Datasheet

TDM Mode, Dynamic Position Data Discrete Data Output Mode
CH2
DOUT1
( )ADS1174
CH4 DIN
SCLK
DRDY
(SPI)
FSYNC
(Frame-Sync)
1 2
16 1715 32 3331
34 35
CH2
DOUT1
( )ADS1178
CH4 CH5
CH8 DIN
80 81 95 96 97 98
99
CH1DOUT1
CH2DOUT2
CH3DOUT3
CH4DOUT4
SCLK
DRDY
(SPI)
FSYNC
(Frame-Sync)
1 2 14 15 16
CH5DOUT5
CH6DOUT6
CH7DOUT7
CH8DOUT8
ADS1178 Only
ADS1174
ADS1178
SBAS373B – OCTOBER 2007 – REVISED SEPTEMBER 2008 ........................................................................................................................................ www.ti.com
In this TDM data output mode, when a channel is In Discrete data output mode, the channel data are
powered down, the data from higher channels shift shifted out in parallel using individual channel data
one position in the data stream to fill the vacated data output pins DOUT[4:1] for the ADS1174, or
slot. Figure 19 shows the data stream with channel 1 DOUT[8:1] for the ADS1178. After the 16th SCLK,
and channel 3 powered down. the channel data are forced to zero. The data are
also forced to zero for powered-down channels.
Figure 20 depicts the data format.
Figure 19. TDM Mode, Dynamic Position Data (Channels 1 and 3 Shown powered Down)
Figure 20. Discrete Data Output Mode
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Product Folder Link(s): ADS1174 ADS1178