DC1250A-AA Linear Technology, DC1250A-AA Datasheet - Page 3

• Manufacturer Part Number: DC1250A-AA
• Description: BOARD EVAL LTM9001-AA
• Manufacturer: Linear Technology
• Type: Baseband Receiverr

Specifications of DC1250A-AA

• Design Resources: Demo Circuit 1250A Schematic
• Frequency: 0Hz ~ 300MHz
• Features: LTM9001 16bit Receiver Subsystem, 162MHz BPF
• Tool / Board Applications: Wireless Connectivity-ZigBee, RF, Infrared, USB
• Mcu Supported Families: LTM9001
• Development Tool Type: Hardware - Eval/Demo Board
• For Use With/related Products: LTM9001
• Lead Free Status / RoHS Status: Not applicable / Not applicable

LTM9001 16-BIT RECEIVER SUBSYSTEM
OUTPUT DATA FORMAT
The default output format for DC1250 is demultiplexed
CMOS output mode, which alternates the digital outputs
coming out of the LTM9001 “A” and “B” channels. The
first output word is shifted out of the “A” channel, the
second word out of the “B” channel, and so on. Thus
each channel is updating at half the data rate. By default,
DC890 and PSCOPE read the board in demultiplexed
CMOS mode.
Removing resistor R19 on the DC1250 would ground the
LVDS pin, and the digital outputs would all come out of
channel “A” at the full data rate. However, PSCOPE is not
currently set up to read the data this way. When using
the outputs in full-data-rate mode, you must manually
configure PSCOPE (see Figure 2) to 2-channel mode,
and ignore the “B” channel display in PSCOPE.
Figure 2. Entering the correct device information for your ADC. Select the correct parameters for the DC1250. Under normal conditions,
PSCOPE should automatically recognize the board and adjust the software settings accordingly.
OTHER BOARD CIRCUITRY
Device U5 is an EEPROM that is used by the PScope
software to identify the board and apply the correct set-
tings for the data collection.
USING PSCOPE SOFTWARE
PScope, downloadable from Linear Technology’s website
http://www.linear.com/, processes data from the DC890
FastDAACS board and displays FFT and signal analysis
information on the computer screen. The on-board
EEPROM U5 should enable automatic board detection
and auto-configuration of the software, but if the user
wishes to change the settings, they can easily do so.
From the Configure menu in the toolbar, uncheck “Auto-
detect Device”. The default settings are shown in Figure
2. The LTM9001 also has an output randomizer, which
the user needs to select if it is enabled on the board (un-
der a different menu option). The software will automati-
cally un-randomize the output by performing an exclu-
sive-OR with each bit and the LSB.
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