MIC4120/4129 Micrel, Inc. MIC4120/4129 6A-Peak Low-Side MOSFET Driver Bipolar/CMOS/DMOS Process General Description Features MIC4120 and MIC4129 MOSFET drivers are resilient, efficient, and easy to use. The MIC4129 is an inverting driver, while the MIC4120 is a non-inverting driver. The MIC4120 and MIC4129 are improved versions of the MIC4420 and MIC4429. • CMOS Construction • Latch-Up Protected: Will Withstand >200mA Reverse Output Current • Logic Input Withstands Negative Swing of Up to 5V • Matched Rise and Fall Times ................................ 25ns • High Peak Output Current ............................... 6A Peak • Wide Operating Range ............................... 4.5V to 20V • High Capacitive Load Drive ............................10,000pF • Low Delay Time .............................................. 55ns Typ • Logic High Input for Any Voltage From 2.4V to VS • Low Equivalent Input Capacitance (typ) ..................6pF • Low Supply Current ...............450µA With Logic 1 Input • Low Output Impedance ......................................... 2.5Ω • Output Voltage Swing Within 25mV of Ground or VS • Exposed backside pad packaging reduces heat - ePAD SOIC-8L (θJA = 58°C/W) - 3mm x 3mm MFL™-8L (θJA = 60°C/W) The drivers are capable of 6A (peak) output and can drive the largest MOSFETs with an improved safe operating margin. The MIC4120/4129 accept any logic input from 2.4V to VS without external speed-up capacitors or resistor networks. Proprietary circuits allow the input to swing negative by as much as 5V without damaging the part. Additional circuits protect against damage from electrostatic discharge. MIC4120/4129 drivers can replace three or more discrete components, reducing PCB area requirements, simplifying product design, and reducing assembly cost. Modern BiCMOS/DMOS construction guarantees freedom from latch-up. The rail-to-rail swing capability insures adequate gate voltage to the MOSFET during power up/down sequencing. Applications • • • • Switch Mode Power Supplies Motor Controls Pulse Transformer Driver Class-D Switching Amplifiers Functional Diagram VS 0.1mA MIC4129 IN V E R T I N G 0.4mA OUT IN 2kΩ MIC4120 NONINVERTING GND Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com August 2005 1 M9999-081105 MIC4120/4129 Micrel, Inc. Ordering Information Part Number Package Configuration Lead Finish MIC4120YME EPAD 8-Pin SOIC Non-Inverting Pb-Free MIC4120YML 8-Pin MLF Non-Inverting Pb-Free MIC4129YME EPAD 8-Pin SOIC Inverting Pb-Free MIC4129YML 8-Pin MLF Inverting Pb-Free Pin Configurations VS 1 8 VS IN 2 7 OU T NC 3 6 OU T GND 4 5 GND EPAD SOIC-8 (ME) MLF-8 (ML) Pin Description Pin Number Pin Name Pin Function Control Input 2 IN 4, 5 GND 1, 8 VS 6, 7 OUT 3 NC EP GND M9999-081105 Ground: Duplicate pins must be externally connected together Supply Input: Duplicate pins must be externally connected together Output: Duplicate pins must be externally connected together Not connected Ground: Backside 2 August 2005 MIC4120/4129 Micrel, Inc. Absolute Maximum Ratings (Notes 1, 2 and 3) Operating Ratings Supply Voltage ...........................................................24V Input Voltage ............................... VS + 0.3V to GND – 5V Input Current (VIN > VS) .......................................... 50mA Storage Temperature............................. –65°C to +150°C Lead Temperature (10 sec.) ................................... 300°C ESD Rating, Note 4 Supply Voltage .............................................. 4.5V to 20V Junction Temperature ............................ –40°C to +125°C Package Thermal Resistance 3x3 MLF™ (θJA) ...............................................60°C/W EPAD SOIC-8 (θJA) ..........................................58°C/W Electrical Characteristics: >1V/µs Symbol (TA = 25°C with 4.5V ≤ VS ≤ 20V unless otherwise specified. Note 3.) Input Voltage slew rate Parameter Conditions Min Typ 2.4 1.9 Max Units INPUT VIH Logic 1 Input Voltage VIL Logic 0 Input Voltage IIN Input Current VIN OUTPUT VOH 1.5 Input Voltage Range –5 0 V ≤ VIN ≤ VS –10 See Figure 1 See Figure 1 RO Output Resistance, Output Low IOUT = 10 mA, VS = 20 V RO Output Resistance, Output High IPK Peak Output Current IR Latch-Up Protection Withstand Reverse Current 0.8 V VS + 0.3 V 10 VS–0.025 High Output Voltage Low Output Voltage VOL V µA V 0.025 V 1.4 5 Ω IOUT = 10 mA, VS = 20 V 1.5 5 Ω VS = 20 V (See Figure 6) 6 A 200 mA SWITCHING TIME tR Rise Time Test Figure 1, CL = 2200 pF 12 30 35 ns ns tF Fall Time Test Figure 1, CL = 2200 pF 13 30 35 ns ns tD1 Delay Time Test Figure 1 45 75 100 ns ns tD2 Delay Time Test Figure 1 50 75 100 ns ns 0.45 60 3 400 mA µA 20 V POWER SUPPLY IS Power Supply Current VS Operating Input Voltage VIN = 3 V VIN = 0 V 4.5 Notes: 1. Functional operation above the absolute maximum stress ratings is not implied. 