DC846A Analog Devices

DEMO MANUAL DC846A LTC2447 4-/8-Channel High Speed, 24-Bit Delta Sigma ADC with Selectable Reference Inputs DESCRIPTION The LTC 2447 is a 4-/8-channel, high speed, 24-bit The LTC2447 performs autozeroing of the ADC by chopping ADC with ten selectable speed/resolution modes from the inputs through the multiplexer outputs. This allows an 6.9Hz/200nV to 3.5kHz/25V (4kHz with external external dual buffer amplifier to isolate the signal inputs RMS RMS oscillator). Key DC specifications include 5ppm INL, 5V from the sampling current of the ADC inputs. offset, 10ppm full-scale error and 20nV/C offset drift. In DC846 is a member of Linear Technologys QuikEval the 6.9Hz/200nV mode, input normal mode rejection RMS family of demonstration boards. It is designed to allow easy of 50Hz and 60Hz noise is better than 87dB. The accuracy evaluation of the LTC2447 and may be connected directly (offset, full-scale, linearity, drift) and power dissipation to the target applications analog signals while using the are independent of the speed selected. The LTC2447 also DC590 USB serial controller board and supplied software has four reference inputs dedicated to the four differential to measure performance. The exposed ground planes allow input channels and corresponding pairs of single-ended proper grounding to prototype circuitry. After evaluating input channels. This allows the inputs to have different with LTCs software, the digital signals can be connected reference sources, facilitating independent ratiometric to the applications processor/controller for development measurements on each channel. of the serial interface. Design files for this circuit board are available at DEMO MANUAL DC846A QUICK START PROCEDURE + 7.5V EXTERNAL AMPLIFIER SUPPLY REFERENCE MONITOR + (SEE HARDWARE SET-UP) (OR EXTERNAL SOURCE SEE HARWARE SET-UP) + 2.5V RESISTIVE SENSOR + RIBBON CABLE R REF TO EXCITATION DC590A VOLTAGE + + + + DIFFERENTIAL SIGNALS SINGLE ENDED SIGNALS COM BIAS (OBSERVE COMMON MODE LIMITATIONS) (OR TIE TO GROUND) Figure 1. Connection Diagram dc846af 2