Rainbow Electronics MAX1669 User Manual

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General Description

The MAX1669 fan controller includes a precise digital
thermometer that reports the temperature of a remote
sensor. The remote sensor is a diode-connected transis­tor—typically a low-cost, easily mounted 2N3906 PNP
type—replacing conventional thermistors or thermocou­ples. Remote accuracy is ±3°C for transistors from multi­ple manufacturers, with no calibration needed. The
MAX1669 has an independent fan controller with a low­current logic output requiring external power compo­nents to interface to a DC brushless fan. The fan
controller has two modes of operation: a low-frequency
(20Hz to 160Hz) PWM mode intended for driving the fan
motor, or a high-impedance DAC output that generates
a variable DC control voltage. In PWM mode, the FAN
frequency can be synchronized to an external clock.

Other key features include general-purpose inputs/out­puts (GPIOs) for fan presence detection and a thermo­stat output intended as a fan override signal in case the
host system loses the ability to communicate. The inter­nal ADC has a wide input voltage range and gives
overrange readings when too large an input voltage is
applied. Other error-checking includes temperature
out-of-range indication and diode open/short faults.

The MAX1669 is available in a space-saving 16-pin
QSOP package that allows it to fit adjacent to the
SLOT1 connector.

Applications

Pentium®CPU Cooling

Desktop Computers

Notebook Computers

Servers

Workstations

Features

♦ Measures Remote CPU Temperature

♦ No Calibration Required

♦ 20Hz to 160Hz PWM Output for Fan

♦ PWM Frequency Sync Input (260kHz)

♦ Flexible Fan Interface: Linear or PWM

♦ SMBus 2-Wire Serial Interface

♦ Programmable Under/Overtemperature Alarms
♦ ALERT Latched Interrupt Output
♦ OVERT Thermostat Output

♦ Two GPIO Pins

♦ Write-Once Configuration Protection

♦ Supports SMBus Alert Response

♦ ±3°C Temperature Accuracy (-40°C to +125°C,

remote)

♦ 3µA Standby Supply Current

♦ +3V to +5.5V Supply Range

♦ Small 16-Pin QSOP Package

MAX1669

Fan Controller and Remote Temperature Sensor

with SMBus Serial Interface

________________________________________________________________ Maxim Integrated Products 1

19-1574; Rev 0; 1/00

PART

MAX1669EEE

-40°C to +85°C

TEMP. RANGE PIN-PACKAGE

16 QSOP

Pentium is a registered trademark of Intel Corp.

Pin Configuration

Ordering Information

Typical Operating Circuit appears at end of data sheet.

TOP VIEW

1

I/O1 OVERT

I/O2

2

ADD0

3

MAX1669

4

ADD1

ADD2

5

AGND

6

DXN

7

DXP

8

16

15

14

13

12

11

10

9

ALERT

SMBDATA

SMBCLK

PGND

FAN

SYNC

V

CC

QSOP

MAX1669

Fan Controller and Remote Temperature Sensor
with SMBus Serial Interface

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VCC= +3.3V, TA= 0°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)

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 AGND...........................................................-0.3V to +6V

DXP, ADD_ to AGND.................................-0.3V to (V

CC

+ 0.3V)

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

SMBCLK, SMBDATA, ALERT, SYNC,

I/O1, I/O2, OVERT, FAN to AGND ......................-0.3V to +6V

FAN to PGND ............................................-0.3V to (V

CC

+ 0.3V)

PGND to AGND ....................................................-0.3V to +0.3V

PWM Current....................................................-50mA to +50mA

SMBDATA Current .............................................-1mA to +50mA

I/O1, I/O2 Current...............................................-1mA to +25mA

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

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

Continuous Power Dissipation (T

A

= +70°C)

16-Pin QSOP (derate 8.30mW/°C above +70°C).......667mW

Operating Temperature Range (extended)......-55°C to +125°C

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

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

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

FAN output set to
DAC mode

FAN output set to
150Hz mode

TR= 0°C to +100°C, diode ideality factor = 1.013

High level

PWM mode, V

FAN

forced to 0.4V

PWM mode, V

FAN

forced to 2.9V

Monotonicity guaranteed

V

DXP

forced to V

DXN

+ 0.65V

SMBus static

Autoconvert mode

From stop bit to conversion complete

VCC, falling edge

VCCinput, disables A/D conversion,
rising edge

Autoconvert mode,
average measured over 1s

CONDITIONS

mA

-10

FAN Output Sink Current

mA

10

FAN Output Source Current

V

0.7

DXN Source Voltage

80 100 120

µARemote-Diode Source Current

Hz

1.6 2 2.4

Conversion Rate

ms

47 62 78

Conversion Time

µA

360

µA

75 150

Average Operating Supply Current

°CTemperature Error, Remote Diode (Note 2)

