MIC429

MIC4420/4429MicrelMIC4420/44296A-Peak Low-Side MOSFET DriverBipolar/CMOS/DMOS ProcessGeneral DescriptionMIC4420, MIC4429 and MIC429 MOSFET drivers aretough, efficient, and easy to use. The MIC4429 and MIC429are inverting drivers, while the MIC4420 is a non-invertingdriver.They are capable of 6A (peak) output and can drive thelargest MOSFETs with an improved safe operating mar-gin. The MIC4420/4429/429 accepts any logic input from2.4V to VS without external speed-up capacitors or resistornetworks. Proprietary circuits allow the input to swingnegative by as much as 5V without damaging the part.Additional circuits protect against damage from electro-static discharge.MIC4420/4429/429 drivers can replace three or more dis-crete components, reducing PCB area requirements,simplifying product design, and reducing assembly cost.Modern BiCMOS/DMOS construction guarantees freedomfrom latch-up. The rail-to-rail swing capability insures ad-equate gate voltage to the MOSFET during power up/down sequencing.Features•CMOS Construction•Latch-Up Protected: Will Withstand >500mAReverse 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 VSApplications••••Switch Mode Power SuppliesMotor ControlsPulse Transformer DriverClass-D Switching AmplifiersFunctional DiagramVS0.4mA0.1mAMIC4429INVERTINGOUTIN2kΩMIC4420NON-INVERTINGGND5-32April 1998MIC4420/4429MicrelOrdering InformationPart No.MIC4420CNMIC4420BNMIC4420CMMIC4420BMMIC4420BMMMIC4420CTMIC4429CNMIC4429BNMIC4429CMMIC4429BMMIC4429BMMMIC4429CTTemperature Range0°C to +70°C–40°C to +85°C0°C to +70°C–40°C to +85°C–40°C to +85°C0°C to +70°C0°C to +70°C–40°C to +85°C0°C to +70°C–40°C to +85°C–40°C to +85°C0°C to +70°CPackage8-Pin PDIP8-Pin PDIP8-Pin SOIC8-Pin SOIC8-Pin MSOP5-Pin TO-2208-Pin PDIP8-Pin PDIP8-Pin SOIC8-Pin SOIC8-Pin MSOP5-Pin TO-220ConfigurationNon-InvertingNon-InvertingNon-InvertingNon-InvertingNon-InvertingNon-InvertingInvertingInvertingInvertingInvertingInvertingInvertingPin ConfigurationsVS1IN2NC3GND48VS7OUT6OUT5GNDPlastic DIP (N)SOIC (M)MSOP (MM)54321OUTGNDVSGNDINTABTO-220-5 (T)Pin DescriptionPin NumberTO-220-512, 43, TAB5Pin NumberDIP, SOIC, MSOP24, 51, 86, 73Pin NameINGNDVSOUTNCPin FunctionControl InputGround: 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.April 19985-33MIC4420/4429MicrelAbsolute Maximum Ratings (Notes 1, 2 and 3)

Supply Voltage..........................................................20VInput Voltage...............................VS + 0.3V to GND – 5VInput Current (VIN > VS).........................................50mAPower Dissipation, TA ≤ 25°C

PDIP...................................................................960WSOIC.............................................................1040mW5-Pin TO-220..........................................................2WPower Dissipation, TC ≤ 25°C

5-Pin TO-220.....................................................12.5WDerating Factors (to Ambient)

PDIP............................................................7.7mW/°CSOIC...........................................................8.3mW/°C5-Pin TO-220................................................17mW/°CStorage Temperature............................–65°C to +150°CLead Temperature (10 sec.)..................................300°C

Operating Ratings

Junction Temperature............................................150°CAmbient Temperature

C Version................................................0°C to +70°CB Version.............................................–40°C to +85°CPackage Thermal Resistance

5-pin TO-220 (θJC)..........................................10°C/W8-pin MSOP (θJA)..........................................250°C/W

Electrical Characteristics: (TA = 25°C with 4.5V ≤ VS ≤ 18V unless otherwise specified.)

