MIC4451/4452

12A-Peak Low-Side MOSFET Driver

Bipolar/CMOS/DMOS Process

General Description Features

MIC4451 and MIC4452 CMOS MOSFET drivers are BiCMOS/DMOS construction
robust, efficient, and easy to use. The MIC4451 is an Latch-up proof: fully-isolated process is inherently
inverting driver, while the MIC4452 is a non-inverting immune to any latch-up
driver.
Input will withstand negative swing of up to 5V
Both versions are capable of 12A (peak) output and can
Matched rise and fall times: 25ns
drive the largest MOSFETs with an improved safe
operating margin. The MIC4451/4452 accepts any logic High peak output current: 12A peak
input from 2.4V to VS without external speed-up capacitors Wide operating range: 4.5V to 18V
or resistor networks. Proprietary circuits allow the input to High capacitive load drive: 62,000Pf
swing negative by as much as 5V without damaging the Low delay time: 30ns (typ.)
part. Additional circuits protect against damage from
electrostatic discharge. Logic high input for any voltage from 2.4V to VS
MIC4451/4452 drivers can replace three or more discrete Low supply current 450A with logic 1 input
components, reducing PCB area requirements, simplifying Low output impedance: 1.0
product design, and reducing assembly cost. Output voltage swing to within 25mV of GND or VS
Modern Bipolar/CMOS/DMOS construction guarantees Low equivalent input capacitance (typ.): 7pF
freedom from latch-up. The rail-to-rail swing capability of
CMOS/DMOS insures adequate gate voltage to the Applications
MOSFET during power up/down sequencing. Since these
Switch mode power supplies
devices are fabricated on a self-aligned process, they have
Motor controls
very low crossover current, run cool, use little power, and
are easy to drive. Pulse transformer driver
Data sheets and support documentation can be found on Class-D switching amplifiers
Micrels web site at: www.micrel.com. Line drivers
Driving MOSFET or IGBT parallel chip modules
Local power ON/OFF switch
Pulse generators
____________________________________________________________________________________________________________
Functional Diagram
VS

MIC4451
0.3mA INVERTING
0.1mA

OUT
IN 2k

MIC4452
NONINVERTING

GND
Micrel Inc. 2180 Fortune Drive San Jose, CA 95131 USA tel +1 (408) 944-01200 fax + 1 (408) 474-1000 http://www.micrel.com

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Micrel Inc. MIC4451/4452

Ordering Information
Part Number
Temperature Range Package Configuration
Standard Pb-Free
MIC4451YN 40C to +85C 8-Pin Plastic DIP Inverting
MIC4451BM MIC4451YM 40C to +85C 8- Pin SOIC Inverting
MIC4451ZT 0C to +70C 5- Pin TO-220 Inverting
MIC4452YN 40C to +85C 8- Pin Plastic DIP Non-Inverting
MIC4452BM MIC4452YM 40C to +85C 8- Pin SOIC Non-Inverting
MIC4452ZT 0C to +70C 5- Pin TO-220 Non-Inverting
MIC4452VM 40C to +125C 8- Pin SOIC Non-Inverting

Pin Configurations

VS 1 8 VS

IN 2 7 OUT

NC 3 6 OUT

GND 4 5 GND

5 OUT
4 GND
3 VS
2 GND
1 IN

Pin Description
Pin Number Pin Number
Pin Name Pin Function
T0-220-5 DIP, SOIC
1 2 IN Control Input.
2, 4 4, 5 GND Ground: Duplicate Pins must be externally connected together.
3, TAB 1, 8 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.

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Absolute Maximum Ratings(1, 2) Operating Ratings

Operating Temperature (Chip) .................................. 150C
Supply Voltage ..............................................................20V
Operating Temperature (Ambient)
Input Voltage .................................... VS + 0.3V to GND 5V
Z Version .................................................. 0C to +70C
Input Current (VIN > VS) .................................................5mA
Power Dissipation, TAMBIENT 25C Y Version ............................................. 40C to + 85C
PDIP ..................................................................960mW V Version ........................................... 40C to + 125C
SOIC ................................................................1040mW Thermal Impedances (To Case)
5-Pin TO-220 ............................................................2W 5-Pin TO-220(JC) ........................................... 10C/W
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(10s) ............................................ 300C

