PRODUCT DATASHEET AAT4901 FastSwitchTM Buffered Power Full-Bridge General Description Features The AAT4901 FastSwitchTM is a member of AnalogicTech's Application Specific Power MOSFETTM (ASPMTM) product family. It is a full-bridge buffered power stage operating with an input voltage range of 2.0V to 5.5V. The device is designed to operate with a switching frequency of up to 2MHz, minimizing the cost and size of external components. The AAT4901 is protected from shoot-through current by integrated break-before-make circuitry. The drivers can be independently controlled and their propagation delay, from input to output, is typically between 8ns-19ns dependent upon logic option. * VIN Range: 2.0V-5.5V * RDS(ON): High-side 220m Low-side 160m * Break-Before-Make Shoot-Through Protection * 4 Options Single Control Input with Enable * Two Logic Versions Dual Control Input with Brake Function Dual Half-bridge * Low Quiescent Current: 10A (max) DC 5mA (max) at 1MHz * Over-Temperature Protection * -40C to +85C Temperature Range * SC70JW-8 Package Four options are offered providing a single input control, dual input control or as two independent half-bridges. Other features include low RDS(ON) and low quiescent current allowing for high efficiency performance. The AAT4901 includes thermal protection to safeguard the device under extreme operating conditions. Applications The AAT4901 is available in the space-saving, Pb-free 8-pin SC70JW package and is rated over the -40C to +85C temperature range. DC Motor Drive Door Locks Dual Low-Side MOSFET Gate Driver Fan Motors High Frequency DC/DC Converters High Speed Line Drive Proximity Detectors Typical Applications IN CIN OUTA AAT4901-1 ENA OUTB ENB GND 4901.2010.01.1.2 www.analogictech.com 1 PRODUCT DATASHEET AAT4901 FastSwitchTM Buffered Power Full-Bridge Pin Descriptions Symbol Pin # -1, -2, -4 1 2 3 4 ENA IN ENB N/C 5 6 7 8 Function -3 Active high enable signal. Supply voltage input; input voltage range from 2.0V to 5.5V. Active high enable signal. 4901-1/-2/-4: No connection. 4901-3: Active high enable signal. Ground connection Output of half-bridge B. Connect to load. Output of half-bridge A. Connect to load. 4901-1/-2/-4: No connection. 4901-3: Active high enable signal. ENC GND OUTB OUTA N/C END Pin Configuration SC70JW-8 (Top View) ENA IN ENB N/C 1 8 2 7 3 6 4 5 N/C OUTA OUTB GND ENA IN ENB ENC AAT4901-1/-2/-4 2 1 8 2 7 3 6 4 5 END OUTA OUTB GND AAT4901-3 www.analogictech.com 4901.2010.01.1.2 PRODUCT DATASHEET AAT4901 FastSwitchTM Buffered Power Full-Bridge Absolute Maximum Ratings1 Symbol VIN VEN VOUT IMAX IMAX(PK) TLEAD Description IN to GND ENA, ENB, ENC, END to GND OUT to GND Maximum Continuous Switch Current Maximum Peak Current Maximum Soldering Temperature (at Leads) Value Units -0.3 to 6.0 -0.3 to VIN + 0.3 -0.3 to VIN + 0.3 0.7 3 300 V V V A A C Value Units 440 225 -40 to 150 mW C/W C Thermal Information Symbol PD JA TJ Description Maximum Power Dissipation (TA = 25C) Thermal Resistance2 Operating Junction Temperature Range 1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at conditions other than the operating conditions specified is not implied. Only one Absolute Maximum Rating should be applied at any one time. 2. Mounted on a FR4 board. 