SymbolINPUTVIHVILVINIINOUTPUTVOHVOLROROIPKIR

High Output VoltageLow Output VoltageOutput Resistance,Output LowOutput Resistance,Output HighPeak Output CurrentLatch-Up Protection

Withstand Reverse Current

See Figure 1See Figure 1

IOUT = 10 mA, VS = 18 VIOUT = 10 mA, VS = 18 VVS = 18 V (See Figure 5)

>500

1.71.56

VS–0.025

0.0252.82.5

VVΩΩAmA

Logic 1 Input VoltageLogic 0 Input VoltageInput Voltage RangeInput Current

0 V ≤ VIN ≤ VS

–5–102.4

1.41.1

0.8VS + 0.310

VVVµA

Parameter

Conditions

Min

Typ

Max

Units

SWITCHING TIME (Note 3)tRtFtD1tD2ISVS

Rise TimeFall TimeDelay TimeDelay Time

Test Figure 1, CL = 2500 pFTest Figure 1, CL = 2500 pFTest Figure 1Test Figure 1

12131848

35357575

nsnsnsns

POWER SUPPLY

Power Supply CurrentOperating Input Voltage

VIN = 3 VVIN = 0 V

4.5

0.4590

1.515018

mAµAV

5-34April 1998

MIC4420/4429MicrelElectrical Characteristics: (TA = –55°C to +125°C with 4.5V ≤ VS ≤ 18V unless otherwise specified.)SymbolINPUTVIHVILVINIINOUTPUTVOHVOLROROHigh Output VoltageLow Output VoltageOutput Resistance,Output LowOutput Resistance,Output HighFigure 1Figure 1IOUT = 10mA, VS = 18VIOUT = 10mA, VS = 18V32.3VS–0.0250.02555VVΩΩLogic 1 Input VoltageLogic 0 Input VoltageInput Voltage RangeInput Current0V ≤ VIN ≤ VS–5–102.40.8VS + 0.310VVVµAParameterConditionsMinTypMaxUnitsSWITCHING TIME (Note 3)tRtFtD1tD2ISVSNOTE 1:NOTE 2:NOTE 3:Rise TimeFall TimeDelay TimeDelay TimeFigure 1, CL = 2500pFFigure 1, CL = 2500pFFigure 1Figure 1323450656060100100nsnsnsnsPOWER SUPPLYPower Supply CurrentOperating Input VoltageVIN = 3VVIN = 0V4.50.450.063.00.418mAmAVFunctional 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 toprevent damage from static discharge.Switching times guaranteed by design.Test CircuitsVS = 18V0.1µF0.1µF1.0µFVS = 18V0.1µF0.1µF1.0µFINMIC4429OUT2500pFINMIC4420OUT2500pFINPUT5V90%10%0VVS90%tD1tPW2.5VtPW ≥ 0.5µstFtD2tRINPUT5V90%10%0VVS90%tD1tPW2.5VtPW ≥ 0.5µstRtD2tFOUTPUT10%0VOUTPUT10%0VFigure 1a. Inverting Driver Switching TimeFigure 1b. Noninverting Driver Switching TimeApril 19985-35MIC4420/4429MicrelTypical Characteristic CurvesRise Time vs. Supply Voltage605040TIME (ns)Fall Time vs. Supply Voltage50Rise and Fall Times vs. Temperature25C = 2200 pFLV = 18VS4020C = 10,000 pFLTIME (ns)C = 10,000 pFLTIME (ns)301530tFALLtRISEC = 4700 pFL2020C = 4700 pFLC = 2200 pFL10C = 2200 pFL10010557911V (V)S1315057911V (V)S13150–60–202060100TEMPERATURE (°C)140Rise Time vs. Capacitive Load504030TIME (ns)Fall Time vs. Capacitive Load5040Delay Time vs. Supply Voltage605030DELAY TIME (ns)TIME (ns)tD240302010V = 5VSV = 12VSV = 18VS20V = 5VS20V = 12VS10V = 18VS10tD1510003000CAPACITIVE LOAD (pF)10,000510003000CAPACITIVE LOAD (pF)10,000046810121416SUPPLY VOLTAGE (V)18Propagation Delay Timevs. Temperature60Supply Current vs. Capacitive Load84V = 15VSIS – SUPPLY CURRENT (mA)Supply Current vs. Frequency1000C = 2200 pFLSUPPLY CURRENT (mA)50TIME (ns)tD2705218V10010V5V4030tD1500 kHz281020C = 2200 pFLV = 18VS200 kHz1420 kHz140010–60001001000CAPACITIVE LOAD (pF)10,000–202060100TEMPERATURE (°C)01001000FREQUENCY (kHz)10,0005-36April 1998MIC4420/4429MicrelTypical Characteristic Curves (Cont.)Quiescent Power SupplyVoltage vs. Supply Current1000900Quiescent Power SupplyCurrent vs. TemperatureLOGIC “1” INPUTV = 18VSSUPPLY CURRENT (µA)600SUPPLY CURRENT (µA)800800LOGIC “1” INPUT700400600200LOGIC “0” INPUT50000481216SUPPLY VOLTAGE (V)20400–60–202060100TEMPERATURE (°C)140High-State Output Resistance52.5Low-State Output Resistance100 mARO U T (Ω )10 mA50 mARO U T (Ω )42100 mA50 mA31.510 mA257911V (V)S1315157911V (V)S1315Effect of Input Amplitudeon Propagation Delay200LOAD = 2200 pFCROSSOVER AREA (A•s) x 10-8Crossover Area vs. Supply Voltage2.0PER TRANSITION160DELAY (ns)1.5120INPUT 2.4VINPUT 3.0VINPUT 5.0VINPUT 8V AND 10V1.080400.50567101112131415V (V)S0567101112131415SUPPLY VOLTAGE V (V)sApril 19985-37MIC4420/4429MicrelApplications InformationSupply BypassingCharging and discharging large capacitive loads quicklyrequires large currents. For example, charging a 2500pFload to 18V in 25ns requires a 1.8 A current from the devicepower supply.The MIC4420/4429 has double bonding on the supply pins,the ground pins and output pins This reduces parasitic leadinductance. Low inductance enables large currents to beswitched rapidly. It also reduces internal ringing that cancause voltage breakdown when the driver is operated at ornear the maximum rated voltage.Internal ringing can also cause output oscillation due tofeedback. This feedback is added to the input signal sinceit is referenced to the same ground.To guarantee low supply impedance over a wide frequencyrange, a parallel capacitor combination is recommended forsupply bypassing. Low inductance ceramic disk capacitorswith short lead lengths (< 0.5 inch) should be used. A 1µFlow ESR film capacitor in parallel with two 0.1 µF low ESRceramic capacitors, (such as AVX RAM GUARD®), pro-vides adequate bypassing. Connect one ceramic capacitordirectly between pins 1 and 4. Connect the second ceramiccapacitor directly between pins 8 and 5.GroundingThe high current capability of the MIC4420/4429 