24-Bit, 2 MSPS, μModule Data Acquisition Solution

The ADAQ4224 is a μModule® precision data acquisition (DAQ) signal chain solution that reduces the development cycle of a precision measurement system by transferring the signal chain design challenge of component selection, optimization, and layout from the designer to the device. With a guaranteed maximum ±1.0 ppm INL and no missing codes at 24 bits, the ADAQ4224 achieves unparalleled precision performance from −40°C to +105°C.

Using system-in-package (SIP) technology, the ADAQ4224 combines the common signal processing blocks required in a data acquisition solution in a small footprint, 14 mm × 9mm, 0.8 mm pitch, 178-ball CSPBGA package.

The ADAQ4224 integrates the following:

* A low noise, high-bandwidth programmable gain instrumentation amplifier (PGIA).

* A second-order anti-aliasing filter.

* A low-noise, low-distortion, high-bandwidth ADC driver.

* A high precision 24-bit, 2 MSPS successive approximation register (SAR) ADC.

* An electrically isolated, I2C compatible temperature sensor with excellent accuracy of ±1°C maximum.

* A 1.8 V low dropout (LDO) regulator.

* Performance critical passives.

The ADAQ4224 incorporates the critical passive components with superior matching and drift characteristics using Analog Devices, Inc., iPassive® technology to minimize temperature dependent error sources and to offer optimized performance. Integrating the critical power supply and reference bypass capacitors reduce sensitivity to the system level board layout. Reducing the solution footprint enables addition of more functions within the system and hence the smaller form factor instruments without sacrificing performance.

The system integration solves many design challenges while the μModule still provides the flexibility of a configurable PGIA to allow gain or attenuation adjustments, as well as supports the acquisition of both single-ended and differential signals. The fast settling of the PGIA and ADC driver stage and no latency of the SAR ADC provide a unique solution for high channel count, multiplexed signal chain architectures and control loop applications.

The digital features include Flexi-SPI serial peripheral interface (SPI), which allow data access via multiple SPI modes as well as offset correction, gain adjustment, and averaging and reduce burden on the host processor. A wide data clocking window, multiple SDO lanes, and optional DDR data clocking reduce the serial clock frequency while operating at full speed of 2 MSPS and make it easier to isolate the DAQ solution, which reduces power dissipation and EMI. Echo clock mode and host clock mode of the ADAQ4224 relax the timing requirements and simplify the use of digital isolators.

The Flexi-SPI, PGIA gain control and I2C-compatible temperature sensor serial user interface is compatible with 1.2 V to 1.8 V logic using a separate VIO supply. The ADAQ4224 operation is specified from −40°C to +105°C.

APPLICATIONS

* Automatic test equipment

* Machine automation

* Process controls

* Medical and industrial instrumentation

* Digital control loops

* High Performance

* Throughput: 2 MSPS, no latency

* INL: ±1 ppm maximum from −40 °C to 105 °C

* Total system dynamic range: 128 dB typical

* SNR: 106.5 dBFS typical, THD: −122 dB typical

* Offset error drift: +4.1 μV/°C maximum

* Gain error drift: +1.50 ppm/°C maximum

* Ease of use features reduce system complexity

* Second-order, 270 kHz anti-aliasing filter

* High-Z PGIA gain options: 1/3, 5/9, 20/9, 20/3

* Flexible external reference voltage: 4.096 V or 5 V

* Differential Input Voltage ranges, ±REFIN/Gain: ±15 V, ±9 V, ±2.25 V, ±0.75 V

* Wide input common-mode voltage range: −8 V to +10 V

* Low input bias current: ±20 pA typical

* High density solution reduces system footprint

* 14 mm × 9 mm, 0.8 mm pitch, 178-ball CSP BGA

* 4× footprint reduction vs. equivalent discrete solution

* On-board reference buffer with an internal VCM generation