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ADS1278EVM Hardware Details
15
SBAU197A – February 2012 – Revised January 2016
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Copyright © 2012–2016, Texas Instruments Incorporated
ADS1x7xEVM-PDK
Some pins on J5 have weak pull-up/down resistors. These resistors provide default settings for many of
the control pins. Many pins on J5 correspond directly to ADS1278 pins. See the
ADS1278 product data
sheet
for complete details on these pins.
5.5.3
Data Output Signals
5.5.3.1
DOUT on Digital Interface J4
In TDM mode, the data from all eight channels can be observed on the DOUT1 pin of the converter. The
DOUT1 signal is used by the ADS1x7xEVM-PDK to read back and display all the channels. The digital
data output pin on the digital interface header J4 is connected to DOUT1 signal via a D flip-flop. The D
flip-flop provides a half cycle delay in order to align the data correctly to reach the higher speeds of the
device. Otherwise, the propagation delay from the MSB in Frame Sync mode may result in missing the
MSB out of the data word.
5.5.3.2
DOUTx Header, J2
All the data output signals (DOUT1 to DOUT8) can be monitored on J2.
Table 9
illustrates the pinout for
J2.
(1)
Pin 1 is top right-hand corner, located next to reference designator.
Table 9. J2, DOUTx Header
Data Out Line
Pin Number
Data Out Line
DOUT1
1
(1)
2
DOUT2
DOUT3
3
4
DOUT4
DOUT5
5
6
DOUT6
DOUT7
7
8
DOUT8
5.6
Power Supply Header, J5
J5 is the power-supply input connector.
Table 10
lists the configuration details for J5. Supplies of 1.8V,
3.3V, and 5.0V are required for operation of the EVM. When using the EVM as part of the EVM-PDK,
these voltages are generated by the MMB0 and no external supplies are required. For operation as a
stand-alone EVM, the power supplies should be connected as shown below.
(1)
Pin 1 is bottom left-hand corner, located next to reference designator.
Table 10. J5 Configuration: Power-Supply Input
Function
Pin Name
Pin Number
(J5)
Pin Name
Function
Not used for this design
Not used
1
(1)
2
Not used
Not used for this design
+5V analog supply
+5VA
3
4
Not used
Not used for this design
Digital ground
DGND
5
6
AGND
Analog ground input
1.8V digital supply
+1.8VD
7
8
Not used
Not used for this design
3.3V digital supply
+3.3VD
9
10
N/A
Do not use
NOTE:
For monitoring the current from each supply, CM1, CM2, and CM3 (0
Ω
resistors) can be
removed and replaced with sense resistors or ammeters.
The ADS1278 digital supplies are connected as follows:
•
IOVDD supply is connected to the +1.8VD pin of the J3 header.
•
DVDD supply is connected to the +3.3VD pin of the J3 header.
The ADS1278 analog supply, AVDD, is connected to the +5VA pin of the J5 header.
