Diff Amps Plot Accuracy Roadmap January 2005 Issue Published Date: January 19, 2005
Reporting very low offset voltage and drift, the LMP8270, LMP8271, and LMP8272 high common mode differential amplifiers claim to redefine accuracy in current-sensing applications. A bi-directional device with a fixed gain of 20, the LMP8271 uses an external reference voltage to set the voltage defining a zero-current condition. An output voltage greater than the reference indicates a charging condition, while an output voltage below the reference identifies a discharging condition. The LMP8270 and LMP8272 are uni-directional amplifiers with fixed gains of 20 and 14, respectively. Features shared by all three devices include a -2V to +27V common-mode input range, supply voltage range of 4.5V to 5.5V, offset voltage of less than 250 µV, and an offset drift of less than 15 µV/°C. Additionally, each amplifier can function over an extended common-mode input range from -5V to +36V. Available in SOIC-8 packages, prices for the LMP8270, LMP8271, and LMP8272 are $1.45, $1.57, and $1.45 each/1,000, respectively. NATIONAL SEMICONDUCTOR, Santa Clara, CA. (800) 272-9959.
