MAXIM MAX6639, MAX6639F User Manual

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim's website at www.maxim-ic.com.

General Description

The MAX6639 monitors its own temperature and one
external diode-connected transistor or the temperatures
of two external diode-connected transistors, typically
available in CPUs, FPGAs, or GPUs. The 2-wire serial
interface accepts standard System Management Bus
(SMBusTM) write byte, read byte, send byte, and
receive byte commands to read the temperature data
and program the alarm thresholds. Temperature data
can be read at any time over the SMBus, and three pro­grammable alarm outputs can be used to generate
interrupts, throttle signals, or overtemperature shut­down signals.

The temperature data is also used by the internal dual­PWM 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. Speed control is
accomplished by tachometer feedback from the fan, so
that the speed of the fan is controlled, not just the PWM
duty cycle. Accuracy of speed measurement is ±4%.

The MAX6639 is available in 16-pin QSOP and 16-pin thin
QFN 5mm x 5mm packages. It operates from 3.0V to 3.6V
and consumes just 500µA of supply current.

Applications

Desktop Computers

Notebook Computers

Projectors

Servers

Networking Equipment

Features

o Two Thermal-Diode Inputs
o Up to 25kHz PWM Output Frequency
o Three Selectable SMBus Addresses
o Local Temperature Sensor
o 1°C Remote Temperature Accuracy
o Two PWM Outputs for Fan Drive (Open Drain; Can

be Pulled Up to +13.5V)

o Programmable Fan-Control Characteristics
o Automatic Fan Spin-Up Ensures Fan Start
o Controlled Rate-of-Change Ensures Unobtrusive

Fan-Speed Adjustments

o ±3% Fan-Speed Measurement Accuracy
o Temperature Monitoring Begins at POR for Fail-

Safe System Protection

o OT and THERM Outputs for Throttling or

Shutdown

o Measures Temperatures Up to +150°C
o MAX6639F is Optimized for n = 1.021 for Penryn

Compatability

MAX6639/MAX6639F

2-Channel Temperature Monitor with Dual,

Automatic, PWM Fan-Speed Controller

________________________________________________________________

Maxim Integrated Products

1

Ordering Information

19-3682; Rev 2; 4/08

EVALUATION KIT

AVAILABLE

PART

O PER A T IN G

RANGE

M EA SU R EM EN T

RANGE

PIN-

PACKAGE

MAX6639AEE

-40°C to
+125°C

16 QSOP

MAX6639ATE

-40°C to
+125°C

16 TQFN ­E P *

M AX6 639FAEE +

-40°C to
+125°C

16 QSOP

16

15

14

13

12

11

10

9

1

2

3

4

5

6

7

8

PWM1

SCL

SDA

ADD

DXP2

DXN

GND

DXP1

TOP VIEW

MAX6639

QSOP

TACH1

PWM2

TACH2

V

CC

FANFAIL

THERM

OT

ALERT

MAX6639

*CONNECT EXPOSED
PAD TO GND.

V

CC

GND

DXP1

OT

PWM1

SDA

SCL

TACH1

PWM2

TACH2

FANFAIL

THERM

ADD

DXP2

DXN

ALERT

15

16

14

13

6

5

7

8

12 4

12 11 9

3

10

THIN QFN

5 mm x 5 mm

Pin Configurations

SMBus is a trademark of Intel Corp.

Typical Application Circuit appears at end of data sheet.

+

Denotes a lead-free package.

*

EP = Exposed pad.

0°C to +150°C

0°C to +150°C

0°C to +150°C

MAX6639/MAX6639F

2-Channel Temperature Monitor with Dual,
Automatic, PWM Fan-Speed Controller

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VCC= +3.0V to +3.6V, TA= 0°C to +125°C, unless otherwise noted. Typical values are at VCC= +3.3V, TA= +85°C.) (Note 1)

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.

