LB1938FA Monolithic Digital IC 1ch, Low-saturation Forward/Reverse Motor Driver Application Note http://onsemi.com Overview The LB1938FA is an H-bridge motor driver that supports low-voltage drive and features low-saturation outputs in an ultraminiature slim package. The LB1938FA provides forward, reverse, brake, and standby modes controlled by two input signals, and is an optimal DC motor driver for notebook personal computers, digital cameras, cell phones, and other portable equipment. Function Ultraminiature Micro8 package (3.0mm x 4.9mm x 1.1mm) The low saturation voltage means that the voltage applied to the motor is higher and IC heat generation is reduced. This allows this IC to be used in environments with higher ambient operating temperatures. Output saturation voltage (high side + low side): VOsat = 0.15V typical (IO = 100mA) The wide usable voltage range and the low standby mode current drain of 0.1 µA make this IC optimal for battery operated equipment. There are no constraints on the relationship between the input signal voltage and the supply voltage. For example, this IC can be use at VCC = 3V and VIN = 5V. Thermal protection circuit limits the drive current and prevents the IC from causing a fire or being destroyed if the IC chip temperature reaches or exceeds 180°C due to large currents flowing when the outputs are shorted due to, for example, motor layer shorting or other phenomena. Typical Applications Package Dimensions unit : mm (typ) Pd max - Ta 700 Allowable Power Dissipation, Pd max - mW DSC Security camera CCTV 600 500 400 Mounted on a specified board 114.3mm76.1mm1.5 mm, glass epoxy resin 300 208 200 100 0 -30 0 30 60 Ambient Temperature, Ta -C Semiconductor Components Industries, LLC, 2013 December, 2013 90 120 ILB01453 1/13 LB1938FA Application Note Pin Assignment Application Circuit Example C1 = 0.1 to 10F VCC 60k CPU 3 60k M 6 OUT2 80k IN2 OUT1 7 Control block 2 80k IN1 1 S-GND 4 8 P-GND ILB01455 Cautions: VCC and GND lines suffer substantial fluctuation in the current quantity, causing a problem of line oscillation in certain cases. In this case, take following points into account: (1) Use a thick and short wiring to reduce the wiring inductance. (2) Insert a capacitor with satisfactory frequency characteristics near IC. *) Electrostatic capacitor C1 is used to stabilize power. Requirement for capacitance value varies depends on substrate wiring, motor, and power. The recommendation range of C1 is approximately 0.1μF to 10μF. Please check supply voltage waveform when motor is under operation and use a capacitor for stable operation. (3) Connect S-GND to the control system GND on the CPU side and P-GND to the power system GND. 2/13 LB1938FA Application Note Specifications Absolute Maximum Ratings at Ta = 25C Parameter Symbol Conditions Ratings Unit Supply voltage VCC max 10.5 V Output current IOUT max 800 mA Output voltage VOUT max VCC+VSF V 10 V 400 mW Input applied voltage VIH max Allowable power dissipation Pd max Mounted on a specified board * Operating temperature range Topr -30 to +85 C Storage temperature range Tstg -55 to +150 C Note *: Mounted on a specified board: 114.3mm x 76.1mm x 1.5mm, glass epoxy resin, wiring density 20% 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 Conditions at Ta = 25C Parameter Symbol Conditions Ratings min typ Unit max Supply voltage VCC 2.2 10 V Input high-level voltage VIH 2.0 9.5 V Input low-level voltage VI L -0.3 +0.3 V Electrical Characteristics at Ta 25C, VCC = 3V Parameter