Linear Technology introduces bidirectional current sensing high voltage amplifier LT1999

MILPITAS, CA – Linear Technology Corporation introduces the LT1999, a high voltage amplifier designed for bidirectional current sensing  in the presence of fast switching common mode voltages from -5V to 80V . This wide input common mode voltage range is achieved with standard low voltage op amp supplies. The 2MHz bandwidth enables the LT1999 to monitor current in H-bridge motor control systems, switching power supplies, solenoids and battery chargers. To achieve excellent accuracy when monitoring motor and solenoid currents, the LT1999 guarantees over 80dB of common mode rejection at 100kHz. This ensures that the LT1999 is not affected by these applications where large square wave input common mode voltages are present.

　　The LT1999 provides a buffered output with three fixed gain options of 10V/V, 20V/V and 50V/V. By default, the reference of the LT1999 output voltage is set between the power supply voltage and ground, so that the output can indicate both the magnitude and direction of the detected current. In addition, the output bias value can be set by a separate input. Over the entire temperature range of -40°C to 125°C, the gain error is guaranteed to be less than 0.5% and the input offset voltage is guaranteed to be less than 1.5mV. The LT1999 operates with an independent 5V power supply, draws only 1.5mA current when operating, and only 10uA in shutdown mode.

　　"The excellent AC performance ensures smooth and continuous operation over the entire common-mode voltage range," said Mike Kultgen, design manager at Linear Technology. "And the differential amplifier architecture makes the LT1999 suitable for a wide variety of applications."

　　The LT1999 series devices are available in 8-lead MSOP and 8-lead SOP packages and are rated for operation from 0°C to 70°C, -40°C to 85°C, -40°C to 125°C.

　　• Input common mode voltage range: -5V to 80V

　　• AC CMRR > 80dB at 100kHz

　　• Input offset voltage: 1.5mV maximum over -40°C to 125°C temperature range

　　• 2MHz bandwidth

　　• Able to withstand 4kV HBM and 1kV CDM

　　• Shutdown mode reduces supply current to <10μA

　　• -55°C to 150°C operating temperature range

　　• 8-lead MSOP and 8-lead SO (narrow) packages

　　, and -55°C to 150°C. The LT1999 is in full production now, priced starting at $1.92 each in 1,000-piece quantities. Photo caption: Accurate bidirectional current sensing for motor and solenoid applications

　　Performance Summary: LT1999

　　• Buffered output with 3 gain options: 10V/V, 20V/V and 50V/V

　　• Gain error: 0.5% maximum