Ordering number: ENA2091 LB11851MC Monolithic Digital IC Microprocessor Fan Motor Interface Driver http://onsemi.com Overview The LB11851MC provides an interface between a microcontroller motor control signal and external MOS transistors. This device can implement a microprocessor fan driver with a minimal number of external components. The LB11851MC is optimal for server and personal computer microprocessor fan drive in response to temperature or other external signals when high precision and high air flow are required. Features • Fan motor interface driver function (FGIN) ⇒ This IC accepts a signal from a microcontroller and interfaces to external power transistors (PMOS and NMOS) to provide high-efficiency low-power single-phase full-wave drive. • Variable speed input pin (PWMIN) ⇒ PMOS side PWM control NMOS side current regeneration using slow decay is used to achieve quite high-speed control. • Built-in kickback absorption circuit (OUT1P/2P) ⇒ This circuit absorbs the kickback current that is generated at phase switching or power on/off to achieve smooth current regeneration and protect the external transistors against destruction or degradation. • Built-in current limiter circuit (SENSE) ⇒ This circuit implements a chopper-type current limiting control that operates at startup and during lock protection mode. The current detection voltage is set to a fixed 0.2V internally. • Built-in microcontroller power supply (5VREG) Semiconductor Components Industries, LLC, 2013 May, 2013 71112 SY 20120702-S00001 No.A2091-1/5 LB11851MC Specifications Absolute Maximum Ratings at Ta = 25°C Parameter Symbol Maximum supply voltage Conditions Ratings Unit VCC max 18 V OUTN pin maximum output current IOUTN max 20 mA OUTP pin maximum output current IOUTP max 20 mA OUT pin voltage handling capacity VOUT max 18 V 20 mA 5VREG maximum output current Allowable power dissipation I5VREG max Pd max Operating temperature Topr Storage temperature Tstg When mounted on the specified circuit board *1 *2 0.75 W -30 to +90 °C -55 to +150 °C *1 Specified substrate : 114.3mm × 76.1mm × 1.6mm, glass epoxy board. *2 Do not exceed Tj max = 150°C Caution 1) Absolute maximum ratings represent the value which cannot be exceeded for any length of time. Caution 2) Even when the device is used within the range of absolute maximum ratings, as a result of continuous usage under high temperature, high current, high voltage, or drastic temperature change, the reliability of the IC may be degraded. Please contact us for the further details. Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect device reliability. Recommended Operating Ranges at Ta = 25°C Parameter Symbol Supply voltage - VCC Conditions Ratings VCC Unit 6 to 16 V PWM high-level input voltage range VPWMINH 2.1 to 5 V PWM low-level input voltage range VPWMINL 0 to 0.4 V FGIN high-level input voltage range VFGINH 2.1 to 5 V FGIN low-level input voltage range VFGINL 0 to 0.3 V SENSE input voltage range VSENop 0 to 5 V Electrical Characteristics at Ta = 25°C, VDD = 12V Parameter Symbol Ratings Conditions min Circuit current ICC1 typ Unit max With no load 3.5 5 6.5 5VREG = 10mA 4.8 5 5.2 V 0.15 0.19 0.23 V VIN = 3V 60 80 100 μA FGIlow VIN = 0V -27 -21 -15 μA PWMIhi VIN = 3V 35 45 55 μA PWMIlow VIN = 0V -27 -21 -14 μA VO12PH IO = 10mA *2 10 11 11.9 V VO12PL IO = 10mA *2 3 4 5 V VO12NH IO = 10mA *1 9 10 11.9 V VO12NL IO = 10mA *1 0.1 1 2 V 5VREG voltage 5VREG SENSE pin detection voltage VSENth FGIN high-level input current FGIhi FGIN low-level input current PWMIN high-level current PWMIN low-level current OUT1P, OUT2P high-level output mA voltage OUT1P, OUT2P low-level output voltage OUT1N, OUT2N high-level output voltage OUT1N, OUT2N low-level output voltage *1 : There is a built-in 100Ω gate protection resistor. *2 : There is a built-in 300Ω gate protection resistor. Truth Table FGIN PWMIN SENSE OUT1P OUT1N OUT2P OUT2N L L L L L H H H H L L OUT2 → 1 drive H L H L H H Regeneration mode H H H L (low side regeneration) H L H H Current limiter H H H L (low side regeneration) H L H L H L H Mode OUT1 → 2 drive Note 1 : For the SENSE pin, the "H" state is 0.2V or higher. Note 2 : The IC goes to regeneration mode (no motor drive applied) when the microcontroller is reset (the output high-impedance state). No.A2091-2/5 LB11851MC Package Dimensions unit : mm (typ) 3426A 4.9 6 Allowable power dissipation, Pd max -- W 6.0 5 0.41 0.835 0.37 1.0 0.21 1.5 1.75 MAX 1 Pd max -- Ta 1.0 3.9 10 Specified circuit board : 114.3×76.1×1.6mm3 glass epoxy board 0.8 0.75 0.6 0.4 0.36 0.2 0.175 0 -30 0 30 60 90 120 Ambient temperature, Ta -- °C SANYO : SOIC10 Pin Assignment OUT2P 1 10 OUT1P OUT2N 2 9 OUT1N 5VREG 3 8 VCC FGIN 4 7 SENSE PWMIN 5 6 GND LB11851MC Top View 1. Power supply (VCC and VM) and ground The wiring is separated into the control IC side (VCC line) and the motor output side (VM line) by the diode DI, which protects the IC from destruction on reverse connection. The application circuit uses 1μF capacitors to prevent line oscillation when kickback occurs. Similarly, 1μF capacitors are also used on the VCC line for power supply line stabilization. 2. PWMIN The LB11851M accepts an open-drain output signal from the microcontroller with this pin and controls the on/off states of the PMOS transistor (OUT1P and OUT2P) outputs accordingly. A constant-current bias is provided from 5VREG internally to the IC. 3. FGIN The LB11851M accepts a CMOS output from the microcontroller with this pin and determines the drive phase output (OUT1P, OUT2P, OUT1N, or OUT2N). 4. 5VREG This is the power supply for the microcontroller, Hall effect sensors, and other circuits. A capacitor with a value of 1μF is used for output stabilization. This pin has an output current capacity of 20mA. 5. SENSE A sensing resistor is used for current detection. If the SENSE pin voltage exceeds 0.2V, the PMOS transistors are turned off and only low side regeneration is performed. No.A2091-3/5 LB11851MC Application Circuit Example (12V) VM=Line C=1 F R1=1k C=1 F 1P 2P 1N 2N RF VCC C=1 F 5VREG SENSE PWMIN PWMOUT H ININ+ FGIN FGOUT Microcontroller LB11851MC VDD PWMIN INPUT OUT2P 2P OUT2N 2N OUT1P 1P OUT1N 1N A/D GND VSS FG No.A2091-4/5 LB11851MC Block Diagram VCC OUT1N 5VREG 20kΩ 5VREG 100Ω 300Ω 5VREG OUT1P 20kΩ Controller PWMIN 5VREG OUT2N FGIN 20kΩ 100Ω OUT2P 300Ω 20kΩ SENSE GND ON Semiconductor and the ON logo are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property. A listing of SCILLC’s product/patent coverage may be accessed at www.onsemi.com/site/pdf/Patent-Marking.pdf. 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