Bits

8

Resolution (Note 1)

310

µAStandby Supply Current

mV

50

POR Threshold Hysteresis

V

1 1.9 2.5

Power-On Reset Threshold

-3 3

V

3 5.5

Supply Voltage Range

V

2.6 2.8 2.95

Undervoltage Lockout Threshold

mV

50

Undervoltage Lockout Hysteresis

UNITSMIN TYP MAXPARAMETER

SMBCLK at 10kHz

3

Low level

81012

ADC AND POWER SUPPLY

FAN OUTPUT

MAX1669

Fan Controller and Remote Temperature Sensor

with SMBus Serial Interface

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VCC= +3.3V, TA= 0°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)

Logic Input High Voltage

PARAMETER MIN TYP MAX UNITS

FAN PWM Frequency Error

-20 +20

%

FAN Total Unadjusted Error

-4 4

%FS

FAN Output Voltage High

2.96 3.06

V

CONDITIONS

PWM mode, any setting

DAC mode, any setting, RL= 10kΩ to GND

DAC mode, FAN duty factor = 1111b,
I

OUT

= 5mA

SYNC Input Low Period

500

ns

SYNC Input High Period

500

ns

SYNC Capture Range

140 260 400

kHz

2.1

V

Logic Input Low Voltage

0.8

V

SMBDATA, ALERT, OVERT, I/O1, I/O2
Output Low Sink Current

6

mA

FAN Output Voltage Low

0.05 0.2

V

ALERT, OVERT, I/O1, I/O2 Output
High Leakage Current

1

µA

Logic Input Current

-1 1

µA

SMBus Input Capacitance

5

pF

SMBus Clock Frequency

DC 100

kHz

SMBCLK Clock Low Time (t

LOW

)

4.7

µs

SMBCLK Clock High Time (t

HIGH

)

4

µs

SMBus Rise Time

1

µs

SMBus Fall Time

300

ns

SMBus Start Condition Setup Time

4.7

µs

SMBus Repeated Start Condition Setup
Time (t

SU:STA

)

500

ns

SMBus Start Condition Hold Time (t

HD:STA

)

4

µs

SMBus Stop Condition Setup Time (t

SU:STO

)

4

µs

SMBus Data Valid to SMBCLK
Rising-Edge Time (t

SU:DAT

)

250

ns

Pin forced to 5.5V

Logic inputs forced to VCCor GND

ADD_, I/O1, I/O2, SYNC, SMBCLK, SMBDATA;
VCC= 3V to 5.5V

ADD_, I/O1, I/O2, SYNC, SMBCLK, SMBDATA;
VCC= 3V to 5.5V

SMBCLK, SMBDATA

(Note 3)

Pin forced to 0.4V

10% to 10% points

90% to 90% points

SMBCLK, SMBDATA, 10% to 90% points

SMBCLK, SMBDATA, 90% to 10% points

90% to 90% points

DAC mode, FAN duty factor = 0000b,
I

OUT

= -5mA

10% of SMBDATA to 90% of SMBCLK

90% of SMBCLK to 10% of SMBDATA

10% or 90% of SMBDATA to 10% of SMBCLK

SMBus Data-Hold Time (t

HD:DAT

)

0

µs

SMBus Bus-Free Time (t

BUF

)

4.7

µs

SMBCLK Falling Edge to SMBus
Data-Valid Time

1

µs

(Note 4)

Between start/stop conditions

Master clocking-in data

SMBus INTERFACE (Figures 7, 8)

Note 1: Guaranteed but not 100% tested.
Note 2: T

R

is the junction temperature of the remote diode. The temperature error specification is optimized to and guaranteed for a
diode-connected 2N3906 transistor with ideality factor = 1.013. Variations in the ideality factor “m” of the actual transistor
used will increase the temperature error by *. See the Temperature Error vs. Remote Diode Temperature graph in the

Typical Operating Characteristics for typical temperature errors using several random 2N3906s. See Remote Diode
Selection for remote diode forward-voltage requirements.