4901.2010.01.1.2 www.analogictech.com 3 PRODUCT DATASHEET AAT4901 FastSwitchTM Buffered Power Full-Bridge Electrical Characteristics1 VIN = 5V, TA = -40 to 85C unless otherwise noted. Typical values are at TA = 25C. Symbol VIN Description Conditions IQAC AC Quiescent Current IQDC DC Quiescent Current IQ(OFF) Off-Supply Current ISD(OFF) Off-Switch Current RDS(ON)H High Side MOSFET On-Resistance RDS(ON)L Low Side MOSFET On-Resistance VONL VONH VHYS ISINK ENA ENA ENA ENA TBBM Break-Before-Make Time TSHDH Chip Thermal Shutdown Temperature (C), ENB (D) Input Low Voltage (C), ENB (D) Input High Voltage (C), ENB (D) Input Hysteresis (C), ENB (D) Input Leakage AAT4901-1 AAT4901-2 IN = 5V, ENB (D) = IN, ENA (C) = 1MHz, IOUT = 0 AAT4901-3 AAT4901-4 AAT4901-1 AAT4901-2 IN = 5V, ENB (D) = IN, ENA (C) = GND, IOUT = 0 AAT4901-3 AAT4901-4 ENB (D) = ENA (C) = GND, IN = OUT = 5.5V ENB (D) = GND, IN = 5.5V, VOUT = 0, or OUT = IN VIN = 4.5V VIN = 3.0V VIN = 2.0V VIN = 4.5V VIN = 3.0V VIN = 2.0V Max Units V 3 1.6 1.6 0.9 5.5 5 4 4 2.5 5.5 10.0 A 1.0 A 1 A 0.03 220 250 340 160 180 240 m 0.4 ENA (C) , ENB (D) = 5.5V ENA (C) Rising ENA (C) Falling Threshold Hysteresis ENA (C) to OUT Delay ENA (C) = GND ENB to OUT HiZ Delay ENA (C) = IN AAT4901-1 AAT4901-2 AAT4901-3 AAT4901-4 AAT4901-1 AAT4901-2 AAT4901-3 AAT4901-4 AAT4901-1 AAT4901-2 AAT4901-3 AAT4901-4 AAT4901-1 AAT4901-2 AAT4901-3 AAT4901-4 200 0.01 5.0 5.0 145 25 15 15 8 14 18 15 7 19 12 10 10 12 11 10 7 12 mA m 1.5 ENA (C) Falling THIZ Typ 2.0 ENA (C) Rising TON-DLY Min Operation Voltage 1.0 V V mV A ns ns C ns ns ns ns 1. The AAT4901 is guaranteed to meet performance specifications over the -40C to +85C operating temperature range and is assured by design, characterization, and correlation with statistical process controls. 4 www.analogictech.com 4901.2010.01.1.2 PRODUCT DATASHEET AAT4901 FastSwitchTM Buffered Power Full-Bridge Typical Characteristics AAT4901-2 AC Quiescent Current vs. Input Voltage (ENB = IN; ENA = 1MHz; IOUT = 0A; TA = 25C) AC Quiescent Current (mA) AC Quiescent Current (mA) AAT4901-1 AC Quiescent Current vs. Input Voltage 4.0 3.3 2.6 1.9 1.2 0.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 (ENB = IN; ENA = 1MHz; IOUT = 0A; TA = 25C) 2.1 1.9 1.7 1.5 1.3 1.1 0.9 0.7 0.5 2.0 2.5 3.0 Input Voltage (V) (ENB = IN; ENA = 1MHz; IOUT = 0A; TA = 25C) 1.5 1.2 0.9 0.6 0.3 2.5 3.0 3.5 4.0 4.0 4.5 5.0 5.5 AAT4901-4 AC Quiescent Current vs. Input Voltage AC Quiescent Current (mA) AC Quiescent Current (mA) AAT4901-3 AC Quiescent Current vs. Input Voltage 0.0 2.0 3.5 Input Voltage (V) 4.5 5.0 5.5 (ENB = IN; ENA = 1MHz; IOUT = 0A; TA = 25C) 1.5 1.2 0.9 0.6 0.3 0.0 2.0 2.5 3.0 Input Voltage (V) 3.5 4.0 4.5 5.0 5.5 Input Voltage (V) (ENB = IN; ENA = 0.1kHz~2000kHz; VONH = 2V; IOUT = 0A; TA = 25C) (ENB = IN; ENA = 0.1kHz~2000kHz; VONH = 2V; IOUT = 0A; TA = 25C) 10 1 0.1 0.01 VIN = 5.0V VIN = 3.0V 0.001 0.1 1 10 100 1000 AC Quiescent Current (mA) AAT4901-2 AC Quiescent Current vs. Switching Frequency AC Quiescent Current (mA) AAT4901-1 AC Quiescent Current vs. Switching Frequency 10 1 0.1 0.01 10000 Switching Frequency (kHz) 4901.2010.01.1.2 VIN = 5.0V VIN = 3.0V 0.001 0.1 1 10 100 1000 10000 Switching Frequency (kHz) www.analogictech.com 5 PRODUCT DATASHEET AAT4901 FastSwitchTM Buffered Power Full-Bridge Typical Characteristics (ENB = IN; ENA = 0.1kHz~2000kHz; VONH = 2V; IOUT = 0A; TA = 25C) (ENB = IN; ENA = 0.1kHz~2000kHz; VONH = 2V; IOUT = 0A; TA = 25C) 10 1 0.1 0.01 VIN = 5.0V VIN = 3.0V 0.001 0.1 1 10 100 1000 AC Quiescent Current (mA) AAT4901-4 AC Quiescent Current vs. Switching Frequency AC Quiescent Current (mA) AAT4901-3 AC Quiescent Current vs. Switching Frequency 10 1 0.1 0.01 VIN = 5.0V VIN = 3.0V 0.001 10000 0.1 1 Switching Frequency (kHz) (ENB = IN, ENA = 1MHz; IOUT = 0A) 4 3 2 0 -40 VIN = 5.0V VIN = 3.0V -15 10 35 60 85 VIN = 5.0V VIN = 3.0V 2 1 0 -40 -15 AC Quiescent Current (mA) AC Quiescent Current (mA) VIN = 5.0V VIN = 3.0V 3 2 1 35 60 85 2 60 85 (ENB = IN, ENA = 1MHz; IOUT = 0A) VIN = 5.0V VIN = 3.0V 1.5 1 0.5 0 -40 Temperature (C) 6 35 AAT4901-3 AC Quiescent Current vs. Temperature (ENB = IN, ENA = 1MHz; IOUT = 0A) 10 10 Temperature (C) 5 -15 10000 3 AAT4901-3 AC Quiescent Current vs. Temperature 0 -40 1000 (ENB = IN, ENA = 1MHz; IOUT = 0A) 4 Temperature (C) 4 100 AAT4901-2 AC Quiescent Current vs. Temperature AC Quiescent Current (mA) AC Quiescent Current (mA) AAT4901-1 AC Quiescent Current vs. Temperature 1 10 Switching Frequency (kHz) -15 10 35 60 85 Temperature (C) www.analogictech.com 4901.2010.01.1.2 PRODUCT DATASHEET AAT4901 FastSwitchTM Buffered Power Full-Bridge Typical Characteristics Low Side RDS(ON) vs. Output Current High Side RDS(ON) vs. Output Current (TA = 25C) 300 350 250 300 RDS(ON)H (m) RDS(ON)L (m) (TA = 25C) 200 150 100 VIN = 2.0V VIN = 3.0V VIN = 4.5V 50 0 0.1 0.2 0.3 0.4 0.5 0.6 250 200 150 100 VIN = 2.0V VIN = 3.0V VIN = 4.5V 50 0 0.1 0.7 0.2 0.3 Output Current (A) Low Side RDS(ON) vs. Temperature 300 350 250 RDS(ON)H (m) RDS(ON)L (m) 400 200 150 100 VIN = 2.0V VIN = 3.0V VIN = 4.5V 50 10 35 60 250 200 150 VIN = 2.0V VIN = 3.0V VIN = 4.5V 100 50 0 -40 85 -15 10 Enable Threshold Voltage (V) 350 RDS(ON) (m) 300 250 200 150 100 High Side Low Side 50 0 3.5 4 85 4.5 5 1.4 1.2 1 0.8 VIH, -40C VIL, -40C VIH, 25C VIL, 25C VIH, 85C VIL, 85C 0.6 0.4 0.2 0 5.5 Input Voltage (V) 4901.2010.01.1.2 60 AAT4901 Enable A/B/C/D Threshold Voltage vs. Input Voltage (IOUT = 0.7A; TA = 25C) 3 35 Temperature (C) MOSFETs RDS(ON) vs. Input Voltage 2.5 0.7 300 Temperature (C) 2 0.6 (IOUT = 0.7A) 350 -15 0.5 High Side RDS(ON) vs. Temperature (IOUT = 0.7A) 0 -40 0.4 Output Current (A) 2 2.5 3 3.5 4 4.5 5 5.5 Input Voltage (V) www.analogictech.com 7 PRODUCT DATASHEET AAT4901 FastSwitchTM Buffered Power Full-Bridge Functional Block Diagram IN OUTA OUTB ENA ENC Control Logic ENB END AAT4901-3 Only GND Functional Description The AAT4901 is a buffered full-bridge driver IC with options to allow the device to function as two independent half-bridges. The output stage is capable of driving output loads of up to 0.7A and features break-before-make timing and very fast propagation delay time, allowing high switching speed up to 2MHz. The enable input (EN), when 8 driven low, turns off the driver and reduces the operating current to less than 1A. Over-temperature shutdown protects the AAT4901 in the case of overload or defective MOSFET. Logic options allow the AAT4901 to be used as a small DC motor driver with break function, a solenoid driver, a dual-low-side MOSFET driver, or as a coil driver. Applications include motor drive, proximity detectors, electronic locks, and DC-DC converters. www.analogictech.com 4901.2010.01.1.2 PRODUCT DATASHEET AAT4901 FastSwitchTM Buffered Power Full-Bridge Options