High precision fixed-gain fully differential amplifiers/ADC drivers offer low power
Analog Devices has released the LTC6363-0.5, LTC6363-1 and LTC6363-2 Precision, Fixed-Gain, Fully Differential Amplifiers, producing a family of ultra-precision fixed-gain variants of the LTC6363 amplifier. The new devices are offered in fixed gains of 0.5, 1 and 2V/V which give flexibility when scaling inputs to the complete range of ADCs.
The precision resistors, which are integrated into the devices, have been created with overall system performance in mind, creating a balance between noise and linearity, and using laser trimmed factory calibration to obtain a level of precision which is challenging and costly to achieve discretely. Initial gain accuracy is 45ppm maximum and varies by only 0.5ppm/C maximum over temperature. Common mode rejection ratio, which is typically restricted by discrete resistor matching, is an excellent 94dB minimum, equivalent to a 0.002% resistor matching.
“One of the challenges when driving high-performance SAR ADCs is finding an appropriate driver that consumes comparable power while maintaining the noise and linearity performance of the ADC. This is where the LTC6363 family excels. For example, the LTC2378-20 20-bit SAR ADC consumes 21mW at 1Msps,” says Maziar Tavakoli, design manager, Linear Products and Solutions. “The LTC6363 family’s noise and linearity have negligible impact on ADC performance while consuming a mere 19mW, comparable to the ADC’s power consumption. Now with the LTC6363-0.5, LTC6363-1 and LTC6363-2 you can get this same ADC driving performance plus the added precision afforded by the precision integrated resistors, all in the same compact MSOP8 package.”