Page 1
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 V
• Low Equivalent Input Capacitance (typ).................7pF
• Low Supply Current..............450µA With Logic 1 Input
• Low Output Impedance ........................................ 1.5Ω
• Output Voltage Swing to Within 25mV of GND or V
S
S
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
IN
2kΩ
0.1mA
0.3mA
MIC4421
INVERTING
MIC4422
NON-INVERTING
V
GND
S
OUT
5-42 April 1998
Page 2
MIC4421/4422 Micrel
Ordering Information
Part No. Temperature Range Package Configuration
MIC4421CN 0°C to +70°C 8-Pin PDIP Inverting
MIC4421BN –40°C to +85°C 8-Pin PDIP Inverting
MIC4421CM 0°C to +70°C 8-Pin SOIC Inverting
MIC4421BM –40°C to +85°C 8-Pin SOIC Inverting
MIC4421CT 0°C to +70°C 5-Pin TO-220 Inverting
MIC4422CN 0°C to +70°C 8-Pin PDIP Non-Inverting
MIC4422BN –40°C to +85°C 8-Pin PDIP Non-Inverting
MIC4422CM 0°C to +70°C 8-Pin SOIC Non-Inverting
MIC4422BM –40°C to +85°C 8-Pin SOIC Non-Inverting
MIC4422CT 0°C to +70°C 5-Pin TO-220 Non-Inverting
Pin Configurations
TAB
VS
IN
NC
GND
1
2
3
4
Plastic DIP (N)
SOIC (M)
TO-220-5 (T)
VS
8
7
OUT
6
OUT
5
GND
5 OUT
4 GND
3VS
2 GND
1IN
5
Pin Description
Pin Number Pin Number Pin Name Pin Function
TO-220-5 DIP, SOIC
1 2 IN Control Input
2, 4 4, 5 GND Ground: Duplicate pins must be externally connected together.
3, TAB 1, 8 V
5 6, 7 OUT Output: Duplicate pins must be externally connected together.
3 NC Not connected.
S
April 1998 5-43
Supply Input: Duplicate pins must be externally connected together.
Page 3
MIC4421/4422 Micrel
Absolute Maximum Ratings (Notes 1, 2 and 3)
Supply Voltage ..............................................................20V
Input Voltage ..................................VS + 0.3V to GND – 5V
Input Current (VIN > VS) ............................................50 mA
Power Dissipation, TA ≤ 25°C
PDIP....................................................................960mW
SOIC .................................................................1040mW
Operating Ratings
Junction Temperature ............................................... 150°C
Ambient Temperature
C Version ................................................... 0°C to +70°C
B Version................................................–40°C to +85°C
Thermal Resistance
5-Pin TO-220 (θJC)..............................................10°C/W
5-Pin TO-220..............................................................2W
Power Dissipation, T
CASE
≤ 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
Electrical Characteristics: (T
Symbol Parameter Conditions Min Typ Max Units
INPUT
V
IH
V
IL
V
IN
I
IN
OUTPUT
V
OH
V
OL
R
O
R
O
I
PK
I
DC
I
R
SWITCHING TIME (Note 3)
t
R
t
F
t
D1
t
D2
Power Supply
I
S
V
S
Logic 1 Input Voltage 2.4 1.3 V
Logic 0 Input Voltage 1.1 0.8 V
Input Voltage Range –5 VS+0.3 V
Input Current 0 V ≤ VIN ≤ V
High Output Voltage See Figure 1 VS–.025 V
Low Output Voltage See Figure 1 0.025 V
Output Resistance, I
Output High
Output Resistance, I
Output Low
Peak Output Current VS = 18 V (See Figure 5) 9 A
Continuous Output Current 2 A
Latch-Up Protection Duty Cycle ≤ 2% >1500 mA
Withstand Reverse Current t ≤ 300 µs
Rise Time Test Figure 1, CL = 10,000 pF 20 75 ns
Fall Time Test Figure 1, CL = 10,000 pF 24 75 ns
Delay Time Test Figure 1 15 60 ns
Delay Time Test Figure 1 35 60 ns
Power Supply Current VIN = 3 V 0.4 1.5 mA
Operating Input Voltage 4.5 18 V
= 25°C with 4.5 V ≤ V
A
= 10 mA, VS = 18 V 0.6 Ω
OUT
= 10 mA, VS = 18 V 0.8 1.7 Ω
OUT
VIN = 0 V 80 150 µA
≤ 18 V unless otherwise specified.)
S
S
–10 10 µA
5-44 April 1998
Page 4
MIC4421/4422 Micrel
Electrical Characteristics: (Over operating temperature range with 4.5V ≤ V
≤ 18V unless otherwise specified.)