Note 3: The SMBus logic block is a static design that works with clock frequencies down to DC. While slow operation is possible, it

violates the 10kHz minimum clock frequency and SMBus specifications, and may monopolize the bus.

Note 4: Note that a transition must internally provide at least a hold time in order to bridge the undefined region (300ns max) of

SMBCLK’s falling edge.

Note 5: Specifications to -40°C are guaranteed by design and not production tested.

MAX1669

Fan Controller and Remote Temperature Sensor
with SMBus Serial Interface

4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS

(VCC= +3.3V, TA= -40°C to +85°C, unless otherwise noted.) (Note 5)

Pin forced to 0.4V

ADD_, I/O1, I/O2, SYNC, SMBCLK, SMBDATA;
VCC= 3V to 5.5V

ADD_, I/O1, I/O2, SYNC, SMBCLK, SMBDATA;
V

CC

= 3V to 5.5V

Logic inputs forced to VCCor GND

Pin forced to 5.5V

µA

-1 1

Logic Input Current

µA

1

ALERT, OVERT, I/O1, I/O2 Output
High Leakage Current

V

0.2

FAN Output Voltage Low

mA

6

SMBDATA, ALERT, OVERT, I/O1, I/O2
Output Low Sink Current

V

0.8

Logic Input Low Voltage

V

2.1

Logic Input High Voltage

DAC mode, FAN duty factor = 1111b,
I

OUT

= 5mA

DAC mode, any setting, RL= 10kΩ to GND

PWM mode, any setting

PWM mode, V

FAN

forced to 0.4V

PWM mode, V

FAN

forced to 2.9V

Monotonicity guaranteed

Autoconvert mode

From stop bit to conversion complete

TR= -55°C to +125°C, diode ideality factor = 1.013

Autoconvert mode, average measured over
1sec, FAN output set to 150Hz mode

CONDITIONS

V

2.94

FAN Output Voltage High

%FS

-5 5

FAN Total Unadjusted Error

%

-25 +25

FAN PWM Frequency Error

mA

-10

FAN Output Sink Current

mA

10

FAN Output Source Current

Hz

1.6 2.4

Conversion Rate

ms

47

Conversion Time

µA

100

Average Operating Supply Current

Bits

8

Temperature Resolution (Note 1)

°C

-5 5

Temperature Error, Remote Diode (Note 2)

UNITSMIN MAXPARAMETER

DAC mode, FAN duty factor = 0000b,
I

OUT

= -5mA

V

3 5.5

Supply Voltage Range

ADC AND POWER SUPPLY

FAN OUTPUT

SMBus INTERFACE







1 013

*

.

=−



m



1 273 15

. ∆T

()



kT C

+

°

()

R

MAX1669

Fan Controller and Remote Temperature Sensor

with SMBus Serial Interface

_______________________________________________________________________________________ 5

Typical Operating Characteristics

(Temperature error = measured - actual, TA= +25°C, unless otherwise noted.)

TEMPERATURE ERROR

vs. LEAKAGE RESISTANCE

40

30

20

10

-10

-20

TEMPERATURE ERROR (°C)

-30

-40

PATH = DXP TO GND; CONFIG = 02h

0

PATH = DXP TO V

1 10 100

LEAKAGE RESISTANCE (MΩ)

(5V); CONFIG = 02h

CC

TEMPERATURE ERROR vs.

COMMON-MODE NOISE FREQUENCY

8

VIN = 50mVp-p AC-COUPLED TO DXN

7

C = DXN - DXP CAPACITANCE

6

5

4

3

2

1

TEMPERATURE ERROR (°C)

0

-1

-2
1M 1G100M10M

C = 2200pF

C = 27nF

FREQUENCY (Hz)

MAX1669-01

MAX1669-04

2.0

1.5

1.0

0.5

0

-0.5

TEMPERATURE ERROR (°C)

-1.0

-1.5

-2.0

2

0

-2

-4

-6

-8

-10

TEMPERATURE ERROR (°C)

-12

-14

-16

TEMPERATURE ERROR

vs. REMOTE DIODE TEMPERATURE

RANDOM 2N3906s FROM
DIFFERENT MANUFACTURERS

-60 20-20 60 100-40 400 80 120 140
TEMPERATURE (°C)

TEMPERATURE ERROR

vs. DXP - DXN CAPACITANCE

V

= 5V

CC

02010 30 40 50

DXP-DXN CAPACITANCE (nF)

MAX1669-02

MAX1669-05

TEMPERATURE ERROR vs.

