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MIC4420/4429
Micrel
MIC4420/4429
6A-Peak Low-Side MOSFET Driver Bipolar/CMOS/DMOS Process
General Description
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. 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.
Features
* 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 .............. 450A With Logic 1 Input * Low Output Impedance ......................................... 2.5 * Output Voltage Swing Within 25mV of Ground or VS
Applications
* * * * Switch Mode Power Supplies Motor Controls Pulse Transformer Driver Class-D Switching Amplifiers
Functional Diagram
VS
0.4mA 0.1mA
MIC4429 INVERTING
OUT IN 2k MIC4420 NON-INVERTING
GND
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Ordering Information
Part No. MIC4420CN MIC4420BN MIC4420CM MIC4420BM MIC4420BMM MIC4420CT MIC4429CN MIC4429BN MIC4429CM MIC4429BM MIC4429BMM MIC4429CT Temperature Range 0C to +70C -40C to +85C 0C to +70C -40C to +85C -40C to +85C 0C to +70C 0C to +70C -40C to +85C 0C to +70C -40C to +85C -40C to +85C 0C to +70C 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 Configuration Non-Inverting Non-Inverting Non-Inverting Non-Inverting Non-Inverting Non-Inverting Inverting Inverting Inverting Inverting Inverting 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) MSOP (MM)
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, MSOP 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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Absolute Maximum Ratings (Notes 1, 2 and 3)
Supply Voltage .......................................................... 20V Input Voltage ............................... VS + 0.3V to GND - 5V Input Current (VIN > VS) ......................................... 50mA Power Dissipation, TA 25C PDIP ................................................................... 960W SOIC ............................................................. 1040mW 5-Pin TO-220 .......................................................... 2W Power Dissipation, TC 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
Operating Ratings
Junction Temperature ............................................ 150C Ambient Temperature C Version ................................................ 0C to +70C B Version ............................................. -40C to +85C Package Thermal Resistance 5-pin TO-220 (JC) .......................................... 10C/W 8-pin MSOP (JA) .......................................... 250C/W
Electrical Characteristics:
Symbol INPUT VIH VIL VIN IIN OUTPUT VOH VOL RO RO IPK IR High Output Voltage Low Output Voltage Output Resistance, Output Low Output Resistance, Output High Peak Output Current Logic 1 Input Voltage Logic 0 Input Voltage Input Voltage Range Input Current Parameter
(TA = 25C with 4.5V VS 18V unless otherwise specified.) Conditions Min Typ Max Units
2.4
1.4 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) >500 1.7 1.5 6 -10
VS-0.025 0.025 2.8 2.5
V V A mA
Latch-Up Protection Withstand Reverse Current
SWITCHING TIME (Note 3) tR tF tD1 tD2 IS VS Rise Time Fall Time Delay Time Delay Time Test Figure 1, CL = 2500 pF Test Figure 1, CL = 2500 pF Test Figure 1 Test Figure 1 12 13 18 48 35 35 75 75 ns ns ns ns
POWER SUPPLY Power Supply Current Operating Input Voltage VIN = 3 V VIN = 0 V 4.5 0.45 90 1.5 150 18 mA A V
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Electrical Characteristics: (TA = -55C to +125C with 4.5V VS 18V unless otherwise specified.)
Symbol INPUT VIH VIL VIN IIN OUTPUT VOH VOL RO RO High Output Voltage Low Output Voltage Output Resistance, Output Low Output Resistance, Output High Figure 1 Figure 1 IOUT = 10mA, VS = 18V IOUT = 10mA, VS = 18V 3 2.3 VS-0.025 0.025 5 5 V V Logic 1 Input Voltage Logic 0 Input Voltage Input Voltage Range Input Current 0V VIN VS -5 -10 2.4 0.8 VS + 0.3 10 V V V A Parameter Conditions Min Typ Max Units
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 = 2500pF Figure 1, CL = 2500pF Figure 1 Figure 1 32 34 50 65 60 60 100 100 ns ns ns ns
POWER SUPPLY Power Supply Current Operating Input Voltage VIN = 3V VIN = 0V 4.5 0.45 0.06 3.0 0.4 18 mA 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 1.0F
0.1F
0.1F
0.1F
1.0F
IN MIC4429
OUT 2500pF
IN MIC4420
OUT 2500pF
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 1a. Inverting Driver Switching Time
Figure 1b. Noninverting Driver Switching Time
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Typical Characteristic Curves
Rise Time vs. Supply Voltage
60 50 40
TIME (ns)
Fall Time vs. Supply Voltage
50
Rise and Fall Times vs. Temperature
