ADI's Precision Fixed-Gain Fully Differential Amplifiers/ADC Drivers with Low-Power

Analog Devices announces LTC6363-0.5, LTC6363-1 and LTC6363-2 Precision, Fixed-Gain, Fully Differential Amplifiers, creating a family of ultra-precision fixed-gain variants of the successful LTC6363 amplifier. The new offerings are available in fixed gains of 0.5, 1 and 2 V/V which provide flexibility when scaling inputs to the full range of ADCs.

The precision resistors, which are integrated in LTC6363-0.5, LTC6363-1 and LTC6363-2, have been designed with overall system performance in mind, striking a balance between noise and linearity and utilizing laser trimmed factory calibration to achieve a level of precision which is difficult and costly to achieve discretely. Initial gain accuracy is 45 ppm maximum and varies by only 0.5 ppm/°C maximum over temperature. Common mode rejection ratio, which is typically limited by discrete resistor matching, is an outstanding 94 dB minimum, equivalent to a 0.002 percent 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 21 mW at 1 Msps,” 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 19 mW, 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.”

The entire LTC6363 family operates with supply voltages from 2.8 (±1.4) to 11 V (±5.5 V) while drawing 1.75 mA typical supply current. The devices are specified for operation over a temperature range from –40°C to 125°C. The LTC6363 fixed-gain series are available in a 3 mm x 5 mm plastic MSOP8 package, and the LTC6363 (without resistors) is also offered in the tiny 2 mm x 3 mm DFN package. 

Summary of Features: LTC6363 series

• Available with User-Settable Gain or Fixed-Gain of 0.5 V/V, 1 V/V or 2 V/V
• 2.9 nV/√Hz Input-Referred Noise
• Drives 20-Bit SAR & Sigma-Delta ADCs
• 2 mA Maximum Supply Current
• 45 ppm Max Gain Error
• 0.5 ppm/°C Max Gain Error Drift
• 94 dB Min CMRR
• 100 µV Max Offset Voltage
• 50 nA Max Input Offset Current
• Fast Settling: 720 ns to 18-Bit, 8 VP-P Output
• 2.8 (±1.4) to 11 V (±5.5 V) Supply Voltage Range
• Differential Rail-to-Rail Outputs
• Input Common Mode Range Includes Ground
• Low Distortion: 118 dB SFDR at 2 kHz, 18 VP-P
• 500 MHz Gain-Bandwidth Product
• 35 MHz -3 dB Bandwidth
• Low Power Shutdown: 20 µA (VS = 3 V)
• 8-Lead MSOP and 2 mm × 3 mm 8-Lead DFN Packages