Features

• Very Wide, Over-the-Top, Input Common Mode Range
    - Extends 44V Above V – (Independent of V +)
    - Extends –0.3V Below V –
• Wide Power Supply Range: 2.85V to 36V
• Input Offset Voltage: 300µV Maximum
• Gain Accuracy: 1% Max
• Gain Configurable with External Resistors
• Operating Current: 150µA
• Slew Rate: 2V/µs
• Sense Input Current When Powered Down: 1nA
• Full-Scale Output Current: 1mA Minimum
• Operating Temperature Range –40°C to 125°C
• Available in 2mm × 3mm DFN and 8-Lead MSOP Packages

Typical Application

Description

The LT6105 is a micropower, precision current sense amplifier with a very wide input common mode range. The LT6105 monitors unidirectional current via the voltage across an external sense resistor. The input common mode range extends from –0.3V to 44V, with respect to the negative supply voltage (V –). This allows the LT6105 to operate as a high side current sense monitor or a low side current sense monitor. It also allows the LT6105 to monitor current on a negative supply voltage, as well as continuously monitor a battery from full charge to depletion. The inputs of LT6105 can withstand differential voltages up to ±44V, which makes it ideal for monitoring a fuse or MOSFET switch.

Gain is configured with external resistors from 1V/V to 100V/V. The input common mode rejection and power supply rejection are in excess of 100dB and the input offset voltage is less than 300µV. A minimum slew rate of 2V/µs ensures fast response to unexpected current changes.

 The LT6105 can operate from an independent power supply of 2.85V to 36V and draws only 150µA. When V+ is powered down, the sense pins are biased off. This prevents loading of the monitored circuit, irrespective of the sense voltage. The LT6105 is available in a 6-lead DFN and 8-lead MSOP package.