LTC1287 Datasheet, PDF (15/16 Pages) Linear Technology – 3V Single Chip 12-Bit Data Acquisition System

LTC1287
APPLICATI S I FOR ATIO
CS
V_CC
+IN
CLK
LTC1287
–IN
D_OUT
GND
V_REF
Figure 18
+3V
1N4148
+2.5V
LTC1287 F18
22µF TANTALUM
CS
V_CC
f
V_IN
+IN
CLK
LTC1287
–IN
D_OUT
GND
V_REF
A “Quick Look” Circuit for the LTC1287
Users can get a quick look at the function and timing of
the LTC1287 by using the following simple circuit
(Figure 19). V_REF is tied to V_CC. V_IN is applied to the +IN
input and the –IN input is tied to the ground plane. CS
is driven at 1/32 the clock rate by the 74HC393 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 20). Note the LSB data is
partially clocked out before CS goes high.
f/32
A1
VCC
CLR1
A2
1QA
CLR2
1QB 74HC393 2QA
1QC
2QB
1QD
2QC
GND
2QD
+3V
0.1µF
TO OSCILLOSCOPE
CLOCK IN
500kHz
Figure 19. "Quick Look" Circuit for the LTC1287
LTC1287 F19
CLK
CS
D_OUT
NULL MSB
BIT (B11)
LSB LSB DATA
(B0) (B1)
VERTICAL: 5V/DIV
HORIZONTAL: 5µs/DIV
Figure 20. Scope Trace of the LTC1287 “Quick Look” Circuit
Showing A/D Output 1010101010 (AAA_HEX)
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 represen-
tation that the interconnection of circuits as described herein will not infringe on existing patent rights.
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