ADI AD7822BRZ

The AD7822/AD7825/AD7829 are high speed, 1-, 4-, and 8-channel, microprocessor-compatible, 8-bit analog-to-digital converters with a maximum throughput of 2 MSPS. The AD7822/ AD7825/AD7829 contain an on-chip reference of 2.5V (2% tolerance); a track-and-hold amplifier; a 420 ns, 8-bit half-flash ADC; and a high speed parallel interface. The converters can operate from a single 3V±10% and 5V±10% supply. The AD7822/AD7825/AD7829 combine the convert start and power-down functions at one pin, that is, the CONVST pin. This allows a unique automatic power-down at the end of a conversion to be implemented. The logic level on the CONVST pin is sampled after the end of a conversion when an EOC (end of conversion) signal goes high. If it is logic low at that point, the ADC is powered down. The AD7822 and AD7825 also have a separate power-down pin. The parallel interface is designed to allow easy interfacing to microprocessors and DSPs. Using only address decoding logic, the parts are easily mapped into the microprocessor address space. The EOC pulse allows the ADCs to be used in a standalone manner.

• 8-bit half-flash ADC with 420 ns conversion time
• One, four, and eight single-ended analog input channels
• Available with input offset adjust
• On-chip track-and-hold
• SNR performance given for input frequencies up to 10 MHz
• On-chip reference (2.5V)
• Automatic power-down at the end of conversion
• Wide operating supply range 3V±10% and 5V±10%
• Input ranges 0V to 2V p-p, VDD = 3V±10%; 0V to 2.5V p-p, VDD = 5V±10%
• Flexible parallel interface with EOC pulse to allow standalone operation

• Data acquisition systems
• DSP front ends
• Disk drives
• Mobile communication systems
• subsampling applications