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Photodiode crams a lot into a small package

Edited by the Electronicstalk editorial team Sep 23, 2003

A new PIN photodiode sensor offers design flexibility by providing a broad range of high-performance features and specifications in compact, surface-mount packaging.

A new PIN photodiode sensor offers design flexibility by providing a broad range of high-performance features and specifications in compact, surface-mount packaging.

The QSB34 has a large surface area of 3 x 3mm and a reception angle of 120 degrees.

Its packaging creates an integral, transparent daylight filter that is optimised for reception of 880 to 940nm wavelength light.

These features provide outstanding sensitivity and reception and even with the filter, the flux response is typically 0.4A/W at 900nm.

The diode's low 25pF capacitance and small series resistance typically delivers a rise time and fall time of 20ns.

Dynamic signal range is typically 60dB, and the QSB34 also offers very good DC signal linearity and low noise.

Fairchild's QSB34 features a low profile (1.25mm height from mounting surface), and is available in two surface mount configurations: gullwing (QSB34GR) for top side mounting, and reversed X-bend (QSB34ZR) for under-board mounting.

The flat, low-profile package of the QSB34GR makes it well suited for use with an auxiliary lens for focused image sensing.

Additionally, the QSB34ZR can be mounted on the rear of the PCB allowing for inclusion of a screen for EMI shielding.

According to Fairchild's Infra-red Product Marketing Manager, Livio Lascu: "The QSB34 provides solutions for a wide variety of applications where a large area photodiode is required.

It may be paired with Fairchild's IR light emitting diodes (LED) to optimise performance for specific applications.

For example, the sensitivity and speed of a QSB34 photosensor make it an ideal companion for the higher radiant intensity of a QED123 LED in the critical operation of a smoke detector.

Likewise, the wide signal reception angle of a QSB34 photosensor, used in conjunction with the lower power consumption of a QED234 LED, make the pair ideal for remote control applications in set-top receivers, DVD players, and other consumer electronic products.

The QSB34 is also ideal for applications such as IR audio and video transmission and IR radiometric measurement systems".

Fairchild's QSB34 comes in lead-free packaging that meets or exceeds the requirements of the joint IPC/JEDEC standard J-STD-020B and is compliant with the European Union requirements, which will take effect in 2005.

Both configurations of this product are available in tape and reel quantities of 1000 units and can sustain an IR reflow temperature of 240C for a maximum of 5s.