CN-0257 is a reference circuit manual published by Analog Devices. This manual introduces the AD5790 true 20-bit voltage output DAC, AD8675 ultra-precision 36V, 2.8nV√Hz, rail-to-rail output operational amplifier, AD8676 ultra-precision 36V, 2.8nV√Hz, dual rail-to-rail output operational amplifier, 20-bit linear low noise precision unipolar +10V DC voltage source connections and applications.
The document details CN-0257, a reference circuit designed for quick system integration to solve analog, mixed-signal, and RF design challenges. It features a 20-bit unipolar +10 V DC voltage source built around the AD5790 True 20-Bit Voltage Output DAC and the AD8675 Ultraprecision Op Amp with minimal external components.
The circuit utilizes internal matched resistors for bias current cancellation and includes an optional low-pass filter to attenuate reference noise. The text provides a simplified schematic, describes component selection (such as precision metal foil resistors), and presents measurement results for integral nonlinearity, differential nonlinearity, and output voltage noise over time.
| Resolution | 20-bit |
|---|---|
| Output Range | +10 V DC |
| Relative Accuracy | ± 2 LSB maximum |
| DNL Specification | -1 to +2 LSB maximum |
| INL Specification | ±2 LSB |
| Noise Spectral Density | 8 nV/√Hz |
The circuit provides a unipolar +10 V DC output voltage.
The circuit uses an AD5790 True 20-Bit Voltage Output DAC and an AD8675 Ultraprecision Op Amp.
The AD5790 offers a relative accuracy specification of ± 2 LSB maximum.
The AD5790 evaluation kit includes self-installing software compatible with Windows XP (SP2) and Vista.