Analog-to-digital converters Two different ADCs were chosen to be tested using the Teradyne J750

Analog-to-digital converters Two different ADCs were chosen to be tested using the Teradyne J750. Since the requirements called for

10- to 12-bit precision, one 10-bit ADC and one 12-bit ADC were chosen.

One device has a parallel output while the other can be configured for either

serial or parallel output. This could allow the cookbook to be more versatile

and ultimately more useful. The two models chosen for the project were the

AD7892 and the AD7470.

AD7892 A 12-bit ADC with an output that can be selected to be

parallel or serial was chosen because of its wide versatility.

• Runs off of a single 5-volt supply.

• The AD7892-1 and AD7892-2 have sampling rates of 500 KSPS and

the AD7892-3 has a sampling rate of 600 KSPS.

• Has a conversion time of 1.47us.

• Has a signal to noise ratio of 70 dB.

• Is available in a 24 lead PDIP package at the cost of $15.45 per device.

AD7470 This chip has a 10-bit parallel output and was chosen to complement the AD7892 and to give a more comprehensive ADC section in the

cookbook.

• Has a sampling rate of 1.75 MSPS.

• Uses a single 2.7 volt to 5.25 volt power supply.

• Comes in the 24-lead TSSOP package at the cost of $3.53 per device.

• Has a wide input bandwidth and no pipeline delay.

There was a very wide array of ADCs available for use, so future teams

or other projects should not have any problem finding alternative devices if

necessary. In order for use to use the AD7470 the team created an adapter

that goes from 24-lead TSSOP to 24-pin DIP.