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MIC4421/4422
Micrel
MIC4421/4422
9A-Peak Low-Side MOSFET Driver
Bipolar/CMOS/DMOS Process
General Description
MIC4421 and MIC4422 MOSFET drivers are rugged, efficient, and easy to use. The MIC4421 is an inverting driver, while the MIC4422 is a non-inverting driver. Both versions are capable of 9A (peak) output and can drive the largest MOSFETs with an improved safe operating margin. The MIC4421/4422 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. MIC4421/4422 drivers can replace three or more discrete components, reducing PCB area requirements, simplifying product design, and reducing assembly cost. Modern Bipolar/CMOS/DMOS construction guarantees freedom from latch-up. The rail-to-rail swing capability of CMOS/ DMOS insures adequate gate voltage to the MOSFET during power up/down sequencing. Since these devices are fabricated on a self-aligned process, they have very low crossover current, run cool, use little power, and are easy to drive.
Features
* BiCMOS/DMOS Construction * Latch-Up Proof: Fully Isolated Process is Inherently Immune to Any Latch-up. * Input Will Withstand Negative Swing of Up to 5V * Matched Rise and Fall Times ............................... 25ns * High Peak Output Current .............................. 9A Peak * Wide Operating Range .............................. 4.5V to 18V * High Capacitive Load Drive ........................... 47,000pF * Low Delay Time ........................................... 30ns Typ. * Logic High Input for Any Voltage from 2.4V to VS * Low Equivalent Input Capacitance (typ) ................. 7pF * Low Supply Current .............. 450A With Logic 1 Input * Low Output Impedance ........................................ 1.5 * Output Voltage Swing to Within 25mV of GND or VS
Applications
* * * * * * * * Switch Mode Power Supplies Motor Controls Pulse Transformer Driver Class-D Switching Amplifiers Line Drivers Driving MOSFET or IGBT Parallel Chip Modules Local Power ON/OFF Switch Pulse Generators
Functional Diagram
VS
0.3mA 0.1mA
MIC4421 INVERTING
OUT IN 2k MIC4422 NON-INVERTING
GND
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Ordering Information
Part No. MIC4421CN MIC4421BN MIC4421CM MIC4421BM MIC4421CT MIC4422CN MIC4422BN MIC4422CM MIC4422BM MIC4422CT Temperature Range 0C to +70C -40C to +85C 0C to +70C -40C to +85C 0C to +70C 0C to +70C -40C to +85C 0C to +70C -40C to +85C 0C to +70C Package 8-Pin PDIP 8-Pin PDIP 8-Pin SOIC 8-Pin SOIC 5-Pin TO-220 8-Pin PDIP 8-Pin PDIP 8-Pin SOIC 8-Pin SOIC 5-Pin TO-220 Configuration Inverting Inverting Inverting Inverting Inverting Non-Inverting Non-Inverting Non-Inverting Non-Inverting Non-Inverting
Pin Configurations
VS 1 IN 2 NC 3 GND 4 8 VS 7 OUT 6 OUT 5 GND
5
Plastic DIP (N) SOIC (M)
5 4 3 2 1
OUT GND VS GND IN
TAB
TO-220-5 (T)
Pin Description
Pin Number TO-220-5 1 2, 4 3, TAB 5 Pin Number DIP, SOIC 2 4, 5 1, 8 6, 7 3 Pin Name IN GND VS OUT NC Pin Function Control Input 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.
