LTC2301/LTC2305

19

23015f

APPLICATIONS INFORMATION

Continuous Read/Write

Once the conversion cycle is complete, the LTC2301/

LTC2305 can be written to and then read from using the

Repeated Start (Sr) command. Figure 9 shows a cycle which

begins with a data Write, a repeated Start, followed by a

Read and concluded with a Stop command. The following

conversion begins after all 16 bits are read out of the device

or after a Stop command. The following conversion will

be performed using the newly programmed data.

Synchronizing Multiple LTC2301/LTC2305s with a

Global Address Call

In applications where several LTC2301/LTC2305s or other

nized 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

channel selection (optional) and simultaneously initiate

a conversion for all ADCs on the bus (see Figure 10).

In order to synchronize multiple converters without chang-

ing the channel, a Stop command 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.

Nap Mode

The ADCs enter nap mode after a conversion is complete

decreases to 225μA in nap mode between conversions,

thereby reducing the average power dissipation as the

sample rate decreases. For example, the LTC2301/LTC2305

draw an average of 300μA at a 1ksps sampling rate. The

reference buffer (REFCOMP) circuitry active when in nap

mode.

Figure 9. Write, Read, Start Conversion

Figure 10. Synchronize Multiple LTC2301/LTC2305s with a Global Address Call

S

CONVERSION

NAP

DATA OUTPUT

CONVERSION

CONVERSION

DATA

OUTPUT

W

ACK

WRITE

7-BIT ADDRESS

Sr

R

ACK

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READ

7-BIT ADDRESS

P

S

SDA

SCL

CONVERSION

NAP

LTC2301/LTC2305

DATA OUTPUT

CONVERSION OF ALL LTC2301/05s

W

ACK

WRITE (OPTIONAL)

GLOBAL ADDRESS

P

LTC2301/LTC2305

LTC2301/LTC2305

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