ltc1272-8 Linear Technology Corporation, ltc1272-8 Datasheet - Page 19

• Manufacturer Part Number: ltc1272-8
• Description: 12-bit, 3?s, 250khz Sampling A/d Converter
• Manufacturer: Linear Technology Corporation

A
PPLICATI
OUTPUT
2.42V
V
REF
*
O
U
+
ANALOG INPUT
S
10µF
**
*
✝
(0V TO 5V)
I FOR ATIO
THE LTC1272 HAS THE SAME 0V TO 5V INPUT RANGE BUT PROVIDES A 2.42V
REFERENCE OUTPUT AS OPPOSED TO THE –5.25V OF THE AD7572. FOR PROPER
OPERATION, REVERSE THE REFERENCE CAPACITOR POLARITY AND SHORT OUT THE
10 RESISTOR.
THE D FLIP-FLOP SYNCHRONIZES THE CONVERSION START SIGNAL (RD ) TO THE
ADC CLK
AN ASYNCHRONOUS CLOCK.
THE LTC1272 CAN ACCOMMODATE THE –15V SUPPLY OF THE AD7572 BUT DOES
NOT REQUIRE IT. PIN 23 OF THE LTC1272 IS NOT INTERNALLY CONNECTED.
U
Ω
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 its circuits as described herein will not infringe on existing patent rights.
DATA
0.1µF
BUS
µ
OUT
P
Figure 23. Plugging the LTC1272 into an AD7572 Socket
Case 2: Clock Not Synchronous with CS and RD
10Ω
SIGNAL TO PREVENT OUTPUT CODE NOISE WHICH OCCURS WITH
W
*
AGND
D11 (MSB)
D10
D9
D8
D7
D6
D5
D4
DGND
A
V
REF
IN
LTC1272
U
CLK OUT
CLK IN
D2/10
BUSY
HBEN
D3/11
D0/8
D1/9
NC
V
RD
CS
DD
✝
ASYNCHRONOUS
EXTERNAL
CLOCK
Q
0.1 F
µ
74HC74
1/2
S
CLK
+
OR
D**
10 F
–15V
µ
†
74HC04
0.1 F
µ
RD
LTC1272 • TA05
+
10 F
5V
µ
CONTROL
LINES
µ
P
LTC1272
19
1272fb