Datasheet

25
LTC1096/LTC1096L
LTC1098/LTC1098L
U
SA
O
PP
L
IC
AT
ITY
P
I
CA
L
A “Quick Look” Circuit for the LTC1096
Users can get a quick look at the function and timing of the
LT1096 by using the following simple circuit (Figure 13).
V
REF
is tied to V
CC
. V
IN
is applied to the +IN input and the
–IN input is tied to the ground. CS is driven at 1/16 the
clock rate by the 74C161 and D
OUT
outputs the data. The
output data from the D
OUT
pin can be viewed on an
oscilloscope that is set up to trigger on the falling edge of
CS (Figure 14). Note the LSB data is partially clocked out
before CS goes high.
CLR
CLK
A
B
C
D
P
GND
V
CC

RC
QA
QB
QC
QD
T
LOAD
74C161
V
IN
TO OSCILLOSCOPE
CLOCK IN 150kHz MAX
LTC1096/8 • F13
V
CC

CLK
D
OUT

V
REF
LTC1096
CS
CH0
CH1
GND
4.7µF
5V
5V
+
MSB
(B7)
NULL
BIT
LSB
(B0)
LSB DATA
(B1)
CS
CLK
D
OUT
VERTICAL: 5V/DIV
HORIZONTAL: 10µs/DIV
LTC1096
+IN
–IN
V
REF
CS
CLK
D
OUT
V
CC
GND
TO µP
63.4k
0.01µF
182k
0.01µF
LT1004-1.2
0.1µF
3V
75k
678Ω
13.5k
LM134
LTC1096/8 • F15
Figure 15. The LTC1096’s High Impedance Input Connects
Directly to This Temperature Sensor, Eliminating Signal
Conditioning Circuitry in This 0°C to 70°C Thermometer
Figure 14. Scope Trace the LTC1096 “Quick Look” Circuit
Showing A/D Output 10101010 (AA
HEX
)
Figure 13. “Quick Look” Circuit for the LTC1096
Figure 15 shows a temperature measurement system.
The LTC1096 is connected directly to the low cost silicon
temperature sensor. The voltage applied to the V
REF
pin
adjusts the full scale of the A/D to the output range of the
sensor. The zero point of the converter is matched to the
zero output voltage of the sensor by the voltage on the
LTC1096’s negative input.