Datasheet

5
LTC1392
TYPICAL PERFORMANCE CHARACTERISTICS
U
W
INPUT
SHIFT
REGISTER
BANDGAP
CONTROL
AND TIMING
CS
4
LTC1392 • BD
SERIAL
PORT
V
REF
= 2.42V
V
REF
= 1V
V
REF
= 0.5V
ANALOG
INPUT
MUX
10-BIT
SAR
10
BITS
C
SAMPLE
V
CC
85
GND
TEMPERATURE
SENSOR
V
CC
GND
D
IN
1
V
REF
+V
IN
–V
IN
6
7
COMP
10-BIT
CAPACITIVE DAC
+
+
–
+
–
–
D
OUT
2
CLK
3
BLOCK DIAGRAM
W
PIN FUNCTIONS
UUU
D
IN
(Pin 1): Digital Input. The A/D configuration word is
shifted into this input.
D
OUT
(Pin 2): Digital Output. The A/D result is shifted out
of this output.
CLK (Pin 3): Shift Clock. This clock synchronizes the serial
data.
CS (Pin 4): Chip Select Input. A logic low on this input
enables the LTC1392.
GND (Pin 5): Ground Pin. GND should be tied directly to
an analog ground plane.
+V
IN
(Pin 6): Positive Analog Differential Input. The pin
can be used as a single-ended input by grounding –V
IN
.
–V
IN
(Pin 7): Negative Analog Differential Input. The input
must be free from noise.
V
CC
(Pin8): Positive Supply. This supply must be kept free
from noise and ripple by bypassing directly to the ground
plane.
Supply Current vs Sample Rate
TIME (SEC)
0
TEMPERATURE (°C)
5
10
15 20
1392 G07
25
70
65
60
55
50
45
40
35
30
25
20
30
V
CC
= 5V
N8
S8
Thermal Response in Stirred
Oil Bath
SAMPLE FREQUENCY (Hz)
SUPPLY CURRENT (µA)
1000
100
10
1
0.1
0.1 10 100 1k 10k 100k
1392 G09
1
V
CC
= 5V
f
CLK
= 250kHz
T
A
= 25°C
CS LOW BETWEEN SAMPLES
CS HIGH BETWEEN
SAMPLES
TIME (SEC)
0
TEMPERATURE (°C)
50
100
150 200
1392 G08
250
70
65
60
55
50
45
40
35
30
25
20
300
V
CC
= 5V
N8
S8
Thermal Response in Still Air