Diodes has created a range of precision current shunt monitors that have a -0.3 to 26V common-mode sense range irrespective of supply voltage, allowing both high-side and low-side measurement – and a reference pin is provided for bi-directional current measurement.

Diodes ZXCT21xQ precision current shunt monitor
Called the ZXCT21xQ family, there are six gain options:

• 50V/V  ZXCT213Q
• 75V/V  ZXCT215Q
• 100V/V  ZXCT214Q
• 200V/V  ZXCT210Q
• 500V/V  ZXCT211Q
• 1kV/V  ZXCT212Q

Inside is a ‘zero-drift’ topology. Each type has A, B and C variants that offer a choice of input offset and gain linearity. C-types are the most precise as all have 0.5% gain linearity, and 200, 500 and 1,000V/V parts exhibit ±35μV input maximum offset (±550nV typical). 10ppm/°C maximum gain error drift is specified in all parts.

Operation is across 2.7V to 26V supplies (100μA max quiescent) and -40 to +125°C, and shunt drops down to 10mV full-scale are supported.

 

This is a slow device, with bandwidth measured in kHz and a 0.4V/µs slew rate. Where high-bandwidth differential input signal are expected, an RRC input filter can be implemented with a series resistor (up to 10Ω to retain accuracy) in each input lead and a capacitor across the inputs. “Ideally, select the capacitor to exactly match the time constant of the shunt resistor and its inductance,” said Diodes.

Packaging is 2 x 2.1mm 6pad SOT363.

All parts are AEC-Q100 Grade 1 qualified for automotive use, manufactured in IATF 16949 certified facilities, and support PPAP documentation.

Automotive applications include current sensing in brush-less dc motor controllers, dc-dc converters, on-board chargers, battery management systems, automated driving unit power supplies and wireless phone chargers.