AAT4901-1/-4 Logic Table AAT4901-1 -1 H-bridge configuration with two enables. Enable B is active high and enables the H-bridge output. Enable A toggles the H-bridge outputs A and B in anti-phase. In steady state, this can provide forward/reverse motor drive signals. AAT4901-2 H-bridge configuration with two enables. Enable A and Enable B are in anti-phase and provide forward/reverse and braking. ENA ENB ENA ENB OUTA OUTB 0 1 0 1 0 0 1 1 0 1 1 0 0 1 0 1 Hi Z Hi Z IN GND Hi Z Hi Z GND IN AAT4901-2 Logic Table ENA ENB OUTA OUTB 0 1 0 1 0 0 1 1 Hi Z IN GND IN Hi Z GND IN IN AAT4901-3 Dual independent half-bridge configuration with four enables. Function similar to 2 x AAT4900. AAT4901-4 -4 AAT4901-3 Logic Table H-bridge with two enables. Enable A and Enable B are in anti-phase and toggle the H-bridge outputs A and B in anti-phase respectively. In steady state, this can provide forward/reverse motor drive signals to adjust the motor speed by various duty cycles. ENA/C ENB/D OUTA/B 0 1 0 1 0 0 1 1 Hi Z Hi Z IN GND Timing Diagram TON-DLY-F V_ENA 50% 50% 50% 50% T ON-DLY-R 90% (OFF) (OFF) Hi Z Hi Z V_OUTA 10% TON-DLY-R V_ENB TON-DLY-F 50% 50% 50% 50% 90% (OFF) (OFF) Hi Z Hi Z V_OUTB 10% TON-DLY-F TON-DLY-R THIZ_GND THIZ_IN Figure 1: AAT4901-4 Timing Diagram. 4901.2010.01.1.2 www.analogictech.com 9 PRODUCT DATASHEET AAT4901 FastSwitchTM Buffered Power Full-Bridge Application Information Where: Input Supply Capacitor The input capacitor provides a low impedance loop for the edges of pulsed current drawn by the AAT4901 and reduces the surge current drawn from the input power. A 4.7F to 10F X7R or X5R low ESR/ESL ceramic capacitor is selected for the input supply decoupling. To minimize the tray resistance, the capacitor should be placed as closely as possible to the input pin. This keeps the high frequency content of input current localized, minimizing EMI and input voltage ripple. Shoot-Through Protection The internal high-side and low-side MOSFETs of the AAT4901 cannot conduct at the same time to prevent shoot-through current. When the high-side MOSFET turns on, the low-side MOSFET turns off first; after 5ns break-before-make time, the high-side MOSFET then turns on. Similarly, before the low-side MOSFET turns on, the high-side MOSFET turns off; after a certain break-before-make time (5ns typ.), the low-side MOSFET turns on. The dead time between the high-side and lowside turn-on should be kept as low as possible to minimize current flows through the body diode of the highside and/or low-side MOSFET(s). The break-before-make shoot-through protection significantly reduces losses associated with the driver at high frequency. Thermal Calculations Eq. 2: TJ(MAX) = PD(MAX) * JA + TA For example, if the AAT4901 drives 2 AAT9560 MOSFETs whose maximum gate charge is specified as 13nC for VGATE = 5V, the total power dissipation in the driver at a switching frequency of 1MHz equals: PD(tot) = 2 * (5V * 13nC * 1MHz) + 5V * 4.0mA = 150mW Gate Drive Current Ratings Assuming that the maximum gate charge of the dual low-side MOSFETs are equal, the maximum gate drive capability for the designed maximum junction temperature without an external resistor can be derived from Equation 1: 1 * 2 * FSW TJ(MAX) - TA - IQAC JA * VIN The relationship between gate capacitance, turn-on/ turn-off time, and the MOSFET driver