ACS709 Current Sensor -75A / +75A
This current sensor is based on Allegro's ACS709LLFTR-35BB-T Hall's overcurrent fault output. is a carrier board or main board for the linear current sensor; Therefore, we recommend that you read
ACS709 datasheet carefully before using this product. The sensor has an operating voltage of 3 V to 5.5 V and an output sensitivity of 18.5 mV/A when Vcc is 3.3 V (or 28 mV/A when Vcc is 5 V).
Technical Specifications
- Optimized accuracy with linear detection range of -37.5 A to 37.5 A, -75 A to 75 A for bidirectional input current
- The conductor path internal resistance is typically 1.1 mΩ and the PCB is made with 2 oz copper, so there is very little power dissipation in the board.
- The integrated shield provides capacitive coupling from the existing conductor to death greatly reduces and prevents offset drift in high-side applications.
- Using a Hall effect sensor allows the IC to electrically separate the current path from the sensor's electronics (up to 2.1 kV RMS) and transmit it anywhere along the sensor's current path. 120 kHz bandwidth, which can optionally be reduced by adding capacitors to the board pins marked "FILT".
- High accuracy and reliability: 2% at room temperature typical total output error, with factory calibration, extremely stable quiescent output voltage
- Automotive-grade operating temperature from -40°C to 150°C
- User-adjustable overcurrent threshold: FAULT The pin output latches low when the current exceeds the configured threshold for a period of time that can be adjusted by the addition of an external capacitor.
Using the Sensor
This sensor The only connections required to use it are input current (IP + and IP-), logic power (VCC and GND) and sensor output (VIOUT). All other pins are optional, as are the two external capacitors.
The sensor requires a 3 V to 5.5 V supply voltage to be connected to the VCC and GND pads labeled on the bottom screen. The sensor outputs an analog voltage that is linearly proportional to the input current. The quiescent output voltage is VCC/2 and varies by 28 mV per ampere per input current (when VCC = 5 V), with positive current increasing the output voltage and negative current decreasing the output voltage. For an arbitrary input current i (in amperes), the sensor's output voltage can be more generally represented as:
VIOUT = (0.028 V / A * i + 2.5 V ) * VCC / 5 V
VZCR pin is the voltage reference output pin and can be used as a zero current (0 A) reference. It will be approximately equal to VCC / 2 and allows you to calculate the current more accurately than the output voltage VIOUT.
The FILT pin allows you to adjust the bandwidth of the board by adding a capacitor, CF, to ground (a ground pad has been added near the FILT pin for convenience). Without any external filter capacitors, the bandwidth is 120 kHz. The datasheet provides more information on how the external filter capacitor affects bandwidth.
The FAULT pin is normally high and latches when the current exceeds the overcurrent fault switching point (Ioc). This switching point is set by the voltage applied to the VOC pin and is connected to the voltage divider shown in the schematic diagram below. By default, Ioc is set to 57 A, but it can be changed by adding external resistors to the voltage divider to vary the VOC voltage. When the FAULT pin is latched low, it can be reset by driving the FAULT_EN input low (this input is pulled high off the board). An external capacitor, COC, can be added to increase overcurrent fault response time. Without this capacitor, error response time is typically below 2 μs.
Installation information
There are two mounting holes on the logic side of the board. This mount has 0.6 inch spacing of holes and is designed for #2 screws.
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