S
Symbol Parameter Conditions Min Typ Max Units
INPUT
V
IH
V
IL
V
IN
I
IN
Logic 1 Input Voltage 2.4 1.4 V
Logic 0 Input Voltage 1.0 0.8 V
Input Voltage Range –5 VS+0.3 V
Input Current 0V ≤ VIN ≤ V
S
–10 10 µA
OUTPUT
V
OH
V
OL
R
O
High Output Voltage Figure 1 VS–.025 V
Low Output Voltage Figure 1 0.025 V
Output Resistance, I
= 10mA, VS = 18V 0.8 3.6 Ω
OUT
Output High
R
O
Output Resistance, I
= 10mA, VS = 18V 1.3 2.7 Ω
OUT
Output Low
SWITCHING TIME (Note 3)
t
R
t
F
t
D1
t
D2
Rise Time Figure 1, CL = 10,000pF 23 120 ns
Fall Time Figure 1, CL = 10,000pF 30 120 ns
Delay Time Figure 1 20 80 ns
Delay Time Figure 1 40 80 ns
POWER SUPPLY
I
S
Power Supply Current VIN = 3V 0.6 3 mA
VIN = 0V 0.1 0.2
V
S
Operating Input Voltage 4.5 18 V
NOTE 1: Functional operation above the absolute maximum stress ratings is not implied.
NOTE 2: Static-sensitive device. Store only in conductive containers. Handling personnel and equipment should be grounded to
prevent damage from static discharge.
NOTE 3: Switching times guaranteed by design.
5
Test Circuits
0.1µF
IN
5V
90%
INPUT
10%
0V
V
S
90%
OUTPUT
10%
0V
Figure 1. Inverting Driver Switching Time
VS = 18V
MIC4421
t
PW
t
D1
VS = 18V
0.1µF 4.7µF
OUT
15000pF
0.1µF
IN
0.1µF 4.7µF
OUT
15000pF
MIC4422
2.5V
≥ 0.5µs
t
PW
t
F
t
D2
t
R
INPUT
OUTPUT
5V
90%
10%
0V
V
90%
10%
0V
2.5V
≥ 0.5µs
t
PW
t
PW
t
S
D1
t
R
t
D2
t
F
Figure 2. Noninverting Driver Switching Time
April 1998 5-45
Page 5
MIC4421/4422 Micrel
4 6 8 1012141618
10
-7
10
-8
10
-9
VOLTAGE (V)
CROSSOVER ENERGY (A•s)
Crossover Energy
vs. Supply Voltage
PER TRANSITION
Typical Characteristic Curves
Rise Time
vs. Supply Voltage
220
200
180
160
140
120
100
80
RISE TIME (ns)
60
40
20
0
4 6 8 1012141618
SUPPLY VOLTAGE (V)
47,000pF
22,000pF
10,000pF
Rise Time
vs. Capacitive Load
300
250
200
5V
Fall Time
vs. Supply Voltage
220
200
180
160
140
120
100
80
FALL TIME (ns)
60
40
20
0
4 6 8 1012141618
SUPPLY VOLTAGE (V)
47,000pF
22,000pF
10,000pF
Fall Time
vs. Capacitive Load
300
250
200
5V
Rise and Fall Times
vs. Temperature
60
CL = 10,000pF
= 18V
V
50
S
40
30
TIME (ns)
20
10
0
-40 0 40 80 120
TEMPERATURE (°C)
t
FALL
t
RISE
150
100
RISE TIME (ns)
50
0
100 1000 10k 100k
CAPACITIVE LOAD (pF)
Supply Current
vs. Capacitive Load
220
VS = 18V
200
180
160
140
120
100
80
60
40
SUPPLY CURRENT (mA)
20
0
100 1000 10k 100k
CAPACITIVE LOAD (pF)
1 MHz
10V
200kHz
18V
50kHz
150
100
FALL TIME (ns)
50
0
100 1000 10k 100k
CAPACITIVE LOAD (pF)
10V
Supply Current
vs. Capacitive Load
150
VS = 12V
120
90
60
30
SUPPLY CURRENT (mA)
1 MHz
0
100 1000 10k 100k
CAPACITIVE LOAD (pF)
200kHz
18V
50kHz
Supply Current
vs. Capacitive Load
75
VS = 5V
60
45
30
15
SUPPLY CURRENT (mA)
1 MHz
0
100 1000 10k 100k
CAPACITIVE LOAD (pF)
200kHz
50kHz
5-46 April 1998
Page 6
MIC4421/4422 Micrel
Typical Characteristic Curves (Cont.)