demandscareful PC board layout for best performance Since theMIC4429 is an inverting driver, any ground lead impedancewill appear as negative feedback which can degrade switch-ing speed. Feedback is especially noticeable with slow-risetime inputs. The MIC4429 input structure includes 300mVof hysteresis to ensure clean transitions and freedom fromoscillation, but attention to layout is still recommended.Figure 3 shows the feedback effect in detail. As the MIC4429input begins to go positive, the output goes negative andseveral amperes of current flow in the ground lead. As littleas 0.05Ω of PC trace resistance can produce hundreds ofmillivolts at the MIC4429 ground pins. If the driving logic isreferenced to power ground, the effective logic input level isreduced and oscillation may result.To insure optimum performance, separate ground tracesshould be provided for the logic and power connections.Connecting the logic ground directly to the MIC4429 GNDpins will ensure full logic drive to the input and ensure fastoutput switching. Both of the MIC4429 GND pins should,however, still be connected to power ground.+15(x2) 1N44485.6 kΩ560 ΩOUTPUT VOLTAGE vs LOAD CURRENT300.1µF50V+120.1µFWIMAMKS 28MIC4429541µF50VMKS 26, 7+29VOLTSBYV 10 (x 2)2830 Ω LINE272625220 µF 50V+35 µF 50VUNITED CHEMCON SXE020406080mA100120140Figure 3. Self-Contained Voltage Doubler5-38April 1998MIC4420/4429Micrelcurrent to destroy the device. The MIC4420/4429 on theother hand, can source or sink several amperes and drivelarge capacitive loads at high frequency. The packagepower dissipation limit can easily be exceeded. Therefore,some attention should be given to power dissipation whendriving low impedance loads and/or operating at high fre-quency.The supply current vs frequency and supply current vscapacitive load characteristic curves aid in determiningpower dissipation calculations. Table 1 lists the maximumsafe operating frequency for several power supply voltageswhen driving a 2500pF load. More accurate power dissipa-tion figures can be obtained by summing the three dissipa-tion sources.Given the power dissipation in the device, and the thermalresistance of the package, junction operating temperaturefor any ambient is easy to calculate. For example, thethermal resistance of the 8-pin MSOP package, from thedata sheet, is 250°C/W. In a 25°C ambient, then, using amaximum junction temperature of 150°C, this package willdissipate 500mW.Accurate power dissipation numbers can be obtained bysumming the three sources of power dissipation in thedevice:• Load Power Dissipation (PL)• Quiescent power dissipation (PQ)• Transition power dissipation (PT)Calculation of load power dissipation differs depending onwhether the load is capacitive, resistive or inductive.Resistive Load Power DissipationDissipation caused by a resistive load can be calculated as:PL = I2 RO Dwhere:I =the current drawn by the loadRO =the output resistance of the driver when the output ishigh, at the power supply voltage used. (See datasheet)D =fraction of time the load is conducting (duty cycle)Table 1: MIC4429 MaximumOperating Frequency18 VInput StageThe input voltage level of the 4429 changes the quiescentsupply current. The N channel MOSFET input stage tran-sistor 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 to55µA maximum.The MIC4420/4429 input is designed to provide 300mV ofhysteresis. This provides clean transitions, reduces noisesensitivity, and minimizes output stage current spikingwhen changing states. Input voltage threshold level isapproximately 1.5V, making the device TTL compatibleover the 4 .5V to 18V operating supply voltage range. Inputcurrent is less than 10µA over this range.The MIC4429 can be directly driven by the TL494, SG1526/1527, SG1524, TSC170, MIC38HC42 and similar switchmode power supply integrated circuits. By offloading thepower-driving duties to the MIC4420/4429, the power sup-ply controller can operate at lower dissipation. This canimprove performance and reliability.The input can be greater than the +VS supply, however,current will flow into the input lead. The propagation delayfor TD2 will increase to as much as 400ns at room tempera-ture. The input currents can be as high as 30mA p-p(6.4mARMS) with the input, 6 V greater than the supplyvoltage. No damage will occur to MIC4420/4429 however,and it will not latch.The input appears as a 7pF capacitance, and does notchange even if the input is driven from an AC source. Careshould be taken so that the input does not go more than 5volts below the negative rail.Power DissipationCMOS circuits usually permit the user to ignore powerdissipation. Logic families such as 4000 and 74C haveoutputs which can only supply a few milliamperes of current,and even shorting outputs to ground will not force enough+18 VWIMAMK221 µF5.0V20 V0.1µF418MIC442956, 7TEK CURRENTPROBE 6302VS18V0 VMax Frequency500kHz700kHz1.6MHz0.1µF10,000 pFPOLYCARBONATE15V10VConditions:1. DIP Package (θJA = 130°C/W)2. TA = 25°C3. CL = 2500pFFigure 3. Switching Time Degradation Due toNegative FeedbackApril 19985-39MIC4420/4429Capacitive Load Power Dissipation