POWER-SUPPLY NOISE FREQUENCY

18

VIN = SQUARE WAVE APPLIED TO

16

14

12

10

TEMPERATURE ERROR (°C)

-2

WITH NO 0.1µF VCC CAPACITOR

V

CC

VIN = 250mVp-p

8

6

4

2

0

1K 10K 100K 1M 10M 100M

VIN = 100mVp-p

PSNF (Hz)

STANDBY SUPPLY CURRENT

vs. SUPPLY VOLTAGE

7

6

5

4

3

2

STANDBY SUPPLY CURRENT (µA)

1

0

3.0 4.03.5 4.5 5.0 5.5
SUPPLY VOLTAGE (V)

MAX1669-03

MAX1669-06

RESPONSE TO THERMAL SHOCK

120

100

80

60

TEMPERATURE (°C)

40

20

0

-2 2 406810

CMPT3906 IMMERSED IN
+115°C FLUORINERT BATH

TIME (sec)

MAX1669-07

PWM FREQUENCY vs. CODE (F3F2F1F0)

180

160

140

120

100

80

60

PWM FREQUENCY (Hz)

40

20

0

042 5 7 8 10 123169111314

V

= +5V

CC

CODE (F3F2F1F0)

V

CC

= +3.3V

MAX1669-08

MAX1669

Fan Controller and Remote Temperature Sensor
with SMBus Serial Interface

6 _______________________________________________________________________________________

Typical Operating Characteristics (continued)

(Temperature error = measured - actual, TA= +25°C, unless otherwise noted.)

Pin Description

NAME FUNCTION

1

I/O1

General-Purpose Open-Drain Logic Input/Output 1. I/O1 is intended for driving LEDs, driving power-plane
switching MOSFETs, or detecting fan presence or chassis intrusion.

2 I/O2

General-Purpose Open-Drain Logic Input/Output 2. I/O2 is intended for driving LEDs, driving power-plane
switching MOSFETs, or detecting fan presence or chassis intrusion.

PIN

3 ADD0 SMBus Address Select Pin 0. See Table 11.

4 ADD1 SMBus Address Select Pin 1. See Table 11.

8 DXP

Combined Current Source and ADC Positive Input from Remote Diode. Place a 2200pF capacitor
between DXP and DXN for noise filtering.

7 DXN

Combined Current Sink and ADC Negative Input from Remote Diode. DXN is normally biased to a diode
voltage above ground.

6 AGND Analog Ground

5 ADD2 SMBus Address Select Pin 2. See Table 11.

13 SMBCLK SMBus Serial-Clock Input

12 PGND Power Ground

11 FAN

Fan-Control Logic Output. Swings from PGND to VCCin PWM mode, or PGND to 0.94 · VCCin DAC mode.

10 SYNC

Oscillator Synchronization Input. Connect to AGND to use internal clock. Capture range is 140kHz to
400kHz. The synchronization signal is internally applied to the FAN PWM clock. See Table 5 for synchro­nized frequencies.

9 V

CC

Supply Voltage Input, +3V to +5.5V. Bypass to AGND with a 0.1µF capacitor.

16

OVERT

Active-Low, Open-Drain Thermostat Output. Activated by T

CRIT

threshold

15

ALERT

Active-Low, Open-Drain SMBus Alert (interrupt) Output

14 SMBDATA Open-Drain SMBus Serial-Data Input/Output

PWM DUTY FACTOR vs. CODE (D3D2D1D0)

100

V

= +3.3V OR +5V

CC

80

60

40

DUTY FACTOR (%)

20

0

042 5 7 8 10 1231 6 9 11 131415

CODE (D3D2D1D0)

MAX1669-09

DAC OUTPUT vs. CODE (D3D2D1D0)

5.0
I

= +10mA TO -10mA

LOAD

4.5

= +5V

V

CC

4.0

3.5

3.0

2.5

2.0

DAC OUTPUT (V)

1.5

1.0

0.5

0

042 5 7 8 10 1231691114

CODE (D3D2D1D0)

13

MAX1669-10

15