Voltage references in embedded design
May 9th, 2008Embedded systems that are dealing with DAC require a good voltage references. Despite all voltage references have their nominal values there are specific tolerances that indicates how much values can vary from nominal value. References as a rule are semiconductors that characteristics are effected by temperature.

For instance if we decide to use a 2.5V voltage reference then (zener) diode LM336A-2.5 may be a good choice for this.
These diodes have low temperature coefficient. It can guarantee that voltage will be in range between 2.44 and 2.54 at 25ºC. This precise zener diode has a third lead that can be used to adjust break down voltage. In the following figure you may see diode with potentiometer where breakdown voltage can be adjusted in range of ±120mV: Read the rest of this entry »