Electrical Characteristics(3)
(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 5 VS + .3 V
IIN Input Current 0 VIN VS 10 10 A
Output
VOH High Output Voltage See Figure 1 VS .025 V
VOL Low Output Voltage See Figure 1 0.025 V
Output Resistance,
RO IOUT = 10mA, VS = 18V 0.6 1.5
Output High
RO Output Resistance, Output Low IOUT = 10mA, VS = 18V 0.8 1.5
IPK Peak Output Current VS = 18V (See Figure 6) 12 A
IDC Continuous Output Current 2 A
Latch-up Protection Duty Cycle 2%
IR >1500 mA
Withstand Reverse Current t 300s
Switching Time(3)
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
VIN = 3V 0.4 1.5 mA
IS Power Supply Current
VIN = 0V 80 150 A
VS Operating Input Voltage 4.5 V

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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 5 VS + .3 V
IIN Input Current 0 VIN VS 10 10 A
Output
VOH High Output Voltage See Figure 1 VS .025 V
VOL Low Output Voltage See Figure 1 0.025 V
RO Output Resistance, Output High IOUT = 10mA, VS = 18V 2.2
Output Resistance,
RO IOUT = 10mA, VS = 18V 2.2
Output Low
Switching Time (3)
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
VIN = 3V 3 mA
IS Power Supply Current
VIN = 0V 0.4
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.

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Test Circuits

Figure 1. Inverting Driver Switching Time Figure 2. Noninverting Driver Switching Time

Figure 3. Peak Output Current Test Circuit

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Typical Characteristics

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Typical Characteristics Curves (Continued)

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Applications Information
Supply Bypassing Input Stage
Charging and discharging large capacitive loads quickly The input voltage level of the MIC4451 changes the
requires large currents. For example, changing a quiescent supply current. The N channel MOSFET input
10,000pF load to 18V in 50ns requires 3.6A. stage transistor drives a 320A current source load. With
The MIC4451/4452 has double bonding on the supply a logic 1 input, the maximum quiescent supply current
pins, the ground pins and output pins. This reduces is 400A. Logic 0 input level signals reduce quiescent
current to 80A typical.
parasitic lead inductance. Low inductance enables large
currents to be switched rapidly. It also reduces internal The MIC4451/4452 input is designed to provide 200mV
ringing that can cause voltage breakdown when the of hysteresis. This provides clean transitions, reduces
driver is operated at or near the maximum rated voltage. noise sensitivity, and minimizes output stage current
Internal ringing can also cause output oscillation due to spiking when changing states. Input voltage threshold
level is approximately 1.5V, making the device TTL
feedback. This feedback is added to the input signal
since it is referenced to the same ground. compatible over the full temperature and operating
supply voltage ranges. Input current is less than 10A.
To guarantee low supply impedance over a wide
The MIC4451 can be directly driven by the TL494,
frequency range, a parallel capacitor combination is
recommended for supply bypassing. Low inductance SG1526/1527, SG1524, TSC170, MIC38C42, and
ceramic disk capacitors with short lead lengths (< 0.5 similar switch mode power supply integrated circuits. By
offloading the power-driving duties to the MIC4451/4452,
inch) should be used. A 1F low ESR film capacitor in
parallel with two 0.1F low ESR ceramic capacitors, the power supply controller can operate at lower

(such as AVX RAM GUARD ), provides adequate dissipation. This can improve performance and reliability.
bypassing. Connect one ceramic capacitor directly The input can be greater than the VS supply, however,
between pins 1 and 4. Connect the second ceramic current will flow into the input lead. The input currents
capacitor directly between pins 8 and 5. can be as high as 30mA p-p (6.4mARMS) with the input.
No damage will occur to MIC4451/4452 however, and it
Grounding will not latch.
The high current capability of the MIC4451/4452 The input appears as a 7pF capacitance and does not
demands careful PC board layout for best performance. change even if the input is driven from an AC source.
Since the MIC4451 is an inverting driver, any ground While the device will operate and no damage will occur
lead impedance will appear as negative feedback which up to 25V below the negative rail, input current will
can degrade switching speed. Feedback is especially increase up to 1mA/V due to the clamping action of the
noticeable with slow-rise time inputs. The MIC4451 input input, ESD diode, and 1k resistor.
structure includes 200mV of hysteresis to ensure clean
transitions and freedom from oscillation, but attention to Power Dissipation
layout is still recommended. CMOS circuits usually permit the user to ignore power
Figure 4 shows the feedback effect in detail. As the dissipation. Logic families such as 4000 and 74C have
MIC4451 input begins to go positive, the output goes outputs which can only supply a few milliamperes of
negative and several amperes of current flow in the current, and even shorting outputs to ground will not
ground lead. As little as 0.05 of PC trace resistance force enough current to destroy the device. The
can produce hundreds of millivolts at the MIC4451 MIC4451/4452 on the other hand, can source or sink
ground pins. If the driving logic is referenced to power several amperes and drive large capacitive loads at high
ground, the effective logic input level is reduced and frequency. The package power dissipation limit can
oscillation may result. easily be exceeded. Therefore, some attention should be
To insure optimum performance, separate ground traces given to power dissipation when driving low impedance
should be provided for the logic and power connections. loads and/or operating at high frequency.
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.

