MIC4420/4429 Micrel MIC4420/4429 6A-Peak Low-Side MOSFET Driver Bipolar/CMOS/DMOS Process General Description Features MIC4420, MIC4429 and MIC429 MOSFET drivers are tough, efficient, and easy to use. The MIC4429 and MIC429 are inverting drivers, while the MIC4420 is a non-inverting driver. • CMOS Construction • Latch-Up Protected: Will Withstand >500mA 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 18V • 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 They are capable of 6A (peak) output and can drive the largest MOSFETs with an improved safe operating margin. The MIC4420/4429/429 accepts 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. MIC4420/4429/429 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 MIC4429 INVERTING 0.4mA 0.1mA OUT IN 2kΩ MIC4420 NON-INVERTING GND 5-32 April 1998 MIC4420/4429 Micrel Ordering Information Part No. MIC4420CN MIC4420BN MIC4420CM MIC4420BM MIC4420BMM MIC4420CT MIC4429CN MIC4429BN MIC4429CM MIC4429BM MIC4429BMM MIC4429CT Temperature Range 0°C to +70°C –40°C to +85°C 0°C to +70°C –40°C to +85°C –40°C to +85°C 0°C to +70°C 0°C to +70°C –40°C to +85°C 0°C to +70°C –40°C to +85°C –40°C to +85°C 0°C to +70°C Package 8-Pin PDIP 8-Pin PDIP 8-Pin SOIC 8-Pin SOIC 8-Pin MSOP 5-Pin TO-220 8-Pin PDIP 8-Pin PDIP 8-Pin SOIC 8-Pin SOIC 8-Pin MSOP 5-Pin TO-220 VS 1 8 VS Configuration Non-Inverting Non-Inverting Non-Inverting Non-Inverting Non-Inverting Non-Inverting Inverting Inverting Inverting Inverting Inverting Inverting Pin Configurations IN 2 7 OUT NC 3 6 OUT GND 4 5 GND 5 Plastic DIP (N) SOIC (M) MSOP (MM) TAB 5 4 3 2 1 OUT GND VS GND IN TO-220-5 (T) Pin Description Pin Number TO-220-5 Pin Number DIP, SOIC, MSOP Pin Name Pin Function 1 2 IN Control Input 2, 4 4, 5 GND 3, TAB 1, 8 VS 5 6, 7 OUT 3 NC April 1998 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. 5-33 MIC4420/4429 Micrel Absolute Maximum Ratings (Notes 1, 2 and 3) Operating Ratings Supply Voltage .......................................................... 20V Input Voltage ............................... VS + 0.3V to GND – 5V Input Current (VIN > VS) ......................................... 50mA Power Dissipation, TA ≤ 25°C PDIP ................................................................... 960W SOIC ............................................................. 1040mW 5-Pin TO-220 .......................................................... 2W Power Dissipation, TC ≤ 25°C 5-Pin TO-220 ..................................................... 12.5W Derating Factors (to Ambient) PDIP ............................................................ 7.7mW/°C SOIC ........................................................... 8.3mW/°C 5-Pin TO-220 ................................................ 17mW/°C Storage Temperature ............................ –65°C to +150°C Lead Temperature (10 sec.) .................................. 300°C Junction Temperature ............................................ 150°C Ambient Temperature C Version ................................................ 0°C to +70°C B Version ............................................. –40°C to +85°C Package Thermal Resistance 5-pin TO-220 (θJC) .......................................... 10°C/W 8-pin MSOP (θJA) .......................................... 