Datasheet

LTC1857/LTC1858/LTC1859
17
185789fa
APPLICATIONS INFORMATION
Figure 9. Nap Mode Operation for the LTC1859*
SGL/
DIFF
1
RD
SCK
SDI
Hi-Z
SDO
BUSY
CONVST
2 3 4 5 6 7 8 15 16
ODD/
SIGN
SELECT
1
SELECT
0
UNI GAIN NAP = 1 SLEEP = 0 DON’T CARE
DON’T
CARE
B14 B13 B12B15 (MSB)
B11 B10 B9 B8 B1 B0 (LSB)
t
CONV
Hi-Z
NAPt
ACQ
t
ACQ
SHIFT CONFIGURATION WORD IN
SGL/
DIFF
12345678 1516
ODD/
SIGN
SELECT
1
SELECT
0
UNI GAIN NAP SLEEP DON’T CARE
B14 B13 B12B15 MSB
B11 B10 B9 B8 B1
1859 F09
B0 (LSB)
Hi-Z
SHIFT A/D RESULT OUT FROM PREVIOUS CONVERSION AND NEW CONFIGURATION WORD IN
Figure 11. Wake Up from Sleep Mode for the LTC1859*
Figure 10. Sleep Mode Operation for the LTC1859*
SGL/
DIFF
1
RD
SCK
SDI
SDO
BUSY
CONVST
2 3 4 5 6 7 8 15 16
ODD/
SIGN
SELECT
1
SELECT
0
UNI GAIN NAP
SLEEP = 0
DON’T CARE
DON’T
CARE
B14 B13 B12B15 (MSB)
B11 B10 B9 B8 B1 B0 (LSB)
WAKE-UP
TIME
READY
t
CONV
SLEEP
SHIFT WAKE-UP CONFIGURATION WORD IN
SGL/
DIFF
12345678 1516
ODD/
SIGN
SELECT
1
SELECT
0
UNI GAIN NAP SLEEP DON’T CARE
B14 B13 B12B15 (MSB)
B11 B10 B9 B8 B1
1859 F11
B0 (LSB)
A/D RESULT NOT VALID
SHIFT A/D RESULT OUT AND NEW CONFIGURATION WORD IN
t
CONV
*For the 12-bit LTC1857 and 14-bit LTC1858, the last four and two bits of the SDO will output zeros respectively.
SGL/
DIFF
1
RD
SCK
SDI
SDO
BUSY
CONVST
2 3 4 5 6 7 8 15 16
ODD/
SIGN
SELECT
1
SELECT
0
UNI GAIN NAP
SLEEP = 1
DON’T CARE
DON’T
CARE
B14 B13 B12B15 (MSB)
B11 B10 B9 B8 B1 B0 (LSB)
SHIFT WAKE-UP CONFIGURATION WORD IN
1859 F10
A/D RESULT NOT VALID
CONVST SHOULD STAY EITHER HIGH OR LOW IN SLEEP MODE
t
CONV
SLEEP