Having built a small, portable 10.000V reference using the Analog Devices AD587 reference chip, now is a good time to evaluate its performance with a bunch of multimeters.
However, I have a feeling that the AD587 with its 10.000V ±5mV @25ºC is going to be the better performer than some of the multimeters being tested. In today’s performance shootout, ranked in order of their pedigree we have:
Following on from a previous post discussing the Analog Devices AD587 precision 10.000V voltage reference, I built a portable device to utilise the chip.
Some requirements of the project were:
10.000V ±5mV output
Battery operated device
Visual, low battery indication
Small, aluminium housing
Clear front panel
Low cost (under $50), readily available components
A low battery indication was a desired feature to prevent the device being used in an important test and the battery level drops low and compromises the AD587’s performance. A simple green LED will suffice. Output performance of 10.000V (± 5mV) couldn’t be compromised so there is no protection to prevent high current draw from the chip, I’ll just have to be sensible.
Voltage references are a humble piece of hardware, their sole function is to provide a stable, known voltage. This constant, known value of voltage can then be used as a reference for ADCs and DACs as well as provide a precision current source.
This model of chip has an output value of 10.000V ± 5mV (that is, an output value of 9.995V to 10.005V) straight out of the factory. A voltage drift of 10ppm/°C at 25°C meaning that the output voltage will drift by 10μV for each 1°C the chip is exposed to. Additionally, the chip has a voltage trim input, so if you have access to a precision voltmeter, the chip’s output value can be adjusted even closer to 10.000V.