CVT
Newbie level 4
precision current source
Hi Everyone
I have not being a member of edaboard for a long time so please inform me if I can place this post in a better place. I thought that this would be a good place since PIN diode are used a lot in RF applications, although this is not an RF application.
MY NEED
I need a good source of information (Technical or Application notes) on PIN Photodiodes. I have searched in google with no success. I would also like to know where I can get a hold of a spice model. Are there companies that provide spice models for PIN Photodiodes? I suspect that I will have to create my own model from a datasheet and for that I will need to a good understanding of how these diodes work. The control signal (optical input) will be a 100 ns pulses a rate varying from 10Hz to 5 Mhz.
I have identified the PC1-6 as the best candidate thus far for my application, low leakage current. **broken link removed**
BACKGROUND
I want to use it in a design as a VERY accurate, EXTREMELY “low leakage current” current source. The reason for it being a Photodiode is so that I can control it (on/off @ fixed on current) with an optical feedback signal. I want to use it to discharge a capacitor in a Charge Recycling Integrator circuit. This type of circuit is used to integrate charge (current) over a very wide dynamic range form 10pA to 10uA. It is clear that with a 10pA signal current flowing into the charging capacitor a leakage of say 50 pA from the supposedly of current source connected to it will give large errors. I have considered usin silicon switches (MESFETS) to connect a current source to the capacitor to discharge it but these cause even bigger errors at low current measurements due to the large injection charges when the MESFET switches.
Any help will be much appreciated
Thanks
Chris
Hi Everyone
I have not being a member of edaboard for a long time so please inform me if I can place this post in a better place. I thought that this would be a good place since PIN diode are used a lot in RF applications, although this is not an RF application.
MY NEED
I need a good source of information (Technical or Application notes) on PIN Photodiodes. I have searched in google with no success. I would also like to know where I can get a hold of a spice model. Are there companies that provide spice models for PIN Photodiodes? I suspect that I will have to create my own model from a datasheet and for that I will need to a good understanding of how these diodes work. The control signal (optical input) will be a 100 ns pulses a rate varying from 10Hz to 5 Mhz.
I have identified the PC1-6 as the best candidate thus far for my application, low leakage current. **broken link removed**
BACKGROUND
I want to use it in a design as a VERY accurate, EXTREMELY “low leakage current” current source. The reason for it being a Photodiode is so that I can control it (on/off @ fixed on current) with an optical feedback signal. I want to use it to discharge a capacitor in a Charge Recycling Integrator circuit. This type of circuit is used to integrate charge (current) over a very wide dynamic range form 10pA to 10uA. It is clear that with a 10pA signal current flowing into the charging capacitor a leakage of say 50 pA from the supposedly of current source connected to it will give large errors. I have considered usin silicon switches (MESFETS) to connect a current source to the capacitor to discharge it but these cause even bigger errors at low current measurements due to the large injection charges when the MESFET switches.
Any help will be much appreciated
Thanks
Chris