Current sense amp with dual comparators and a precision 400mV voltage reference

Linear Technology has announced its latest LT6109, incorporated with a current sense amplifier, dual comparators and a precision 400mV voltage reference. When connected to a current shunt resistor, the high side current sense 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.

Linear Technology says the LT6109 is used for current measurement and load current fault monitoring. From the input of the amplifier to the output of the comparators, the LT6109 responds to threshold exceeding events within 1.4µsec.

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 LT6109 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 as explained by Linear Technology

Key features of the LT6109 includes:
Fast Step Response: 500ns
Low Offset Voltage: 350µV Maximum
Low Input Bias Current: 300nA Maximum
Internal Latching Comparators with Reset
Fast Response Time: 500ns
Total Threshold Error: ±2% Maximum
Two Comparator Polarity Options
Wide Supply Range: 2.7V to 60V
Supply Current: 550µA
Low Shutdown Current: 5µA
Specified for Operation from-40°C to 125°C
"The LT6109 is not simply an integration of separate devices," says Kris Lokere, Design Manager for Linear Technology. "Each element offers outstanding performance, and in combination, this part sets a new standard in current monitoring."

Availability: Now in production quantities.
Price: $1.84 each for 1K units.
Package: small 10-lead MSOP.

For more information, visit www.linear.com/product/LT6109.