current rating can be determined by: Eq. 4: IG(MAX) = CG(MAX) * dV dt Where: TJ(MAX) - TA JA = IQAC * VCC + QG(tot)FSW * VCC 10 The maximum junction temperature for the SC70JW-8 package can be derived from Equation 1: Eq. 3: QG(MAX) = In the dual low-side MOSFET driver application, the power dissipation of the AAT4901 includes the power dissipation in the MOSFETs due to charging and discharging the gate capacitance, the AC quiescent current power dissipation, and transient power in the driver during output transitions. As the transient power is usually very small, its losses can be ignored. Maximum package power dissipation can be estimated by the following equation: Eq. 1: PD(MAX) = VCC * IIN = TJ(MAX) = junction temperature of the dice (C). TA = ambient temperature (C). JA = thermal resistance (225C/W). IQAC = AC quiescent current of the driver (mA). QG(tot) = total gate charge of external low side MOSFETs (nC). FSW = switching frequency (MHz). IG(MAX) = peak drive current for a given voltage CG(MAX) = maximum gate capacitance dV = MOSFET gate-to-source voltage dt = rising time of MOSFET gate-to-source voltage www.analogictech.com 4901.2010.01.1.2 PRODUCT DATASHEET AAT4901 FastSwitchTM Buffered Power Full-Bridge The relationship between CG(MAX) , QG(MAX) , and VGATE is given by: Eq. 5: CG(MAX) = 2-Phase Synchronous Buck Converter QG(MAX) VGATE The peak current drive requirements for a given MOSFET gate voltage can be derived from Equations 4 and 5: Eq. 6: IG(MAX) = VIN = 5V VGATE = 5V FSW = 1MHz JA = 225C/W IQAC = 4.0mA TJ(MAX) = 120C TA = 85C tRISE = dt = 10ns 1 120C - 85C * - 4.0mA = 13.6nC 2 * 1MHz 225C/W * 5V CG(MAX) = QG(MAX) 13.6nC = = 2.7nF VGATE 5V IG(MAX) = QG(MAX) 13.6nC = = 1.36A dt 10ns 4901.2010.01.1.2 The most common AAT4901 applications include multiphase DC/DC converter output power stages, DC motor drive, a dual low-side MOSFET driver, and a 3-state highspeed high-current line driver. Figure 2 shows a typical configuration when used as a 2-phase buck converter power stage with synchronous rectification. The EN pin can be used to force outputs OUTA/OUTB to a high impedance state; this allows the output inductor to operate in discontinuous condition mode (DCM) and improves efficiency under light load conditions. The body diode associated with the low-side switching device gives the AAT4901 inductive switching capability, and clamps the LX node at one diode drop below GND during the break-before-make time. The multiphase buck converter assures a stable, high-performance topology for high currents and low voltages which are demanded in computers, workstation, telecom and datacom servers. Figure 3 illustrates output ripple current reduction due to 2-phase cancellation. QG(MAX) dt Design Example QG(MAX) = Typical Applications Motor Drive The AAT4901 is ideally suited for use as an efficient output driver for DC motor control due to its full bridge output stage with integrated MOSFETs. The inductive load switching capability of the AAT4901 eliminates the need for external diodes during commutation time. In applications where rotation is always in the same direction, a single half-bridge AAT4900 can be used to drive a DC motor. If needed to control the rotation in both directions, full-bridge motor control circuits can be applied as shown in Figure 4. In this configuration