2. Static-sensitive device. Store only in conductive containers. Handling personnel and equipment should be grounded to prevent damage from static discharge. 3. Specification for packaged product only. 4. Devices are ESD sensitive. Handling precautions recommended. Human body model: 1.5kΩ in series with 100pF. August 2005 3 M9999-081105 MIC4120/4129 Micrel, Inc. Test Circuits VS = 20V VS = 20V 0.1µF 0.1µF IN OUT 2200pF MIC4129 INPUT 5V 90% INPUT tD1 tP W tF tD2 0.1µF 0.1µF IN OUT 2200pF MIC4120 2.5V 10% 0V VS 90% 1.0µF tR 5V 90% 2.5V 10% 0V VS 90% 1.0µF tD1 tP W tR tD2 tF OUTPUT OUTPUT 10% 0V 10% 0V Figure 1. Inverting Driver Switching Time M9999-081105 Figure 2. Non-inverting Driver Switching Time 4 August 2005 MIC4120/4129 Micrel, Inc. Typical Characteristics 50 50 40 40 30 20 4700pF 2200pF 10 0 5 3.0 RESISTANCE (Ω) 2.5 30 20 60 50 10000pF 4700pF 20 10 10 15 INPUT VOLTAGE (V) F all T ime DELAY TIME (ns) 60 10000pF FALL TIME (ns) RISE TIME (ns) 60 R is e T ime 0 5 2200pF Delay T ime vs . Input V oltage td2 40 30 td1 20 10 10 15 INPUT VOLTAGE (V) 20 0 5 10 15 INPUT VOLTAGE (V) 20 Output R es is tanc e vs . S uppl y V oltage Output High 2.0 1.5 Output Low 1.0 0.5 0 5 10 15 SUPPLY VOLTAGE (V) August 2005 20 5 M9999-081105 MIC4120/4129 Micrel, Inc. Applications Information Grounding Supply Bypassing The high current capability of the MIC4120/4129 demands careful PC board layout for best performance. Since the MIC4129 is an inverting driver, any ground lead impedance will appear as negative feedback which can degrade switching speed. Feedback is especially noticeable with slow-rise time inputs. Charging and discharging large capacitive loads quickly requires large currents. For example, charging a 2500pF load to 18V in 25ns requires a 1.8 A current from the device power supply. Figure 3 shows the feedback effect in detail. As the MIC4129 input begins to go positive, the output goes negative and several amperes of current flow in the ground lead. As little as 0.05Ω of PC trace resistance can produce hundreds of millivolts at the MIC4129 ground pins. If the driving logic is referenced to power ground, the effective logic input level is reduced and oscillation may result. The MIC4120/4129 has double bonding on the supply pins, the ground pins and output pins This reduces parasitic lead inductance. Low inductance enables large currents to be switched rapidly. It also reduces internal ringing that can cause voltage breakdown when the driver is operated at or near the maximum rated voltage. Internal ringing can also cause output oscillation due to feedback. This feedback is added to the input signal since it is referenced to the same ground. To insure optimum performance, separate ground traces should be provided for the logic and power connections. Connecting the logic ground directly to the MIC4129 GND pins will ensure full logic drive to the input and ensure fast output switching. Both of the MIC4129 GND pins should, however, still be connected to power ground. To guarantee low supply impedance over a wide frequency range, a parallel capacitor combination is recommended for supply bypassing. Low inductance ceramic capacitors should be used. A 1µF low ESR film capacitor in parallel with two 0.1 µF low ESR ceramic capacitors provide adequate bypassing. Connect one ceramic capacitor directly between pins 1 and 4. Connect the second ceramic capacitor directly between pins 8 and 5. M9999-081105 The E-Pad and MLF packages have an exposed pad under the package. It's important for good thermal performance that this pad is connected to a ground plane. 