VCCto GND..............................................................-0.3V to +4V

PWM1, PWM2, TACH1, and TACH2 to GND ......-0.3V to +13.5V

DXP1 and DXP2 to GND ..........................-0.3V to +(V

CC

+ 0.3V)

DXN to GND ..........................................................-0.3V to +0.8V

SCL, SDA, THERM, OT, FANFAIL, ADD,

and ALERT to GND ..............................................-0.3V to +6V

SDA, OT, THERM, ALERT, FANFAIL,

PWM1, and PWM2 Current .............................-1mA to +50mA

DXN Current .......................................................................±1mA

ESD Protection (all pins, Human Body Model) ..................2000V

Continuous Power Dissipation (T

A

= +70°C)

16-Pin QSOP (derated 8.3mW/°C above +70°C) ....... 667mW

16-Pin TQFN 5mm x 5mm

(derated at 33.3mW/°C above +70°C)................2666.7mW

Operating Temperature Range .........................-40°C to +125°C

Junction Temperature......................................................+150°C

Storage Temperature Range ............................-65°C to +150°C

Lead Temperature (soldering, 10s) .................................+300°C

PARAMETER

CONDITIONS

Operating Supply Voltage Range

V

CC

V

Standby Current SMB static, sleep mode 3 10 µA

Operating Current Interface inactive, ADC active 0.5 1 mA

VCC = +3.3V, +60°C ≤ TA ≤ +100°C and
+60°C ≤ T

R

≤ +100°C

VCC = +3.3V, +40°C ≤ TA ≤ +100°C and
0°C ≤ T

R

≤ +145°C

External Temperature Error
MAX6639AEE, MAX6639ATE:
n = 1.008
MAX6639FAEE: n = 1.021

V

CC

= +3.3V, 0°C ≤ TR ≤ +145°C

°C

VCC = +3.3V, +25°C ≤ TA ≤ +100°C

Internal Temperature Error
MAX6639AEE, MAX6639ATE

V

CC

= +3.3V, 0°C ≤ TA ≤ +125°C

°C

VCC = +3.3V, +25°C ≤ TA ≤ +100°C

Internal Temperature Error
MAX6639FAEE

V

CC

= +3.3V, 0°C ≤ TA ≤ +125°C

°C

Supply Sensitivity of Temperature
Measurement

°C

Temperature Resolution

11 Bits

Conversion Time

ms

Conversion-Rate Timing Error -10

%

PWM Frequency Error -10

%

Tachometer Accuracy TA = +60°C to +100°C ±3 %

High level 70

130

Remote-Diode Sourcing Current

Low level 7.0 10

µA

DXN Source Voltage 0.7 V

SYMBOL

MIN TYP MAX UNITS

+3.0 +3.6

-1.0 +1.0

-2.5 +2.5

-3.8 +3.8

-2.0 +2.0

-4.0 +4.0

-7.7 -2.5

-10.4 -0.1

±0.2 °C/V

+0.125

125

100

+10

+10

13.0

MAX6639/MAX6639F

2-Channel Temperature Monitor with Dual,

Automatic, PWM Fan-Speed Controller

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VCC= +3.0V to +3.6V, TA= 0°C to +125°C, unless otherwise noted. Typical values are at VCC= +3.3V, TA= +85°C.) (Note 1)

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

DIGITAL INPUTS AND OUTPUTS

ALERT, FANFAIL, THERM, OT, SDA
I

SINK

= 6mA

0.4

Output Low Voltage (Sink
Current) (OT, ALERT, FANFAIL,

THERM, SDA, PWM1, and PWM2)

V

OL

PWM1, PWM2, I

SINK

= 4mA 0.4

V

Output High Leakage Current
(OT, ALERT, FANFAIL, THERM,
SDA, PWM1, and PWM2)

I

OH

1µA

Logic-Low Input Voltage (SDA,
SCL, THERM, TACH1, TACH2)

V

IL

0.8 V

Logic-High Input Voltage (SDA,
SCL, THERM, TACH1, TACH2)

V

IH

VCC = 3.3V 2.1 V

Input Leakage Current (SDA,
SCL, THERM, TACH1, TACH2)

V

IN

= VCC or GND 1 µA

Input Capacitance C

IN

5pF

SMBus TIMING (Note 2)

Serial Clock Frequency f

SCL

(Note 3) 10 100 kHz

Clock Low Period t

LOW

10% to 10% 4 µs

Clock High Period t

HIGH

90% to 90% 4.7 µs

Bus Free Time Between STOP
and START Conditions

t

BUF

4.7 µs

SMBus START Condition Setup
Time

t

SU:STA

90% of SMBCLK to 90% of SMBDATA 4.7 µs

START Condition Hold Time

10% of SDA to 10% of SCL 4 µs

STOP Condition Setup Time

90% of SCL to 10% of SDA 4 µs

Data Setup Time

10% of SDA to 10% of SCL

ns

Data Hold Time

10% of SCL to 10% of SDA (Note 4)

ns

SMBus Fall Time t

F

300 ns

SMBus Rise Time t

R

ns

SMBus Timeout

58 74 90 ms

Note 1: All parameters tested at a single temperature. Specifications are guaranteed by design.
Note 2: Timing specifications guaranteed by design.
Note 3: The serial interface resets when SCL is low for more than t

TIMEOUT

.

