LMP90100EB/NOPB National Semiconductor, LMP90100EB/NOPB Datasheet - Page 19

• Manufacturer Part Number: LMP90100EB/NOPB
• Description: EVAL BOARD FOR LMP90100
• Manufacturer: National Semiconductor

Specifications of LMP90100EB/NOPB

• Main Purpose: Interface, Analog Front End (AFE)
• Embedded: No
• Utilized Ic / Part: LMP90100
• Primary Attributes: 8 Programmable Output Data Rates Per Channel
• Secondary Attributes: SPI Interface
• Silicon Manufacturer: National
• Silicon Core Number: LMP90100
• Kit Application Type: Data Converter
• Application Sub Type: ADC
• Kit Contents: LMP90100 Evaluation Board
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

© 2009 National Semiconductor Corporation
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Step 2: Configure Inputs – click on the “INPUT MUX” block to set “VINP = 100: VIN4” and
“VINN = 011: VIN3”. Click on the “View Schematic” button located next to the block diagram.
This should open up a PDF of the schematic for a thermocouple.
Step 3: Select Reference – click on the “VREF MUX” block to choose “VREF_SEL = 0: VREF1”.
Make sure the value for VREF1 = 5.0V.
Step 4: Source IB1/IB2? – this step can be ignored because neither IB1 nor IB2 is connected to the
inputs.
Step 5: Set Gain – since the differential junction across a thermocouple is low, the maximum gain
can be 128x. Click on the “FGA” block, “PGA” block, or the “Gain” slider to select the gain.
Step 6: Set Buffer – click on the “BUFF” block to include or exclude the buffer from the signal path.
Step 7: Set Calibration - click on the “No Calibration” block to enable or disable calibration. Refer
to the LMP90100 datasheet to more information on the LMP90100’s background calibration types
and modes.
Step 8: Int/Ext CLK? – click on the “CLK MUX” block and make sure the internal clock is selected.
Step 9: Performance - click on the “Performance” mini-tab. This tab displays the Estimated
Device Performance base on the block diagram that you’ve configured, as well as the Measured
System Performance if you’ve connected a board and ran the LMP90100.
Figure 15 - Recommended LMP90100 Configuration for a Thermocouple
Page 19 of 30
with Sensor AFE Software User’s Guide
lmp90100eb_usersguide_20101227_v23.doc
LMP90100 Evaluation Board