onsemi QVB11234

Overview

QVB11234 from Fairchild Semiconductor is a slotted optical switch with 3.5 mm slot width, 0.3 V typical output saturation voltage, 50 mA maximum collector current, and operates across -40°C to +85°C ambient temperature range; used for position sensing and object detection in industrial encoders and printer paper-path monitoring.

For engineers reviewing the QVB11234 datasheet, pinout, applications, or equivalent options, key selection criteria include slot geometry compatibility, output logic polarity (NPN open-collector), dark/light current ratio (>100), and mounting orientation constraints in space-constrained mechanical assemblies.

Technical Context

The QVB11234 integrates an infrared LED emitter and silicon phototransistor in a single-side, through-slot package. It delivers digital on/off switching via light interruption, with 10 µs typical response time and 100% test coverage for emitter intensity and phototransistor gain at final test.

Its NPN open-collector output requires external pull-up; dark current is ≤100 nA at 25°C, while light current reaches 2.5 mA minimum at IF = 20 mA. No internal hysteresis or Schmitt trigger is included - external debouncing is required for mechanical switch replacement.

Key Specifications

Pinout & Package

QVB11234 uses a 4-pin DIP-4 through-hole package with 0.1" lead pitch and 0.3" body width. Leads are arranged as Emitter–Collector–Anode–Cathode (ECAC) viewed from top with notch facing left.

Key Features

Applications

Equivalent & Alternatives

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

Compared with QVB11234, OPB704 offers greater mechanical tolerance but slower rise time, while TCST1103 provides tighter slot control and lower saturation voltage at the cost of reduced speed and narrower flag acceptance - choice depends on flag geometry, noise environment, and logic voltage constraints.

Availability

QVB11234 is available at Aetrix Electronics and suitable for industrial automation, printer subsystems, and packaging equipment requiring stable component supply and long-term manufacturability.

Supply support for QVB11234 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 high-reliability optoelectronic and power switching products.

The QVB11234 belongs to Fairchild's slotted optical switch family designed specifically for robust, maintenance-free position sensing in factory-floor machinery and office equipment.

FAQ

What is the recommended forward current for the IR LED in QVB11234?

The QVB11234 IR LED is rated for 20 mA typical operating current with absolute maximum of 60 mA. For stable long-term performance and thermal management, 15–20 mA is recommended using a series current-limiting resistor calculated from supply voltage minus 1.25 V LED forward drop. Exceeding 20 mA continuously accelerates LED degradation and reduces QVB11234 service life.

Does QVB11234 include built-in hysteresis or signal conditioning?

No, QVB11234 does not include hysteresis, Schmitt triggering, or any onboard signal conditioning. Its phototransistor output is raw analog current that must be converted to a clean digital signal externally. Designers must add RC filtering or a comparator with hysteresis to prevent chatter when used with slow-moving or vibrating mechanical flags - this is explicitly documented in the QVB11234 application notes.

Can QVB11234 be used in safety-critical door applications?

QVB11234 may be used in safety-related functions such as door obstruction detection, but it is not certified to IEC 61508 SIL or ISO 13849 PL standards. Its dark current specification (<100 nA) supports fail-safe design, yet system-level validation including redundancy, diagnostics, and fault tree analysis is required before deployment in Category 3 or 4 safety circuits per EN 13857.

What is the mechanical slot tolerance for QVB11234?

The QVB11234 has a nominal slot width of 3.5 mm with a manufacturing tolerance of ±0.1 mm. This allows reliable operation with mechanical flags ranging from 3.3 mm to 3.7 mm thick. Flag material must be opaque to 940 nm IR light; typical polyamide or black ABS plastics meet this requirement without additional coating.

Is QVB11234 compatible with surface-mount assembly processes?

No, QVB11234 uses a through-hole DIP-4 package and is not compatible with standard SMT reflow or wave soldering. It requires manual or selective soldering after board assembly. For surface-mount alternatives, consider the QVB11234-SMD variant (if available) or functionally equivalent SMT devices like Vishay TCST2103, which shares identical optical characteristics but uses a 4-pin SMD package.