Note 4: A transition must internally provide at least a hold time to bridge the undefined region (300ns max) of SCL's falling edge.

t

HD:STO

t

SU:STO

t

SU:DAT

t

HD:DAT

250

300

t

TIMEOUT

1000

MAX6639/MAX6639F

2-Channel Temperature Monitor with Dual,
Automatic, PWM Fan-Speed Controller

4 _______________________________________________________________________________________

Typical Operating Characteristics

(VCC= 3.3V, TA= +25°C.)

STANDBY SUPPLY CURRENT

vs. SUPPLY VOLTAGE

MAX6639 toc01

SUPPLY VOLTAGE (V)

SUPPLY CURRENT (μA)

5.04.54.03.5

1

2

3

4

5

6

7

8

9

10

0

3.0 5.5

OPERATING SUPPLY CURRENT

vs. SUPPLY VOLTAGE

MAX6639 toc02

SUPPLY VOLTAGE (V)

SUPPLY CURRENT (μA)

5.04.54.03.5

300

400

500

600

700

800

200

3.0 5.5

REMOTE TEMPERATURE ERROR

vs. REMOTE-DIODE TEMPERATURE

MAX6639 toc03

TEMPERATURE (°C)

TEMPERATURE ERROR (°C)

100755025

-1

0

1

2

-2
0125

FAIRCHILD 2N3906

LOCAL TEMPERATURE ERROR

vs. DIE TEMPERATURE

MAX6639 toc04

TEMPERATURE (°C)

TEMPERATURE ERROR (°C)

100755025

-0.5

-1.0

-1.5

0

0.5

1.0

-2.0
0125

LOCAL TEMPERATURE ERROR

vs. POWER-SUPPLY NOISE FREQUENCY

MAX6639 toc06

FREQUENCY (Hz)

TEMPERATURE ERROR (°C)

10k1k100

-1.5

-1.0

-0.5

0

0.5

1.0

1.5

2.0

-2.0
1 10 100k

VIN = 250mV

P-P

SQUARE WAVE APPLIED TO

V

CC

WITH NO BYPASS CAPACITOR

REMOTE TEMPERATURE ERROR

vs. COMMON-MODE NOISE FREQUENCY

MAX6639 toc07

FREQUENCY (Hz)

TEMPERATURE ERROR (°C)

10k1k100

-1.5

-1.0

-0.5

0

0.5

1.0

1.5

2.0

-2.0

0.1 1 10 100k

VIN = AC-COUPLED TO DXP AND DXN
V

IN

= 100mV

P-P

SQUARE WAVE

REMOTE TEMPERATURE ERROR

vs. DIFFERENTIAL NOISE FREQUENCY

MAX6639 toc08

FREQUENCY (Hz)

TEMPERATURE ERROR (°C)

10k1k100

-1.5

-1.0

-0.5

0

0.5

1.0

1.5

2.0

-2.0

10 100k

VIN = AC-COUPLED TO DXP
V

IN

= 100mV

P-P

SQUARE WAVE

TEMPERATURE ERROR

vs. DXP-DXN CAPACITANCE

MAX6639 toc09

DXP-DXN CAPACITANCE (nF)

TEMPERATURE ERROR (°C)

101

-5.0

-4.0

-3.0

-2.0

-1.0

0

1.0

2.0

-6.0

0.1 100

REMOTE TEMPERATURE ERROR

vs. POWER-SUPPLY NOISE FREQUENCY

MAX6639 toc05

FREQUENCY (Hz)

TEMPERATURE ERROR (°C)

10k1k100

-1.5

-1.0

-0.5

0

0.5

1.0

1.5

2.0

-2.0

10 100k

VIN = 250mV

P-P

SQUARE WAVE APPLIED TO

V

CC

WITH NO BYPASS CAPACITOR

MAX6639/MAX6639F

2-Channel Temperature Monitor with Dual,

Automatic, PWM Fan-Speed Controller

_______________________________________________________________________________________ 5

PIN

T Q FN - EP

FUNCTION

1, 15 3, 1

PWM2,

Open-Drain Output to Power-Transistor Driving Fan. Connect to the gate of a MOSFET or base of a
bipolar transistor. PWM_ requires a pullup resistor. The pullup resistor can be connected to a
supply voltage as high as 13.5V, regardless of the MAX6639’s supply voltage.

