EVALUATION KIT AVAILABLE MAX6620 Quad Linear Fan-Speed Controller General Description Features The MAX6620 controls the speeds of up to four fans Controls Up to Four Independent Fans With Linear (DC) Drive using four independent linear voltage outputs. The drive voltages for the fans are controlled directly over Uses Four External Low-Cost Pass Transistors 2 the I C interface. Each output drives the base of an 1% Accuracy Precision RPM Control external bipolar transistor or the gate of a FET in high- Controlled Voltage Rate-Of-Change for Best side drive configuration. Voltage feedback at the fans Acoustics power-supply terminal is used to force the correct out- 2 I C Bus Interface put voltage. 3.0V to 5.5V Supply Voltage Range The MAX6620 offers two methods for fan control. In RPM mode, the MAX6620 monitors four fan tachometer 250A (typ) Operating Supply Current logic outputs for precise (1%) control of fan RPM and 3A (typ) Shutdown Supply Current detection of fan failure. In DAC mode, each fan is dri- Small 5mm x 5mm Footprint ven with a voltage resolution of 9 bits and the tachome- ter outputs of the fans are monitored for failure. The DAC START input selects the fan power-supply voltage at startup to ensure appropriate fan drive when Ordering Information power is first applied. A watchdog feature turns the fans fully on to protect the system if there are no valid PART TEMP RANGE PIN-PACKAGE 2 I C communications within a preset timeout period. MAX6620ATI+ -40C to +125C 28 TQFN-EP* The MAX6620 operates from a 3.0V to 5.5V power sup- 2 +Denotes a lead-free package. ply with low 250A supply current, and the I C-compati- *EP = Exposed paddle. ble interface makes it ideal for fan control in a wide range of cooling applications. The MAX6620 is avail- able in a 28-pin TQFN package and operates over the -40C to +125C automotive temperature range. Pin Configuration Applications Consumer Products TOP VIEW Servers Communications Equipment 21 20 19 18 17 16 15 Storage Equipment TACH1 22 14 TACH4 13 DACFB4 DACFB1 23 24 12 DACOUT4 DACOUT1 MAX6620 25 11 GND GND 26 10 FAN GND VCC 27 9 X2 + FAN FAIL 28 8 X1 12 3 45 6 7 Typical Application Circuit appears at end of data sheet. TQFN (5mm 5mm 0.8mm) For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxims website at www.maximintegrated.com. 19-4039 Rev 1 1/13 SCL TACH2 SDA DACFB2 WD START DACOUT2 GND GND ADDR DACOUT3 DAC START DACFB3 SPINUP START TACH3MAX6620 Quad Linear Fan-Speed Controller ABSOLUTE MAXIMUM RATINGS VCC to GND ..........................................................-0.3V to +6.0V Continuous Power Dissipation (T = +70C) A FAN FAIL, SDA, SCL to GND ...............................-0.3V to +6.0V 28-Pin TQFN (derate 34.5mW/C above +70C) ....2758.6mW ADDR, SPINUP START, DAC START, WD START, Operating Temperature Range .........................-40C to +125C X1, X2 to GND ........................................-0.3V to (V + 0.3V) Junction Temperature......................................................+150C CC All Other Pins to GND..........................................-0.3V to +13.5V Storage Temperature Range .............................-65C to +150C Input Current at DACOUT Pins (Note 1) ...............+5mA/-50mA Soldering Temperature (reflow) .......................................+260C Input Current at Any Pin (Note 1)..........................................5mA Lead Temperature (soldering, 10s) .................................+300C ESD Protection (all pins, Human Body Model) (Note 2) ...2000V Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. DC and AC electrical specifica- tions do not apply when operating the device beyond its rated operating conditions. Note 2: Human Body Model, 100pF discharged through a 1.5k resistor. 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. ELECTRICAL CHARACTERISTICS (T = -40C to +125C, V = 3.0V to 5.5V, unless otherwise noted. Typical values are at T = +25C, V = 3.3V.) (Note 3) A CC A CC PARAMETER SYMBOL CONDITION MIN TYP MAX UNITS Operating Supply Voltage V 3.0 5.5 V CC Operating Supply Current I V = 5.5V 0.25 0.60 mA CC CC 2 I C inactive 0.2 0.5 mA Quiescent Supply Current Shutdown mode 3 20 A V 10 12 13.5 FANHI V Supply Voltage V FAN V 4.0 5.0 5.5 FANLO V + 10V < V < 11.5V, GND DACOUT -18 V = 12V FAN DACOUT Output Current I mA DACOUT V + 3V < V < 10V, GND DACOUT -16 V = 12V FAN V - FAN DACOUT Output Voltage V I = 5mA 0.05 V DACOUT DACOUT 0.1 V = V 256/535 FAN FANHI At DACFB , V = V 256/567 DAC Feedback Voltage at Half FAN FANLO code = 0x100, DAC V FBHS Scale V = 12V 5.54 5.74 5.94 FAN I = 5mA DACOUT V = 5V 2.05 2.25 2.45 FAN V = V 511/535 FAN FANHI DAC FBFS At DACFB , V = V 511/567 FAN FANLO DAC Feedback Voltage at Full code = 0x1FF, V Scale V = 12V 11.25 11.45 11.65 FAN I = 5mA DACOUT V DACFB511 V = 5V 4.3 4.5 4.7 FAN Drive Voltage Resolution 9 Bit DACFB Impedance R 1M DACFB TACH Minimum Input Pulse Width 25 s Internal Reference Frequency (Note 4) -3 +3 % Accuracy Using 32.768kHz crystal -0.1 +0.1 TACH Count Accuracy (Note 4) % Using on-chip oscillator -2 +2 2 Maxim Integrated