MAX1136_09 Datasheet, PDF (16/22 Pages) Maxim Integrated Products – 2.7V to 3.6V and 4.5V to 5.5V, Low-Power, 4-/12-Channel, 2-Wire Serial 10-Bit ADCs

2.7V to 3.6V and 4.5V to 5.5V, Low-Power,
4-/12-Channel, 2-Wire Serial 10-Bit ADCs
MASTER TO SLAVE
SLAVE TO MASTER
A. SINGLE CONVERSION WITH INTERNAL CLOCK
1
7
11
S SLAVE ADDRESS R A CLOCK STRETCH
tACQ
tCONV
8
RESULT 2 MSBs A
8
RESULT 8 LSBs
11
A P or Sr
NUMBER OF BITS
B. SCAN MODE CONVERSIONS WITH INTERNAL CLOCK
1
7
11
S SLAVE ADDRESS R A
CLOCK STRETCH
tACQ1
tCONV1
tACQ2
tCONV2
8
1
8
1
CLOCK STRETCH RESULT 1 ( 2MSBs) A RESULT 1 (8 LSBs) A
tACQN
tCONVN
8
1
8
11
RESULT N (8MSBs) A RESULT N (8LSBs) A P or Sr
NUMBER OF BITS
Figure 10. Internal Clock Mode Read Cycles
The device memory contains all of the conversion
results when the MAX1136–MAX1139 release SCL. The
converted results are read back in a first-in-first-out
(FIFO) sequence. If AIN_/REF is set to be a reference
input or output (SEL1 = 1, Table 6), AIN_/REF will be
excluded from a multichannel scan. The memory con-
tents can be read continuously. If reading continues
past the result stored in memory, the pointer will wrap
around and point to the first result. Note that only the
current conversion results will be read from memory.
The device must be addressed with a read command
to obtain new conversion results.
The internal clock mode’s clock stretching quiets the
SCL bus signal reducing the system noise during con-
version. Using the internal clock also frees the bus
master (typically a microcontroller) from the burden of
running the conversion clock, allowing it to perform
other tasks that do not need to use the bus.
MASTER TO SLAVE
SLAVE TO MASTER
A. SINGLE CONVERSION WITH EXTERNAL CLOCK
1
7
11
8
1
8
S SLAVE ADDRESS R A RESULT (2 MSBs) A RESULT (8 LSBs)
11
A P OR Sr
t_ACQ
t_CONV
NUMBER OF BITS
B. SCAN MODE CONVERSIONS WITH EXTERNAL CLOCK
1
7
11
8
1
8
1
S _{SLAVE ADDRESS} R A _{RESULT 1 (2 MSBs)} A _{RESULT 2 (8 LSBs)} A
t_ACQ1
t_CONV1
t_ACQ2
Figure 11. External Clock Mode Read Cycle
8
1
8
11
RESULT N (2 MSBs) ^A RESULT N (8 LSBs) ^{A P OR Sr}
t_ACQN
t_CONVN
NUMBER OF BITS
16 ______________________________________________________________________________________