POWER AND LINEAR IC SOLUTIONS

New Amplifier Enables High Performance Current Sensing

Linear Technology’s LTC6102 is a high-side current-sense amplifier that incorporates zero-drift technology, offering an input offset voltage of only 10µV and an offset drift of 50nV/°C maximum.



Although it provides major advantages in applications such as controlling motor torque, solenoid force, LED intensity, solar cell exposure and battery power, the direct measurement and monitoring of current can prove a challenging task for designers. New current-sense amplifiers such as the LTC6102 solve these difficulties.

A current-sense amplifier precisely senses current and converts it into a voltage that can be amplified, conditioned and measured by readily available amplifiers, comparators, and ADCs. Current is sensed by placing a small sense resistor in series with the power supply to the load. The LTC6102 extracts this small 'sense voltage' from the high common-mode voltage of the power supply. This sense voltage is then amplified and translated into a ground-referenced signal.

Modern current-sense amplifiers such as the LTC6102 feature high input impedance, high gain with good gain accuracy, and a wide common-mode range with good common-mode rejection. The device can be used with a significantly smaller sense resistor than traditional components, reducing power loss and heat dissipation from the sense resistor.

It can also accept sense voltages up to 2V. This, combined with zero-offset operation, provides over 106dB of dynamic range, allowing the LTC6102 to resolve micro-amps from amps of current. By using precision resistors, the designer can control the gain of the device to a precision better than 99%.

The LTC6102’s very high input impedance limits input bias current to less than 300pA. The device can operate with an input common-mode voltage up to 105V. Common-mode rejection of 130dB contributes less than 32µV of offset error across a full 100V of input common-mode voltage range. For fault protection, the device has a 1µs response time, allowing it to quickly initiate a power shutdown in the event of unexpected load or supply changes.

Features

• High performance current-sense amplifier
• Supply range up to 105V
• ±10µV maximum input offset
• ±50nV/°C maximum input offset drift
• 1µs step response
• Gain configurable via external resistors
• 3nA maximum input bias current
• Power supply rejection ratio 130dB (minimum)
• Output current up to 1mA
• Operating Temperature Range: –40°C to +125°C
• Eight-lead MSOP or 3mm x 3mm DFN package

Applications

• Motor control
• Solenoid force monitoring
• LED intensity control
• Solar cell exposure
• Battery power sensing and charging

For further information, including Datasheets and information on how to obtain a free Demo Board* or Samples*, please click here

* Free Demo Board and Samples are limited to current or potential customers with valid opportunities that will be approved by local Arrow employees.