DDC112 Datasheet, PDF (22/24 Pages) Burr-Brown (TI) – Dual Current Input 20-Bit ANALOG-TO-DIGITAL CONVERTER

RETRIEVAL BEFORE AND AFTER CONV
TOGGLES (CONTINUOUS MODE)
For the absolute maximum time for data retrieval, data can
be retrieved before and after CONV toggles. Nearly all of
T_INT is available for data retrieval. Figure 26 illustrates how
this is done by combining the two previous methods. You
must pause the retrieval during CONV’s toggling to prevent
digital noise, as discussed previously, and finish before the
next data is ready. The maximum number of DDC112s that
can be daisy-chained together is:
T_INT – 20µs – 2µs
40 τ _DCLK
For T_INT = 500µs and DCLK = 10MHz, the maximum
number of DDC112s is 119.
CONV
DVALID
DXMIT
DCLK
DOUT
T_INT
t₂₈
T_INT
t₂₉
t₂₆
T_INT
•••
•••
•••
•••
•••
•••
•••
•••
•••
•••
•••
•••
Side B
Data
Side A
Data
SYMBOL
t₂₆
t₂₈
t₂₉
DESCRIPTION
Hold Time for DXMIT HIGH Before Falling
Edge of DVALID
Data Retrieval Shutdown Before Edge of CONV
Data Retrieval Start-Up After Edge of CONV
CLK = 10MHz
MIN
TYP
MAX
2
10
10
CLK = 15MHz
MIN
TYP
MAX
1.33
10
10
UNITS
µs
µs
µs
FIGURE 26. Readback Before and After CONV Toggles.
®
DDC112
22