AN-1409
APPLICATION NOTE
One Technology Way • P. O. Box 9106 • Norwood, MA 02062-9106, U.S.A. • Tel: 781.329.4700 • Fax: 781.461.3113 • www.analog.com
Achieving Pseudosimultaneous Sampling by Using the AD7616 Flexible Sequencer
and Burst Mode
by Ke n Ye, Kerwin Yu, and Aidan Frost
Rev. 0 | Page 1 of 8
INTRODUCTION
The AD7616 is a cost and performance optimized, 16-bit,
2 × 8 channel analog-to-digital converter (ADC) with dual
simultaneous sampling. The dual ADC architecture enables
the AD7616 to sample two analog channels simultaneously.
For power line applications, sample the voltage channel and
current channel inputs concurrently to reduce the phase error
between these inputs.
However, in a 3-phase power measurement system, dual-
channel simultaneous sampling is not sufficient for concurrently
sampling six analog channels. The phase error between the
samples of the different phases can cause some level of error for
power measurement, and it is difficult to compensate accurately
in the software, especially when taking harmonic content into
account.
This application note introduces a method for achieving
pseudosimultaneous sampling by using the AD7616 input
channels and by minimizing the phase mismatch between the
16 channels. When using this method, it minimizes the
channel-to-channel phase mismatching without diminishing
the amplitude accuracy performance.
For this application note, a theoretical analysis was done by using a
mathematical simulation to show how the accuracy of the signal
amplitude can be influenced, and how accurate channel-to-channel
matching can be using this method. In addition, an on-board
test result was implemented to prove the simulation results in
practice.
AN-1409 Application Note
Rev. 0 | Page 2 of 8
TABLE OF CONTENTS
Introduction ...................................................................................... 1
Revision History ............................................................................... 2
Pseudosimultaneous Sampling ....................................................... 3
Boundary Condition for Using Pseudo-Simultaneous
Sampling ........................................................................................ 3
Using the AD7616 to Implement Pseudosimultaneous Sampling
............................................................................................................. 5
Flexible Sequencer .........................................................................5
Burst Mode .....................................................................................5
Practice Testing ..............................................................................6
Conclusion..........................................................................................8
REVISION HISTORY
8/2016—Revision 0: Initial Version