ADA4945-1 Fully Differential ADC Driver

By Analog Devices Inc 85

ADA4945-1 Fully Differential ADC Driver

Analog Devices' ADA4945-1 is a low noise, low distortion, fully differential amplifier with two selectable power modes. The device operates over a broad power supply range of 3 V to 10 V. The low DC offset, DC offset drift, and excellent dynamic performance of the ADA4945-1 makes it well suited for a variety of data acquisition and signal processing applications. The device is an ideal choice for driving high resolution, high-performance successive approximation register (SAR) and Σ-Δ analog-to-digital converters (ADCs) on 4 mA of quiescent current (full power mode). The device can also be selected to operate on 1.4 mA of quiescent current (low power mode) to scale the power consumption to the desired performance necessary for an ADC drive application. The adjustable common-mode voltage allows the ADA4945-1 to match the input common-mode voltage of multiple ADCs. The internal common-mode feedback loop provides exceptional output balance, as well as suppression of even order harmonic distortion products. The ADA4945-1, differential gain configurations are achieved with a simple external feedback network of four resistors determining the closed-loop gain of the amplifier. The ADA4945-1 is fabricated using Analog Devices' proprietary silicon germanium (SiGe), complementary bipolar process, enabling the device to achieve low levels of distortion with an input voltage noise of only 1.8 nV/√Hz (full power mode). The ADA4945-1 is available in a RoHS compliant, 3 mm x 3 mm, 16-lead LFCSP and is specified to operate from -40°C to +125°C.

  • Broad power supply range: 3 V to 10 V
  • Wide input common-mode voltage range: -VS to +VS - 1.3 V
  • Rail-to-rail output
  • Fully specified dual power mode operation
    • 4 mA full power mode (145 MHz)
    • 1.4 mA low power mode (80 MHz)
  • Full power mode
    • Low harmonic distortion
    • -133 dBc HD2 and -140 dBc HD3 at 1 kHz
    • -133 dBc HD2 and -116 dBc HD3 at 100 kHz
    • Fast settling time
      • 18-bit: 100 ns
      • 16-bit: 50 ns
  • ±115 μV maximum offset voltage from -40°C to +125°C
  • Adjustable output clamps for ADC input protection
  • Low power Σ-Δ, PulSAR®, and SAR ADC drivers
  • Single-ended to differential converters
  • Differential buffers
  • Medical imaging
  • Process control
  • Portable electronics