Datasheet

9
LTC2400
FU CTIO AL BLOCK DIAGRA
UU
W
TEST CIRCUITS
Figure 1. LTC2400 State Transition Diagram
APPLICATIONS INFORMATION
WUU
U
AUTOCALIBRATION
AND CONTROL
DAC
DECIMATING FIR
INTERNAL
OSCILLATOR
SERIAL
INTERFACE
ADC
∑
∫∫∫
GND
V
CC
V
IN
SDO
SCK
V
REF
CS
F
O
(INT/EXT)
2400 FD
3.4k
SDO
2400 TA03
HI-Z TO V
OH
V
OL
TO V
OH
V
OH
TO HI-Z
C
LOAD
= 20pF
3.4k
SDO
2400 TA04
HI-Z TO V
OL
V
OH
TO V
OL
V
OL
TO HI-Z
C
LOAD
= 20pF
V
CC
Converter Operation Cycle
The LTC2400 is a low power, delta-sigma analog-to-
digital converter with an easy to use 3-wire serial interface.
Its operation is simple and made up of three states. The
converter operating cycle begins with the conversion,
followed by a low power sleep state and concluded with
the data output (see Figure 1). The 3-wire interface con-
sists of serial data output (SDO), a serial clock (SCK) and
a chip select (CS).
Initially, the LTC2400 performs a conversion. Once the
conversion is complete, the device enters the sleep state.
While in this sleep state, power consumption is reduced by
CONVERT
SLEEP
DATA OUTPUT
2400 F01
0
1
CS AND
SCK