board is a simple carrier of Allegro’s ±75A ACS709 Hall effect-based
linear current sensor with overcurrent fault output, which offers a
low-resistance (~1.1 mΩ) current path and electrical isolation up to
2.1 kV RMS. The sensor has optimized accuracy for currents from -37.5 A
to 37.5 A, and the analog voltage output is linear for current
magnitudes up to 75 A. The ratiometric output voltage is centered at
VCC/2 and has a typical error of ±2%. It operates from 3 V to 5.5 V, so
it can interface directly to both 3.3 V and 5 V systems.
- Optimized accuracy for bidirectional
input current from -37.5 A to 37.5 A, with a linear sensing range from
-75 A to 75 A (see warning note below for thermal limitations).
- Conductive path internal resistance is
typically 1.1 mΩ, and the PCB is made with 2-oz copper, so very little
power is lost in the board.
- Integrated shield greatly reduces
capacitive coupling from current conductor to die and prevents offset
drift in high-side applications.
- Use of a Hall effect sensor means the
IC is able to electrically isolate the current path from the sensor’s
electronics (up to 2.1 kV RMS), which allows the sensor to be inserted
anywhere along the current path and to be used in applications that
require electrical isolation.
- 120 kHz bandwith that can optionally be decreased by adding a capacitor across the board pins marked “FILT”.
- High accuracy and reliability: typical
total output error of 2% at room temperature with factory calibration,
an extremely stable quiescent output voltage
- Automotive-grade operating temperature range of -40°C to 150°C.
- User-settable overcurrent threshold: FAULT pin
output latches low when current exceeds the configured threshold for a
duration that can be set through the addition of an external capacitor.