Assembly Options - Linear Technology DC1925A Series Demo Manual

DEMO MANUAL DC1925A

ASSEMBLY OPTIONS

Table 1. DC1925A Assembly Options
ASSEMBLY VERSION
DC1925A-A
DC1925A-B
DC1925A-C
DC890 QUICK START PROCEDURE DC890 QUICK START PROCEDURE
Check to make sure that all switches and jumpers are
set as shown in the connection diagram of Figure 1.
In particular make sure that VCCIO (JP3) is set to the
2.5V position. Operating the DC1925A with the DC890
while JP3 is in the 3.3V position will cause noticeable
performance degradation in SNR and THD. The default
connections configure the ADC to use the onboard refer-
ence and regulators to generate the required common
mode voltages. The analog input is DC coupled. Connect
the DC1925A to a DC890 USB high speed data collection
board using connector P1. Then, connect the DC890 to a
host PC with a standard USB A/B cable. Apply ±9V to the
indicated terminals. Then apply a low jitter differential sine
source to J2 and J4. Connect a low jitter 80MHz 2.5V
sine wave or square wave to connector J1. Note that J1
has a 50Ω termination resistor to ground.
DC590 SETUP
IMPORTANT! To avoid damage to the DC1925A, make
sure that VCCIO (JP6) of the DC590 is set to 3.3V before
connecting the DC590 to the DC1925A.
VCCIO (JP3) of the DC1925A should be in the 3.3V position
for DC590 operation. To use the DC590 with the DC1925A,
it is necessary to apply –9V and ground to the –9V and
GND terminals. Connect the DC590 to a host PC with a
standard USB A/B cable. Connect the DC1925A to a DC590
USB serial controller using the supplied 14-conductor
ribbon cable. Apply a signal source to J4 and J2 or J4
depending on how the DC1925A is configured.
2
U1 PART NUMBER MAX CONVERSION RATE
LTC2378CMS-20
LTC2377CMS-20
LTC2376CMS-20
NUMBER OF BITS
1Msps
500ksps
250ksps
Run the PScope software (PScope.exe version K73 or
later) supplied with the DC890 or download it from www.
linear.com/software.
Complete software documentation is available from the
Help menu. Updates can be downloaded from the Tools
menu. Check for updates periodically as new features
may be added.
The PScope software should recognize the DC1925A and
configure itself automatically.
Click the Collect button (See Figure 5) to begin acquiring
data. The Collect button then changes to Pause, which
can be clicked to stop data acquisition.
P-P
Run the QuikEval software (version K92-01 or later) sup-
plied with the DC590 or download it from www.linear.
com/software. The correct control panel will be loaded
automatically. Click the Collect button (See Figure 6) to
begin reading the ADC.
MAX CLK IN FREQUENCY
20 80MHz
20 40MHz
20 20MHz
dc1925af