6 August 2005 MIC4120/4129 Micrel, Inc. Input Stage can easily be exceeded. Therefore, some attention should be given to power dissipation when driving low impedance loads and/or operating at high frequency. The input voltage level of the 4129 changes the quiescent supply current. The N channel MOSFET input stage transistor drives a 450µA current source load. With a logic “1” input, the maximum quiescent supply current is 450µA. Logic “0” input level signals reduce quiescent current to 55µA maximum. The supply current vs frequency and supply current vs capacitive load characteristic curves aid in determining power dissipation calculations. Table 1 lists the maximum safe operating frequency for several power supply voltages when driving a 2500pF load. More accurate power dissipation figures can be obtained by summing the three dissipation sources. The MIC4120/4129 input is designed to provide hysteresis. This provides clean transitions, reduces noise sensitivity, and minimizes output stage current spiking when changing states. Input voltage threshold level is approximately 1.5V, making the device TTL compatible over the 4.5V to 20V operating supply voltage range. Input current is less than 10µA over this range. Given the power dissipation in the device, and the thermal resistance of the package, junction operating temperature for any ambient is easy to calculate. For example, the thermal resistance of the 8-pin EPAD MSOP package, from the data sheet, is 60°C/W. In a 25°C ambient, then, using a maximum junction temperature of 150°C, this package will dissipate 2W. The MIC4129 can be directly driven by the MIC9130, MIC3808, MIC38HC42 and similar switch mode power supply. By offloading the power-driving duties to the MIC4120/4129, the power supply controller can operate at lower dissipation. This can improve performance and reliability. Accurate power dissipation numbers can be obtained by totaling the three sources of power dissipation in the device: The input can be greater than the +VS supply, however, current will flow into the input lead. The propagation delay for TD2 will increase to as much as 400ns at room temperature. The input currents can be as high as 30mA p-p (6.4mARMS) with the input, 6 V greater than the supply voltage. No damage will occur to MIC4120/4129 however, and it will not latch. • Load Power Dissipation (PL) • Quiescent power dissipation (PQ) • Transition power dissipation (PT) Calculation of load power dissipation differs depending upon whether the load is capacitive, resistive or inductive. Resistive Load Power Dissipation The input appears as a 7pF capacitance, and does not change even if the input is driven from an AC source. Care should be taken so that the input does not go more than 5 volts below the negative rail. Dissipation caused by a resistive load can be calculated as: PL = I2 RO D Power Dissipation where: CMOS circuits usually permit the user to ignore power dissipation. Logic families such as 4000 and 74C have outputs which can only supply a few milliamperes of current, and even shorting outputs-to-ground will not force enough current to destroy the device. The MIC4120/4129, on the other hand, can source or sink several amperes and drive large capacitive loads at high frequency. The package power dissipation limit I = the current drawn by the load RO = the output resistance of the driver when the output is high, at the power supply voltage used. (See data sheet) D = fraction of time the load is conducting (duty cycle) +18 V WIMA MK22 1 µF 5.0V 1 8 MIC4121 0V 5 0.1µ F LOGIC� GROUND POWER� GROUND 4 6, 7 0.1µF Table 1: MIC4129 Maximum 18 V TEK CURREN T P ROBE 6 3 0 2 Operating Frequency VS 0V 20V 15V 10V 2,500 pF POLYCARBONATE 6 AMPS Conditions: PC TRACE RESISTANCE = 0.05 Ω Max Frequency 1MHz 1.5MHz 3.5MHz TA = 25°C, 3. CL = 2500pF Figure 3. Switching Time Degradation Due to Negative Feedback August 2005 7 M9999-081105 MIC4120/4129 Micrel, Inc. Capacitive Load Power Dissipation Transition Power Dissipation Dissipation caused by a capacitive load is simply the energy placed in, or removed from, the load capacitance by the driver. The energy stored in a capacitor is described by the equation: Transition power is dissipated in the driver each time its output changes