Analog Devices' ADC with internal reference delivers high accuracy with low power in small packages


Allows industrial- and medical-equipment designers to optimize operating and static power budgets

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The AD7091R core draws 349 ?A (typ) at 3 V when operating at 1 MSPS.

Analog Devices has introduced the first product in a series of ultra-low-power, 12-bit, 1-MSPS SAR (successive approximation register) ADCs with internal 2.5-V reference. The new ADC is designed for USB or battery powered data-acquisition modules, handheld meters, field instruments, energy harvesting applications, and medical devices such as portable electrocardiograms and heart rate monitors. The most power-efficient converter in its class, the device dissipates over 70% lower power than its closest SAR ADC competitor in a package that is 33% smaller than competing 12-bit converters with internal references. "The AD7091R operates at over 3.5 times the power efficiency of competing ADCs, and of discrete ADC and reference two-chip alternatives," said Mike Britchfield, vice president, Industrial and Instrumentation Group, Analog Devices. "The significant power-performance advantage was designed specifically for system engineers working within stringent system power constraints." The AD7091R core draws 349 ?A (typ) at 3 V when operating at 1 MSPS. The device's power automatically scales with throughput. It draws 264-nA power-down current and 21.6-μA standby current, which allows designers to further optimize energy consumption for intermittent or one-shot conversions. The new device also achieves a 4.5-ppm/?C reference temperature coefficient. Key AD7091R 12-bit A/D Converter Features

  • Low power:
    • 349 μA (typ) at 3 V and 1 MSPS
    • 264-nA power-down current
    • 21.6-μA standby current
  • Flexible power/throughput rate management
  • Fast throughput: 1 MSPS
  • Power supply: 2.7 to 5.25 V
  • DC Accuracy: ±1 LSB INL
  • 4.5 ppm/?C 2.5V internal reference
  • High-speed serial interface: SPI-, QSPI-, MICROWIRE-, and DSP-compatible
  • Serial interface voltage: 1.65 to 5.25 V
Pricing, availability, and complementary products The AD7091R is rated over a -40 to 125 °C temperature range and is available now in 5 x 3-mm, 10-lead MSOP or 3 x 2-mm, 10 lead LFCSP. The EVAL-AD7091RSDZ evaluation board for the AD7091R is now available and priced at $59.00. The EVAL-SDP-CB1Z controller board must be ordered with the evaluation board and is priced at $99.00. For ease of design in, IBIS models and software drivers are also now available. When coupled with low-power amplifiers, the AD7091R ADC is part of a chipset that reduces signal-chain power dissipation. When used with the AD8031 op amp with rail-to-rail inputs and output, power is reduced by over 45% compared to previous offerings. For low-bandwidth applications, the AD8420 instrumentation amplifier used together with the AD7091R ADC provides a cost-sensitive combination that dissipates more than 60 percent lower power than previous offerings. Analog Devices Product deeplink