250°C/W Electrical Characteristics: Symbol (TA = 25°C with 4.5V ≤ VS ≤ 18V unless otherwise specified.) Parameter Conditions Min Typ 2.4 1.4 Max Units INPUT VIH Logic 1 Input Voltage VIL Logic 0 Input Voltage VIN Input Voltage Range IIN Input Current 0 V ≤ VIN ≤ VS VOH High Output Voltage See Figure 1 VOL Low Output Voltage See Figure 1 RO Output Resistance, Output Low IOUT = 10 mA, VS = 18 V RO Output Resistance, Output High IPK Peak Output Current IR Latch-Up Protection Withstand Reverse Current 1.1 V 0.8 V –5 VS + 0.3 V –10 10 µA OUTPUT VS–0.025 V 0.025 V 1.7 2.8 Ω IOUT = 10 mA, VS = 18 V 1.5 2.5 Ω VS = 18 V (See Figure 5) 6 A >500 mA SWITCHING TIME (Note 3) tR Rise Time Test Figure 1, CL = 2500 pF 12 35 ns tF Fall Time Test Figure 1, CL = 2500 pF 13 35 ns tD1 Delay Time Test Figure 1 18 75 ns tD2 Delay Time Test Figure 1 48 75 ns 0.45 90 1.5 150 mA µA 18 V POWER SUPPLY IS Power Supply Current VS Operating Input Voltage VIN = 3 V VIN = 0 V 4.5 5-34 April 1998 MIC4420/4429 Micrel Electrical Characteristics: (TA = –55°C to +125°C with 4.5V ≤ VS ≤ 18V unless otherwise specified.) Symbol Parameter Conditions Min Typ Max Units INPUT VIH Logic 1 Input Voltage 2.4 VIL Logic 0 Input Voltage VIN Input Voltage Range IIN Input Current 0V ≤ VIN ≤ VS VOH High Output Voltage Figure 1 VOL Low Output Voltage Figure 1 RO Output Resistance, Output Low IOUT = 10mA, VS = 18V RO Output Resistance, Output High V 0.8 V –5 VS + 0.3 V –10 10 µA OUTPUT VS–0.025 V 0.025 V 3 5 Ω IOUT = 10mA, VS = 18V 2.3 5 Ω SWITCHING TIME (Note 3) tR Rise Time Figure 1, CL = 2500pF 32 60 ns tF Fall Time Figure 1, CL = 2500pF 34 60 ns tD1 Delay Time Figure 1 50 100 ns tD2 Delay Time Figure 1 65 100 ns VIN = 3V VIN = 0V 0.45 0.06 3.0 0.4 mA mA 18 V POWER SUPPLY IS Power Supply Current VS Operating Input Voltage NOTE 1: NOTE 2: NOTE 3: 4.5 Functional operation above the absolute maximum stress ratings is not implied. Static-sensitive device. Store only in conductive containers. Handling personnel and equipment should be grounded to prevent damage from static discharge. Switching times guaranteed by design. Test Circuits VS = 18V VS = 18V 0.1µF 0.1µF IN 1.0µF OUT 2500pF IN 2.5V tPW ≥ 0.5µs VS 90% tD1 tPW OUT MIC4420 5V 90% 10% 0V 1.0µF 2500pF MIC4429 INPUT 0.1µF 0.1µF tF tD2 INPUT 5V 90% 2.5V tPW ≥ 0.5µs 10% 0V tR VS 90% tD1 tPW tR tD2 tF OUTPUT OUTPUT 10% 0V 10% 0V Figure 1a. Inverting Driver Switching Time April 1998 Figure 1b. Noninverting Driver Switching Time 5-35 5 MIC4420/4429 Micrel Typical Characteristic Curves Rise Time vs. Supply Voltage Fall Time vs. Supply Voltage 60 50 40 20 C L = 4700 pF 30 TIME (ns) 30 C L = 4700 pF 20 20 10 10 7 9 11 13 15 t FALL tRISE 10 C L = 2200 pF C L = 2200 pF 5 C L = 2200 pF VS = 18V C L = 10,000 pF TIME (ns) TIME (ns) 25 C L = 10,000 pF 40 0 Rise and Fall Times vs. Temperature 50 5 0 15 5 7 VS (V) 9 11 VS (V) 13 0 –60 15 50 40 40 30 30 20 60 100 TEMPERATURE (°C) 140 Delay Time vs. Supply Voltage Fall Time vs. Capacitive Load Rise Time vs. Capacitive Load 50 –20 60 VS = 12V 10 VS = 18V tD2 20 DELAY TIME (ns) VS = 5V 20 TIME (ns) TIME (ns) 50 VS = 5V VS = 12V VS = 18V 10 40 30 20 tD1 10 5 1000 3000 CAPACITIVE LOAD (pF) 5 1000 10,000 Propagation Delay Time vs. Temperature 0 10,000 3000 CAPACITIVE LOAD (pF) 84 6 CL= 2200 pF 40 30 tD1 20 10 –60 C L = 2200 pF V S = 18V –20 20 60 100 TEMPERATURE (°C) 70 SUPPLY CURRENT (mA) IS – SUPPLY CURRENT (mA) TIME (ns) 50 18 1000 VS = 15V t D2 8 10 12 14 16 SUPPLY VOLTAGE (V) Supply Current vs. Frequency Supply Current vs. Capacitive Load 60 4 56 42 500 kHz 28 200 kHz 18V 10V 100 5V 10 14 