SPC-PSD
High Speed Position Sensing Detector with Signal Processing Circuit
Features
- 400 kHz Bandwidth
- Analogue outputs of all sum and differential signals
- Laser trimmed resistors
- Inputs for external adjustment of offset voltages
- Good thermal tracking
- Small size
Applications
- Analogue PSD front-end in displacement measuring systems for OEM as well as evaluation purposes.
The SiTek SPC PSD is a PSD with a 400kHz attached signal processing circuit. The PSD currents are output as bipolar voltages representing the position and intensity of the centroid of a light spot on the PSD. The intensity signal can be used for external normalisation of the position (difference) signal in regard to light intensity dependence.
Inputs are available for external adjustment of offset voltages.
In order to obtain maximum precision, high reliability and small size the SPC electronics are built using thick film technology and laser trimmed resistors on a 20,5 x 20,5 mm2 ceramic substrate. The SPC PSD is delivered with surface mount or DIL Leads.
SPC PSD Models
One Dimensional SPC PSD Series
| Model No. | Pkg. Type | Active Area |
|---|---|---|
| 1L2.5 SPC-PSD | Surface Mount | 2.5 x 0.6mm |
| 1L5 SPC-PSD | Surface Mount | 5.0 x 1.0mm |
| 1L10 SPC-PSD | Surface Mount | 10.0 x 2.0mm |
Two Dimensional SPC PSD Series - Duolateral
| Model No. | Pkg. Type | Active Area |
|---|---|---|
| 2L2 SPC-PSD | Surface Mount | 2.0 x 2.0 mm |
| 2L4 SPC-PSD | Surface Mount | 4.0 x 4.0 mm |
| 2L10 SPC-PSD | Surface Mount | 10.0 x 10.0 mm |
Test conditions: Room temperature 23 degrees celsius, Power supply voltage + 15 V, Light source wavelength 940 nm. Position non-linearity are valid within 80 % of the detector length.
Package: 16 pin ceramic substrate, 20,5 x 20,5 mm2, with protective window.
Application Information
Inputs 2, 6, 7 and 14 are used for external offset compensating voltages. Such a voltage can, as shown in the figure, be derived from a voltage divider and connected to the SPC input through a suitable series resistor.