Supply Current
180
160
140
120
100
80
60
40
SUPPLY CURRENT (mA)
20
vs. Frequency
VS = 18V
0.1µF
0
10k 100k 1M 10M
0.01µF
FREQUENCY (Hz)
1000pF
Propagation Delay
vs. Supply Voltage
50
40
30
20
TIME (ns)
10
0
4 6 8 1012141618
SUPPLY VOLTAGE (V)
t
Supply Current
120
100
80
60
40
20
SUPPLY CURRENT (mA)
vs. Frequency
VS = 12V
0.1µF
0
10k 100k 1M 10M
FREQUENCY (Hz)
0.01µF
1000pF
SUPPLY CURRENT (mA)
Propagation Delay
vs. Input Amplitude
120
110
VS = 10V
100
90
t
D2
D1
80
70
60
50
TIME (ns)
40
30
20
10
0
0246810
INPUT (V)
t
D2
t
D1
TIME (ns)
Supply Current
60
50
40
30
20
10
vs. Frequency
VS = 5V
0.01µF
0.1µF
1000pF
0
10k 100k 1M 10M
FREQUENCY (Hz)
Propagation Delay
vs. Temperature
50
40
30
20
10
0
-40 0 40 80 120
TEMPERATURE (°C)
t
D2
t
D1
5
Quiescent Supply Current
1000
QUIESCENT SUPPLY CURRENT (µA)
vs. Temperature
VS = 18V
INPUT = 1
100
INPUT = 0
10
-40 0 40 80 120
TEMPERATURE (°C)
High-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
4 6 8 1012141618
HIGH-STATE OUTPUT RESISTANCE (Ω)
SUPPLY VOLTAGE (V)
April 1998 5-47
TJ = 150°C
TJ = 25°C
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
4 6 8 1012141618
LOW-STATE OUTPUT RESISTANCE (Ω)
SUPPLY VOLTAGE (V)
TJ = 150°C
TJ = 25°C
Page 7
MIC4421/4422 Micrel
E
T
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.
V
S
1µF
V
Ø
2
M Ø
V
S
3
S
Ø
DRIVE SIGNAL
1
CONDUCTION ANGLE
CONTROL 0° TO 180°
CONDUCTION ANGLE
CONTROL 180° TO 360°
MIC4451
DRIVE
LOGIC
V
S
MIC4452
Ø
1
1µF
PHASE 1 of 3 PHASE MOTOR
DRIVER USING MIC4420/4429
Figure 3. Direct Motor Drive
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 0.1µF 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.
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 0.05Ω 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.
0.1µF
50V
0.1µF
WIMA
MKS 2
2
+15
1
MIC4421
4
(x2) 1N4448
+
1µF
50V
MKS 2
8
6, 7
5
UNITED CHEMCON SXE
5.6 kΩ
560 Ω
+
560µF 50V
BYV 10 (x 2)
100µF 50V
OUTPUT VOLTAGE vs LOAD CURREN
30
29
28
27
VOLTS
26
+
25
0 50 100 150 200 250 300 350
12 Ω LIN
mA
Figure 4. Self Contained Voltage Doubler
5-48 April 1998
Page 8
MIC4421/4422 Micrel
Ω
R
Input Stage
The input voltage level of the MIC4421 changes the quiescent supply current. The N channel MOSFET input stage
transistor drives a 320µA current source load. With a logic “1”
input, the maximum quiescent supply current is 400µA. Logic
“0” input level signals reduce quiescent current to 80µA
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 ±10µA.
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 (6.4mA
) with the input. No damage will
RMS
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 1kΩ 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
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 130°C/W. In a 25°C ambient, then, using
a maximum junction temperature of 150°C, 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.
5
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)
+18
WIMA
MKS-2
1 µF
0 V
LOGIC
GROUND
POWE
GROUND
5.0V
0.1µF
300 mV
1
MIC4421
4
TEK CURRENT
6, 7
PROBE 6302
0.1µF
8
5
6 AMPS
PC TRACE RESISTANCE = 0.05
18 V
2,500 pF
POLYCARBONATE
0 V
Figure 5. Switching Time Degradation Due to
Negative Feedback
April 1998 5-49
Table 1: MIC4421 Maximum
Operating Frequency
V
S
18V 220kHz
15V 300kHz
10V 640kHz
5V 2MHz
Conditions: 1. θJA = 150°C/W
2. TA = 25°C
3. CL = 10,000pF
Max Frequency
Page 9
MIC4421/4422 Micrel
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 V
2
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 (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 P
PL = PL1 + P
L2
L
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:
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 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 + P
T
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.
PQ = VS [D IH + (1 – D) IL]
where:
IH = quiescent current with input high
IL = quiescent current with input low
D = fraction of time input is high (duty cycle)
VS = power supply voltage
5-50 April 1998
Page 10
MIC4421/4422 Micrel
V
+18
WIMA
MK22
1 µF
5.0V
0 V
0.1µF
2
1
MIC4421
4
TEK CURRENT
8
6, 7
5
PROBE 6302
0.1µF
Figure 6. Peak Output Current Test Circuit
18 V
0 V
10,000 pF
POLYCARBONATE
5
April 1998 5-51
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