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(Notes 1, 2 and 3)
Absolute Maximum Ratings
Operating Ratings
Junction Temperature ............................................... 150C Ambient Temperature C Version ................................................... 0C to +70C B Version ................................................ -40C to +85C Thermal Resistance 5-Pin TO-220 (JC) .............................................. 10C/W
Supply Voltage .............................................................. 20V Input Voltage .................................. VS + 0.3V to GND - 5V Input Current (VIN > VS) ............................................ 50 mA Power Dissipation, TA 25C PDIP .................................................................... 960mW SOIC ................................................................. 1040mW 5-Pin TO-220 .............................................................. 2W Power Dissipation, TCASE 25C 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 ............................... -65C to +150C Lead Temperature (10 sec) ....................................... 300C
Electrical Characteristics:
Symbol INPUT VIH VIL VIN IIN OUTPUT VOH VOL RO RO IPK IDC IR High Output Voltage Low Output Voltage Output Resistance, Output High Output Resistance, Output Low Peak Output Current Logic 1 Input Voltage Logic 0 Input Voltage Input Voltage Range Input Current Parameter
(TA = 25C with 4.5 V VS 18 V unless otherwise specified.) Conditions Min Typ Max Units
2.4
1.3 1.1 0.8 VS+0.3 10
V V V A
-5 0 V VIN VS See Figure 1 See Figure 1 IOUT = 10 mA, VS = 18 V IOUT = 10 mA, VS = 18 V VS = 18 V (See Figure 5) 2 Duty Cycle 2% t 300 s >1500 0.6 0.8 9 -10
VS-.025 0.025
V V 1.7 A A mA
Continuous Output Current Latch-Up Protection Withstand Reverse Current
SWITCHING TIME (Note 3) tR tF tD1 tD2 Power Supply IS VS Power Supply Current Operating Input Voltage VIN = 3 V VIN = 0 V 4.5 0.4 80 1.5 150 18 mA A V Rise Time Fall Time Delay Time Delay Time Test Figure 1, CL = 10,000 pF Test Figure 1, CL = 10,000 pF Test Figure 1 Test Figure 1 20 24 15 35 75 75 60 60 ns ns ns ns
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(Over operating temperature range with 4.5V VS 18V unless otherwise specified.) Conditions Min Typ Max Units
Electrical Characteristics:
Symbol INPUT VIH VIL VIN IIN OUTPUT VOH VOL RO RO High Output Voltage Low Output Voltage Output Resistance, Output High Output Resistance, Output Low Logic 1 Input Voltage Logic 0 Input Voltage Input Voltage Range Input Current Parameter
2.4
1.4 1.0 0.8 VS+0.3 10
V V V A
-5 0V VIN VS Figure 1 Figure 1 IOUT = 10mA, VS = 18V IOUT = 10mA, VS = 18V 0.8 1.3 -10
VS-.025 0.025 3.6 2.7
V V
SWITCHING TIME (Note 3) tR tF tD1 tD2 IS VS NOTE 1: NOTE 2: NOTE 3: Rise Time Fall Time Delay Time Delay Time Figure 1, CL = 10,000pF Figure 1, CL = 10,000pF Figure 1 Figure 1 23 30 20 40 120 120 80 80 ns ns ns ns
POWER SUPPLY Power Supply Current Operating Input Voltage VIN = 3V VIN = 0V 4.5 0.6 0.1 3 0.2 18 mA V
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
0.1F
0.1F
4.7F
0.1F
0.1F
4.7F
IN MIC4421
OUT 15000pF
IN MIC4422
OUT 15000pF
INPUT
5V 90% 10% 0V VS 90% tD1 tPW
2.5V tPW 0.5s tF tD2 tR
INPUT
5V 90% 10% 0V VS 90% tD1 tPW tR
2.5V tPW 0.5s tD2 tF
OUTPUT 10% 0V
OUTPUT 10% 0V
Figure 1. Inverting Driver Switching Time April 1998 5-45
Figure 2. Noninverting Driver Switching Time
MIC4421/4422
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Typical Characteristic Curves
220 200 180 160 140 120 100 80 60 40 20 0
Rise Time vs. Supply Voltage
47,000pF
22,000pF 10,000pF 4 6 8 10 12 14 16 SUPPLY VOLTAGE (V) 18
220 200 180 160 140 120 100 80 60 40 20 0
Fall Time vs. Supply Voltage
60 50
TIME (ns)
Rise and Fall Times vs. Temperature
CL = 10,000pF VS = 18V tFALL
RISE TIME (ns)
FALL TIME (ns)
40 30 20 10
47,000pF
22,000pF 10,000pF 4 6 8 10 12 14 16 SUPPLY VOLTAGE (V) 18
tRISE
0
-40 0 40 80 TEMPERATURE (C)
120
300 250 200 150
Rise Time vs. Capacitive Load
5V
300 250 FALL TIME (ns) 200 150
Fall Time vs. Capacitive Load
CROSSOVER ENERGY (A*s)
10-7
Crossover Energy vs. Supply Voltage
PER TRANSITION
RISE TIME (ns)
5V
10-8
10V 100 50 0 100 18V
10V 100 18V 50 0 100 1000 10k CAPACITIVE LOAD (pF) 100k
1000 10k CAPACITIVE LOAD (pF)
100k
10-9
4
6
8 10 12 14 VOLTAGE (V)
16
18
220 200 180 160 140 120 100 80 60 40 20 0
Supply Current vs. Capacitive Load
VS = 18V
SUPPLY CURRENT (mA)
150 120 90 60
Supply Current vs. Capacitive Load
VS = 12V
SUPPLY CURRENT (mA)
75 60 45 30
Supply Current vs. Capacitive Load
VS = 5V
SUPPLY CURRENT (mA)
1
z MH
kH z
20
20
100
1000 10k CAPACITIVE LOAD (pF)
100k
0
100
1000 10k CAPACITIVE LOAD (pF)
100k
0
100
1000 10k CAPACITIVE LOAD (pF)
20
30
1M
H
H
H
50
50
0k
0k
15
0k
50
Hz
kH z
1M
Hz
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kH z
z
z
z
100k
MIC4421/4422
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Typical Characteristic Curves (Cont.)
