Datasheet

LTC2487
21
2487fd
Figure 10. Synchronize Multiple LTC2487s with a Global Address Call
Figure 8. Write, Read, Start Conversion
Figure 9. Start a New Conversion Without Reading Old Conversion Result
7-BIT ADDRESS
CONVERSION CONVERSIONADDRESSSLEEP DATA OUTPUTDATA INPUT
7-BIT ADDRESSS RW ACK ACKWRITE Sr PREAD
2487 F08
7-BIT ADDRESS
CONVERSION CONVERSIONSLEEP DATA INPUT
S W ACK WRITE (OPTIONAL) P
2487 F09
GLOBAL ADDRESS
SCL
SDA
…
ALL LTC2487s IN SLEEP CONVERSION OF ALL LTC2487s
DATA INPUT
S W ACK WRITE (OPTIONAL) P
2487 F10
LTC2487 LTC2487 LTC2487
can be written into the device and a Stop command will
initiate the next conversion (see Figure 9).
Synchronizing Multiple LTC2487s with a Global
Address Call
In applications where several LTC2487s (or other I
2
C
delta-sigma ADCs from Linear Technology Corporation)
are used on the same I
2
C bus, all converters can be syn-
chronized through the use of a global address call. Prior
to issuing the global address call, all converters must have
completed a conversion cycle. The master then issues a
Start, 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 chan-
nel selection (optional) converter confi guration (optional)
and simultaneously initiate a start of conversion for all
delta-sigma ADCs on the bus (see Figure 10). In order
to synchronize multiple converters without changing
the channel or confi guration, a Stop may be issued after
acknowledgement of the global write command. Global
read commands are not allowed and the converters will
NAK a global read request.
APPLICATIONS INFORMATION