onsemi QVL25335

Overview

QVL25335 from Fairchild Semiconductor is a slotted optical switch integrating an infrared LED emitter and an NPN silicon photodarlington detector in a single 4-pin injection-molded housing. It delivers 5.0 mA on-state collector current at 10 mA LED drive, 30 V collector-emitter breakdown, and operates across –40°C to +85°C - used for object detection in industrial limit switches and printer paper-path sensing.

For engineers reviewing the QVL25335 datasheet, pinout, applications, or equivalent options, key selection criteria include its 20 mm slot width, visible-light-filtering sensor, high CTR, PC board mount configuration, and 1.0 V saturation voltage under 2 mA load - all critical for reliable opto-isolated presence detection in space-constrained assemblies.

Technical Context

The QVL25335 functions as a through-beam interrupt sensor: IR light from the internal LED crosses a 20 mm air gap and is detected by the photodarlington output stage. Its photodarlington architecture provides high current transfer ratio (CTR), enabling direct interface with logic-level inputs without external amplification.

Electrical isolation is achieved via physical slot separation; no galvanic connection exists between input (LED) and output (phototransistor) sides. The device supports DC or pulsed operation, with absolute max ratings of 50 mA forward current and 40 mA collector current - derated linearly above 25°C.

Key Specifications

Pinout & Package

Package: 4-pin DIP-style slotted optical switch housing with 0.100" pin pitch, 20 mm slot width, and PC board mount orientation. Dimensions comply with Fairchild DS300380 mechanical drawing.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar slotted optical switch applications.

Compared with OPB937 and TCST2103, the QVL25335 uniquely balances 20 mm mechanical tolerance, high-output photodarlington gain, and surface-mount-compatible DIP packaging - making it optimal for mid-volume industrial and office equipment requiring reliability, serviceability, and automated manufacturing.

Availability

QVL25335 is available at Aetrix Electronics and suitable for industrial limit switches, printer paper-path sensing, copy machine document feeders, and vending machine door interlocks requiring stable component supply and long-term production continuity.

Supply support for QVL25335 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 discrete semiconductor manufacturer, acquired by ON Semiconductor in 2016; legacy products like QVL25335 remain widely supported in industrial design libraries.

The QVL25335 belongs to Fairchild's slotted optical switch product line, engineered for robust, maintenance-free object detection in electromechanical systems where contactless sensing and high noise immunity are essential.

FAQ

What is the maximum continuous forward current rating for the QVL25335?

The QVL25335 has a maximum continuous forward current (IF) rating of 50 mA per its Absolute Maximum Ratings table. This applies to the integrated infrared LED emitter. Operation above this value risks permanent degradation of the LED junction. Derating is not required below 25°C, but thermal management becomes critical above that temperature - the QVL25335 datasheet specifies linear derating of 1.67 mW/°C for power dissipation.

Does the QVL25335 require an external pull-up resistor on its output?

Yes, the QVL25335 output is an open-collector photodarlington configuration. A pull-up resistor must be connected between PIN 3 (collector) and the positive supply rail to generate a valid logic-high level when the slot is obstructed. Typical values range from 2.2 kΩ to 10 kΩ depending on rise time and drive strength requirements. The QVL25335 itself does not include internal pull-up circuitry.

Can the QVL25335 operate reliably under fluorescent lighting conditions?

Yes, the QVL25335 incorporates a sensor filter specifically designed to attenuate visible light while transmitting near-infrared wavelengths emitted by its internal LED. This spectral selectivity minimizes false triggering caused by ambient fluorescent or incandescent lighting - a key feature confirmed in the device's "Features" section and validated in application testing per Fairchild DS300380.

What is the recommended soldering profile for the QVL25335?

The QVL25335 supports both hand-soldering and flow soldering. For iron soldering, use 240°C for up to 5 seconds; for wave soldering, use 260°C for up to 10 seconds. The datasheet specifies RMA flux and recommends methanol or isopropanol for post-solder cleaning. Keep the soldering iron tip at least 1.6 mm from the housing to prevent thermal damage to the plastic package or internal optics.

Is the QVL25335 RoHS compliant?

The original QVL25335 datasheet (DS300380, issued 2001) predates RoHS legislation and does not declare compliance. However, ON Semiconductor - which assumed Fairchild's product lines - confirms legacy equivalents such as the FODM8071 are RoHS-compliant. For new designs requiring RoHS, consult Aetrix Electronics for verified drop-in replacements; the QVL25335 itself should be treated as non-RoHS unless explicitly requalified and marked.