MAX6639ATE+T Maxim Integrated Products, MAX6639ATE+T Datasheet - Page 6

• Manufacturer Part Number: MAX6639ATE+T
• Description: IC TEMP MONITOR 2CH 16-TQFN
• Manufacturer: Maxim Integrated Products

Specifications of MAX6639ATE+T

• Function: Fan Control, Temp Monitor
• Topology: ADC, PWM Generator, Tach Counter
• Sensor Type: External & Internal
• Sensing Temperature: 0°C ~ 150°C, External Sensor
• Output Type: I²C™/SMBus™
• Output Alarm: Yes
• Output Fan: Yes
• Voltage - Supply: 3 V ~ 3.6 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 16-TQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

2-Channel Temperature Monitor with Dual,
Automatic, PWM Fan-Speed Controller
Figure 1. SMBus Protocols
6
Write Byte Format
Read Byte Format
Send Byte Format
S = START CONDITION
P = STOP CONDITION
S
S
_______________________________________________________________________________________
DXP1
DXP2
S
DXN
ADD
SDA
SCL
ADDRESS
Slave Address: equiva-
lent to chip-select line
ADDRESS
7 bits
Slave Address: equiva-
lent to chip-select line of
a 3-wire interface
7 bits
ADDRESS
INTERFACE AND
TEMPERATURE
7 bits
PROCESSING
REGISTERS
BLOCK
SMBus
WR
WR
ACK
GND
V
CC
ACK
WR
GENERATOR
BLOCK
Command Byte: sends com-
mand with no data, usually
used for one-shot command
PWM
Block Diagram
SHADED = SLAVE TRANSMISSION
/// = NOT ACKNOWLEDGED
COMMAND
MAX6639
Command Byte: selects
which register you are
reading from
8 bits
LOGIC
COMMAND
8 bits
ACK
PWM1
PWM2
OT
THERM
FANFAIL
ALERT
TACH1
TACH2
ACK
Command Byte: selects which
register you are writing to
ACK
COMMAND
P
8 bits
S
Receive Byte Format
The MAX6639 monitors its own temperature and a
remote-diode-connected transistor or the temperatures
of two external-diode-connected transistors, which typi-
cally reside on the die of a CPU or other integrated cir-
cuit. The 2-wire serial interface accepts standard
SMBus write byte, read byte, send byte, and receive
byte commands to read the temperature data and pro-
gram the alarm thresholds. Temperature data can be
read at any time over the SMBus, and a programmable
alarm output can be used to generate interrupts, throt-
tle signals, or overtemperature shutdown signals.
The temperature data is also used by the internal dual-
PWM fan-speed controller to adjust the speed of up to
two cooling fans, thereby minimizing noise when the
system is running cool, but providing maximum cooling
when power dissipation increases. RPM feedback
allows the MAX6639 to control the fan’s actual speed.
S
Slave Address: repeated
due to change in data-
flow direction
ADDRESS
7 bits
ADDRESS
ACK
7 bits
Data Byte: data goes into the register
set by the command byte (to set
thresholds, configuration masks, and
sampling rate)
RD
DATA
RD
8 bits
Detailed Description
ACK
ACK
Data Byte: reads data from
the register commanded
by the last read byte or
write byte transmission;
also used for SMBus alert
response return address
Data Byte: reads from
the register set by the
command byte
DATA
8 bits
DATA
8 bits
ACK
///
///
P
1
P
P