25 C L = 2200 pF VS = 18V
40
20
C L = 10,000 pF
TIME (ns)
C L = 10,000 pF
TIME (ns)
30
15
30
t FALL tRISE
C L = 4700 pF
20
20
C L = 4700 pF C L = 2200 pF
10
C L = 2200 pF
10 0 10
5
5
7
9
11 VS (V)
13
15
0
5
7
9
11 VS (V)
13
15
0 -60
-20
20 60 100 TEMPERATURE (C)
140
Rise Time vs. Capacitive Load
50 40 30
TIME (ns)
Fall Time vs. Capacitive Load
50 40
Delay Time vs. Supply Voltage
60 50
30 DELAY TIME (ns)
TIME (ns)
tD2 40 30 20 tD1 10
20
VS = 5V
20
VS = 5V VS = 12V VS = 18V
VS = 12V 10
VS = 18V
10
5 1000
3000 CAPACITIVE LOAD (pF)
10,000
5 1000
3000 CAPACITIVE LOAD (pF)
10,000
0
4
6
8 10 12 14 16 SUPPLY VOLTAGE (V)
18
Propagation Delay Time vs. Temperature
60
Supply Current vs. Capacitive Load
84
VS = 15V
IS - SUPPLY CURRENT (mA)
Supply Current vs. Frequency
1000
CL= 2200 pF SUPPLY CURRENT (mA)
50
TIME (ns)
t D2
70 56 42
18V
100
10V 5V
40
30
tD1
500 kHz
28
10
20 C L = 2200 pF V S = 18V
200 kHz
14
20 kHz
0
10 -60
0
0 100 1000 CAPACITIVE LOAD (pF)
10,000
-20
20 60 100 TEMPERATURE (C)
140
0
100 1000 FREQUENCY (kHz)
10,000
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Typical Characteristic Curves (Cont.)
Quiescent Power Supply Voltage vs. Supply Current
1000 900
LOGIC "1" INPUT VS = 18V
SUPPLY CURRENT (A)
Quiescent Power Supply Current vs. Temperature
SUPPLY CURRENT (A)
800
800
600
LOGIC "1" INPUT
700
400
600
200
LOGIC "0" INPUT
500
0
0 4 8 12 16 SUPPLY VOLTAGE (V) 20
400 -60
-20
20 60 100 TEMPERATURE (C)
140
High-State Output Resistance
5
2.5
Low-State Output Resistance
100 mA
ROUT ( )
4
ROUT ( )
2
10 mA
50 mA
100 mA 50 mA
1.5
5
3
10 mA
2
1
5 7 9 11 VS (V) 13 15
5
7
9
11 VS (V)
13
15
Effect of Input Amplitude on Propagation Delay
200
LOAD = 2200 pF
CROSSOVER AREA (A*s) x 10
-8
Crossover Area vs. Supply Voltage
2.0
PER TRANSITION
160
DELAY (ns)
1.5
120
INPUT 2.4V INPUT 3.0V
1.0
80 INPUT 5.0V 40 INPUT 8V AND 10V
0.5
0
5 6 7 8 9 10 11 12 13 14 15 V (V)
S
0
5 6 7 8 9 10 11 12 13 14 15 SUPPLY VOLTAGE V (V) s
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Applications Information Supply Bypassing
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 1F low ESR film capacitor in parallel with two 0.1 F 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 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. 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 0.05 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 k 560 0.1F 50V + 1 8 2 0.1F WIMA MKS 2 MIC4429
26 30 29
VOLTS
OUTPUT VOLTAGE vs LOAD CURRENT
1F 50V MKS 2 6, 7 +
BYV 10 (x 2)
28 30 LINE 27
5 4
220 F 50V + 35 F 50V UNITED CHEMCON SXE
25 0 20 40 60 80 mA 100 120 140
Figure 3. Self-Contained Voltage Doubler
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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. 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. 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 250C/W. In a 25C ambient, then, using a maximum junction temperature of 150C, 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 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) Table 1: MIC4429 Maximum Operating Frequency
18 V
Input Stage
The input voltage level of the 4429 changes the quiescent supply current. The N channel MOSFET input stage transistor drives a 450A current source load. With a logic "1" input, the maximum quiescent supply current is 450A. Logic "0" input level signals reduce quiescent current to 55A 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 10A 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.
5
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
+18 V
WIMA MK22 1 F 5.0V 2 0V 0.1F 4
1 8 MIC4429 5 6, 7
TEK CURRENT PROBE 6302
VS 18V
0V
Max Frequency 500kHz 700kHz 1.6MHz
0.1F
10,000 pF POLYCARBONATE
15V 10V
Conditions: 1. DIP Package (JA = 130C/W) 2. TA = 25C 3. CL = 2500pF
Figure 3. Switching Time Degradation Due to Negative Feedback April 1998 5-39
MIC4420/4429
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 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 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 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 high quiescent current with input low fraction of time input is high (duty cycle) power supply voltage
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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. 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 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. 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 MIC4429 5 6, 7
TEK CURRENT PROBE 6302
0V 0.1F 10,000 pF POLYCARBONATE
5
Figure 6. Peak Output Current Test Circuit
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