and optical test conditions.
Can the QCK4 be used in life support systems?
No, the QCK4 is explicitly excluded from life support applications per Fairchild's Life Support Policy. The datasheet states: "FAIRCHILD'S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT EXPRESS WRITTEN APPROVAL." Designers must obtain formal written authorization from ON Semiconductor (Fairchild's successor) before considering QCK4 in any system where failure could result in injury or sustain life.
QCK4 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
QCK4 FAQ
1.How can I place an order for QCK4 through Aetrix?
Please submit a Request for Quotation (RFQ) for QCK4 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 QCK4 reliable?
The price and inventory of QCK4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for QCK4 is usually 5 days.
3.What payment methods are accepted for QCK4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for QCK4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for QCK4?
QCK4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your QCK4 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 QCK4?
For technical support, including QCK4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your QCK4 requirements.
6.How does Aetrix verify that QCK4 is sourced from the original manufacturer or authorized distributors?
All QCK4 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 QCK4 meets industry standards.
7.What is the process for return or replacement of QCK4?
All QCK4 units undergo pre-shipment inspection (PSI). If there is an issue with QCK4, 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 QCK4 part is unused and in its original packaging.
Return procedure for QCK4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
QCK4 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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