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Evaluating Performance with the ADCPro Software

Note that with the Internal Reference off, the IDAC controls are disabled, because the IDACs cannot be

used unless the internal reference is turned on.

The Power Supply control selects between single supply (+5V) mode and bipolar supply (±2.5V) mode.

The EVM draws its supply voltages from the MMB3 motherboard, and has onboard circuitry to select

between the +5V and bipolar supplies.

The Reference Select control selects between VREF0 and the Internal Reference. When VREF0 is

selected, the VREF value is set to 2.048V, with switch S1 set to BUFF. S1 should not be set to the AVDD

position, in order to prevent the reference from exceeding the maximum specified input.

There are two checkboxes that, when enabled, allow the REF0P and REF0N pins to be selected as

GPIOs. These checkboxes are enabled only in modes that allow these pins to be used as GPIOs.

The Internal Reference control selects whether the reference is off, on, or follows the START signal (refer

to the ADS1247 data sheet for more details on these choices). When the internal reference is enabled, the

IDAC controls are enabled as well, because the IDACs cannot function unless the internal reference is

turned on. Note that the internal reference does not necessarily have to be used as the ADC reference in

order to use the IDACs, but it does need to be turned on.

The IDAC Magnitude control sets the amount of current each of the two IDACs provide.

The IDAC0 and IDAC 1 Routing controls allow you to specify whether the IDAC0 or IDAC1 currents go to

the Analog inputs or turn the IDAC off. If the AIN button is selected, this option enables the corresponding

IDAC controls on the I/O Config tab.

SBAU148B– June 2009– Revised May 2011 ADS1147EVM, ADS1247EVM, ADS1147EVM-PDK, ADS1247EVM-PDK

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