I need a voltage reference with the following specs:
Vin = 900mV to 5V Vref = anywhere from 100mV to 900mV, but must be fixed value (max 10% tolerance). So if the reference is 500mV, min/max is 450mV/550mV Reference current = max 10uA
The normal two transistor bandgap with temperature compensation has a nominal value of 1150mV, which is too high since then we need more than 1150mV to operate it.
Been playing with a resistor fed forward biased diode to yield say300mV. But tempco is 2mV/K, initial tolerance in the range of +/- 25mV due to production spread, combined with no way to provide accurate current for the diode means that this is not a feasable way forward
Googling commercial ICs got me nowhere, minimum 1.2V reference at this low drive current :-(
Anyone got an idea?