AD7708BRUZ-REEL

The AD7708/AD7718 are complete analog front-ends for low frequency measurement applications. The AD7718 contains a 24-bit Σ-∆ ADC with PGA and can be configured as 4/5 fully-differential input channels or 8/10 pseudo-differential input channels. Two pins on the device are configurable as analog inputs or reference inputs. The AD7708 is a 16-bit version of the AD7718. Input signal ranges from 20 mV to 2.56 V can be directly converted using these ADCs. Signals can be converted directly from a transducer without the need for signal conditioning. The device operates from a 32 kHz crystal with an on-board PLL generating the required internal operating frequency. The output data rate from the part is software programmable. The peak-to-peak resolution from the part varies with the programmed gain and output data rate. The part operates from a single 3 V or 5 V supply. When operating from 3 V supplies, the power dissipation for the part is 3.84 mW typ. Both parts are pin-for-pin compatible allowing an upgradable path from 16 to 24 bits without the need for hardware modifications. The AD7708/AD7718 are housed in 28-lead SOIC and TSSOP packages.

Applications

• Industrial Process Control
• Instrumentation
• Pressure Transducers
• Portable Instrumentation
• Smart Transmitters
• Data Acquisition
• Programmable Logic Controllers
• Converting Single-Ended Inputs
• Combined Ratiometric and Absolute Value Measurement System
• Optimizing Throughput while Maximizing 50 Hz and 60 Hz Rejection in a Multiplexed Data Acquisition System

Key features

• 8-/10-Channel, High Resolution - ADCs
• AD7708 Has 16-Bit Resolution
• AD7718 Has 24-Bit Resolution
• Factory-Calibrated
• Single Conversion Cycle Setting
• Programmable Gain Front End
• Simultaneous 50 Hz and 60 Hz Rejection
• VREF Select Allows Absolute and Ratiometric Measurement Capability
• Operation Can Be Optimized for Analog Performance <CHOP=0> or Channel Throughput <CHOP=1>
• 3-Wire Serial
• SPI, QSPI, MICROWIRE, and DSP-Compatible
• Schmitt Trigger on SCLK
• Specified for Single 3 V and 5 V Operation
• Normal: 1.28 mA Typ @3V
• Power-Down: 30 μA (32 kHz Crystal Running)
• On-Chip Functions Rail-to-Rail Input Buffer and PGA 2-Bit Digital I/O Port