LTC1291 Linear Technology, LTC1291 Datasheet - Page 5

• Manufacturer Part Number: LTC1291
• Description: Single Chip 12-Bit Data Acquisition System
• Manufacturer: Linear Technology

PI FU CTIO S
TYPICAL PERFOR
#
1
2, 3
4
5
6
7
8
100
250
200
100
150
10
50
U
1
100
0
–50
D
Sample-and-Hold Acquisition
Time vs Source Resistance
V
T
0V TO 5V INPUT STEP
PIN
CS
CH0, CH1
GND
D
D
CLK
V
OUT
V
CC
A
CC
IN
OUT
CC
MSB-FIRST DATA
–25
= 25°C
= 5V
(V
= 5V
Delay Time vs Temperature
V
AMBIENT TEMPERATURE (°C)
U
REF
IN
R
)
0
SOURCE
R
FUNCTION
Chip Select Input
Analog Inputs
Analog Ground
Digital Data Input
Digital Data Output
Shift Clock
Positive Supply and
Reference Voltage
SOURCE
25
+
+
–
LSB-FIRST DATA
1k
U
50
+ ( )
75
W
100
A
1291 G13
1291 G10
U
10k
125
This clock synchronizes the serial data transfer.
DESCRIPTION
A logic low on this input enables the LTC1291.
These inputs must be free of noise with respect to GND.
GND should be tied directly to an analog ground plane.
The multiplexer address is shifted into this input.
The A/D conversion result is shifted out of this output.
This pin provides power and defines the span of the A/D converter. This supply must be kept free of noise and
ripple by bypassing directly to the analog ground plane.
CE
C
1000
HARA TERISTICS
600
900
800
700
500
400
300
200
100
1.0
0.4
0.8
0.6
0.2
0
0
100
–50
Maximum Clock Rate vs Source
Resistance
Input Channel Leakage Current
vs Temperature
–30
–10
AMBIENT TEMPERATURE (°C)
C
10
1k
R
SOURCE –
30
OFF CHANNEL
50
R
SOURCE
+V
( )
ON CHANNEL
GUARANTEED
IN
10k
70
V
CLK = 1MHz
–
CC
90 110
+
–
= 5V
+IN
–IN
1291 G14
1291 G11
100k
130
* MAXIMUM CLK FREQUENCY REPRESENTS THE CLK
**MAXIMUM R
FREQUENCY AT WHICH A 0.1LSB SHIFT IN THE
ERROR AT ANY CODE TRANSITION FROM ITS 1MHz
VALUE IS FIRST DETECTED.
VALUE AT WHICH A 0.1LSB CHANGE IN FULL SCALE
ERROR FROM ITS VALUE AT R
DETECTED.
100
10k
1k
10
1
10
Maximum Filter Resistor vs
Cycle Time
C
FILTER
FILTER
+V
IN
REPRESENTS THE FILTER RESISTOR
R
FILTER
1µF
100
CYCLE TIME (µs)
FILTER
+
–
LTC1291
= 0 IS FIRST
1k
1291 G12
5
10k