Supply Current vs. Frequency
VS = 18V
SUPPLY CURRENT (mA)
180
SUPPLY CURRENT (mA)
120 100
Supply Current vs. Frequency
VS = 12V
SUPPLY CURRENT (mA)
60 50
Supply Current vs. Frequency
VS = 5V
0.01 0.1 F F
160 140
F
F
120 100 80 60 40 20 0 10k
80 60 40 20 0 10k
F
40 30 20 10 0 10k
1000 pF
0.1
0.1
0.01
F
1000 pF
0.01
100k 1M FREQUENCY (Hz)
10M
100k 1M FREQUENCY (Hz)
10M
100k 1M FREQUENCY (Hz)
1000 pF
10M
50 40
Propagation Delay vs. Supply Voltage
TIME (ns)
TIME (ns)
30 20 10 0
TIME (ns)
tD2
tD1
4
6 8 10 12 14 16 SUPPLY VOLTAGE (V)
18
120 110 100 90 80 70 60 50 40 30 20 10 0
Propagation Delay vs. Input Amplitude
VS = 10V
50 40 30 20
Propagation Delay vs. Temperature
tD2
5
tD1
tD2
10
tD1 8
0
2
4 6 INPUT (V)
10
0
-40 0 40 80 TEMPERATURE (C)
120
1000
HIGH-STATE OUTPUT RESISTANCE ()
VS = 18V INPUT = 1
100 INPUT = 0
10
-40 0 40 80 TEMPERATURE (C)
120
2.4 2.2 2.0 1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0
LOW-STATE OUTPUT RESISTANCE ()
QUIESCENT SUPPLY CURRENT (A)
Quiescent Supply Current vs. Temperature
High-State Output Resist. vs. Supply Voltage
Low-State Output Resist. vs. Supply Voltage
2.4 2.2 2.0 1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0
TJ = 150C TJ = 25C
TJ = 150C
TJ = 25C
4
6 8 10 12 14 16 SUPPLY VOLTAGE (V)
18
4
6 8 10 12 14 16 SUPPLY VOLTAGE (V)
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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 1F low ESR film capacitor in parallel with two 0.1F low ESR ceramic capacitors, (such as AVX RAM Guard(R)), provides adequate bypassing. Connect one ceramic capacitor directly between pins 1 and 4. Connect the second ceramic capacitor directly between pins 8 and 5. Grounding The high current capability of the MIC4421/4422 demands careful PC board layout for best performance. Since the MIC4421 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 MIC4421 input structure includes about 200mV of hysteresis to ensure clean transitions and freedom from oscillation, but attention to layout is still recommended. Figure 5 shows the feedback effect in detail. As the MIC4421 input begins to go positive, the output goes negative and several amperes of current flow in the ground lead. As little as 0.05 of PC trace resistance can produce hundreds of millivolts at the MIC4421 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 MIC4421 GND pins will ensure full logic drive to the input and ensure fast output switching. Both of the MIC4421 GND pins should, however, still be connected to power ground.
