LTC2379-18
TIMING DIAGRAMS
Normal Mode, Multiple Devices
Since SDO is shared, the RDL/SDꢁ input of each ADC must
be used to allow only one LTC2379-18 to drive SDO at a
timeinordertoavoidbusconflicts. AsshowninFigure14,
the RDL/SDꢁ inputs idle high and are individually brought
low to read data out of each device between conversions.
When RDL/SDꢁ is brought low, the MSꢀ of the selected
device is output onto SDO.
Figure 14 shows multiple LTC2379-18 devices operating
in normal mode (CHAꢁI = 0) sharing CIV, SCK and SDO.
ꢀy sharing CIV, SCK and SDO, the number of required
signals to operate multiple ADCs in parallel is reduced.
RDL
RDL
ꢀ
A
COIVERT
CIV
CIV
CHAꢁI
ꢀUSY
SDO
ꢁRQ
CHAꢁI
LTC2379-18
ꢀ
LTC2379-18
A
DꢁGꢁTAL HOST
SDO
RDL/SDꢁ
RDL/SDꢁ
SCK
SCK
DATA ꢁI
CLK
237918 F15
POWER-DOWI
AID ACQUꢁRE
COIVERT
COIVERT
POWER-DOWI AID ACQUꢁRE
CHAꢁI = 0
t
CIVL
CIV
t
COIV
ꢀUSY
t
ꢀUSYLH
RDL/SDꢁ
A
ꢀ
RDL/SDꢁ
t
SCK
t
t
QUꢁET
SCKH
19
SCK
SDO
1
2
3
16
17
18
20
21
34
35
36
t
t
SCKL
HSDO
t
t
DSDO
DꢁS
D0
t
EI
Hi-Z
Hi-Z
Hi-Z
D17
A
D16
D15
D1
D17
D16
D15
D1
ꢀ
D0
ꢀ
A
A
A
A
ꢀ
ꢀ
ꢀ
237918 F14
Figure 14. Normal Mode With Multiple Devices Sharing CNV, SCK and SDO
237918fa
17
Linear Systems [ Linear Systems ]
