Page 1
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 V
• 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 V
S
S
Applications
• Switch Mode Power Supplies
• Motor Controls
• Pulse Transformer Driver
• Class-D Switching Amplifiers
Functional Diagram
IN
2kΩ
0.1mA
0.4mA
V
S
MIC4429
INVERTING
OUT
MIC4420
NON-INVERTING
GND
5-32 April 1998
Page 2
MIC4420/4429 Micrel
Ordering Information
Part No. Temperature Range Package Configuration
MIC4420CN 0°C to +70°C 8-Pin PDIP Non-Inverting
MIC4420BN –40°C to +85°C 8-Pin PDIP Non-Inverting
MIC4420CM 0°C to +70°C 8-Pin SOIC Non-Inverting
MIC4420BM –40°C to +85°C 8-Pin SOIC Non-Inverting
MIC4420BMM –40°C to +85°C 8-Pin MSOP Non-Inverting
MIC4420CT 0°C to +70°C 5-Pin TO-220 Non-Inverting
MIC4429CN 0°C to +70°C 8-Pin PDIP Inverting
MIC4429BN –40°C to +85°C 8-Pin PDIP Inverting
MIC4429CM 0°C to +70°C 8-Pin SOIC Inverting
MIC4429BM –40°C to +85°C 8-Pin SOIC Inverting
MIC4429BMM –40°C to +85°C 8-Pin MSOP Inverting
MIC4429CT 0°C to +70°C 5-Pin TO-220 Inverting
Pin Configurations
TAB
VS
IN
NC
GND
1
2
3
4
Plastic DIP (N)
SOIC (M)
MSOP (MM)
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
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.
April 1998 5-33
DIP, SOIC, MSOP
S
3 NC Not connected.
Supply Input: Duplicate pins must be externally connected together.
Page 3
MIC4420/4429 Micrel
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 ≤ 25°C
PDIP................................................................... 960W
SOIC ............................................................. 1040mW
5-Pin TO-220.......................................................... 2W
Operating Ratings
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
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
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
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 1.4 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–0.025 V
Low Output Voltage See Figure 1 0.025 V
Output Resistance, I
Output Low
Output Resistance, I
Output High
Peak Output Current VS = 18 V (See Figure 5) 6 A
Latch-Up Protection >500 mA
Withstand Reverse Current
Rise Time Test Figure 1, CL = 2500 pF 12 35 ns
Fall Time Test Figure 1, CL = 2500 pF 13 35 ns
Delay Time Test Figure 1 18 75 ns
Delay Time Test Figure 1 48 75 ns
Power Supply Current VIN = 3 V 0.45 1.5 mA
Operating Input Voltage 4.5 18 V
= 25°C with 4.5V ≤ V
A
= 10 mA, VS = 18 V 1.7 2.8 Ω
OUT
= 10 mA, VS = 18 V 1.5 2.5 Ω
OUT
VIN = 0 V 90 150 µA
≤ 18V unless otherwise specified.)
S
S
–10 10 µA
5-34 April 1998
Page 4
MIC4420/4429 Micrel
Electrical Characteristics: (T
= –55°C to +125°C with 4.5V ≤ V
A
≤ 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 V
Logic 0 Input Voltage 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–0.025 V
Low Output Voltage Figure 1 0.025 V
Output Resistance, I
= 10mA, VS = 18V 3 5 Ω
OUT
Output Low
R
O
Output Resistance, I
= 10mA, VS = 18V 2.3 5 Ω
OUT
Output High
SWITCHING TIME (Note 3)
t
R
t
F
t
D1
t
D2
Rise Time Figure 1, CL = 2500pF 32 60 ns
Fall Time Figure 1, CL = 2500pF 34 60 ns
Delay Time Figure 1 50 100 ns
Delay Time Figure 1 65 100 ns
POWER SUPPLY
I
S
Power Supply Current VIN = 3V 0.45 3.0 mA
VIN = 0V 0.06 0.4 mA
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 1a. Inverting Driver Switching Time
VS = 18V
MIC4429
t
PW
t
D1
VS = 18V
0.1µF 1.0µF
OUT
2500pF
0.1µF
IN
0.1µF 1.0µF
OUT
2500pF
MIC4420
2.5V
≥ 0.5µs
t
PW
t
F
t
D2
t
R
INPUT
OUTPUT
5V
90%
10%
0V
V
90%
10%
0V
t
PW
t
S
D1
t
R
2.5V
t
D2
t
PW
≥ 0.5µs
t
F
Figure 1b. Noninverting Driver Switching Time
April 1998 5-35
Page 5
MIC4420/4429 Micrel
Typical Characteristic Curves
Rise Time vs. Supply Voltage
60
50
C = 10,000 pF
V (V)
S
L
C = 4700 pF
L
C = 2200 pF
L
40
30
TIME (ns)
20
10
0
579111315
Rise Time vs. Capacitive Load
50
40
30
V = 5V
20
TIME (ns)
10
S
V = 12V
S
V = 18V
S
Fall Time vs. Supply Voltage
50
40