Applications Information
Supply Bypassing Charging and discharging large capacitive loads quickly requires large currents. For example, charging a 10,000pF load to 18V in 50ns requires 3.6A. The MIC4421/4422 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.
VS 1F
MIC4451
VS
O2 O1 DRIVE SIGNAL CONDUCTION ANGLE CONTROL 0 TO 180 CONDUCTION ANGLE CONTROL 180 TO 360 DRIVE LOGIC VS 1F VS O1 M O3
MIC4452
PHASE 1 of 3 PHASE MOTOR DRIVER USING MIC4420/4429
Figure 3. Direct Motor Drive
+15 (x2) 1N4448 5.6 k 560 0.1F 50V
+
OUTPUT VOLTAGE vs LOAD CURRENT 30 29
VOLTS
28 12 LINE 27 26 25 0 50 100 150 200 250 300 350 mA
1 8 2 0.1F WIMA MKS 2 MIC4421 5 4
1F 50V MKS 2 6, 7
+
BYV 10 (x 2)
+ 560F 50V 100F 50V UNITED CHEMCON SXE
Figure 4. Self Contained Voltage Doubler
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MIC4421/4422
Input Stage The input voltage level of the MIC4421 changes the quiescent supply current. The N channel MOSFET input stage transistor drives a 320A current source load. With a logic "1" input, the maximum quiescent supply current is 400A. Logic "0" input level signals reduce quiescent current to 80A typical. The MIC4421/4422 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 full temperature and operating supply voltage ranges. Input current is less than 10A. The MIC4421 can be directly driven by the TL494, SG1526/ 1527, SG1524, TSC170, MIC38C42, and similar switch mode power supply integrated circuits. By offloading the power-driving duties to the MIC4421/4422, 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 input currents can be as high as 30mA p-p (6.4mARMS) with the input. No damage will occur to MIC4421/4422 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. While the device will operate and no damage will occur up to 25V below the negative rail, input current will increase up to 1mA/V due to the clamping action of the input, ESD diode, and 1k resistor. Power Dissipation 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 MIC4421/4422 on the other hand, can source or sink several amperes and drive large capacitive loads at high frequency. The package power
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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. 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 10,000pF load. More accurate power dissipation figures can be obtained by summing the three dissipation sources. 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 plastic DIP package, from the data sheet, is 130C/W. In a 25C ambient, then, using a maximum junction temperature of 150C, this package will dissipate 960mW. 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 Dissipation caused by a resistive load can be calculated as: 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)
5
WIMA MKS-2 1 F
5.0V
1 8 MIC4421 6, 7
TEK CURRENT PROBE 6302
18 V
0V 0.1F 4
5 0.1F
0V 2,500 pF POLYCARBONATE
Table 1: MIC4421 Maximum Operating Frequency VS Max Frequency 18V 220kHz 15V 10V 5V
Conditions: 1. JA = 150C/W 2. TA = 25C 3. CL = 10,000pF
LOGIC GROUND 300 mV POWER GROUND
6 AMPS PC TRACE RESISTANCE = 0.05
300kHz 640kHz 2MHz
Figure 5. Switching Time Degradation Due to Negative Feedback April 1998 5-49
MIC4421/4422
Capacitive Load 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: 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 in 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 where: f = Operating Frequency C = Load Capacitance VS = Driver Supply Voltage Inductive Load Power Dissipation 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: PL1 = I2 RO D 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 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 3.0mA. Quiescent power can therefore be found from: 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 (VS)2 Transition Power Dissipation
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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 VS 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 curve "Crossover Energy vs. Supply Voltage." Total power (PD) then, as previously described is just 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 Hertz 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. 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 dual transition (once up, once down) for both drivers is stated in Figure 7 in ampere-nanoseconds. This figure must be multiplied by the number of repetitions per second (frequency) to find Watts. RO = Output resistance of a driver in Ohms. VS = Power supply voltage to the IC in Volts.
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+18 V
WIMA MK22 1 F 5.0V 2 0V 0.1F 4 18 V
1 8 MIC4421 5 6, 7
TEK CURRENT PROBE 6302
0V 0.1F 10,000 pF POLYCARBONATE
Figure 6. Peak Output Current Test Circuit
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