Page 1
MIC4451/4452
12A-Peak Low-Side MOSFET Driver
Bipolar/CMOS/DMOS Process
General Description
MIC4451 and MIC4452 CMOS MOSFET drivers are
robust, efficient, and easy to use. The MIC4451 is an
inverting driver, while the MIC4452 is a non-inverting
driver.
Both versions are capable of 12A (peak) output and can
drive the largest MOSFETs with an improved safe
operating margin. The MIC4451/4452 accepts any logic
input from 2.4V to V
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.
MIC4451/4452 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.
Data sheets and support documentation can be found on
Micrel’s web site at: www.micrel.com
____________________________________________________________________________________________________________
without external speed-up capacitors
S
.
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: 12A peak
• Wide operating range: 4.5V to 18V
• High capacitive load drive: 62,000Pf
• Low delay time: 30ns (typ.)
• Logic high input for any voltage from 2.4V to V
• Low supply current 450µA with logic 1 input
• Low output impedance: 1.0
• Output voltage swing to within 25mV of GND or V
• Low equivalent input capacitance (typ.): 7pF
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
V
S
0.3mA
0.1mA
IN
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-01200 • fax + 1 (408) 474-1000 • http://www.micrel.com
October 2011
2k
MIC4451
INVERTING
OUT
MIC4452
NONINVERTING
GND
M9999-103111-B
Page 2
Micrel Inc. MIC4451/4452
Ordering Information
Part Number
Standard Pb-Free
MIC4451YN
MIC4451BM MIC4451YM
MIC4451ZT
MIC4452YN
MIC4452BM MIC4452YM
MIC4452ZT
MIC4452VM
Pin Configurations
Temperature Range Package Configuration
40°C to +85°C
40°C to +85°C
0°C to +70°C
40°C to +85°C
40°C to +85°C
0°C to +70°C
40°C to +125°C
VS
1
2
IN
3
NC
GND
4
8-Pin Plastic DIP Inverting
8- Pin SOIC Inverting
5- Pin TO-220 Inverting
8- Pin Plastic DIP Non-Inverting
8- Pin SOIC Non-Inverting
5- Pin TO-220 Non-Inverting
8- Pin SOIC Non-Inverting
VS
8
7
OUT
6
OUT
5
GND
5OUT
4GND
3VS
2GND
1IN
Pin Description
Pin Number
T0-220-5
1 2 IN Control Input.
2, 4 4, 5 GND Ground: Duplicate Pins must be externally connected together.
3, TAB 1, 8 VS Supply Input: Duplicate pins must be externally connected together.
5 6, 7 OUT Output: Duplicate pins must be externally connected together.
3 NC Not Connected.
October 2011 2
Pin Number
DIP, SOIC
Pin Name Pin Function
M9999-103111-B
Page 3
Micrel Inc. MIC4451/4452
Absolute Maximum Ratings
Supply Voltage ..............................................................20V
Input Voltage .................................... V
Input Current (V
Power Dissipation, T
PDIP ..................................................................960mW
SOIC ................................................................1040mW
5-Pin TO-220 ............................................................2W
Power Dissipation, T
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(10s) ............................................ 300°C
> VS) .................................................5mA
IN
25°C
AMBIENT
25°C
CASE
(1, 2)
+ 0.3V to GND −5V
S
Operating Ratings
Operating Temperature (Chip) .................................. 150°C
Operating Temperature (Ambient)
Z Version .................................................. 0°C to +70°C
Y Version............................................. −40°C to + 85°C
V Version........................................... −40°C to + 125°C
Thermal Impedances (To Case)
5-Pin TO-220(JC) ........................................... 10°C/W
Electrical Characteristics
(TA = 25oC, with 4.5V ≤ VS ≤ 18V unless otherwise specified.)
Symbol Parameter Condition Min. Typ. Max. Units
Input
VIH Logic 1 Input Voltage 2.4 1.3 V
VIL Logic 0 Input Voltage 1.1 0.8 V
VIN Input Voltage Range
IIN Input Current 0 VIN VS
Output
VOH High Output Voltage See Figure 1
VOL Low Output Voltage See Figure 1 0.025 V
RO
RO Output Resistance, Output Low I
IPK Peak Output Current VS = 18V (See Figure 6) 12 A
IDC Continuous Output Current 2 A
IR
Switching Time
tR Rise Time Test Figure 1, CL = 15,000pF 20 40 ns
tF Fall Time Test Figure 1, CL = 15,000pF 24 50 ns
tD1 Delay Time Test Figure 1 25 50 ns
tD2 Delay Time Test Figure 1 40 60 ns
Power Supply
IS Power Supply Current
VS Operating Input Voltage 4.5 V
October 2011 3
Output Resistance,
Output High
Latch-up Protection
Withstand Reverse Current
(3)
(3)
I
OUT
OUT
Duty Cycle 2%
t ≤ 300s
V
V
−5
−10
−.025
V
S
= 10mA, VS = 18V 0.6 1.5
= 10mA, VS = 18V 0.8 1.5
>1500
= 3V
IN
= 0V
IN
VS + .3 V
10 A
V
mA
0.4
80
1.5
150
M9999-103111-B
mA
A
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Micrel Inc. MIC4451/4452
Electrical Characteristics
(Over operating temperature range with 4.5V ≤ VS ≤ 18V unless otherwise specified.)