state, because during the transition, for a very brief interval, both the N- and P-channel MOSFETs in the output totem-pole are ON simultaneously, and a current is conducted through them from V+S to ground. The transition power dissipation is approximately: E = 1/2 C V2 As this energy is lost in the driver each time the load is charged or discharged, for power dissipation calculations the 1/2 is removed. This equation also shows that it is good practice not to place more voltage on the capacitor than is necessary, as dissipation increases as the square of the voltage applied to the capacitor. For a driver with a capacitive load: PT = 2 f VS (A•s) where (A•s) is a time-current factor derived from the typical characteristic curves. Total power (PD) then, as previously described is: PD = PL + PQ +PT PL = f C (VS)2 Definitions where: CL = Load Capacitance in Farads. f = Operating Frequency C = Load Capacitance VS =Driver Supply Voltage D = Duty Cycle expressed as the fraction of time the input to the driver is high. Inductive Load Power Dissipation f = Operating Frequency of the driver in Hertz. For inductive loads the situation is more complicated. For the part of the cycle in which the driver is actively forcing current into the inductor, the situation is the same as it is in the resistive case: IH = Power supply current drawn by a driver when both inputs are high and neither output is loaded. IL = Power supply current drawn by a driver when both inputs are low and neither output is loaded. PL1 = I2 RO D ID = Output current from a driver in Amps. However, in this instance the RO required may be either the on resistance of the driver when its output is in the high state, or its on resistance when the driver is in the low state, depending on how the inductor is connected, and this is still only half the story. For the part of the cycle when the inductor is forcing current through the driver, dissipation is best described as PD = Total power dissipated in a driver in Watts. PL = Power dissipated in the driver due to the driver’s load in Watts. PQ = Power dissipated in a quiescent driver in Watts. PT = Power dissipated in a driver when the output changes states (“shoot-through current”) in Watts. NOTE: The “shoot-through” current from a dual transition (once up, once down) for both drivers is shown by the "Typical Characteristic Curve": Crossover Area vs. Supply Voltage and is in ampere-seconds. This figure must be multiplied by the number of repetitions per second (frequency) to find Watts. PL2 = I VD (1-D) where VD is the forward drop of the clamp diode in the driver (generally around 0.7V). The two parts of the load dissipation must be summed in to produce PL PL = PL1 + PL2 Quiescent Power Dissipation Quiescent power dissipation (PQ, as described in the input section) depends on whether the input is high or low. A low input will result in a maximum current drain (per driver) of ≤0.2mA; a logic high will result in a current drain of ≤2.0mA. Quiescent power can therefore be found from: RO = Output resistance of a driver in Ohms. VS = Power supply voltage to the IC in Volts. PQ = VS [D IH + (1-D) IL] where: IH = IL = D= VS = quiescent current with input high quiescent current with input low fraction of time input is high (duty cycle) power supply voltage M9999-081105 8 August 2005 MIC4120/4129 Micrel, Inc. +18 V WIMA MK22 1 µF 5.0V 1 2 8 MIC4129 0V 6, 7 5 0.1µ F 18 V TEK CURREN T P ROBE 6 3 0 2 0.1µF 4 0V 10,000 pF POLYCARBONATE Figure 4. Peak Output Current Test Circuit August 2005 9 M9999-081105 MIC4120/4129 Micrel, Inc. Package Information 8-Pin 3x3 MLF (ML) 8-Pin Exposed Pad SOIC (ME) MICREL INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA TEL + 1 (408) 944-0800 FAX + 1 (408) 474-1000 WEB http://www.micrel.com This information furnished by Micrel in this data sheet is believed to be accurate and reliable. However no responsibility is assumed by Micrel for its use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer. Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A Purchaser's use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser's own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. © 2004 Micrel Incorporated M9999-081105 10 August 2005