Programmable clock generator
Phil Pemberton
Posts: 16
Hi,
Does anyone happen to know what chip Parallax used on the SX to generate the programmable oscillator output signal? I'm designing a 'reimplementable coprocessor' (which is just a fancy way of saying 'a really fast FPGA hooked up to a USB port') and need to generate a variable clock signal of up to 100MHz for the FPGA. I was looking at the Dallas EconOscillator chips, but DigiKey has them listed as 'Non-stock' ("you're gonna need to buy 6,000 of those, sir") and Maxim/Dallas Direct are showing a 12-week leadtime on them.
Ideally I want a chip with no EEPROM on it with a frequency divider that I can change on-the-fly. The old Cypress ICD2053B would have been ideal, but it looks like it's been obsolete since the late '90s.
Does anyone know what chip Parallax used on the SX-Key? Seems like a variant of the osc circuit on the 'Key would be ideal for my needs...
Thanks.
Does anyone happen to know what chip Parallax used on the SX to generate the programmable oscillator output signal? I'm designing a 'reimplementable coprocessor' (which is just a fancy way of saying 'a really fast FPGA hooked up to a USB port') and need to generate a variable clock signal of up to 100MHz for the FPGA. I was looking at the Dallas EconOscillator chips, but DigiKey has them listed as 'Non-stock' ("you're gonna need to buy 6,000 of those, sir") and Maxim/Dallas Direct are showing a 12-week leadtime on them.
Ideally I want a chip with no EEPROM on it with a frequency divider that I can change on-the-fly. The old Cypress ICD2053B would have been ideal, but it looks like it's been obsolete since the late '90s.
Does anyone know what chip Parallax used on the SX-Key? Seems like a variant of the osc circuit on the 'Key would be ideal for my needs...
Thanks.
Comments
the current SX-Keys use the Cypress ICD2053B chip but as you know, this device is obsolete. The new SX-Key will come with an ICS307-02 chip, so this might be a device you should have a look at.
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Greetings from Germany,
G
I'm looking at the Cypress Cy22150 and Cy22393 at the moment. The parameter calculation algorithm is available (it's on the Cypress Knowledgebase site and IIRC it's in the datasheet too), and it seems to be able to manage an output frequency of 1 to 200MHz, which is ideal for what I want to do.
Interestingly enough, Digikey only seem to be stocking the lead-tinned versions of those parts, and not the RoHS/Pb-free versions... Hmm.