
LTC2495
2495fd
24bitsarereadoutofthedeviceorafteraSTOPcommand.
Thefollowingconversionwillbeperformedusingthenewly
programmed data. In cases where the same speed (1x/2x
mode), rejection frequency (50Hz, 60Hz, 50Hz and 60Hz)
and gain is used but the channel is changed, a STOP or
repeated START may be issued after the first byte (channel
selection data) is written into the device.
Discarding a Conversion Result and Initiating a New
Conversion with Optional Write
At the conclusion of a conversion cycle, a write cycle
can be initiated. Once the write cycle is acknowledged, a
STOP command will start a new conversion. If a new input
channel or conversion configuration is required, this data
can be written into the device and a STOP command will
initiate the next conversion (see Figure 9).
Figure 10. Synchronize Multiple LTC2495s with a Global Address Call
Synchronizing Multiple LTC2495s with a Global
Address Call
In applications where several LTC2495s (or other I2C delta-
sigmaADCsfromLinearTechnologyCorporation)areused
on the same I2C bus, all converters can be synchronized
through the use of a global address call. Prior to issuing the
global address call, all converters must have completed a
conversioncycle.ThemasterthenissuesaSTART,followed
by the global address 1110111, and a write request. All
converters will be selected and acknowledge the request.
The master then sends a write byte (optional) followed by
the STOP command. This will update the channel selection
(optional)converterconfiguration(optional)andsimultane-
ouslyinitiateaSTARTofconversionforalldelta-sigmaADCs
on the bus (see Figure 10). In order to synchronize multiple
converters without changing the channel or configuration,
a STOP may be issued after acknowledgement of the global
write command. Global read commands are not allowed
and the converters will NACK a global read request.
applications inForMation
Figure 8. Write, Read, START Conversion
Figure 9. Start a New Conversion Without Reading Old Conversion Result
7-BIT ADDRESS
CONVERSION
ADDRESS
SLEEP
DATA OUTPUT
DATA INPUT
7-BIT ADDRESS
S
R
W ACK
ACK
WRITE
Sr
P
READ
2495 F08
7-BIT ADDRESS
CONVERSION
SLEEP
DATA INPUT
S
W ACK
WRITE (OPTIONAL)
P
2495 F09
GLOBAL ADDRESS
SCL
SDA
LTC2495
…
ALL LTC2495s IN SLEEP
CONVERSION OF ALL LTC2495s
DATA INPUT
S
W ACK WRITE (OPTIONAL)
P
2495 F10