Datasheet

12
LTC1091/LTC1092
LTC1093/LTC1094
U
S
A
O
PP
L
IC
AT
I
WU
U
I FOR ATIO
D
IN
1 D
IN
2
D
OUT
1
D
OUT
2
CS
SHIFT MUX
ADDRESS IN
1 NULL BIT
SHIFT A/D CONVERSION
RESULT OUT
1091/2/3/4 AI01
the first CLK pulse enables D
OUT
. After one null bit, the A/D
conversion result is output on the D
OUT
line. Bringing CS
high resets the LTC1092 for the next data exchange.
2. Input Data Word
The LTC1092 requires no D
IN
word. It is permanently
configured to have a single differential input and to operate
in unipolar mode. The conversion result is output on the
D
OUT
line in MSB-first sequence, followed by LSB-first
sequence, providing easy interface to MSB- or LSB-first
serial ports. The following disussion applies to the con-
figuration of the LTC1091/LTC1093/LTC1094.
The LTC1091/LTC1093/LTC1094 clock data into the D
IN
input on the rising edge of the clock. The input data words
are defined as follows:
SELECT
1
START
SELECT
0
UNI
MSBF
MUX ADDRESS
LTC1093/LTC1094 DATA INPUT (D
IN
)WORD:
MSB-FIRST/
LSB-FIRST
UNIPOLAR/
BIPOLAR
1091/2/3/4 AI02
ODD/
SIGN
SGL/
DIFF
START
MSBF
MUX ADDRESS
LTC1091 DATA INPUT (D
IN
) WORD:
MSB-FIRST/
LSB-FIRST
ODD/
SIGN
SGL/
DIFF
t
CONV
t
CYC
t
SMPL
Hi-Z
FILLED WITH ZEROS
1091/2/3/4 AI03
CLK
START
Hi-Z
ODD/SIGN
MSBF
SGL/
DIFF
D
IN
D
OUT
CS
B1B9 B0
DON’T CARE
t
CONV
t
CYC
t
SMPL
Hi-Z
FILLED WITH
ZEROS
1091/2/3/4 AI04
CLK
START
Hi-Z
ODD/SIGN
MSBF
SGL/
DIFF
D
IN
D
OUT
CS
B1B9 B0 B1 B9
DON’T CARE
LTC1091 Operating Sequence
Example: Differential Inputs (CH1
+
, CH0
–
)
MSB-First Data (MSBF = 1)
LSB-First Data (MSBF = 0)