Diodes has announced precision bi-directional current monitors in a 2.2 x 2.2mm package.
Called the ZXCT199 series, they are rail-to-rail voltage output type devices with gains of 50V/V, 100V/V or 200V/V (typically 120dB common-mode rejection).
Input is taken across a shunts at common-mode voltages from -0.1V to +26V, independent of the 2.7 to 26V supply voltage, from which a maximum of 100μA is drawn.
The internal op-amp (see diagram) is chopper-stabilised for accuracy and low drift (0.5uV/°C max). Temperature range is -40°C to 125°C.
- ZXCT199Ax
±150μV max (±5μVtyp) offset
±1.0% max (±0.03% typ) gain error - ZXCT199Bx
±100μV max (±5μVtyp) offset
±1.0% max (±0.03% typ) gain error - ZXCT199Cx
±80μV max (±5μVtyp) offset
±0.8% max (±0.03% typ) gain error
– gain errors are over the full temperature range, and ‘x’ in the part number selects the gain: 1= 50V/V, 2=100V/V or 3=200V/V
“Their low offset voltage enables current sensing with maximum drops across shunts as low as 10mV full-scale,” according to the company. “This allows high currents to be measured via low-value shunt resistor components.”
Although there is no shut-down pin, the data sheet points out that the IC’s current consumption is low enough for it to be powered from an MCU I/O pin.
Packaging is 6pin SOT363.
Applications are foreseen in include laptop PCs, battery chargers, industrial servos, servers, power supply racks in server farms and robots.
The ZXCT199 product page can be found here, and the data sheet is worth a look as it has sensible advice on reference setting and transient protection.