the motor can be controlled to run clockwise, counter-clockwise, stop rapidly ("regeneration" braking) or free run (coast) to a stop. www.analogictech.com 11 PRODUCT DATASHEET AAT4901 FastSwitchTM Buffered Power Full-Bridge On/Off (EN) VIN: 2.0V ~ 5.5V VCC PWM1 SW1 CIN GND FB 2 -Phase DC/DC Controller PWM2 SW2 1 2 3 4 ENA END IN OUTA AAT4901-3 ENB OUTB ENC GND 8 7 IL1 6 IL2 L1 IL1 + IL2 VOUT L2 5 R1 CO R2 Figure 2: AAT4901 in 2-Phase Synchronous Buck Converter Power Stage. OUTA OUTB IL2 IL1 IL1+IL2 Figure 3: Output Current Ripple Reduction (IL1+IL2) due to 2-Phase Cancellation. When the voltage applied between the DC motor by the input(s) logic control is reversed, it could change the rotation direction. When both outputs (OUTA/OUTB) are floating, the motor winding acts as a regeneration; the current inside the motor winding would continue to flow into the input capacitor through the internal MOSFET parasitic diode and decay to zero rapidly, stopping the motor rapidly. When both outputs are connected to the input supply (or ground) simultaneously, the motor coasts and the winding current decays slowly due to the winding resistor until the motor free runs to a stop. The speed of a DC motor is directly proportional to the supply voltage. It can be controlled by simply adjusting the voltage sent to the motor, but this is quite inefficient. 12 A better method is to switch the motor's supply on and off rapidly. If the switching is fast enough, the motor doesn't notice it, it only notices the average effect. The time it takes a motor to speed up and slow down under switching conditions is dependent on the inertia of the rotor (basically how heavy it is) and the amount of friction and load torque. Figure 5 shows the speed of a motor that is being turned on and off at a fairly low switching frequency. The average speed is around 150, although it varies quite a bit. If the supply voltage is switched quickly enough, the motor will not have time to change speed much and the speed will be quite steady. When the duty cycle (D = TON/T) is increased, the average speed of the motor increases. Thus the speed is controlled by the duty cycle of the PWM (Pulse Width Modulation). www.analogictech.com 4901.2010.01.1.2 PRODUCT DATASHEET AAT4901 FastSwitchTM Buffered Power Full-Bridge VIN: 2.0~5.5V VIN: 2.0~5.5V 1 CLK/DIR 8 ENA 2 EN IN OUTA AAT4901-1 3 4 C1 4.7F/16V ENB OUTB N/C GND 1 CLK/DIR Brake N/C 7 2 M 6 CLK/DIR 3 Brake 5 4 C1 4.7F/16V ENA N/C IN OUTA AAT4901-2 ENB OUTB N/C GND 8 7 M 6 5 VIN: 2.0~5.5V VIN: 2.0~5.5V EN 1 CLK/DIR 8 ENA CLK/DIR END 2 1 N/C ENA 8 7 IN 2 M OUTA AAT4901-3 3 IN 6 ENB OUTB ENC GND 3 OUTA AAT4901-4 ENB OUTB N/C GND 7 M 6 5 4 4 C1 4.7F/16V 5 C1 4.7F/16V Figure 4: Full-Bridge Motor Driver Using AAT4901. 200 20 Motor Speed 15 100 10 Supply Voltage 50 Supply Voltage Motor Speed 150 5 0 0 Ton T Time Figure 5: Motor Speed vs. Supply Voltage. 