Texas Instruments ADS1278-SP, Руководство пользователя, Страница: 10 / 32

Quick Reference
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10 SBAU324 – September 2018
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ADS1278EVM-CVAL Evaluation Module User's Guide
3 Quick Reference
Table 4 provides a quick summary of the connections required for operation of the EVM as a standalone.
Table 4. Critical Connections
Function Header/Pin Pin Name Description
Interface
SCLK J4.3 CLKX SCLK
DIN J4.11 DX Data In
DOUT J4.13 DR Data Out
Interrupt J4.15 INT DRDY/FSYNC
Power
1.8 V J5.7 +1.8VD Digital supply
3.3 V J5.9 +3.3VD Digital supply
5.0 V J5.3 +5VA Analog supply
Analog Inputs
Channels 1-4 J3.1-8 Analog Inputs
Channels 5-8 J1.3-10 Analog Inputs
CAUTION
When using the ADS1278EVM-CVAL with the MMB0 EVM, the DIP switches
S1 and S2 must all be switched up, away from the center of the board. Failure
to do so may damage the EVM.
3.1 Analog Inputs
The analog inputs for the ADS1278EVM-CVAL are connected to J1 and J3 . Channels 1-4 connect to J3
and provisions are provided to buffer these signals before being connected to the converter. Switches S4,
S5, S7 , and S8 control whether the buffered or unbuffered signal is connected to the ADS1278-SP.
Channels 5-8 connect to J1 and have an RC filter available to filter the input before connecting to the
converter. Channels 5-8 do not have provisions for buffering the signal.
3.2 Digital Control
The digital control signals can be applied directly to J4 (top or bottom side).
3.3 Power Supply
The ADS1278EVM-CVAL requires power rails as follows:
• 5.0-V analog supply - supplied by MMB0 motherboard via J13B
• 3.3-V digital supply - supplied by MMB0 motherboard
• 1.8-V digital supply - supplied by MMB0 motherboard
3.4 Voltage Reference
The ADS1278EVM-CVALhas two options for the reference voltage. Switch S3 selects the reference
voltage from either the buffered REF5025 or a external reference voltage that is connected to the
reference pins of
J3 ( J3.18 = REFN and J3.20 = REFP). Regardless of the reference source, the voltage
being provided to the ADS1278-SP can be monitored at testpoints TP2, REFN , and TP3, REFP , as shown
in Figure 9 below.