Operating Principles; Quick Start Procedure - Linear Technology DC890B Quick Start Manual

QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 890B

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 475 resistor). Refer to the QuickEval-II

QUICK START PROCEDURE

To prevent damage to the DC890B, it is important to
follow the equipment setup procedure outlined be-
low:
1. Do not plug the DC890B into the PC USB port
before running the installation program
2. Download the QuickEval-II installation program
from http://www.linear.com/software/.
3. Run the QuickEval-II installation program and
follow the on-screen instructions.
 NOTE:
The QuickEval-II evaluation software
requires a PC running Windows98, 2000, or XP
with an available USB port.
4. Connect the DC890B to the USB port and supply
external power to the DC890B, if you will be us-
ing the LVDS mode. Do not use a USB cable
longer than 2m or the board may not reset prop-
erly. (See note in trouble shooting section.)
5. Connect only 2.5V CMOS or LVDS output ADC
demonstration circuits directly to the DC890B via
the 100 pin edge connector. All Linear Technol-
ogy DC890 compatible demo boards meet these
requirements. Apply DC power to the ADC dem-
onstration 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.
Downloaded from Elcodis.com electronic components distributor
Software Help for information on the various operating
modes and options. The Conversion clock to the
DC890B is supplied via the ADC demonstration circuit
either from an optional on board oscillator if installed
or an external signal generator connected to the ADC
demonstration circuit.
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 ana-
log input signal to the ADC demonstration board.
8. Open the QuickEval-II software and from the
Configure Menu, select FastDAACS. Then also
from the Configure menu, click on Device and
scroll through the list of Linear Technology Cor-
poration ADCs and select the device part number
on the attached demo board.
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 QuickEval-II
page 1.
11. If the sampled signal is not coherent with the en-
code 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 QuickEval-II Software.
FastDAACS
2