Circuit current Symbol Ratings min typ Unit max ICC1 Standby 0.1 5 A ICC2 Forward/reverse drive 14 19 mA ICC3 Output saturation voltage Conditions VOsat1 Brake Upper + lower IO = 100mA 20 29 mA 0.15 0.2 V 0.35 0.5 V for forward/reverse rotation VOsat2 Upper + lower IO = 300mA for forward/reverse rotation VOsat3 Spark killer diode forward Upper IO = 100mA for braking 0.1 0.15 V VSF IO = 300mA 0.9 1.7 V IRS VOUT = 10V 0.1 5 A IIN VIN = 5V 75 98 A voltage Spark killer diode inverse current Input current Thermal protection operating TSD Design target value * 180 C temperature Note *: Design target value: Measurement with a single unit not made. 3/13 LB1938FA Application Note Pin Functions Pin No. Pin name Pin Function 2 IN1 Control signal input pin 3 IN2 Control signal input pin 7 OUT1 Out pin 6 OUT2 Out pin 1 VCC Power supply voltage pin 4 S-GND Signal ground pin 8 P-GND Power ground pin 5 NC No connect Equivalent Circuit 4/13 LB1938FA Application Note Truth Table IN1 IN2 OUT1 OUT2 Mode L L OFF OFF Standby H L H L Forward rotation L H L H Reverse rotation H H H H Brake Operation explanation Output stage transistor function Thermal protection function LB1938FA incorporates thermal shutdown circuitry. When junction temperature Tj exceeds 180C, the output current flowing between OUT1 and OUT2 is reduced; therefore, the heat generation is reduced. The thermal shutdown circuit does not guarantee the protection of the final product because it operates when the temperature exceed the junction temperature of Tjmax=150C. 5/13 LB1938FA Application Note VO(sat) - IO 0.4 0.3 0.2 0.1 0 0 100 200 300 400 Output current, IO - mA VCC = 3V 0.4 IO = 3 0 0 mA 0.3 0.2 A IO = 100m 0.1 0 -40 500 -20 0 20 40 60 80 100 Ambient temperature, Ta - C ILB01459 ICC - Tc 28 VO(sat) - Ta 0.5 VCC = 3V Output saturation voltage, VO(sat) - V Output saturation voltage, VO(sat) - V 0.5 140 ILB01458 ICC - VCC 28 24 120 VCC = VIN 24 16 12 Forw ard o r 8 Bra k VC e mode C =5 V rever se mo de, V CC = 5V 3V Current drain, ICC - mA Current drain, ICC - mA e Brake mod 20 4 20 16 Forward or e IN1 reverse mod IN2 4 6 12 8 4 3V 0 -40 -20 0 20 40 60 80 100 Case temperature, Tc - C 120 0 140 1 2 3 5 7 8 Supply voltage, VCC - V IIN - VIN 160 0 ILB01457 9 10 ILB01460 ICC Standby Mode Temperature Characteristics 2.0 VCC = 3V VCC = 11V Current drain, ICC - A Input current, IIN - A 1.6 120 80 40 1.2 0.8 0.4 0.29 0 0 1 2 3 4 5 6 7 8 Input voltage, VIN - V 9 10 ILB01461 0 -40 Under 0.01A -20 0 20 40 60 80 Case temperature, Tc - C 100 120 140 ILB01462 IN Pin Input Current Temperature Characteristics 100 VIN = 5V Input current, IIN - A 80 60 40 20 0 -40 -20 0 20 40 60 80 Case temperature, Tc - C 100 120 140 ILB01463 6/13 LB1938FA Application Note Waveform example *Please refer to the following test circuit diagram 1. No load VCC=3V IN2=“L” High No load VCC=3V IN2=“H” Ch1 IN1 5V/div High High Ch2 VOUT1 2V/div High Low Ch3 VOUT2 2V/div High High Low Off High Low Off High Ch1 IN1 5V/div Low High Ch2 VOUT1 2V/div High High Ch3 VOUT2 2V/div Low T=2ms/div T=2ms/div No load VCC=6V IN2=“L” High No load VCC=6V IN2=“H” Ch1 IN1 5V/div High Low High Off High Low High High Ch2 VOUT1 2V/div Low Off High High High No load VCC=3V IN2= Time scale expansion “fall time” Low High Low t=3.1us High High T=1us/div Ch3 VOUT2 2V/div High T=2ms/div T=2ms/div High Ch2 VOUT1 2V/div Low Ch3 VOUT2 2V/div Low Ch1 IN1 5V/div High No load VCC=3V IN2=“H” Time scale expansion Ch1 IN1 5V/div Ch2 VOUT1 2V/div Ch3 VOUT2 2V/div Low Low High “rise time” High