|
|
Post by pt3r on Mar 12, 2021 7:58:51 GMT
Having a look at the MCP4822 datasheet I noticed that it has built in output Op Amps. Does this mean that I don't need to add an extra buffer on this output signals when using them in a module, since the chip has already buffered outputs? Can any of the electronic specialists shed their light?
|
|
|
|
Post by keurslagerkurt on Mar 12, 2021 10:54:30 GMT
Have not yet experimented with the chip myself, but looking at the datasheet the outputs look perfectly fine to be connected directly without buffer.
I would just be careful to not run them directly to ground or something, a little output impedance is needed as the output opamps would try to deliver 'infinite' amps (but there is probably some safety system in the chip, or maybe even a little resistance, but I don't see it on the circuit diagram)
|
|
XODES
New Member
Posts: 39
|
Post by XODES on Mar 12, 2021 19:23:23 GMT
Quote from the datasheet, page 18 :
"The DAC’s outputs are buffered with a low-power, precision CMOS amplifier. This amplifier provides low offset voltage and low noise. The output stage enables the device to operate with output voltages close to the power supply rails. Refer to Section 1.0 “ElectricalCharacteristics” for the analog output voltage range and load conditions. In addition to resistive load-driving capability, the amplifier will also drive high capacitive loads without oscillation. The amplifier’s strong outputs allow VOUT to be used as a programmable voltage reference in a system."
So basically, you should be able to drive without additional buffers, yet if you're about to make this output available to the outside world, it would be good practice to add a 1K resistor in series in order to protect it, in case say you accidentally connect it to power or ground.
|
|
|
|
Post by onkelhoste on Mar 13, 2021 14:42:22 GMT
[] ... it would be good practice to add a 1K resistor in series in order to protect it, ... I do so. Works fine fore me. |
|
