Datasheet

6
LTC1090
1090fc
UU
U
PI FU CTIO S
# PIN FUNCTION DESCRIPTION
1-8 CH0 to CH7 Analog Inputs The analog inputs must be free of noise with respect to AGND.
9 COM Common The common pin defines the zero reference point for all single ended inputs. It must be free
of noise and is usually tied to the analog ground plane.
10 DGND Digital Ground This is the ground for the internal logic. Tie to the ground plane.
11 AGND Analog Ground AGND should be tied directly to the analog ground plane.
12 V
–
Negative Supply Tie V
–
to most negative potential in the circuit. (Ground in single supply applications.)
13,14 REF
–
, REF
+
Reference Inputs The reference inputs must be kept free of noise with respect to AGND.
15 CS Chip Select Input A logic low on this input enables data transfer.
16 D
OUT
Digital Data Output The A/D conversion result is shifted out of this output.
17 D
IN
Data Input The A/D configuration word is shifted into this input.
18 SCLK Shift Clock This clock synchronizes the serial data transfer.
19 ACLK A/D Conversion Clock This clock controls the A/D conversion process.
20 V
CC
Positive Supply This supply must be kept free of noise and ripple by bypassing directly to the analog ground
plane.
BLOCK DIAGRA
W
D
IN
17
D
OUT
16
SCLK
18
LTC1090 • BD01
CH0
1
CH1
2
CH2
3
CH3
4
CH4
5
CH5
6
CH6
7
CH7
8
COM
9
V
CC
20
INPUT SHIFT
REGISTER
OUTPUT
SHIFT
REGISTER
CS
15
ACLK
19
CONTROL
AND
TIMING
10-BIT
SAR
SAMPLE
AND HOLD
ANALOG
INPUT
MUX
COMP
REF
–
13
10-BIT
CAPACITIVE
DAC
REF
+
V
–
12
AGND
11
DGND
10
14