I've been using AD8237 INA for a few designs. This amplifier has such good performance, probably the best on market regarding gain error and accuracy. But for the last year it had frequent stocking shortage. Now it's unavailable everywhere with very long lead time. Is there a good substitute for this part with more reliable availability?
The most important figures of merit for my application are:
zero input common mode requirement and true rail-to-rail input, the input range must cover Vcm = 0 for the entire output range and power supply range.
gain error temperature dependency,
input offset voltage temperature dependency,
gain range at least 10-100, externally set using resistor divider,
supply voltage as low as 2.7V,
low power consumption,
If quiescent current is above 150uA, it should have a shutdown / enable pin.
small package size, but preferrably not BGA.
The above figures of merits should be as close as possible to AD8237, if not better.
Pin compatibility with AD8237 is not required. These figures of merit are more important.
The substitute part must use a resistor divider to set the gain. The type of INA with a single gain resistor like AD8227 won't work.
It's strongly preferred that the voltage at Vref pin (for DC biasing) has the same gain as differential input, not a unity gain.
AD8237 allows this configuration, so the transfer function is Vout = Gain * (Vin,diff + Vref). This is desired.
Most INAs allow only unity gain on Vref pin, so the transfer function is Vout = (Gain * Vin,diff) + Vref. This is not desired.
added "requirement on gain range"
[edited by: zguo at 1:05 AM (GMT -5) on 24 Nov 2021]