Dissipation caused by a capacitive load is simply the energyplaced in, or removed from, the load capacitance by thedriver. The energy stored in a capacitor is described by theequation:

E = 1/2 C V2

As this energy is lost in the driver each time the load ischarged or discharged, for power dissipation calculationsthe 1/2 is removed. This equation also shows that it is goodpractice not to place more voltage on the capacitor than isnecessary, as dissipation increases as the square of thevoltage applied to the capacitor. For a driver with a capaci-tive load:

PL = f C (VS)2

where:

f =Operating FrequencyC =Load CapacitanceVS =Driver Supply VoltageInductive Load Power Dissipation

For inductive loads the situation is more complicated. Forthe part of the cycle in which the driver is actively forcingcurrent into the inductor, the situation is the same as it is inthe resistive case:

PL1 = I2 RO D

However, in this instance the RO required may be either theon resistance of the driver when its output is in the highstate, or its on resistance when the driver is in the low state,depending on how the inductor is connected, and this is stillonly half the story. For the part of the cycle when theinductor is forcing current through the driver, dissipation isbest described as

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 dissipa-tion must be summed in to produce PL

PL = PL1 + PL2

Quiescent Power Dissipation

Quiescent power dissipation (PQ, as described in the inputsection) depends on whether the input is high or low. A lowinput 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:

PQ = VS [D IH + (1-D) IL]

where:IH =IL =D =VS =

quiescent current with input highquiescent current with input low

fraction of time input is high (duty cycle)power supply voltage

MicrelTransition Power Dissipation

Transition power is dissipated in the driver each time itsoutput changes state, because during the transition, for avery brief interval, both the N- and P-channel MOSFETs inthe output totem-pole are ON simultaneously, and a currentis conducted through them from V+S to ground. The transi-tion power dissipation is approximately:

PT = 2 f VS (A•s)

where (A•s) is a time-current factor derived from the typicalcharacteristic curves.

Total power (PD) then, as previously described is:

PD = PL + PQ +PT

Definitions

CL =Load Capacitance in Farads.

D =Duty Cycle expressed as the fraction of time the

input to the driver is high.f =Operating Frequency of the driver in HertzIH =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.ID =Output current from a driver in Amps.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 dualtransition (once up, once down) for both driversis shown by the \"Typical Characteristic Curve :Crossover Area vs. Supply Voltage and is inampere-seconds. This figure must be multipliedby the number of repetitions per second (fre-quency) to find Watts.RO =Output resistance of a driver in Ohms.VS =Power supply voltage to the IC in Volts.

5-40April 1998

MIC4420/4429Micrel+18 VWIMAMK221 µF5.0V20 V0.1µF418MIC442956, 718 VTEK CURRENTPROBE 63020.1µF0 V10,000 pFPOLYCARBONATEFigure 6. Peak Output Current Test CircuitApril 19985-41