Ch1 IN1 5V/div High Ch2 VOUT1 2V/div t=2.2us High Ch3 VOUT2 2V/div T=1us/div 7/13 LB1938FA Application Note No load VCC=6V IN2=“H” Time scale expansion “fall time” No load VCC=6V IN2=“H” Time scale expansion Ch1 IN1 5V/div Low High Low High High t=2.4us t=3.4us High Ch2 VOUT1 2V/div Low Ch2 VOUT1 2V/div High High T=1us/div No load VCC=10V IN2=“H” Time scale expansion Low Ch1 IN1 5V/div Low High Ch2 VOUT1 5V/div Low High Low Ch3 VOUT2 5V/div High “rise time” High t=2.6us High t=3.8us Ch3 VOUT2 5V/div T=1us/div No load VCC=10V IN2=“H” Time scale expansion “fall time” High Ch1 IN1 5V/div High Low Ch3 VOUT2 5V/div High “rise time” High High Ch1 IN1 5V/div Ch2 VOUT1 5V/div Ch3 VOUT2 5V/div T=1us/div T=1us/div (Test circuit diagram 1) 10uF VCC=3V/6V/10V + LB1938FA VIN1=3V (f=100Hz,duty=50%) "H" "L" VIN2=3V 8/13 LB1938FA Application Note *Please refer to the following test circuit diagram 2. DC motor load VCC=3V IN2=“L” Current waveform example “motor start” Low Ch1 IN1 5V/div High Ch2 VOUT1 2V/div High Off Off Ch3 VOUT2 2V/div Low Ch4 Icoil 200mA/div Forward Standby T=20ms/div When DC motor starts up, the current value becomes high. However, rotation of DC motor starts, induced voltage Ea is generated and current decreases according to the rotation frequency. If a coil resistance is set to Rcoil and motor voltage is set to VCC, then motor current is obtained as follows: Im = (VCC-Ea)/Rcoil. DC motor load VCC=3V IN2=“H” Current waveform example “brake current” High Low High High High Ch2 VOUT1 2V/div High Ch3 VOUT2 2V/div Low High High Brake Ch1 IN1 5V/div Brake Ch4 Icoil 200mA/div Reverse T=20ms/div When DC motor is under rotation, if brake mode is set, then DC motor becomes short-brake status, and speed falls rapidly. In this case, current Im (Im = Ea / Rcoil) flows to the opposite direction by the induced voltage Ea generated during motor rotation. If DC motor stops rotation, then Ea=0, and current becomes 0. 9/13 LB1938FA Application Note DC motor load VCC=3V Current waveform example High Low High High High High Brake “active reverse brake current” High Low Low Ch1 IN1 5V/div Ch2 IN2 5V/div Ch3 VOUT2 2V/div Forward Reverse Ch4 Icoil 200mA/div T=20ms/div If rotation direction is switched while DC motor is rotating, then torque of reverse-rotation is generated, the speed of motor rotation becomes slow and reverse rotation is performed. In this case, since voltage of VCC is added to induced voltage Ea generated during motor rotation, the motor current flows into the motor coil which is obtained as follows: Im= (VCC+Ea) / Rcoil. When you switch from forward to reverse, if the current exceeds Iomax, make sure to set brake mode until the induced voltage is reduced between forward and reverse. (Test circuit diagram 2) 10/13 LB1938FA Application Note OUT1 (Circuit diagram of the evaluation board) OUT2 Evaluation board description (NC) 5 OUT2 6 OUT1 7 P-GND 8 P-GND 10uF C1 + 4 S-GND 3 IN2 1 VCC 2 IN1 LB1938FA IC1 VCC SW1 SW2 S-GND IN2 IN1 VIN *VIN terminal is a power supply input terminal for switches. 5V are to impress it and can perform the setting that is in a state by the switch operation and logic input. Operation method Power supply injection order: VCC VIN Truth value table IN1 IN2 OUT1 OUT2 Mode L L OFF OFF Standby H L H L Forward L H L H Reverse H H H H Brake 11/13 LB1938FA Application Note Recommended Soldering Footprint 12/13 LB1938FA Application Note 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. 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