AD7928 Datasheet

• Fast throughput rate: 1 MSPS
• Specified for AV_DD of 2.7 V to 5.25 V
• Low Power:
  6.0 mW max at 1 MSPS with 3 V supply
  13.5 mW max at 1 MSPS with 5 V supply
• Eight (single-ended) inputs with sequencer
• Wide input bandwidth: AD7928, 70 dB min SINAD at 50 kHz input frequency
• Flexible power/serial clock speed management
• No pipeline delays
• High speed serial interface SPI^®/QSPI^™/MICROWIRE^™/DSP compatible

The AD7928 are, respectively, 12-bit, high speed, low power, 8-channel, successive approximation ADCs. The parts operate from a single 2.7 V to 5.25 V power supply and feature throughput rates up to 1 MSPS. The parts contain a low noise, wide bandwidth track-and-hold amplifier that can handle input frequencies in excess of 8 MHz.

The conversion process and data acquisition are controlled using CS and the serial clock signal, allowing the device to easily interface with microprocessors or DSPs. The input signal is sampled on the falling edge of CS and conversion is also initiated at this point. There are no pipeline delays associated with the part.

The AD7928 use advanced design techniques to achieve very low power dissipation at maximum throughput rates. At maximum throughput rates, the AD7928 consume 2 mA maximum with 3 V supplies; with 5 V supplies, the current consumption is 2.7 mA maximum.

Through the configuration of the control register, the analog input range for the part can be selected as 0 V to REF_IN or 0 V to 2 × REF_IN, with either straight binary or twos complement output coding. The AD7928 each feature eight single-ended analog inputs with a channel sequencer to allow a preprogrammed selection of channels to be converted sequentially.

The conversion time for the AD7928 is determined by the SCLK frequency, which is also used as the master clock to control the conversion.