National Semiconductor Corporation introduced the industry’s highest-precision programmable gain amplifier (PGA), enabling a new level of signal-conditioning performance in sensor interface applications and data acquisition systems targeting the industrial and instrumentation markets.
National’s LMP8100A delivers guaranteed 0.03 percent gain accuracy using a software adjustable gain (in 1V/V increments) from 1V/V to 16V/V over the full industrial temperature range of -40 degrees C to 125 degrees C. National also offers the LMP8100 semi-precision grade PGA, which provides guaranteed 0.075 percent gain accuracy over the -40 degrees C to 85 degrees C temperature rage. The amplifiers closed-loop gain is set by an array of 16 precision thin-film resistors. At the core of the PGAs is a precision 33 MHz CMOS input, rail-to-rail, input/output (RRIO) operational amplifier with a typical open-loop gain of 110 dB.
Many instrumentation products require the designer to scale the output of a sensor to the full-scale input of an analog-to-digital converter (ADC) to ensure optimal sensitivity. National offers this analog signal-path solution for instrumentation products by combining the LMP8100A with a 1 mega-samples per second (MSPS), 12-bit, one-channel ADC — such as the ADC121S021, ADC121S051 or ADC121S101.
Key Features – LMP8100 Precision Gain Amplifier
The LMP8100A provides four levels of internal frequency compensation, which at the higher gain settings increases the usable signal bandwidth. Its input zero calibration feature allows the user to measure the output offset voltage to calibrate any errors resulting from temperature or voltage shifts. The amplifier’s control modes are programmed via a serial port that also allows several devices to be cascaded, permitting an array of LMP8100 amplifiers to be programmed by a single microcontroller serial data stream. The device’s control-mode registers are double-buffered to ensure glitch-free transitions between programmed settings.
The LMP8100A has a slew rate of 12 V/us and a 33 MHz unity-gain bandwidth. The device’s supply voltage range is 2.7V to 5.5V, with a 5.3mA supply current and output current of 20 mA. A power-conserving shutdown mode reduces current consumption to 20 uA.
Built on National’s proprietary VIP50 BiCMOS process technology, the LMP8100A and LMP8100 are the latest additions to the company’s LMP(R) precision and low-voltage, low-power amplifier families. These amplifiers dramatically improve system accuracy and power consumption.