siliconchip.com.au Australia’s electronics magazine July 2019 67
SCIt was then left operating undis-
turbed for four hours, during which the
ambient temperature rose to 27°C and
the measured output fell to 9.99997V –
a drop of only 0.06mV or 60μV.
So our impression is that togeth-
er with the trimming adaptor, the
AD584LH module can be used to
make a very stable and accurate volt-
age reference.
Which to choose?
If you just want a reference for
checking 3-½ digit DMMs, analog me-
ters and the like, the ML005 module
would be ideal and has the price ad-
vantage over the other two modules.
But if you want a portable refer-
ence for checking instruments ‘in the
field’, the KKmoon module would be
the one to go for.
If you want the highest accuracy and
stability, we’d suggest you choose the
module based on the AD584LH device,
together with the trimming adaptor cir-
cuit shown in Fig.7. This gives you a
voltage reference comparable to com-
mercial units costing over 10 times its
modest cost of $23.
You can find a quick gestalt on the
same three modules at siliconchip.
com.au/link/aaoiThe alternative “high-
precision” AD584-
based module. It
uses an AD584LH
as opposed to the
AD584JH used in
the ML005 module.
However, when
measured, this module
displayed worse
accuracy than the
other two.