AD7478A Datasheet

• Fast throughput rate: 1 MSPS
• Specified for V_DD of 2.35 V to 5.25 V
• Low power
  3.6 mW at 1 MSPS with 3 V supplies
  12.5 mW at 1 MSPS with 5 V supplies
• Wide input bandwidth
  71 dB SNR at 100 kHz input frequency
• Flexible power/serial clock speed management
• No pipeline delays
• High speed serial interface
  SPI/QSPI/MICROWIRE/DSP compatible
• Standby mode: 1 µA maximum
• 6-lead SC70 package
• 8-lead MSOP
• Qualified for automotive applications

• Battery-powered systems
  Personal digital assistants
  Medical instruments
  Mobile communications
• Instrumentation and control systems
• Data acquisition systems
• High speed modems
• Optical sensors

The AD7478A are 8-bit high speed, low power, successive-approximation analog-todigital converters (ADCs), respectively. The parts operate from a single 2.35 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 13 MHz. The conversion process and data acquisition are controlled using CS and the serial clock, allowing the devices to interface with microprocessors or DSPs. The input signal is sampled on the falling edge of CS, and the conversion is also initiated at this point. There are no pipeline delays associated with the parts. The AD7478A use advanced design techniques to achieve low power dissipation at high throughput rates. The reference for the part is taken internally from V_DD to allow the widest dynamic input range to the ADC. Thus, the analog input range for the part is 0 V to V_DD. The conversion rate is determined by the SCLK.

PRODUCT HIGHLIGHTS

1. First 8-bit ADCs in a SC70 package.
2. High throughput with low power consumption.
3. Flexible power/serial clock speed management. The conversion rate is determined by the serial clock, allowing the conversion time to be reduced through the serial clock speed increase. This allows the average power consumption to be reduced when a power-down mode is used while not converting. The parts also feature a power-down mode to maximize power efficiency at lower throughput rates. Current consumption is 1 µA maximum and 50 nA typically when in power-down mode.
4. Reference derived from the power supply.
5. No pipeline delay. The parts feature a standard successive approximation ADC with accurate control of the sampling instant via a CS input and once-off conversion control.