2, 16 4, 2

TACH2,

Tachometer Inputs. Connect to the tachometer output of the fan. TACH_ requires a pullup resistor.
The pullup resistor can be connected to a supply voltage as high as 13.5V, regardless of the
MAX6639’s supply voltage.

35

Active-Low, Open-Drain, Fan-Failure Output. Open circuit when VCC = 0.

46

Active-Low, Open-Drain Thermal Alarm Output. Typically used for clock throttling. Open circuit
when V

CC

= 0.

57OT

Active-Low, Open-Drain Overtemperature Output. Typically used for system shutdown or clock
throttling. Can be pulled up to 5.5V regardless of V

CC

. Open circuit when VCC = 0.

68VCCPower-Supply Input. 3.3V nominal. Bypass VCC to GND with a 0.1µF capacitor.

7 10 GND Ground. Connect to a clean ground reference.

8, 10 9, 12

DXP1,

C om b i ned C ur r ent S our ce and A/D P osi ti ve Inp ut for Rem ote D i od e. C onnect to anod e of r em ote­d i od e- connected tem p er atur e- sensi ng tr ansi stor . D o not l eave unconnected ; connect to D X N i f no
r em ote d i od e i s used . P l ace a 2200p F cap aci tor b etw een D X P _ and D X N for noi se f i l ter i ng .

911DXN

11 13 ADD

Address Input. Sets device slave address. Connect to GND, V

CC

, or leave unconnected to give

three unique addresses. See Table 1.

12 14

Active-Low, Open-Drain SMBus Alert Output

13 16 SCL

SMBus Serial-Clock Input. Can be pulled up to 5.5V regardless of V

CC

. Open circuit when VCC =

14 15 SDA

SMBus Serial-Data Input/Output, Open Drain. Can be pulled up to 5.5V regardless of V

CC

. Open

circuit when V

CC

= 0.

——EP

Exposed Pad (TQFN package only). Internally connected to GND. Connect EP to a large PCB pad
for optimum performance and enhanced thermal dissipation. Not intended as an electrical
connection point.

Pin Description

Typical Operating Characteristics (continued)

(VCC= 3.3V, TA= +25°C.)

PWMOUT FREQUENCY

vs. DIE TEMPERATURE

MAX6639 toc10

TEMPERATURE (°C)

PWMOUT FREQUENCY (Hz)

85603510-15

31

32

33

34

35

30

-40 110

PWMOUT FREQUENCY

vs. SUPPLY VOLTAGE

MAX6639 toc11

SUPPLY VOLTAGE (V)

PWMOUT FREQUENCY (Hz)

5.04.54.03.5

31

32

33

34

35

30

3.0 5.5

QSOP

NAME

PWM1

TACH1

FANFAIL

THERM

DXP2

Rem ote D i od e C ur r ent S i nk Inp ut. C onnect C athod e of the Rem ote- D i od e- C onnected Tr ansi stor to D X N

ALERT

MAX6639/MAX6639F

Detailed Description

The MAX6639 monitors its own temperature and a
remote-diode-connected transistor or the temperatures
of two external-diode-connected transistors, which typi­cally reside on the die of a CPU or other integrated cir­cuit. The 2-wire serial interface accepts standard
SMBus write byte, read byte, send byte, and receive
byte commands to read the temperature data and pro­gram 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, throt­tle signals, or overtemperature shutdown signals.

The temperature data is also used by the internal dual­PWM 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.

2-Channel Temperature Monitor with Dual,
Automatic, PWM Fan-Speed Controller

6 _______________________________________________________________________________________

GND

SMBus

INTERFACE AND

REGISTERS

LOGIC

PWM

GENERATOR

BLOCK

V

CC

TEMPERATURE

PROCESSING

BLOCK

SDA

SCL

ADD

DXP1

DXN

PWM1

PWM2

TACH1

TACH2

DXP2

OT

THERM

FANFAIL

ALERT

MAX6639

Block Diagram

Write Byte Format

Read Byte Format

Send Byte Format

Receive Byte Format

Slave Address: equiva­lent to chip-select line of
a 3-wire interface

Command Byte: selects which
register you are writing to

Data Byte: data goes into the register
set by the command byte (to set
thresholds, configuration masks, and
sampling rate)

