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Rise time requirements of ADG3308

Question asked by AndrewC on Jul 9, 2018
Latest reply on Jul 18, 2018 by AndrewC

I am looking at using an ADG3308 for level translation between 5 and 3.3 V on a SPI interface between a microcontroller (5 V) and a MEMS accelerometer (3.3 V).

I notice that in the Theory of Operation, Input Driving Requirements section (top of second column, page 16 in Rev. E datasheet), it states:

To ensure correct operation of the ADG3308/ADG3308-1, the circuit that drives the input of the device should be able to ensure rise/fall times of less than 3 ns when driving a load consisting of a 6 kΩ resistor in parallel with the input capacitance of the ADG3308/ADG3308-1 channel.

I assume the low rise time is required to trigger the one-shot generator correctly.

The microcontroller I am using gives it's I/O port rise time as 10-25 ns, which seems to comparable to other MCUs I have looked at. Does this mean the ADG3308 will not work in my application? If so, is there an alternative part which can handle slower rise times?


Thanks in advance,