LTC1272-3CCS Linear Technology, LTC1272-3CCS Datasheet - Page 17

• Manufacturer Part Number: LTC1272-3CCS
• Description: 12-Bit/ 3us/ 250kHz Sampling A/D Converter
• Manufacturer: Linear Technology

A
Compatibility with the AD7572
Figure 21 shows the simple, single 5V configuration
recommended for new designs with the LTC1272. If an
AD7572 replacement or upgrade is desired, the LTC1272
can be plugged into an AD7572 socket with minor modi-
fications. It can be used as a replacement or to upgrade
with sample-and-hold, single supply operation and re-
duced power consumption.
The LTC1272, while consuming less power overall than
the AD7572, draws more current from the 5V supply (it
draws no power from the –15V supply). Also, a 1 s
PPLICATI
OUTPUT
2.42V
V
REF
O
U
S
8 OR 12-BIT
PARALLEL
ANALOG INPUT
0.1 F
I FOR ATIO
U
(0V TO 5V)
BUS
+
10 F
Figure 21. Single 5V Supply, 3 s, 12-Bit Sampling ADC
*
W
D11 (MSB)
D10
D9
D8
D7
D6
D5
D4
DGND
A
V
AGND
REF
IN
LTC1272
CLK OUT
U
CLK IN
D2/10
BUSY
HBEN
D3/11
D0/8
D1/9
V
NC
RD
CS
DD
minimum time between conversions must be provided to
allow the sample-and-hold to reacquire the analog input.
Figure 22 shows that if the clock is synchronous with CS
and RD, it is only necessary to short out the 10 series
resistor and reverse the polarity of the 10 F bypass
capacitor on the V
and can be removed, or, because there is no internal
connection to pin 23, it can remain unmodified. The clock
can be considered synchronous with CS and RD in cases
where the LTC1272 CLK IN signal is derived from the same
clock as the microprocessor reading the LTC1272.
10 F
CONTROL
LINES
P
+
5V
0.1 F*
*
FOR GROUNDING AND BYPASSING HINTS
SEE FIGURE 11 AND APPLICATION HINTS
SECTION
REF
pin. The –15V supply is not required
LTC1272 • TA03
LTC1272
17