LTC1292 LINER [Linear Technology], LTC1292 Datasheet - Page 22

• Manufacturer Part Number: LTC1292
• Description: Single Chip 12-Bit Data Acquisition Systems
• Manufacturer: LINER [Linear Technology]

LTC1292/LTC1297
A “Quick Look” Circuit for the LTC1292
Users can get a quick look at the function and timing of
the LTC1292 by using the “Quick Look” circuit in Figure
26. V
and the –IN input is tied to the ground plane. CS is driven
at 1/32 the clock rate by the CD4520 and D
the data. The output data from the D
viewed on an oscilloscope that is set up to trigger on the
falling edge of CS (Figure 27). Note the LSB data is
partially clocked out before CS goes high.
22
A
PPLICATI
REF
Figure 27. Scope Trace of the LTC1292 “Quick Look”
Circuit Showing A/D Output 101010101010 (AAA
D
is tied to V
CLK
OUT
CS
NULL
O
BIT
V
IN
U
CC
(B11)
S
MSB
. V
VERTICAL: 5V/DIV
HORIZONTAL: 2 s/DIV
I FOR ATIO
U
IN
is applied to the +IN input
CS
+IN
–IN
GND
TO OSCILLOSCOPE
LTC1297
340
(B0)
LSB
W
TANTALUM
Figure 28. “Quick Look” Circuit for the LTC1297
22µF
D
V
LSB-FIRST DATA
CLK
V
OUT
REF
OUT
CC
0.02 F
(B1)
OUT
pin can be
U
HEX
f/64
outputs
CLOCK IN 1MHz
)
f
A “Quick Look” Circuit for the LTC1297
A circuit similar to the one used for the LTC1292 can be
used for the LTC1297(Figure 28). A one shot has been
generated with NAND gates, a resistor and capacitor to
satisfy the setup time t
slower clock is used. When CS goes low the one shot is
triggered. This turns off the clock to the LTC1297 for a
fixed time to meet t
shifted out one bit at a time. CS is driven at 1/64 the
clock rate by the 74HC393. The output data from the
D
trigger on the falling edge of CS. See Figure 29.
OUT
pin can be viewed on an oscilloscope that is set to
Figure 29. Scope Trace of the LTC1297 “Quick Look”
Circuit Showing A/D Output 101010101010 (AAA
A1
CLR1
1QA
1QB
1QC
1QD
GND
D
CLK
74HC393
OUT
CS
CLR2
2QA
2QB
2QC
2QD
V
NULL
A2
BIT
CC
suCS
(B11)
MSB
VERTICAL: 5V/DIV
HORIZONTAL: 5 s/DIV
suCS
. Once the clock starts D
(B0)
LSB
. This can be eliminated if a
LSB-FIRST DATA
LTC1292/7 F28
(B1)
5V
0.1µF
HEX
OUT
)
is