DAC5688: CONFIG26 io_1p8_3p3 default value

Nicholas Vrahoretis

Part Number: DAC5688
Other Parts Discussed in Thread: SN74AXC4T774

There's no information in the datasheet for default values for the CMOS IO threshold values. I'm looking to interface this DAC with a 1.8V IO FPGA bank

over 1 year ago

0 Matthew Kramer over 1 year ago

TI__Intellectual 1660 points

Good Morning,

Page 22 of the datasheet Shows the default value for register CONFIG26. Bit 7 (io_1p8_3p3) has a default value of 0, indicating 3.3V IO is default. You'll need to program bit 7 of CONFIG26 to 1 to use with a 1.8V FPGA.

Regards,

Matt

0 Nicholas Vrahoretis over 1 year ago in reply to Matthew Kramer

Prodigy 30 points

Thanks for the help Matt. So I need a level shifter to set the threshold to 1.8V? Interesting

0 Chase W over 1 year ago in reply to Nicholas Vrahoretis

TI__Mastermind 18145 points

Hi Nicholas,

Yes, it seems that is the case. We suggest to use a level shifter to convert 1.8V to 3.3V and to simply use this device with IO levels set to 3.3V. An example level shifter which we use often for SPI is the SN74AXC4T774.

Regards, Chase

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DAC5688: CONFIG26 io_1p8_3p3 default value