20 kHz 0 0 140 0 100 1000 CAPACITIVE LOAD (pF) 5-36 10,000 0 100 1000 FREQUENCY (kHz) 10,000 April 1998 MIC4420/4429 Micrel Typical Characteristic Curves (Cont.) Quiescent Power Supply Voltage vs. Supply Current Quiescent Power Supply Current vs. Temperature 900 LOGIC “1” INPUT VS = 18V 800 600 SUPPLY CURRENT (µA) SUPPLY CURRENT (µA) 1000 LOGIC “1” INPUT 400 200 800 700 600 500 LOGIC “0” INPUT 0 0 4 8 12 16 SUPPLY VOLTAGE (V) 400 –60 20 –20 20 60 100 TEMPERATURE (°C) 140 Low-State Output Resistance High-State Output Resistance 2.5 5 100 mA 5 2 ROUT (Ω ) ROUT (Ω ) 4 50 mA 10 mA 100 mA 50 mA 1.5 3 10 mA 2 1 5 7 9 11 VS (V) 13 15 Effect of Input Amplitude on Propagation Delay 5 7 13 15 2.0 LOAD = 2200 pF PER TRANSITION -8 CROSSOVER AREA (A•s) x 10 160 DELAY (ns) 11 VS (V) Crossover Area vs. Supply Voltage 200 120 INPUT 2.4V INPUT 3.0V 80 INPUT 5.0V 40 INPUT 8V AND 10V 1.5 1.0 0.5 0 0 5 6 7 8 9 10 11 12 13 14 15 V (V) 5 S April 1998 9 5-37 6 7 8 9 10 11 12 13 14 15 SUPPLY VOLTAGE V (V) s MIC4420/4429 Micrel Applications Information Grounding Supply Bypassing The high current capability of the MIC4420/4429 demands careful PC board layout for best performance Since the MIC4429 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. The MIC4429 input structure includes 300mV of hysteresis to ensure clean transitions and freedom from oscillation, but attention to layout is still recommended. 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. The MIC4420/4429 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 guarantee low supply impedance over a wide frequency range, a parallel capacitor combination is recommended for supply bypassing. Low inductance ceramic disk capacitors with short lead lengths (< 0.5 inch) should be used. A 1µF low ESR film capacitor in parallel with two 0.1 µF low ESR ceramic capacitors, (such as AVX RAM GUARD®), provides adequate bypassing. Connect one ceramic capacitor directly between pins 1 and 4. Connect the second ceramic capacitor directly between pins 8 and 5. Figure 3 shows the feedback effect in detail. As the MIC4429 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 MIC4429 ground pins. If the driving logic is referenced to power ground, the effective logic input level is reduced and oscillation may result. To insure optimum performance, separate ground traces should be provided for the logic and power connections. Connecting the logic ground directly to the MIC4429 GND pins will ensure full logic drive to the input and ensure fast output switching. Both of the MIC4429 GND pins should, however, still be connected to power ground. +15 (x2) 1N4448 5.6 kΩ OUTPUT VOLTAGE vs LOAD CURRENT 560 Ω 30 0.1µF 50V 1 8 2 0.1µF WIMA MKS 2 29 1µF 50V MKS 2 6, 7 BYV 10 (x 2) VOLTS + + 28 30 Ω LINE 27 MIC4429 26 5 4 220 µF 50V + 35 µF 50V UNITED CHEMCON SXE 25 0 20 40 60 80 100 120 140 mA Figure 3. Self-Contained Voltage Doubler 5-38 April 1998 MIC4420/4429 Micrel Input Stage The input voltage level of the 4429 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 MIC4420/4429 input is designed to provide 300mV of 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 18V operating supply voltage range. Input current is less than 10µA over this range. The MIC4429 can be directly driven by the TL494, SG1526/ 1527, SG1524, TSC170, MIC38HC42 and similar switch mode power supply integrated circuits. By offloading the power-driving duties to the MIC4420/4429, the power supply controller can operate at lower dissipation. This can improve performance and reliability. 