Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPMICsPMIC - temperature management Internal, External PWM QSOP 16

General Description

The MAX6643/MAX6644/MAX6645 monitor temperature

and automatically adjust fan speed to ensure optimum

cooling while minimizing acoustic noise from the fan.

Each device measures two temperature locations.

The MAX6643/MAX6644/MAX6645 generate a PWM

waveform that drives an external power transistor, which

in turn modulates the fan’s power supply. The

MAX6643/MAX6644/MAX6645 monitor temperature and

adjust the duty cycle of the PWM output waveform to con-

trol the fan’s speed according to the cooling needs of the

system. The MAX6643 monitors its own die temperature

and an optional external transistor’s temperature, while the

MAX6644 and MAX6645 each monitor the temperatures

of one or two external diode-connected transistors.

The MAX6643 and MAX6644 have nine selectable trip

temperatures (in 5°C increments). The MAX6645 is fac-

tory programmed and is not pin selectable.

All versions include an overtemperature output (OT).

OT can be used for warning or system shutdown. The

MAX6643 also features a FULLSPD input that forces the

PWM duty cycle to 100%. The MAX6643/MAX6644/

MAX6645 also feature a FANFAIL output that indicates

a failed fan. See the Selector Guide for a complete list

of each device’s functions.

The MAX6643 and MAX6644 are available in a small

16-pin QSOP package and the MAX6645 is available in

a 10-pin µMAX

package. All versions operate from

3.0V to 5.5V supply voltages and consume 500µA (typ)

supply current.

Applications

Networking Equipment

Storage Equipment

Servers

Desktop Computers

Workstations

Features

♦ Simple, Automatic Fan-Speed Control

♦ Internal and External Temperature Sensing

♦ Detect Fan Failure Through Locked-Rotor Output,

Tachometer Output, or Fan-Supply Current

Sensing

♦ Multiple, 1.6% Output Duty-Cycle Steps for Low

Audibility of Fan-Speed Changes

♦ Pin-Selectable or Factory-Selectable Low-

Temperature Fan Threshold

♦ Pin-Selectable or Factory-Selectable High-

Temperature Fan Threshold

♦ Spin-Up Time Ensures Fan Start

♦ Fan-Start Delay Minimizes Power-Supply Load at

Power-Up

♦ 32Hz PWM Output

♦ Controlled Duty-Cycle Rate-of-Change Ensures

Good Acoustic Performance

♦ 2°C Temperature-Measurement Accuracy

♦ FULLSPD/FULLSPD Input Sets PWM to 100%

♦ Pin-Selectable OT Output Threshold

♦ 16-Pin QSOP and 10-Pin µMAX Packages

MAX6643/MAX6644/MAX6645

Automatic PWM Fan-Speed Controllers with

Overtemperature Output

________________________________________________________________ Maxim Integrated Products 1

Ordering Information

19-3305; Rev 2; 3/07

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.

EVALUATION KIT

AVAILABLE

Pin Configurations, Typical Operating Circuit, and Selector

Guide appear at end of data sheet.

PART TEMP RANGE

PIN-

PACKAGE

PKG

CODE

MAX6643LBFAEE -40°C to +125°C 16 QSOP E16-1

MAX6643LBBAEE -40°C to +125°C 16 QSOP E16-1

MAX6644LBAAEE -40°C to +125°C 16 QSOP E16-1

MAX6645ABFAUB -40°C to +125°C 10 µMAX U10-2

µMAX is a registered trademark of Maxim Integrated Products, Inc.

Summary of content (17 pages)

