LTC2301 Linear Technology Corporation, LTC2301 Datasheet - Page 20

• Manufacturer Part Number: LTC2301
• Description: (LTC2301 / LTC2305) 12-Bit ADCs
• Manufacturer: Linear Technology Corporation

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APPLICATIONS INFORMATION
LTC2301/LTC2305
Sleep Mode
The ADCs enter sleep mode after a conversion is complete
(t
only 7μA in sleep mode, provided that none of the digital
inputs are switching. When the LTC2301/LTC2305 are
properly addressed, the ADCs are released from sleep
mode and require 200ms (t
the respective 2.2μF and 10μF bypass capacitors on the
V
be initiated before this time as shown in Figure 11.
Acquisition
The LTC2301/LTC2305 begin acquiring the input signal at
different instances depending on whether a read or write
operation is being performed. If a read operation is being
20
REF
CONV
and REFCOMP pins. A new conversion should not
) if the SLP bit is set to a logic 1. The ADCs draw
SDA
SCL
CONVERSION
REFWAKE
Figure 12a. Timing Diagram Showing Acquisition During a Read Operation
Figure 12b. Timing Diagram Showing Acquisition During a Write Operation
SDA
SCL
S
A2
5
Figure 11. Exiting Sleep Mode and Starting a New Conversion
A1
6
) to wake up and charge
7-BIT ADDRESS
A0
7
A6
1
R/W
SLEEP
8
A5
2
9
A4
3
A3
4
S/D
R/W
1
A2
5
O/S
2
ACK
A1
6
performed, acquisition of the input signal begins on the
rising edge of the 9th clock pulse following the address
frame as shown in Figure 12a.
If a write operation is being performed, acquisition of the
input signal begins on the falling edge of the sixth clock
cycle after the D
Figure 12b. The LTC2301/LTC2305 will acquire the signal
from the input channel that was most recently programmed
by the D
the input signal before initiating a new conversion.
Board Layout and Bypassing
To obtain the best performance, a printed circuit board with
a solid ground plane is required. Layout for the printed
board should ensure digital and analog signal lines are
t REFWAKE
X
3
A0
7
X
4
R/W
8
IN
UNI
5
word. A minimum of 240ns is required to acquire
9
SLP
6
ACQUISITION BEGINS
t
ACQ
IN
X
7
ACQUISITION BEGINS
P
t
ACQ
B11
word has been shifted in as shown in
1
8
X
23015 F12a
CONVERSION
B10
2
9
23015 F12b
23015 F11
23015f