Linear Technology LT6109 current sense device

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Linear Technology has released the LT6109, a high side current sense device that incorporates a current sense amplifier, dual comparators and a precision 400 mV voltage reference.

When connected to a current shunt resistor, the amplifier precisely extracts the shunt voltage, amplifies it and translates it to ground. This output is available for monitoring and can be connected to either of the on-chip comparators.

The device is suitable for current measurement and load current fault monitoring, especially since each element offers precision and speed.

The amplifier has less than 350 µV of offset and the combined threshold error of the comparators and reference is less than 2%. From the input of the amplifier to the output of the comparators, the amplifier responds to threshold exceeding events within 1.4 µs.

External resistors set the amplifier gain and comparator trip points and since the gain resistors are the primary determinants of the amplifier’s accuracy, using precision resistors enables accuracy better than 1%.

Two versions of the device are available, the LT6109-1 and the LT6109-2. The comparator inputs of the LT6109-1 are connected to the internal reference in opposing polarity, allowing for window comparison, such as for overcurrent and undercurrent conditions.

The comparator inputs of the LT6109-2 are connected in the same polarity, allowing for two threshold levels, such as “warning” and “emergency disconnect”. The open-drain outputs ensure easy interface to other system components and comparator latching enables detection of high-speed events.