4901.2010.01.1.2 www.analogictech.com 13 PRODUCT DATASHEET AAT4901 FastSwitchTM Buffered Power Full-Bridge There is also a diode connected in reverse across the field winding, to absorb the current in the field winding when all four MOSFETs in the bridge are turned off. The minimum switching frequency is chosen based on motor characteristics (the equivalent inductance and the parasitic series resistor) and the percentage of current variation to the average current specified. The minimum switching frequency is in direct proportion to the parasitic series resister, and in inverse proportion to the equivalent inductance and allowable current ripple. During period (A), to make the motor run forwards, Q4 is turned on, and Q1 has the PWM signal applied to it. The current path is shown in blue in Figure 7. At period (B) Q4 is kept on, so when the Q1 PWM signal is off, current can continue to flow around the bottom loop through Q3's parasitic diode. At period (C), to make the motor run backwards or control the speed, Q3 is turned on, and Q2 has the PWM signal applied to it. At period (D), Q3 is kept on, so when the Q2 PWM signal is off, current can continue to flow around the bottom loop through Q4's parasitic diode. At period (E), when the motor is running forwards for example, the motor is now acting as a generator and forcing current through its armature, through Q2's diode, through the battery (thereby charging the battery) and back through Q3's diode. When driving a high-voltage DC motor, external highvoltage MOSFETs are needed to commutate the motor. In this application, the AAT4901 can be configured as a double-ended gate driver, as illustrated in Figure 6. The full-bridge power stage operates the motor drive control as shown in Figure 7. Each side of the motor can be connected either to the battery's positive terminal or to the battery's negative terminal through the switch. Note that only one MOSFET on each side of the motor may be turned on at any one time; otherwise the high-side and low-side MOSFETs will short out the battery and burn out. High-Voltage Rail VIN: 5.0V CLK1 1 2 CLK2 3 4 C1 4.7F/16V ENA N/C(END) IN OUTA AAT4901-1,-2,-4 (-3) ENB OUTB N/C(ENC) GND 8 7 to Motor 6 5 Figure 6: Double-Ended Gate Driver. 14 www.analogictech.com 4901.2010.01.1.2 PRODUCT DATASHEET AAT4901 FastSwitchTM Buffered Power Full-Bridge VBAT + VBAT + Lf Lf Field winding Field winding Q1 Q2 Q1 Q2 La La Ia Ia Q3 Q4 armature Q3 VBAT - armature Q4 VBAT Period (A) Period (B) VBAT + VBAT + Lf Field winding Lf Q1 Field winding Q2 Q1 La Q2 La Ia Q3 Ia Q4 armature Q3 VBAT - armature Q4 VBAT Period (D) Period (C) VBAT + Lf Field winding Q1 Q2 La Ia Q3 armature Q4 VBAT Period (E) Figure 7: Full-Bridge Motor Drive Control. Dual Channel, High Speed, High Current 3-State Line Driver Dual Low-Side MOSFET Driver The AAT4901-3 is ideally suited for dual channel, high speed, high current 3-state line driver applications such as CCD clock drivers. The low quiescent power dissipation makes this part attractive in battery powered products. The 3A peak drive capability also makes the AAT4901-3 an excellent choice for driving high speed capacitive lines. The 20ns fast switching/delay time allows clocking speeds up to 10MHz. 4901.2010.01.1.2 The AAT4901-3 is also ideally suited for dual low-side MOSFET driver applications due to its dual independent half-bridge output configuration. It can be used in a push-pull topology as illustrated in Figure 9 or in other applications which require the ability to drive the MOSFETs quickly, due to the AAT4901's extremely low RDS(ON) (220m typ.) and very fast propagation time (20ns typ.) www.analogictech.com 15 PRODUCT DATASHEET AAT4901 FastSwitchTM Buffered Power Full-Bridge ENA 3-State IN ENB OUTA ENC OUTB END 3-State GND Figure 8: AAT4901-3 Dual Channel High-Speed High-Current 3-State Line Driver. VOUT VIN + + VCC: 5.0V EN PWM A 1 2 3 PWM B 4 ENA END OUTA IN AAT4901-3 ENB OUTB ENC GND 8 7 6 5 C1 4.7F/16V Figure 9: Push-Pull Topology MOSFET Driver with AAT4901. 