LTC2440 Linear Technology, LTC2440 Datasheet - Page 9

• Manufacturer Part Number: LTC2440
• Description: 24-Bit High Speed Differential delta-sigma ADC
• Manufacturer: Linear Technology

APPLICATIO S I FOR ATIO
CONVERTER OPERATION
Converter Operation Cycle
The LTC2440 is a high speed, delta-sigma analog-to-
digital converter with an easy to use 4-wire serial interface
(see Figure 1). Its operation is made up of three states. The
converter operating cycle begins with the conversion,
followed by the low power sleep state and ends with the
data output (see Figure 2). The 4-wire interface consists
of serial data input (SDI), serial data output (SDO), serial
clock (SCK) and chip select (CS). The interface, timing,
FU CTIO AL BLOCK DIAGRA
TEST CIRCUITS
REF
REF
GND
V
IN
IN
CC
+
–
+
–
U
+
–
∫
U
SDO
U
Hi-Z TO V
V
V
1.69k
+
OL
OH
∫
TO V
DAC
TO Hi-Z
U
–
OH
OH
C
LOAD
W
2440 TA03
∫
= 20pF
Figure 1. Functional Block Diagram
U
∑
W
ADC
Figure 2. LTC2440 State Transition Diagram
2440 F01
FALSE
AUTOCALIBRATION
DECIMATING FIR
SDO
AND CONTROL
DATA OUTPUT
Hi-Z TO V
V
V
CONVERT
CS = LOW
OH
OL
SCK
SLEEP
AND
V
TO Hi-Z
TO V
CC
TRUE
1.69k
OL
C
OL
2440 F02
LOAD
2440 TA04
= 20pF
OSCILLATOR
INTERFACE
INTERNAL
SERIAL
LTC2440
sn2440, 2440fas
(INT/EXT)
F
SDO
SCK
CS
SDI
BUSY
EXT
9
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