Hall Sensor Amplifier by LT6011 Micropower Op Amp
This application is a low power hall sensor amplifier based on LT6011 , Linear Technology's dual operational amplifier fits 25uV input precision micropower operation and wide 2.7V to 36V supply range. HW-108A is the hall element in the application. At 1V DC bias, it consumes about 2.5 mA with a sensitivity of 4mV/mT. Reducing the bias voltage reduces the power consumption but it also reduces the sensitivity. At this point, to lower the power consumption, micropower amplification takes an important role. Circuit operation is as follows. The LT1790 micropower reference gives a fixed output of 1.25V. The voltage divider circuitry made up of 7.87kΩ and 100kΩ resistors reduces the voltage and the voltage across the 7.87kΩ becomes 0.09V. LT1782 acts as a buffer. So when this 0.09V is applied as bias voltage across the hall sensor bridge, the current is only 0,23mA. This is about 1/10 of the original value. This means that your batteries will last 10 times longer. On the other hand t...