Datasheet

LTC2440
9
2440fd
FUNCTIONAL BLOCK DIAGRAM
TEST CIRCUITS
APPLICATIONS INFORMATION
Figure 1. Functional Block Diagram
Figure 2. LTC2440 State Transition Diagram
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,
operation cycle and data out format is compatible with
the LTC2410.
AUTOCALIBRATION
AND CONTROL
DAC
DECIMATING FIR
INTERNAL
OSCILLATOR
SERIAL
INTERFACE
ADC
GND
V
CC
IN
+
IN
–
SDO
SCK
REF
+
REF
–
CS
SDI
BUSY
EXT
f
O
(INT/EXT)
2440 F01
–+
+
–
1.69k
SDO
2440 TA03
Hi-Z TO V
OH
V
OL
TO V
OH
V
OH
TO Hi-Z
C
LOAD
= 20pF
1.69k
SDO
2440 TA04
Hi-Z TO V
OL
V
OH
TO V
OL
V
OL
TO Hi-Z
C
LOAD
= 20pF
V
CC
CONVERT
SLEEP
DATA OUTPUT
2440 F02
TRUE
FALSE
CS = LOW
AND
SCK