MAX7501 Maxim, MAX7501 Datasheet - Page 9

• Manufacturer Part Number: MAX7501
• Description: Digital Temperature Sensors and Thermal Watchdog with Bus Lockup Protection
• Manufacturer: Maxim

Table
Table
Queue Bits
temperature rises above the T
ed when the temperature drops below the T
See
ture shutdown block in interrupt mode. OS is asserted
in interrupt mode when the temperature rises above the
T
deasserted only after performing a read operation.
Set bit D0, the shutdown bit, to zero for normal opera-
tion. Set bit D0 to 1 to shut down the MAX7500/
MAX7501/MAX7502 internal blocks, dropping the sup-
ply current to 3µA. The I
long as the shutdown bit is set. The T
configuration registers can still be written to and read
from while in shutdown.
In comparator mode, the OS output behaves like a ther-
mostat. The output asserts when the temperature rises
above the limit set in the T
deasserts when the temperature falls below the limit set
in the T
can be used to turn on a cooling fan, initiate an emer-
gency shutdown signal, or reduce system clock speed.
Table
X = Don’t care.
COMMAND
OS
Read
Write
D4
Figure
value or falls below the T
0
0
1
1
D7
0
HYST
5. Configuration Register Definition
7. T
6. Configuration Register Fault
4. Set bit D1 to 1 to run the over-tempera-
register. In comparator mode, the OS output
OS
1 = negative
1 = negative
0 = positive
0 = positive
Digital Temperature Sensors and Thermal
Sign bit
Sign bit
D15
and T
D3
_______________________________________________________________________________________
0
1
0
1
D6
0
Watchdog with Bus Lockup Protection
HYST
2
C interface remains active as
64°C
64°C
MSB
MSB
D14
T
OS
OS
OS
Register Definitions
NO. OF FAULTS
value. OS is deassert-
and T
register. The output
32°C
32°C
1 (POR state)
D5
D13
HYST
0
UPPER BYTE
HYST
OS
2
4
6
value. OS is
16°C
16°C
, T
D12
HYST
HYST
Registers
Fault queue
D4
value.
D11
8°C
8°C
, and
D10
4°C
4°C
Fault queue
In interrupt mode, exceeding T
remains asserted until a read operation is performed on
any of the registers. Once OS has asserted due to
crossing above T
again only when the temperature drops below T
The output remains asserted until it is reset by a read.
Putting the MAX7500/MAX7501/MAX7502 into shut-
down mode also resets OS.
The T
bytes, with bits D15–D7 containing the data. Bits
D6–D0 are don’t cares when writing to these two regis-
ters and read-back zeros when reading from these reg-
isters. The LSB represents 0.5 C while the MSB
represents 64 C. See
Figure 4. OS Timing Diagram
(COMPARATOR MODE)
OS SET ACTIVE LOW
OS SET ACTIVE LOW
(INTERRUPT MODE)
2°C
2°C
D9
D3
TEMPERATURE
OS
OS OUTPUT
OS OUTPUT
1°C
1°C
D8
and T
T
HYST
T
OS
OS polarity
0.5°C
0.5°C
LSB
LSB
HYST
D7
D2
OS
Table
and is then reset, it is asserted
registers are accessed with 2
D6
0
x
OPERATION
READ
D5
7.
x
0
Comparator/
LOWER BYTE
interrupt
OS
D4
D1
0
x
also asserts OS. OS
OPERATION
READ
D3
0
x
D2
0
x
Shutdown
OPERATION
D0
D1
READ
0
x
HYST
D0
x
0
9
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