Symbol Parameter Condition Min. Typ. Max. Units
Input
VIH Logic 1 Input Voltage 2.4 V
VIL Logic 0 Input Voltage 0.8 V
VIN Input Voltage Range
IIN Input Current 0 VIN VS
Output
VOH High Output Voltage See Figure 1
VOL Low Output Voltage See Figure 1 0.025 V
RO Output Resistance, Output High I
RO
Switching Time
tR Rise Time Test Figure 1, CL = 15,000pF 50 ns
tF Fall Time Test Figure 1, CL = 15,000pF 60 ns
tD1 Delay Time Test Figure 1 65 ns
tD2 Delay Time Test Figure 1 80 ns
Power Supply
IS Power Supply Current
VS Operating Input Voltage 4.5 18 V
Notes:
1. Functional operation above the absolute maximum stress ratings is not implied.
2. Static-sensitive device. Store only in conductive containers. Handling personnel and equipment should be grounded to prevent damage from static
discharge.
3. Specification for packaged product only.
Output Resistance,
Output Low
(3)
= 10mA, VS = 18V 2.2
OUT
= 10mA, VS = 18V 2.2
I
OUT
= 3V
V
IN
= 0V
V
IN
−5
−10
− .025
V
S
VS + .3 V
10 A
V
3
0.4
mA
October 2011 4
M9999-103111-B
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Micrel Inc. MIC4451/4452
Test Circuits
Figure 1. Inverting Driver Switching Time Figure 2. Noninverting Driver Switching Time
Figure 3. Peak Output Current Test Circuit
October 2011 5
M9999-103111-B
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Micrel Inc. MIC4451/4452
Typical Characteristics
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Micrel Inc. MIC4451/4452
Typical Characteristics Curves (Continued)
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M9999-103111-B
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Micrel Inc. MIC4451/4452
Applications Information
Supply Bypassing
Charging and discharging large capacitive loads quickly
requires large currents. For example, changing a
10,000pF load to 18V in 50ns requires 3.6A.
The MIC4451/4452 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 0.1µF 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 MIC4451/4452
demands careful PC board layout for best performance.
Since the MIC4451 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 MIC4451 input
structure includes 200mV of hysteresis to ensure clean
transitions and freedom from oscillation, but attention to
layout is still recommended.
Figure 4 shows the feedback effect in detail. As the
MIC4451 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 MIC4451
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 MIC4451
GND pins will ensure full logic drive to the input and
ensure fast output switching. Both of the MIC4451 GND
pins should, however, still be connected to power
ground.
Input Stage
The input voltage level of the MIC4451 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 MIC4451/4452 input is designed to provide 200mV
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 MIC4451 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 MIC4451/4452,
the power supply controller can operate at lower
dissipation. This can improve performance and reliability.
The input can be greater than the V
supply, however,
S
current will flow into the input lead. The input currents
can be as high as 30mA p-p (6.4mA
) with the input.
RMS
No damage will occur to MIC4451/4452 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
MIC4451/4452 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.
