The SXUVPS4 (part number ODD-SXU-013) and SXUVPS4C (ODD-SXU-023) are quadrant photodiodes from Opto Diode, a division of ITW, manufactured in Camarillo, California. Each puts a 2.51 mm-diameter (Ø0.099 in) circular active area, divided into four 1.25 mm² quadrants, in a TO-5 five-pin package — 5 mm² of detection area whose four photocurrents can be compared to read beam position. The SXUVPS4C datasheet lists a windowless package and prints a responsivity figure at 254 nm; the SXUVPS4 datasheet makes no window statement and gives responsivity only as a curve. The category page lists the SXUVPS4C as a “Quadrant UV Enhanced Photodiode.” Specifications below are from the two controlled datasheets, both Revision October 10, 2024.
Two models, one quadrant geometry
Both models share the same detector layout: one circular active area split into quadrants Q1–Q4 by 0.001 in (25 µm) gaps. The SXUV product-category page lists the SXUVPS4 as “Circular Active Area (4 Quadrants)” and the SXUVPS4C as a “Quadrant UV Enhanced Photodiode”; the differences the datasheets print are below.
| Model | Part number | What its datasheet specifies | Datasheet |
|---|---|---|---|
| SXUVPS4 | ODD-SXU-013 | Ships with a temporary cover protecting the photodiode and wire bond; capacitance 500 pF max per element at VR = 0 V; responsivity given as a typical photon-responsivity curve | |
| SXUVPS4C | ODD-SXU-023 | Windowless package; responsivity 0.02 A/W typ at 254 nm; capacitance 100 pF typ / 300 pF max per element; dark current 1 nA typ / 100 nA max at VR = ±18 V |
Specifications — per element, 25 °C
Both datasheets head their electro-optical tables “Per Element”: every value below describes one 1.25 mm² quadrant, not the whole device. Size front-end electronics on a single element.
| Parameter | Conditions | SXUVPS4 | SXUVPS4C |
|---|---|---|---|
| Active area | per element | 1.25 mm² typ | 1.25 mm² typ |
| Responsivity | SXUVPS4C: at 254 nm | see curve | 0.02 A/W typ |
| Shunt resistance | V = ±10 mV | 100 MΩ min | 100 MΩ min |
| Capacitance | VR = 0 V | 500 pF max | 100 pF typ / 300 pF max |
| Dark current | VR = ±18 V | not specified | 1 nA typ / 100 nA max |
| Response time | VR = 0 V (SXUVPS4: RL = 50 Ω) | 1 µs typ | 1 µs typ |
The SXUVPS4 datasheet gives the active-area condition as a radius callout, R.049 [1.25 mm]; the SXUVPS4C gives it as “Per Quadrant.” Both electro-optical tables are headed “Per Element.”
Both sheets print the same typical photon-responsivity curve, plotted from 1 nm to 1000 nm. The SXUVPS4C datasheet adds two more curves — capacitance versus voltage and dark current versus voltage — each plotted from 0 to 25 V, showing capacitance falling steeply as bias is applied. Thermal limits are identical for both models: –10 to +40 °C ambient, –20 to +80 °C in nitrogen or vacuum, and 260 °C lead soldering (0.08 in from the case, 10 seconds).
How a quadrant photodiode reads beam position
A quadrant layout is the standard detector geometry for beam centering. A spot centered on the pattern illuminates all four quadrants equally, so the four photocurrents match; any displacement shifts light onto some quadrants at the expense of the others. Summing the currents pairwise — left pair versus right pair, top pair versus bottom pair — and dividing each difference by the total gives two normalized position signals that are insensitive to overall intensity changes. As a general rule for quadrant detectors — neither datasheet specifies a spot size — the beam is normally sized to sit within the active circle while spanning the inter-quadrant gaps, so that all four quadrants are illuminated near center. The SXUVPS4C package drawing labels the electrical arrangement: the four cathodes on pins 1–4 and a common anode on pin 5, so each quadrant is read out against a shared return.
Where they fit in the SXUV line
SXUV is Opto Diode’s radiation-hardened photodiode family, engineered to hold its response after exposure to EUV and UV conditions — the property that puts the family in dose and power monitoring roles — and the family is characterized for detection from 1 nm to 190 nm. The SXUVPS4 and SXUVPS4C datasheets specify no wavelength range of their own; their typical responsivity curve is plotted from 1 nm to 1000 nm. The quadrant models add position readout to the family’s stability: where a single-element detector like the SXUV100 reports how much radiation arrives, a quadrant device also reports where the beam sits. Both models appear in the detector tables of our photodiodes for space and astronomy guide, and the SXUV category page links a DigiKey listing for each of them.
Frequently asked questions
What is the difference between the SXUVPS4 and the SXUVPS4C?
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The SXUVPS4C datasheet lists “Windowless Package” as a feature and specifies responsivity at 254 nm (0.02 A/W typical per element), lower capacitance (100 pF typical / 300 pF max versus 500 pF max), and a dark current of 1 nA typical, 100 nA max at VR = ±18 V. The SXUVPS4 datasheet specifies no responsivity figure and no dark current, and notes that the part ships with a temporary cover protecting the photodiode and wire bond; it makes no statement about a window. Opto Diode’s SXUV category page describes the SXUVPS4C as a “Quadrant UV Enhanced Photodiode.” Both share the same four-quadrant, 5 mm² geometry and TO-5 five-pin package.
Are the published specifications per element or for the whole device?
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Per element. Both datasheets head their tables “Per Element,” so 1.25 mm² active area, 100 MΩ minimum shunt resistance, and the capacitance figures each describe one quadrant. The full device is 5 mm² across a 2.51 mm-diameter circular active area.
What is a quadrant photodiode used for?
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Reading beam position. Comparing the photocurrents of the four quadrants — left pair against right pair, top against bottom — gives normalized position signals, so the detector reports where a beam sits as well as how much light arrives. Equal currents on all four quadrants mean the beam is centered.
How should the SXUVPS4 be handled on receipt?
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It ships with a temporary cover protecting the photodiode and wire bond, and the datasheet directs users to review Opto Diode’s “Handling Precautions for IRD Detectors” before removing that cover — published on this site as Handling Precautions for AXUV, SXUV, and UVG Detectors. Opto Diode also publishes Proper Use of AXUV, SXUV, and UVG Detectors, which adds the operating envelope, an incoming functional check, and correct anode/cathode wiring to avoid photo-emission error. Storage and operation are rated -10 to +40 °C in ambient and -20 to +80 °C in nitrogen or vacuum.
Specifying a quadrant detector for beam position or alignment monitoring? Opto Diode typically responds to online requests within 1–2 business days.
Reviewed and updated August 2026.