DDC114 Datasheet, PDF (20/30 Pages) Burr-Brown (TI) – Quad Current Input 20-Bit ANALOG-TO-DIGITAL CONVERTER

DDC114
SBAS255A − JUNE 2004 − REVISED NOVEMBER 2004
Changing Between Modes
Changing from the cont to ncont mode occurs whenever
T_INT < t₆. 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 DDC114 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.
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Changing from the ncont to cont mode occurs when T_INT
is increased so that T_INT is always ≥ t₆ as shown in
Figure 19 (see Figure 14 and Table 8, page 18). 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 < t₆. 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.
CONV
State
5
Integration
Status
Integrate A
m/r/az
Status
m/r/az B
mbsy
4
5
Continuous
Integrate B
Int A
8
Non−Continuous
76
5
Int B Int A
m/r/az A
m/r/az B
m/r/az A
m/r/az B
Figure 18. Changing from Continuous Mode to Non-Continuous Mode
CONV
State
Integration
Status
m/r/az
Status
3
4
Int A Int B
1
2
Non−Continuous
m/r/az A
m/r/az B
mbsy
3
Continuous
Integrate A
4
Integrate B
m/r/az A
Figure 19. Changing from Non-Continuous Mode to Continuous Mode
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