Texas Instruments recommends a 4-layer PCB with a solid ground plane, and placing the ADC close to the analog signal sources. Additionally, use short and direct traces for the analog inputs, and keep digital signals away from the analog signals. Refer to the TI application note 'AN-1187: PCB Layout Guidelines for ADCs' for more details.
The ADS7804U/1K requires a clock signal with a frequency between 1 MHz and 4 MHz. The clock source should have a low jitter and a stable frequency. A crystal oscillator or a high-quality clock generator can be used as the clock source. The clock signal should be connected to the CLK pin, and the clock frequency should be set according to the desired conversion rate.
Texas Instruments recommends using a 10 μF ceramic capacitor and a 1 μF ceramic capacitor in parallel, connected between the AVDD pin and the AGND pin, to decouple the power supply. Additionally, a 100 nF capacitor can be used to filter the power supply. The power supply should be well-regulated and have a low noise level.
The ADS7804U/1K has a parallel digital interface, and can be interfaced with a microcontroller or FPGA using a 16-bit or 18-bit bus. The digital interface requires a 3-state output driver, and the data should be latched on the rising edge of the clock signal. The interface timing and protocol should be according to the ADS7804U/1K datasheet and the microcontroller or FPGA datasheet.
The ADS7804U/1K has an operating temperature range of -40°C to 85°C. Temperature affects the ADC's performance, with changes in offset, gain, and linearity. The ADC's performance is specified over the entire temperature range, and the user should consider the temperature effects when designing the system.
ADS7804U/1K datasheet
by Texas Instruments
