We would like to know about MP3430 - 90V step up converter

Hi Team,

We are designing a radiation detector using a Si- photodiode for detecting X ray for that we need to give a very high reverse bias voltage of around 75V to the diode. Since we a going to give such a high voltage only to reverse bias the diode there won’t be much current consumption . And the diode itself produce nano amps of current only.

We came across this IC MP3430 - 90V setp up converter with APD current monitoring. Can we disable the current monitoring feature. We have already designed an Charge amplifier circuit to convert the photdiode current into voltage. We only need to bias the diode with 50 - 75 V .Does this IC works without current monitoring feature.
It would be helpful if you suggest any IC that produce 75V from 5V input to reverse bias the diode and works in minimal load current.

Thanks

Hi,

Please let us know what should we do if we don’t use the current montoring feature of MP3430. (MONIN ,APD, RLIM,MON1, MON2 )Should I left these pins floating or should I tie to some voltage.

Also please suggest the layout, routing guidlines, PCB stack up to be used.

Design requirement:
Vin - 5V
Vout - 30V to 90V
Load current - in micro amps
Application - To Reverse bias the photodiode

What kind of filtering should I use in the output side for the mentioned load current?

Thanks

What an unclear datasheet. There is really no explanation of what is going on in the APD section. I would GUESS that there is a current regulator whose maximum current is set by Rilim and then for reasons that are unclear we are provided with not one but two current measurement pins, despite the fact that the Ilim pin also seems to have a voltage responsive to diode current.

It looks like the operation of the current regulation part and the voltage generation part are separate. Get a demo and see?