Datasheet

2
dc890bf
DEMO MANUAL DC890B
QUICK START PROCEDURE
To prevent damage to the DC890B, it is important to follow
the equipment setup procedure outlined below:
1. Do not plug the DC890B into the PC USB port before
running the installation program
2. Download the PScope installation program from
http://www.linear.com/software/.
3. Run the PScope installation program and follow the
on-screen instructions.
NOTE: The PScope evaluation software requires a PC
running Windows98, 2000, XP, or later, with an available
USB port.
4. Connect the DC890B to the USB port and supply ex-
ternal power to the DC890B, if you will be using the
LVDS mode. Do not use a USB cable longer than 2m or
the board may not reset properly. (See note in Trouble
Shooting section.)
5. Connect only 2.5V CMOS or LVDS output ADC demon-
stration circuits directly to the DC890B via the 100 pin
edge connector. All Linear Technology DC890 compat-
ible demo boards meet these requirements. Apply DC
power to the ADC demonstration circuit.
6. Each ADC demonstration board also comes with a quick
start guide similar to this one and should be referred to
for specific usage details relevant to the demonstration
circuit being evaluated. Please refer to it for proper
jumper settings, input power requirements and input
signal levels and frequency ranges.
7. Apply an appropriate conversion clock and analog input
signal to the ADC demonstration board.
8. ADC board will be automatically detected and config-
ured.
9. Select processing options (the hammer icon) menu
and verify that under trigger mode, no trigger wait is
selected
10. Enter the exact sample rate in MHz and select the sample
size in the provided fields in PScope page 1.
NOTE: Minimum sample rate in LVDS mode is 50Msps.
11. If the sampled signal is not coherent with the encode
clock, select an appropriate windowing function from
the pull down menu.
12. Initiate a data collection cycle by clicking the green
collect button; it will turn red during the collection
cycle. An FFT should appear on the screen along with
a plot of the sampled data. Make sure the input level is
not over ranging the ADC. See online help for specific
guidance on using the PScope software.
OPERATING PRINCIPLES
The DC890B is capable of collecting a block of data samples
from an ADC demonstration circuit initiated either by an
internally generated trigger or an externally supplied 2.5V
CMOS level trigger of user selected edge. The external
trigger is TTL or CMOS compatible (the trigger line is
diode clamped to the 2.5V Rail through a 475Ω resistor).
Refer to the PScope software help for information on the
various operating modes and options. The conversion
clock to the DC890B is supplied via the ADC demonstra-
tion circuit either from an optional on board oscillator if
installed or an external signal generator connected to the
ADC demonstration circuit.