Industrial and Sensor ICs
Volume 9, Issue 4 YOUR SEMICONDUCTOR SOLUTIONS RESOURCE

Data Acquisition Chip Reduces Components for High Channel Count Applications

In industrial or sensor applications that require accurate data acquisition of a large number of channels, the ADAS1128 is a 24-bit current-to-digital converter that integrates 128 data conversion channels, an on-chip temperature sensor, and a reference buffer into a small 10 mm × 10 mm package—all without sacrificing performance. Sample rates up to 13 kSPS are supported, along with an ultralow noise floor (down to 0.4 fC). Power savings are substantial, consuming a mere 4.5 mW/channel at full speed.

While the ADAS1128 is primarily designed to digitize currents below 700 nA, the input range and type can easily be modified with the addition of external resistors, due to the virtual ground provided by the ADAS1128's analog input. For higher current applications, a current divider can be placed in front of the analog inputs of the ADAS1128. Although the ADAS1128 does not operate on large voltages (3.3 V and 2.5 V), it can be used to digitize high voltages. For voltage applications, a series resistor in front of the analog inputs is all that is required.

ADAS1128

You can explore this new collection of tested circuits and find solutions for many common applications. Each circuit includes detailed design documentation, common circuit variations, and more. For more information, please visit www.analog.com/circuits.

High Accuracy, Multichannel PulSAR ADCs Optimized for Lower Power, Space-Constrained Designs

The latest 14-bit and 16-bit multichannel PulSAR® ADCs from Analog Devices are ideal in monitoring applications such as optical modules for telecommunications and include the ability to monitor all key module measurements such as laser bias current, received optical power, transceiver input voltage, and temperature monitoring.

For portable and battery operated equipment that require small packages and low power, the devices all fit in the 4 mm × 4 mm, 20-lead LFCSP, dissipating just 3.5 mW when operating at 2.5 V and 250 kSPS. In addition, the devices offer 1.5 LSBs INL at 16 bits and 92.5 dB SINAD for the highest accuracy and best noise performance available. Pin-for-pin compatibility provides users with the ability to increase the sampling rate to 500 kSPS or upgrade from 14-bit to 16-bit accuracy.

These devices integrate a number of components for use in a multichannel, low power data acquisition system.

AD76xx Features

  • 14-/16-bit SAR ADC with no missing codes
  • 4-/8-channel, low crosstalk multiplexer
  • Internal low drift reference and buffer
  • Temperature sensor
  • Selectable 1-pole filter
  • Channel sequencer
Part
Number
Channels Resolution
(Bits)
Sampling
Rate (kSPS)
INL Error
(ppm)
Voltage
Supply (V)
Price
($U.S.)
AD7682 4 16 250 22 2.7 to 5 3.99
AD7689A 8 16 250 60 2.7 to 5 5.99
AD7689B 8 16 250 22 2.7 to 5 6.99
AD7699 8 16 500 22 5 7.99
AD7949 8 14 250 60 2.7 to 5 3.99

ADI engineers recommend the ADA4841-2 driver amplifier as a complementary component for very low noise, small, and low power applications.

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