High Linearity
Position Sensing Detector
1L20 -
one dimensional PSD
The SiTek 1L20 PSD functions accor-
ding to the Lateral Effect-Photodiode prin-
ciple. It is an analogue device and therefore
displays excellent position resolution. The
resolution is determined by the system sig-
nal-to noise ratio.
The 1L20 is operated in the biased mode.
Typical applications include: distance and
height measurement, alignment, position
and motion measurements and vibration
studies.
Special UV- or YAG-enhanced and
Nuclear versions are available.
Parameter
Symbol
Min.
Typ.
Max.
U n i t
Active area
20 x 3
mm
2
Position non-linearity
0,1
0,2
%()
Detector resistance
R
det
40
50
80
k
Dark current
I
d
50
250
nA
Noise current
I
noise
0,5
1,0
pA/sHz
Responsivity
r
0,63
A/W
Capacitance
C
j
45
55
pF
Rise time (10-90%)
t
r
0,5
1,0
s
Reverse voltage (bias)
V
r
5
15
20
V
Thermal drift
20
100
ppm/C
Maximum ratings
Reverse voltage
V
R-max
30
V
Operating temperature
T
oper
70
C
Storage temperature
T
stg
100
C
Test conditions:
Package:
Room temperature 23C. Reverse voltage 15 V. Light-source wavelength 940 nm.
Position non-linearity and thermal drift are valid within 80% of the detector length.
22-pin ceramic DIL-package, 31,8 x 9,9 mm
2
, with protective window.
Distributor: Laser Components GmbH, Germany, Phone: 0049 (0)8142 28640, www.lasercomponents.com
1 L 2 0
Pin configuration: 12
Bias
Note:
Outputs Y1, Y2 are interchangeable.
11
Output Y1
The anodes Y1, Y2 must be
22
Output Y2
at negative potential compared
1-10 & 13-21 N/C
to the cathode.
Application information:
The inherent resolution of a PSD is very good. It is proven to be better than one part in one million. The per-
formance of a PSD based measurement system is thus limited by its mechanical, optical and electrical components.
To get the best performance you have to consider:
Modulated light source. Modulation makes it possible to avoid influence of other light sources.
Stable temperature.
Mechanical stable system.
High optical resolution.
High resolution in division of the sum- and difference signals.
Resolution, optical sensitivity and measurement speed are related to each other in the PSD measurement
system and you have to make the proper choices and tradeoffs for your system. Further information as schematics
of a recommended hook-up is obtainable from your local distributor or from SiTek Electro Optics AB.
SiTek PSD Position Measurement electronic boards:
For most position measurement applications the SiTek PM-kit offers a complete and easy-to use solution. It is
a series of general purpose, high performance, low-noise electronic boards designed for SiTek PSD. You can
easily build your own measurement system using our PM-kit. Further information is obtainable from your local
distributor or from SiTek Electro Optics AB.
Information in this data sheet is believed to be reliable. However, no responsibility is assumed for possible inaccuracies or omissions.
Specifications are subjected to change without notice.
Distributor: Laser Components GmbH, Germany, Phone: 0049 (0)8142 28640, www.lasercomponents.com
Issue: 01 /02 / V2 / pdf / sitek / 1l20.pdf
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