MAX1617A Datasheet, PDF (14/18 Pages) Maxim Integrated Products – Remote/Local Temperature Sensor with SMBus Serial Interface

Remote/Local Temperature Sensor
with SMBus Serial Interface
Table 8. RLTS and RRTE Temp Register Update Timing Chart
OPERATING MODE
Auto-Convert
CONVERSION INITIATED BY:
Power-on reset
NEW CONVERSION RATE
(CHANGED VIA WRITE TO
WCRW)
n/a (0.25Hz)
Auto-Convert
1-shot command, while idling
between automatic conversions
n/a
Auto-Convert
1-shot command that occurs
during a conversion
n/a
Auto-Convert
Rate timer
0.0625Hz
Auto-Convert
Rate timer
0.125Hz
Auto-Convert
Rate timer
0.25Hz
Auto-Convert
Rate timer
0.5Hz
Auto-Convert
Rate timer
1Hz
Auto-Convert
Rate timer
2Hz
Auto-Convert
Rate timer
4Hz
Auto-Convert
Rate timer
8Hz
Hardware Standby
STBY pin
n/a
Software Standby
RUN/STOP bit
n/a
Software Standby
1-shot command
n/a
TIME UNTIL RLTS AND RRTE
ARE UPDATED
156ms max
156ms max
When current conversion is
complete (1-shot is ignored)
20sec
10sec
5sec
2.5sec
1.25sec
625ms
312.5ms
237.5ms
156ms
156ms
156ms
The address pin states are checked at POR and SPOR
only, and the address data stays latched to reduce qui-
escent supply current due to the bias current needed
for high-Z state detection.
The MAX1617A also responds to the SMBus Alert
Response slave address (see the Alert Response
Address section).
POR and UVLO
The MAX1617A has a volatile memory. To prevent ambig-
uous power-supply conditions from corrupting the data in
memory and causing erratic behavior, a POR voltage
detector monitors V_CC and clears the memory if V_CC falls
below 1.7V (typical, see Electrical Characteristics table).
When power is first applied and V_CC rises above 1.75V
(typical), the logic blocks begin operating, although reads
and writes at V_CC levels below 3V are not recommended.
A second V_CC comparator, the ADC UVLO comparator,
prevents the ADC from converting until there is sufficient
headroom (V_CC = 2.8V typical).
The SPOR software POR command can force a power-on
reset of the MAX1617A registers via the serial interface.
Use the SEND BYTE protocol with COMMAND = FCh.
This is most commonly used to reconfigure the slave
address of the MAX1617A “on the fly,” where external
hardware has forced new states at the ADD0 and ADD1
address pins prior to the software POR. The new address
takes effect less than 100µs after the SPOR transmission
stop condition.
Table 9. Slave Address Decoding (ADD0
and ADD1)
ADD0
GND
GND
GND
High-Z
High-Z
High-Z
V_CC
V_CC
V_CC
ADD1
GND
High-Z
V_CC
GND
High-Z
V_CC
GND
High-Z
V_CC
ADDRESS
0011 000
0011 001
0011 010
0101 001
0101 010
0101 011
1001 100
1001 101
1001 110
Note: High-Z means that the pin is left unconnected and floating.
Power-Up Defaults:
• Interrupt latch is cleared.
• Address select pins are sampled.
• ADC begins auto-converting at a 0.25Hz rate.
• Command byte is set to 00h to facilitate quick
remote Receive Byte queries.
• T_HIGH and T_LOW registers are set to max and min
limits, respectively.
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