Datasheet
LTC1857/LTC1858/LTC1859
14
185789fa
Figure 6a. Mode 1 for the LTC1859*. CONVST Starts a Conversion, Data Output is Always Enabled (RD = 0)
Figure 6b. Mode 2 for the LTC1859*. CONVST and RD Tied Together. CONVST Starts a Conversion, Data is Read by RD
SGL/
DIFF
1
t
4
RD = 0
SCK
SDI
SDO
CONVST
BUSY
2345678 1516
ODD/
SIGN
SELECT
1
SELECT
0
UNI GAIN NAP SLEEP DON’T CARE
DON’T
CARE
B14 B13 B12B15 (MSB)
B11 B10 B9 B8 B1 B0 (LSB)
t
ACQ
t
7
t
6
t
2
t
CONV
t
1
t
10
t
11
SHIFT CONFIGURATION WORD IN
SGL/
DIFF
1 2 3 4 5 6 7 8 15 16
ODD/
SIGN
SELECT
1
SELECT
0
UNI GAIN NAP SLEEP DON’T CARE
B14 B13 B12B15 (MSB)
B11 B10 B9 B8 B1
1859 F06a
B0 (LSB)
SHIFT A/D RESULT OUT AND NEW CONFIGURATION WORD IN
t
5
t
3
t
12
t
12
SGL/
DIFF
1
t
4
CONVST = RD
SCK
SDI
Hi-Z
SDO
BUSY
2 3 4 5 6 7 8 15 16
ODD/
SIGN
SELECT
1
SELECT
0
UNI GAIN NAP SLEEP DON’T CARE
DON’T
CARE
B14 B13 B12B15 (MSB)
B11 B10 B9 B8 B1 B0 (LSB)
t
ACQ
t
13
t
2
t
CONV
Hi-Z
t
10
t
11
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 F06b
B0 (LSB)
Hi-Z
SHIFT A/D RESULT OUT AND NEW CONFIGURATION WORD IN
t
5
t
3
t
9
t
8
t
7
t
6
Figure 7. Operating Sequence for the LTC1859*
SGL/
DIFF
1
t
4
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 SLEEP DON’T CARE
DON’T
CARE
B14 B13 B12B15 (MSB)
B11 B10 B9 B8 B1 B0 (LSB)
t
ACQ
t
13
t
2
t
1
t
CONV
Hi-Z
t
10
t
11
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 F07
B0 (LSB)
Hi-Z
SHIFT A/D RESULT OUT AND NEW CONFIGURATION WORD IN
t
5
t
3
t
9
t
8
t
7
t
6
*For the 12-bit LTC1857 and 14-bit LTC1858, the last four and two bits of the SDO will output zeros respectively.
APPLICATIONS INFORMATION