Hi..
One of the signal which is ( -3.3V to 0 ) need to clamp to level of 0V.
I can do that using the level shifter by using a voltage divider pulled up to Vref; but need to implement some other technique.
Basically I want to block (-3.3V to 0 ) range to ADC and allowing only ( 0 to +3.3VDC) signal to process.
ADC is referenced to +3.3VDC and negative reference is tied to GND internally.
It would be better to connect a series resistor to the input (say 10k) with a Schottky diode (cathode) to ground. That will avoid the offset voltage of the diode. The diode will limit the negative voltage to about 0.4-0.5V which should cause no problem.
What is the highest frequency of the voltage you are converting?
It would be better to connect a series resistor to the input (say 10k) with a Schottky diode (cathode) to ground. That will avoid the offset voltage of the diode. The diode will limit the negative voltage to about 0.4-0.5V which should cause no problem.
Sorry guys..
I wrongly mention -3.3V to 0 as signal swing.
Actual swing is -3.3V to 0 to +3.3V.
And I want to block that negative part of it.
Thanks for help buddy!!
Sorry guys..
I wrongly mention -3.3V to 0 as signal swing.
Actual swing is -3.3V to 0 to +3.3V.
And I want to block that negative part of it.
Thanks for help buddy!!
A simple 1K resistor in series with the ADC input is all thats required, the internal diodes will do the rest.
During the small [-0.7v] negative swing due to the internal clamp diode turn on voltage, the ADC will reads zero counts.
I am using 56F8037 Freescale Micro controller and data sheet recommends ADC Input as -0.3 to 4V as Analog Input Voltage Range.
I cant see details about internal diodes in 56F8037