C = 10,000 pF
L
30
C = 4700 pF
S
L
C = 2200 pF
L
20
TIME (ns)
10
0
579111315
V (V)
Fall Time vs. Capacitive Load
50
40
30
20
TIME (ns)
10
V = 5V
S
V = 12V
S
V = 18V
S
Rise and Fall Times vs. Temperature
25
C = 2200 pF
L
V = 18V
S
20
15
10
TIME (ns)
5
0
–60 –20 20 60 100
t
FALL
t
RISE
TEMPERATURE (°C)
140
Delay Time vs. Supply Voltage
60
50
40
30
20
DELAY TIME (ns)
10
t
D2
t
D1
5
1000
CAPACITIVE LOAD (pF)
3000
Propagation Delay Time
vs. Temperature
60
t
50
40
TIME (ns)
30
20
C = 2200 pF
L
V = 18V
S
10
–60 –20 20 60 100
D2
TEMPERATURE (°C)
10,000
1000
3000
CAPACITIVE LOAD (pF)
10,000
5
Supply Current vs. Capacitive Load
84
V = 15V
S
70
56
42
t
D1
28
14
S
I – SUPPLY CURRENT (mA)
0
140
0 100 1000
CAPACITIVE LOAD (pF)
500 kHz
200 kHz
20 kHz
10,000
0
4 6 8 1012141618
SUPPLY VOLTAGE (V)
Supply Current vs. Frequency
1000
SUPPLY CURRENT (mA)
C = 2200 pF
L
100
10
0
0 100 1000
FREQUENCY (kHz)
18V
10V
5V
10,000
5-36 April 1998
Page 6
MIC4420/4429 Micrel
Typical Characteristic Curves (Cont.)
Quiescent Power Supply
Voltage vs. Supply Current
1000
800
600
400
SUPPLY CURRENT (µA)
200
0
0481216
LOGIC “1” INPUT
LOGIC “0” INPUT
SUPPLY VOLTAGE (V)
High-State Output Resistance
5
100 mA
OUT
R ( )Ω
4
10 mA
3
50 mA
20
Quiescent Power Supply
Current vs. Temperature
900
LOGIC “1” INPUT
V = 18V
800
700
600
SUPPLY CURRENT (µA)
500
400
S
–60 –20 20 60 100
TEMPERATURE (°C)
Low-State Output Resistance
2.5
2
OUT
R ( )Ω
1.5
100 mA
10 mA
140
5
50 mA
2
5913
71115
V (V)
S
Effect of Input Amplitude
on Propagation Delay
200
LOAD = 2200 pF
160
120
INPUT 2.4V
80
DELAY (ns)
40
0
INPUT 3.0V
INPUT 5.0V
INPUT 8V AND 10V
567 11 13
8 9 10 12 14
V (V)
S
15
1
5913
71115
V (V)
S
Crossover Area vs. Supply Voltage
2.0
-8
CROSSOVER AREA (A•s) x 10
PER TRANSITION
1.5
1.0
0.5
0
567 11 13
8 9 10 12 14
SUPPLY VOLTAGE V (V)
s
15
April 1998 5-37
Page 7
MIC4420/4429 Micrel
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 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.
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 0.05Ω 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.
0.1µF
50V
0.1µF
WIMA
MKS 2
2
+15
1
MIC4429
4
(x2) 1N4448
+
1µF
50V
MKS 2
8
6, 7
5
UNITED CHEMCON SXE
5.6 kΩ
560 Ω
30
29
28
27
VOLTS
26
25
+
220 µF 50V
BYV 10 (x 2)
+
35 µF 50V
Figure 3. Self-Contained Voltage Doubler
5-38 April 1998
OUTPUT VOLTAGE vs LOAD CURRENT
30 Ω LINE
0 20 40 60 80 100 120 140
mA
Page 8
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
(6.4mA
voltage. No damage will occur to MIC4420/4429 however,
and it will not latch.
) with the input, 6 V greater than the supply
RMS
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 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)
5
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.
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 µF
0 V
5.0V
0.1µF
2
1
MIC4429
4
TEK CURRENT
6, 7
PROBE 6302
0.1µF
8
5
18 V
0 V
10,000 pF
POLYCARBONATE
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
V
S
Max Frequency
18V 500kHz
15V 700kHz
10V 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
Page 9
MIC4420/4429 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 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
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
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
+
to ground. The transi-
S
tion 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 +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.
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 ≤2.0mA.
Quiescent power can therefore be found from:
PQ = VS [D IH + (1-D) IL]
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.
5-40 April 1998
Page 10
MIC4420/4429 Micrel
+18 V
WIMA
MK22
1 µF
0 V
5.0V
0.1µF
1
8
2
MIC4429
4
Figure 6. Peak Output Current Test Circuit
6, 7
5
TEK CURRENT
PROBE 6302
0.1µF
18 V
0 V
10,000 pF
POLYCARBONATE
5
April 1998 5-41
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