MAX31785ETL+ Maxim Integrated Products, MAX31785ETL+ Datasheet - Page 14

• Manufacturer Part Number: MAX31785ETL+
• Description: Board Mount Temperature Sensors 6Ch Intelligent Fan Controller
• Manufacturer: Maxim Integrated Products

Specifications of MAX31785ETL+

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

6-Channel Intelligent Fan Controller
The MAX31785 is a closed-loop fan controller. Automatic
closed-loop fan control saves system power by operat-
ing the fans at the lowest possible speeds. Added ben-
efits of slower fan speeds include lower audible noise,
longer fan life, and reduced system maintenance. Based
on a user-programmable lookup table (LUT), the device
automatically adjust the speeds of the six independent
fans based on one or more of the 11 available tem-
perature sensors. Temperature offset can be added to
Table 1. PMBus Command Codes
PMBus is a trademark of SMIF, Inc.
14
CODE
2Ah
3Ah
3Bh
7Ah
8Bh
8Dh
9Ah
9Bh
9Ch
00h
03h
10h
11h
12h
19h
20h
40h
42h
43h
44h
4Fh
51h
78h
79h
7Eh
80h
81h
90h
98h
99h
PAGE
CLEAR_FAULTS
WRITE_PROTECT
STORE_DEFAULT_ALL
RESTORE_DEFAULT_ALL
CAPABILITY
VOUT_MODE
VOUT_SCALE_MONITOR
FAN_CONFIG_1_2
FAN_COMMAND_1
VOUT_OV_FAULT_LIMIT
VOUT_OV_WARN_LIMIT
VOUT_UV_WARN_LIMIT
VOUT_UV_FAULT_LIMIT
OT_FAULT_LIMIT
OT_WARN_LIMIT
STATUS_BYTE
STATUS_WORD
STATUS_VOUT
STATUS_CML
STATUS_MFR_SPECIFIC
STATUS_FANS_1_2
READ_VOUT
READ_TEMPERATURE_1
READ_FAN_SPEED_1
PMBUS_REVISION
MFR_ID
MFR_MODEL
MFR_REVISION
MFR_LOCATION
COMMAND NAME
Detailed Description
Read Word
Read Word
Read Word
Read Word
Read Word
Send Byte
Send Byte
Send Byte
Read Byte
Read Byte
Read Byte
Read Byte
Read Byte
Read Byte
Read Byte
Read Byte
Read Byte
Read Byte
Block R/W
R/W Word
R/W Word
R/W Word
R/W Word
R/W Word
R/W Word
R/W Word
R/W Word
R/W Byte
R/W Byte
R/W Byte
TYPE
PAGE
R/W
R/W
R/W
R/W
R/W
0–5
—
—
—
—
—
—
—
—
—
—
—
W
W
W
R
R
R
R
R
R
R
R
R
R
R
PAGE
6–16
individual sensors to compensate for thermal differences
in a system. Alternately, an external host can manually
command the fan speeds and the device automatically
adjusts the fan speeds. The device can also monitor up
to six remote voltages.
The device provides ALERT and FAULT output sig-
nals. Host communications are conducted through a
PMBusK-compatible communications port. Address
input connections are also provided to allow up to four
MAX31785 devices to reside on the system’s I/O bus.
R/W
R/W
R/W
R/W
R/W
—
—
—
—
—
—
—
—
—
—
—
W
W
W
(NOTE 1)
R
R
R
R
R
R
R
R
R
R
R
PAGE
17–22
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
—
—
—
—
—
—
—
—
W
W
W
R
R
R
R
R
R
R
R
R
R
R
PAGE
R/W
R/W
R/W
255
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
W
W
W
R
R
R
R
R
R
R
R
R
NO. OF
BYTES
1
0
1
0
0
1
1
2
1
2
2
2
2
2
2
2
1
2
1
1
1
1
2
2
2
1
1
1
2
8
(NOTE 2)
STORED
FLASH
FIXED
FIXED
FIXED
FIXED
FIXED
N
N
N
N
N
N
N
N
N
N
N
N
N
N
N
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
DEFAULT
(NOTE 2)
00h/10h
(Note 3)
VALUE
7FFFh
FFFFh
7FFFh
7FFFh
0000h
0000h
7FFFh
7FFFh
0000h
0000h
0000h
0000h
3030h
4Dh
00h
00h
40h
00h
00h
00h
00h
00h
00h
11h
53h
—
—
—