LTC2379-18 Datasheet, PDF (18/24 Pages) Linear Technology – 18-Bit, 1.6Msps, Low Power SAR ADC with 101dB SNR

LTC2379-18
TIMING DIAGRAM
When CHAIN = OV_DD, the LTC2379-18 operates in Chain
Mode. In Chain Mode, SDO is always enabled and RDL/SDI
serves as the serial data input pin (SDI) where daisychain
data output from another ADC can be input.
This is useful for applications where hardware constraints
may limit the number of lines needed to interface to a large
number of converters. Figure 15 shows an example with
two daisy chained devices. The MSB of converter A will
appear at SDO of converter B after 18 SCK cycles. The
MSB of converter A is clocked in at the SDI/RDL pin of
converter B on the rising edge of the first SCK.
OV_DD
CHAIN ^CNV
LTC2379-18
RDL/SDI
SDO
A
SCK
OV_DD
CHAIN ^CNV
LTC2379-18
RDL/SDI
B
BUSY
SDO
SCK
CONVERT
DIGITAL HOST
IRQ
DATA IN
POWER-DOWN
AND ACQUIRE
CHAIN = OV_DD
RDL/SDI_A = 0
CONVERT
CNV
CLK
POWER-DOWN AND ACQUIRE
237918 F15a
t_CYC
CONVERT
t_CNVL
BUSY
t_BUSYLH
SCK
t_CONV
SDO_A = RDL/SDI_B
SDO_B
t_DSDOBUSYL
t_SCKCH
t_SCKH
1
2
3
16
17
18
19
20
34
35
36
t_SSDISCK
t_HSDISCK
t_HSDO
t_DSDO
t_SCKL
D17_A D16_A D15_A
D1_A D0_A
t_QUIET
D17_B D16_B D15_B
D1_B D0_B D17_A D16_A
Figure 15. Chain Mode Timing Diagram
D1_A
D0_A
237918 F15
18
237918p