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 MIC4420/4429 however, and it will not latch. 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. 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 +18 V 1 2 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 MSOP package, from the data sheet, is 250°C/W. In a 25°C ambient, then, using a maximum junction temperature of 150°C, this package will dissipate 500mW. Accurate power dissipation numbers can be obtained by summing the three sources of power dissipation in the device: • Load Power Dissipation (PL) • Quiescent power dissipation (PQ) • Transition power dissipation (PT) Calculation of load power dissipation differs depending on whether the load is capacitive, resistive or inductive. Resistive Load Power Dissipation 6, 7 TEK CURRENT PROBE 6302 PL = I2 RO D where: 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) Table 1: MIC4429 Maximum Operating Frequency WIMA MK22 1 µF 8 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. Dissipation caused by a resistive load can be calculated as: Power Dissipation 5.0V current to destroy the device. The MIC4420/4429 on the other hand, can source or sink several amperes and drive large capacitive loads at high frequency. The package power dissipation limit can easily be exceeded. Therefore, some attention should be given to power dissipation when driving low impedance loads and/or operating at high frequency. 18 V MIC4429 0V 0V 5 0.1µF 4 0.1µF 10,000 pF POLYCARBONATE VS 18V Max Frequency 500kHz 15V 10V 700kHz 1.6MHz Conditions: 1. DIP Package (θJA = 130°C/W) 2. TA = 25°C 3. CL = 2500pF Figure 3. Switching Time Degradation Due to Negative Feedback April 1998 5-39 5 MIC4420/4429 Capacitive Load Power Dissipation Micrel where: 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: 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: PL = f C (VS)2 where: f = Operating Frequency C = Load Capacitance VS = Driver Supply Voltage Inductive Load Power Dissipation 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 Transition Power Dissipation 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: 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 Definitions CL = Load Capacitance in Farads. 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: D = Duty Cycle expressed as the fraction of time the input to the driver is high. f = Operating Frequency of the driver in Hertz PL1 = I2 RO D IH = Power supply current drawn by a driver when both inputs are high and neither output is loaded. 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 IL = Power supply current drawn by a driver when both inputs are low and neither output is loaded. ID = Output current from a driver in Amps. PD = Total power dissipated in a driver in Watts. PL2 = I VD (1-D) PL = Power dissipated in the driver due to the driver’s load in Watts. 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 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. 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. PQ = VS [D IH + (1-D) IL] VS = Power supply voltage to the IC in Volts. 5-40 April 1998 MIC4420/4429 Micrel +18 V WIMA MK22 1 µF 5.0V 1 8 2 6, 7 TEK CURRENT PROBE 6302 18 V MIC4429 0V 0V 5 0.1µF 4 0.1µF 10,000 pF POLYCARBONATE 5 Figure 6. Peak Output Current Test Circuit April 1998 5-41