16 www.analogictech.com 4901.2010.01.1.2 PRODUCT DATASHEET AAT4901 FastSwitchTM Buffered Power Full-Bridge OUTA VIN U1 AAT4901 C C1 3 1 JP1 2 3 1 JP2 2 1 3 4 8 3 1 JP3 2 3 1 JP4 2 L1 ENA IN ENB OUTA ENC OUTB END GND TP1 2 7 Load Motor 6 5 C2 L2 TP2 C3 OUTB 4.7F M1 GND M2 GND M3 GND M4 Figure 10: AAT4901 Evaluation Board Schematic. Figure 11: AAT4901 Evaluation Board Top Side Layout. Figure 12: AAT4901 Evaluation Board Bottom Side Layout. Component Part Number Description Manufacturer U1 C1 C2, C3 L1, L2 Load AAT4901 GRM21BR61C475KA88 Not Populated Not Populated Not Populated Buffered Power Full-Bridge Cap Ceramic 4.7F 0805 X5R 16V 10% AnalogicTech Murata Table 1: AAT4901 Evaluation Board Bill of Materials. 4901.2010.01.1.2 www.analogictech.com 17 PRODUCT DATASHEET AAT4901 FastSwitchTM Buffered Power Full-Bridge Ordering Information Package Marking1 Part Number (Tape and Reel)2 SC70JW-8 SC70JW-8 SC70JW-8 SC70JW-8 D2RYY D3RYY D4RYY 2SRYY AAT4901IJS-1-T1 AAT4901IJS-2-T1 AAT4901IJS-3-T1 AAT4901IJS-4-T1 All AnalogicTech products are offered in Pb-free packaging. The term "Pb-free" means semiconductor products that are in compliance with current RoHS standards, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. For more information, please visit our website at http://www.analogictech.com/aboutus/quality.php. Package Information SC70JW-8 2.20 0.20 1.75 0.10 0.50 BSC 0.50 BSC 0.50 BSC 0.225 0.075 2.00 0.20 0.100 7 3 0.45 0.10 4 4 0.05 0.05 0.15 0.05 1.10 MAX 0.85 0.15 0.048REF 2.10 0.30 All measurements in millimeters. 1. XXGYY: XX denotes Device code, G denotes assembly code, and YY denotes date code. 2. Sample stock is generally held on part numbers listed in BOLD. Advanced Analogic Technologies, Inc. 3230 Scott Boulevard, Santa Clara, CA 95054 Phone (408) 737-4600 Fax (408) 737-4611 (c) Advanced Analogic Technologies, Inc. AnalogicTech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an AnalogicTech product. No circuit patent licenses, copyrights, mask work rights, or other intellectual property rights are implied. AnalogicTech reserves the right to make changes to their products or specifications or to discontinue any product or service without notice. Except as provided in AnalogicTech's terms and conditions of sale, AnalogicTech assumes no liability whatsoever, and AnalogicTech disclaims any express or implied warranty relating to the sale and/or use of AnalogicTech products including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right. In order to minimize risks associated with the customer's applications, adequate design and operating safeguards must be provided by the customer to minimize inherent or procedural hazards. Testing and other quality control techniques are utilized to the extent AnalogicTech deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed. AnalogicTech and the AnalogicTech logo are trademarks of Advanced Analogic Technologies Incorporated. All other brand and product names appearing in this document are registered trademarks or trademarks of their respective holders. 18 www.analogictech.com 4901.2010.01.1.2