0.05% voltage reference for under a microamp

TI has introduced a voltage reference that typically runs from 680nA and yet has a max initial error of ±0.05% and a max temperature coefficient of 10ppm/°C across -40 to 125°C – and it will operate down to -55°C.

Called REF35, it will run from up to 6V and different versions offer outputs of 1.024, 1.2, 1.25, 1.6, 1.8, 2.048, 2.5, 3, 3.3, 4.096 or 5V.

It can deliver up to 10mA (500mV max drop-out) and sink 5mA – one potential application, according to TI, is both powering and referencing a DAC or ADC.

Long-term stability is claimed to be 20ppm at 1,000 hours and it exhibits 20ppm thermal hysteresis (cycling from 25°C to -40, then to +125 and back to 25°C). Peak to peak output 1/f noise (100mHz to 10Hz) is 8.5 ppm.

There is a shutdown pin that can reduce 25°C power consumption to 50nA, but looking at the data sheet, this expands to 1.2μA max over -40 to 125°C, whihc is not much below the maximum enabled power consumption over the same temperature range, which is 2.6μA (1.3μA of max is 85°C).

“REF35 does not use an internal pull-up resistor,” said TI. “Instead, it uses a ‘clean EN’ technology. This allows EN pin to left floating and at the same time no extra current is drawn from the supply when EN pin is pulled low in shut-down mode. It is to be noted that for applications where EN pin is left floating, total parasitic capacitance on EN pin should be restricted within 30pF.”

An input capacitor is suggested and an output capacitor is compulsory. A noise reduction pin allows another capacitor, working with an internal resistor, to quieten the internal bandgap reference.

Packaging is 6pin SOT-23.

The part is new enough for just about every graph in the advanced data sheet to be blank.

REF70 and REF20-Q1 are further new TI voltage references, the former a 2ppm/°C maximum drift part and the latter automotive rated.

The REF35 product page is here, and its initial data sheet here