Datasheet

19
LTC1291
1291fa
Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However,
no responsibility is assumed for its use. Linear Technology Corporation makes no representation that
the interconnection of its circuits as described herein will not infringe on existing patent rights.
U
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data is output MSB-first. CS is driven at 1/64, the clock
frequency by the 74HC393 and D
OUT
outputs the data.
The output data from the D
OUT
pin can be viewed on a
oscilloscope that is set up to trigger on the falling edge
of CS (Figure 17).
A “Quick Look” Circuit for the LTC1291
Users can get a quick look at the function and timing of
the LTC1291 by using the following simple circuit
(Figure 16). D
IN
is tied to V
CC
. This requires V
IN
be
applied to CH1 with respect to the ground plane. The
Figure 16. “Quick Look” Circuit for the LTC1291
A1
CLR1
1QA
1QB
1QC
1QD
GND
V
CC
A2
CLR2
2QA
2QB
2QC
2QD
74HC393
0.1µF
V
IN
TO OSCILLOSCOPE
0.1µF
5V
22µF TANTALUM
f
f/64
CLOCK IN 1MHz
LTC1291 F16
V
CC
(V
REF
)
CLK
D
OUT
D
IN
LTC1291
CS
CH0
CH1
GND
+
CLK
CS
D
OUT
NULL
BIT
MSB
(B11)
LSB
(B0)
FILLS WITH
ZEROES
VERTICAL: 5V/DIV
HORIZONTAL: 5µs/DIV
Figure 17. Scope Trace of the LTC1291 "Quick Look"
Circuit Showing Output 101010101010 (AAA
HEX
)