How to use the LDAC pin on DACs (Digital-to-Analog converters)

The [latex]\overline{\text{LDAC}}[/latex] pin on Digital-to-Analog converters (DACs) provides a convenient way to tell the DAC when an output.

For example, if you have an 8-channel I²C DAC, you need to set the DAC registers for the channels one after another using the I²C protocol, but often you want all channels to change their analog outputs at the same time (after writing all the values to the corresponding registers).  The [latex]\overline{\text{LDAC}}[/latex] pin allows you to do that by driving it high (e.g. 3.3V).

Using it is simple:

• If you don’t want to use the [latex]\overline{\text{LDAC}}[/latex] pin, tie it to GND. This will cause the DAC’s outputs to be updated immediately whenever the registers or corresponding inputs are changed.
• Don’t leave the [latex]\overline{\text{LDAC}}[/latex] pin floating ! Always connect it to an output of e.g. a microcontroller or tie it to GND
• If you want to use the pin, connect it to a GPIO output of a microcontroller. By default, drive it high (e.g. to 3.3V). Whenever you are finished updating the DAC register, drive it low for at least 10 microseconds (typical value that will work for most DACs). The DAC will then update its analog outputs, all at once.