PAGE 1
KIT ATION EVALU E L B A AVAIL 19-3305; Rev 2; 3/07 Automatic PWM Fan-Speed Controllers with Overtemperature Output The MAX6643/MAX6644/MAX6645 monitor temperature and automatically adjust fan speed to ensure optimum cooling while minimizing acoustic noise from the fan. Each device measures two temperature locations. The MAX6643/MAX6644/MAX6645 generate a PWM waveform that drives an external power transistor, which in turn modulates the fan’s power supply.
PAGE 2
MAX6643/MAX6644/MAX6645 Automatic PWM Fan-Speed Controllers with Overtemperature Output ABSOLUTE MAXIMUM RATINGS VDD to GND ..............................................................-0.3V to +6V PWM_OUT, OT, and FANFAIL to GND.....................-0.3V to +6V FAN_IN1 and FAN_IN2 to GND...........................-0.3V to +13.2V DXP_ to GND.........................................................-0.3V to +0.8V FULLSPD, FULLSPD, TH_, TL_, TACHSET, and OT_ to GND ..................................-0.
PAGE 3
Automatic PWM Fan-Speed Controllers with Overtemperature Output (VDD = +3.0V to +5.5V, TA = -40°C to +125°C, unless otherwise noted. Typical values are at VDD = +3.3V, TA = +25°C.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS DIGITAL INPUTS (FULLSPD, FULLSPD, TACHSET) Logic-Input High VIH Logic-Input Low VIL VDD = 5.5V 3.65 VDD = 3.0V 2.2 V VDD = 3.0V Input Leakage Current VIN = GND or VDD -1 0.8 V +1 µA Note 1: All parameters tested at TA = +25°C.
PAGE 4
Automatic PWM Fan-Speed Controllers with Overtemperature Output MAX6643/MAX6644/MAX6645 Pin Description PIN FUNCTION MAX6644 MAX6645 1, 15 1, 15 — TH1, TH2 High-Temperature Threshold Inputs. Connect to VDD, GND, or leave unconnected to select the upper fan-control trip temperature (THIGH), in 5°C increments. See Table 1. 2, 3 2, 3 — TL2, TL1 Low-Temperature Threshold Inputs. Connect to VDD, GND, or leave unconnected to select the lower fan-control trip temperature (TLOW), in 5°C increments.
PAGE 5
Automatic PWM Fan-Speed Controllers with Overtemperature Output PIN MAX6643 MAX6644 MAX6645 NAME FUNCTION 12 12 9 PWM_OUT PWM Output for Driving External Power Transistor. Connect to the gate of an n-channel MOSFET or to the base of an npn. PWM_OUT requires a pullup resistor. The pullup resistor can be connected to a supply voltage as high as 5.5V, regardless of the supply voltage. 13, 14 13, 14 — OT2, OT1 Overtemperature Threshold Inputs.
PAGE 6
Table 2. Setting TLOW SPIN-UP TL1 TLOW (°C) L SUFFIX 0 0 15 0 High-Z 20 0 1 25 TL2 High-Z 0 30 High-Z High-Z 35 High-Z 1 40 1 0 45 1 High-Z 50 1 1 55 DUTY CYCLE (MAX6643 and MAX6644) TIME STARTUP To control fan speed based on temperature, THIGH is set to the temperature beyond which the fan should spin at 100%. TLOW is set to the temperature below which the duty cycle can be reduced to its minimum value.
PAGE 7
Automatic PWM Fan-Speed Controllers with Overtemperature Output Fan-Fail Sensing The MAX6643/MAX6644/MAX6645 feature a FANFAIL output. The FANFAIL output is an active-low, opendrain alarm. The MAX6643/MAX6644/MAX6645 detect fan failure either by measuring the fan’s speed and recognizing when it is too low, or by detecting a lockedrotor logic signal from the fan. Fan-failure detection is enabled only when the duty cycle of the PWM drive signal is equal to 100%.
PAGE 8
MAX6643/MAX6644/MAX6645 Automatic PWM Fan-Speed Controllers with Overtemperature Output Table 3.
PAGE 9
