Datasheet

DDC112
19
SBAS085B
www.ti.com
CONV
4214
Non-Continuous Continuous
33
State
mbsy
m/r/az
Status
Integration
Status
m/r/az A m/r/az B m/r/az A
Int BInt A Integrate A Integrate B
FIGURE 18. Changing from Continuous Mode to Non-Continuous Mode.
FIGURE 19. Changing from Non-Continuous Mode to Continuous Mode.
CONV
8745
Continuous Non-Continuous
5 65
State
Integration
Status
m/r/az
Status
mbsy
m/r/az B m/r/az A m/r/az B m/r/az A m/r/az B
Integrate A Integrate B Int AInt A Int B
Changing Between Modes
Changing from the cont to ncont mode occurs whenever
T
INT
< t
6
. Figure 18 shows an example of this transition.
In this figure, the cont mode is entered when the integration
on side A is completed before the m/r/az cycle on side B is
complete. The DDC112 completes the measurement on
sides B and A during states 8 and 7 with the input signal
shorted to ground. Ncont integration begins with state 6.
Changing from the ncont to cont mode occurs when T
INT
is
increased so that T
INT
is always ≥ t
6
(see Figure 14). With a
longer T
INT
, the m/r/az cycle has enough time to finish before
the next integration begins and continuous integration of the
input signal is possible. For the special case of the very first
integration when changing to the cont mode, T
INT
can be
< t
6
. This is allowed because there is no simultaneous
m/r/az cycle on the side B during state 3—
there is no need
to wait for it to finish before ending the integration on side A.