Slave Address: equiva­lent to chip-select line

Command Byte: selects
which register you are
reading from

Slave Address: repeated
due to change in data­flow direction

Data Byte: reads from
the register set by the
command byte

Command Byte: sends com­mand with no data, usually
used for one-shot command

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

S = START CONDITION SHADED = SLAVE TRANSMISSION
P = STOP CONDITION /// = NOT ACKNOWLEDGED

Figure 1. SMBus Protocols

S ADDRESS RD ACK DATA /// P

7 bits 8 bits

WRS ACK COMMAND ACK P

8 bits

ADDRESS

7 bits

P

1

ACKDATA

8 bits

ACKCOMMAND

8 bits

ACKWRADDRESS

7 bits

S

S ADDRESS WR ACK COMMAND ACK S ADDRESS

7 bits8 bits7 bits

RD ACK DATA

8 bits

/// P

SMBus Digital Interface

From a software perspective, the MAX6639 appears as
a set of byte-wide registers. This device uses a stan­dard SMBus 2-wire/I2C-compatible serial interface to
access the internal registers.

The MAX6639 features an address select input (ADD)
that allows the MAX6639 to have three unique addresses
(see Table 1).

The MAX6639 employs four standard SMBus protocols:
write byte, read byte, send byte, and receive byte
(Figures 1, 2, and 3). The shorter receive byte protocol
allows quicker transfers, provided that the correct data
register was previously selected by a read byte instruc­tion. Use caution with the shorter protocols in multimas­ter systems, since a second master could overwrite the
command byte without informing the first master.

Table 4 details the register addresses and functions,
whether they can be read or written to, and the power-

on reset (POR) state. See Tables 5–9 for all other regis­ter functions and the

Register Descriptions

section.

Temperature Reading

Temperature data can be read from registers 00h and
01h. The temperature data format for these registers is
8 bits, with the LSB representing 1°C (Table 2) and the
MSB representing +128°C. The MSB is transmitted first.
Three additional temperature bits provide resolution
down to 0.125°C and are in the channel 1 extended
temperature (05h) and channel 2 extended temperature
(06h) registers. All values below 0°C clip to 00h.

MAX6639/MAX6639F

2-Channel Temperature Monitor with Dual,

Automatic, PWM Fan-Speed Controller

_______________________________________________________________________________________ 7

SCL

A = START CONDITION
B = MSB OF ADDRESS CLOCKED INTO SLAVE
C = LSB OF ADDRESS CLOCKED INTO SLAVE
D = R/W BIT CLOCKED INTO SLAVE

AB CDEFG

HIJ

SDA

t

SU:STAtHD:STA

t

LOW

t

HIGH

t

SU:DAT

t

SU:STOtBUF

LMK

E = SLAVE PULLS SMBDATA LINE LOW
F = ACKNOWLEDGE BIT CLOCKED INTO MASTER
G = MSB OF DATA CLOCKED INTO SLAVE
H = LSB OF DATA CLOCKED INTO SLAVE

I = MASTER PULLS DATA LINE LOW
J = ACKNOWLEDGE CLOCKED INTO SLAVE
K = ACKNOWLEDGE CLOCK PULSE
L = STOP CONDITION
M = NEW START CONDITION

Figure 2. SMBus Write Timing Diagram

SCL

AB CDEFG HIJ

K

SDA

t

SU:STA

t

HD:STA

t

LOWtHIGH

t

SU:DAT

t

HD:DAT

t

SU:STO

t

BUF

A = START CONDITION
B = MSB OF ADDRESS CLOCKED INTO SLAVE
C = LSB OF ADDRESS CLOCKED INTO SLAVE
D = R/W BIT CLOCKED INTO SLAVE
E = SLAVE PULLS SMBDATA LINE LOW

L

M

F = ACKNOWLEDGE BIT CLOCKED INTO MASTER
G = MSB OF DATA CLOCKED INTO MASTER
H = LSB OF DATA CLOCKED INTO MASTER
I = MASTER PULLS DATA LINE LOW

J = ACKNOWLEDGE CLOCKED INTO SLAVE
K = ACKNOWLEDGE CLOCK PULSE
L = STOP CONDITION
M = NEW START CONDITION

Figure 3. SMBus Read Timing Diagram

ADD INPUT STATE

I2C SLAVE ADDRESS

BINARY

EQUIVALENT

V

CC

5Eh 0101 111

Floating 5Ch 0101 110

GND 58h 0101 100

Table 1. I2C Slave Address