October 2011 8
M9999-103111-B
Page 9
Micrel Inc. MIC4451/4452
LOGIC
GROUND
POWER
GROUND
0 V
5.0V
0.1µF
300 mV
+18
1
MIC4451
4
12 AMPS
WIMA
MKS-2
1µF
TEK CURRENT
6, 7
PROBE 6302
0.1µF
8
5
PC TRACE RESISTANCE = 0.05
18 V
2,500 pF
POLYCARBONATE
0 V
Figure 4. Switching Time Degradation Due to Negative
Feedback
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
125°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 (P
• Quiescent power dissipation (P
• Transition power dissipation (P
)
L
)
Q
)
T
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:
= I2 RO D
P
L
where:
I = the current drawn by the load
R
= the output resistance of the driver when the output
O
is high, at the power supply voltage used. (See data
sheet)
D = fraction of time the load is conducting (duty cycle)
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:
2
E = 1/2 C V
VS Max. Frequency
18V 220kHz
15V 300kHz
10V 640kHz
5V 2MHz
Table 1: MIC4451 Maximum Operating Frequency
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:
= f C (VS)2
P
L
where:
f = Operating Frequency
C = Load Capacitance
V
= Driver Supply Voltage
S
October 2011 9
M9999-103111-B
Page 10
Micrel Inc. MIC4451/4452
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:
= I2 RO D
P
L1
However, in this instance the R
required may be either
O
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:
= I VD (1 – D)
P
L2
where V
is the forward drop of the clamp diode in the
D
driver (generally around 0.7V). The two parts of the load
dissipation must be summed in to produce P
:
L
P
= PL1 + PL2
L
Quiescent Power Dissipation
Quiescent power dissipation (P
, as described in the
Q
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:
= VS [D IH + (1 – D) IL]
P
Q
where:
I
= quiescent current with input high
H
I
= quiescent current with input low
L
D = fraction of time input is high (duty cycle)
V
= power supply voltage
S
where (A × s) is a time-current factor derived from the
typical characteristic curve “Crossover Energy vs.
Supply Voltage.” Total power (P
) then, as previously
D
described is:
= PL + PQ + PT
P
D
Definitions
C
= Load Capacitance in Farads.
L
D = Duty Cycle expressed as the fraction of time the
input to the driver is high.
f = Operating Frequency of the driver in Hertz
I
= Power supply current drawn by a driver when both
H
inputs are high and neither output is loaded.
= Power supply current drawn by a driver when both
I
L
inputs are low and neither output is loaded.
= Output current from a driver in Amps.
I
D
P
= Total power dissipated in a driver in Watts.
D
P
= Power dissipated in the driver due to the driver’s
L
load in Watts.
= Power dissipated in a quiescent driver in Watts.
P
Q
P
= Power dissipated in a driver when the output
T
changes states (“shoot-through current”) in watts.
= Output resistance of a driver in Ωs.
R
O
V
= Power supply voltage to the IC in volts.
S
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 transition power dissipation is
S
approximately:
= 2 f VS (A × s)
P
T
October 2011 10
M9999-103111-B
Page 11
Micrel Inc. MIC4451/4452
0
Package Information
PIN 1
DIMENSIONS:
INCH (MM)
0.380 (9.65)
0.370 (9.40)
0.135 (3.43)
0.125 (3.18)
0.255 (6.48)
0.245 (6.22)
0.300 (7.62)
0.013 (0.330
0.010 (0.254
0.018 (0.57)
0.100 (2.54)
0.130 (3.30)
0.0375 (0.952)
0.380 (9.65)
0.320 (8.13)
8-Pin Plastic DIP (N)
.026 (0.65)
MAX)
0.157 (3.99)
0.150 (3.81)
0.050 (1.27)
TYP
PIN 1
0.020 (0.51)
0.013 (0.33)
0.0098 (0.249)
0.0040 (0.102)
DIMENSIONS:
INCHES (MM)
45°
0.010 (0.25)
0.007 (0.18)
0.064 (1.63)
0.045 (1.14)
0.197 (5.0)
0.189 (4.8)
SEATING
PLANE
0°–8°
0.050 (1.27)
0.016 (0.40)
0.244 (6.20)
0.228 (5.79)
8-Pin SOIC (M)
October 2011 11
M9999-103111-B
Page 12
Micrel Inc. MIC4451/4452
Package Information (Continued)
5-Pin TO-220 (T)
October 2011 12
M9999-103111-B
Page 13
Micrel Inc. MIC4451/4452
MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http://www.micrel.com
Micrel makes no representations or warranties with respect to the accuracy or completeness of the information furnished in this data sheet. This
information is not intended as a warranty and Micrel does not assume responsibility for its use. Micrel reserves the right to change circuitry,
specifications and descriptions at any time without notice. No license, whether express, implied, arising by estoppel or otherwise, to any intellectual
property rights is granted by this document. Except as provided in Micrel’s terms and conditions of sale for such products, Micrel assumes no liability
whatsoever, and Micrel disclaims any express or implied warranty relating to the sale and/or use of Micrel products including liability or warranties
relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right.
Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product
can nt
reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical impla
into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A
Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk and Purchaser agrees to fully
October 2011 13
indemnify Micrel for any damages resulting from such use or sale.
© 1998 Micrel, Incorporated.
M9999-103111-B
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