Quick Start Procedure - Linear Technology DC416 Demo Manual

DEMO MANUAL DC416

quick start proceDure

3. If the intent is to do an evaluation of AC performance,
connect a sinusoidal (or other) input signal to J1, or
J1 and J2, with a nominal DC bias of 2.5V. If only J1 is
used (single-ended operation), JP3 should be installed.
This converter converts unipolar differential inputs from
0 – V .
REF
NOTE: The A inputs do not have 50Ω termination. Most
IN
generators will produce the correct signal level only if the
cable is terminated at 50Ω. If you are driving this from
a generator, you should use 50Ω through terminators.
Take care not to overdrive the inputs if you do not use
terminators.
4. Connect a 20MHz digital clock to CLKIN. With default
jumpers in place, this will result in a 250ksps conver-
sion rate.
SIGNAL
SOURCE
IF DIFFERENTIAL
SIGNAL SOURCE
CLOCK
SOURCE
2
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IF U2 POPULATED WITH BIPOLAR AMPLIFIER
+
–
+
–
Figure 1. Proper Measurement Equipment Setup
5. Collect data via PScope for a Fourier transform into the
frequency domain, or to allow data to be collected and
saved to a file for subsequent import and analysis in
Excel, Matlab or other analysis packages.
Duplication of the FFT results shown in the data sheet
requires the use of a low jitter clock and waveform genera-
tors synchronized such that the input waveform must be
within a few ppm of an exact multiple of the conversion
clock divided by the FFT size (termed coherent). For 250kHz
sample rate and a 4096 point FFT, input frequencies should
be an exact multiple of 61.035156Hz, and preferably a prime
number multiple or at least an odd number multiple. The
use of an even number multiple will exercise a minimal
number of codes, producing poor results.
SERIAL DATA
COLLECTION SYSTEM
PARALLEL
DATA
COLLECTION
SYSTEM
USE EITHER
PARALLEL OR SERIAL
DATA COLLECTION SYSTEM
DC416 F01
dc416f