Automatic PWM Fan-Speed Controllers with Overtemperature Output 1 +VFAN (5V OR 12V) TH1 VDD TL2 TH2 +VFAN (5V OR 12V) 16 4.7kΩ 2 3 4 TO FANFAIL ALARM 5 6 7 MAX6644 TL1 OT1 OT2 FANFAIL TACHSET PWM_OUT DXP2 FAN_IN1 GND FAN_IN2 15 14 4.7kΩ 4.7kΩ 13 N 12 11 10 N CURRENT-SENSE 0.1μF MODE CURRENT-SENSE MODE 0.1μF 8 OT DXP1 2.0Ω 9 2.0Ω TO OVERTEMPERATURE ALARM Figure 3. MAX6644 Using Two External Transistors to Measure Remote Temperatures and Control Two 2-Wire Fans.
PAGE 10
MAX6643/MAX6644/MAX6645 Automatic PWM Fan-Speed Controllers with Overtemperature Output +VFAN (5V OR 12V) VDD (+3.0V TO +5.5V) 4.7kΩ TO FANFAIL ALARM 1 2 3 4 5 VDD FANFAIL PWM_OUT TACHSET DXP2 GND DXP1 MAX6645 FAN_IN1 FAN_IN2 OT 10 4.7kΩ 9 TACHOMETER 8 MODE 4.7kΩ N TACHOMETER 7 MODE 6 TO OVERTEMPERATURE ALARM Figure 5.
PAGE 11
Automatic PWM Fan-Speed Controllers with Overtemperature Output MAX6643/MAX6644/MAX6645 +VFAN (5V OR 12V) VDD (+3.0V TO +5.5V) 1 2 4.7kΩ 3 4 TO FANFAIL ALARM 5 6 7 8 TH1 VDD TL2 TH2 MAX6643 TL1 OT1 FANFAIL OT2 TACHSET PWM_OUT FULLSPD FAN_IN1 GND FAN_IN2 DXP OT 16 15 14 13 4.7kΩ 4.7kΩ 12 N 11 (TACHOMETER MODE) 10 (TACHOMETER MODE) 9 TO OVERTEMPERATURE ALARM +VFAN (5V OR 12V) VDD (+3.0V TO +5.5V) 1 2 4.
PAGE 12
MAX6643/MAX6644/MAX6645 Automatic PWM Fan-Speed Controllers with Overtemperature Output Effect of Series Resistance ADC Noise Filtering Series resistance in a sense diode contributes additional errors. For nominal diode currents of 10µA and 100µA, change in the measured voltage is: The integrating ADC has inherently good noise rejection, especially of low-frequency signals such as 60Hz/120Hz power-supply hum. Micropower operation places constraints on high-frequency noise rejection.
PAGE 13
Automatic PWM Fan-Speed Controllers with Overtemperature Output 6) Use wide traces. Narrow traces are more inductive and tend to pick up radiated noise. The 10-mil widths and spacings are recommended, but are not absolutely necessary (as they offer only a minor improvement in leakage and noise), but use them where practical. 7) Placing an electrically clean copper ground plane between the DXP traces and traces carrying highfrequency noise signals helps reduce EMI.
PAGE 14
Automatic PWM Fan-Speed Controllers with Overtemperature Output MAX6643/MAX6644/MAX6645 Pin Configurations TOP VIEW TH1 1 16 VDD TH1 1 16 VDD TL2 2 15 TH2 TL2 2 15 TH2 TL1 3 14 OT1 TL1 3 14 OT1 DXP2 3 13 OT2 FANFAIL 4 13 OT2 GND 4 DXP1 5 FANFAIL 4 MAX6643 TACHSET 5 FULLSPD (FULLSPD) 6 MAX6644 FANFAIL 1 TACHSET 12 PWM_OUT TACHSET 5 12 PWM_OUT 11 FAN_IN1 DXP2 6 11 FAN_IN1 GND 7 10 FAN_IN2 GND 7 10 FAN_IN2 DXP 8 9 OT DXP1 8 QSOP 9 10 VDD 2 MAX6645 9 PWM_OUT 8 FAN
PAGE 15
Automatic PWM Fan-Speed Controllers with Overtemperature Output FULLSPD/(FULLSPD) DXP1/(DXP) DXP2 TEMPERATURE DUTY CYCLE TEMPERATURE SENSOR PWM GENERATOR LOGIC PWM_OUT ANALOG SENSE TACHOMETER MAX6643 MAX6644 MAX6645 FAN_IN1 LOCKED ROTOR IN FAN-FAIL DETECTION ANALOG SENSE TACHOMETER FAN_IN2 OT TH TL LOCKED ROTOR IN THRESHOLD SELECTION OT1 OT2 TH1 TH2 TL1 TL2 () ARE FOR MAX6643 ONLY. TACHSET FANFAIL Typical Operating Circuit +VFAN (5V OR 12V) VDD (+3.0V TO +5.5V) 1 2 4.
PAGE 16
Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.) QSOP.EPS MAX6643/MAX6644/MAX6645 Automatic PWM Fan-Speed Controllers with Overtemperature Output PACKAGE OUTLINE, QSOP .150", .
PAGE 17
Automatic PWM Fan-Speed Controllers with Overtemperature Output 10LUMAX.EPS e 4X S 10 10 INCHES H Ø0.50±0.1 0.6±0.1 1 1 0.6±0.1 BOTTOM VIEW TOP VIEW D2 MILLIMETERS MAX DIM MIN 0.043 A 0.006 A1 0.002 A2 0.030 0.037 D1 0.116 0.120 D2 0.114 0.118 E1 0.116 0.120 0.114 0.118 E2 0.187 0.199 H 0.0157 0.0275 L L1 0.037 REF b 0.007 0.0106 e 0.0197 BSC c 0.0035 0.0078 0.0196 REF S α 0° 6° MAX MIN 1.10 0.05 0.15 0.75 0.95 2.95 3.05 2.89 3.00 2.95 3.05 2.89 3.00 4.75 5.05 0.40 0.70 0.940 REF 0.270 0.