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 Micrel Inc. MIC4451/4452

+18
Resistive Load Power Dissipation
WIMA Dissipation caused by a resistive load can be calculated
MKS-2
1 F as:

5.0V 1 TEK CURRENT

18 V
PL = I2 RO D
8 PROBE 6302
6, 7
MIC4451

0V 5 0V where:
0.1F 4 0.1F
2,500 pF
POLYCARBONATE
I = the current drawn by the load
LOGIC 12 AMPS
RO = the output resistance of the driver when the output
GROUND is high, at the power supply voltage used. (See data
300 mV PC TRACE RESISTANCE = 0.05 sheet)
POWER
GROUND D = fraction of time the load is conducting (duty cycle)

Capacitive Load Power Dissipation

Figure 4. Switching Time Degradation Due to Negative Dissipation caused by a capacitive load is simply the
Feedback energy placed in, or removed from, the load capacitance
by the driver. The energy stored in a capacitor is
The supply current vs. frequency and supply current vs described by the equation:
capacitive load characteristic curves aid in determining
power dissipation calculations. Table 1 lists the
maximum safe operating frequency for several power E = 1/2 C V2
supply voltages when driving a 10,000pF load. More
accurate power dissipation figures can be obtained by VS Max. Frequency
summing the three dissipation sources. 18V 220kHz
Given the power dissipation in the device, and the 15V 300kHz
thermal resistance of the package, junction operating
10V 640kHz
temperature for any ambient is easy to calculate. For
example, the thermal resistance of the 8-pin plastic DIP 5V 2MHz
package, from the data sheet, is 130C/W. In a 25C
ambient, then, using a maximum junction temperature of Table 1: MIC4451 Maximum Operating Frequency
125C, this package will dissipate 960mW.
Accurate power dissipation numbers can be obtained by As this energy is lost in the driver each time the load is
summing the three sources of power dissipation in the charged or discharged, for power dissipation calculations
device: the 1/2 is removed. This equation also shows that it is
Load Power Dissipation (PL) good practice not to place more voltage on the capacitor
than is necessary, as dissipation increases as the
Quiescent power dissipation (PQ)
square of the voltage applied to the capacitor. For a
Transition power dissipation (PT) driver with a capacitive load:

Calculation of load power dissipation differs depending PL = f C (VS)2

on whether the load is capacitive, resistive or inductive.
where:
f = Operating Frequency
C = Load Capacitance
VS = Driver Supply Voltage

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Inductive Load Power Dissipation

where (A s) is a time-current factor derived from the
For inductive loads the situation is more complicated.
typical characteristic curve Crossover Energy vs.
For the part of the cycle in which the driver is actively
Supply Voltage. Total power (PD) then, as previously
forcing current into the inductor, the situation is the same
described is:
as it is in the resistive case:

PD = PL + PQ + PT
PL1 = I2 RO D
Definitions
However, in this instance the RO required may be either CL = Load Capacitance in Farads.
the on resistance of the driver when its output is in the D = Duty Cycle expressed as the fraction of time the
high state, or its on resistance when the driver is in the input to the driver is high.
low state, depending on how the inductor is connected,
and this is still only half the story. For the part of the f = Operating Frequency of the driver in Hertz
cycle when the inductor is forcing current through the IH = Power supply current drawn by a driver when both
driver, dissipation is best described as: inputs are high and neither output is loaded.
IL = Power supply current drawn by a driver when both
PL2 = I VD (1 D) inputs are low and neither output is loaded.
ID = Output current from a driver in Amps.
where VD is the forward drop of the clamp diode in the PD = Total power dissipated in a driver in Watts.
driver (generally around 0.7V). The two parts of the load PL = Power dissipated in the driver due to the drivers
dissipation must be summed in to produce PL: load in Watts.
PQ = Power dissipated in a quiescent driver in Watts.
PL = PL1 + PL2 PT = Power dissipated in a driver when the output
changes states (shoot-through current) in watts.
Quiescent Power Dissipation RO = Output resistance of a driver in s.
Quiescent power dissipation (PQ, as described in the VS = Power supply voltage to the IC in volts.
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 = 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 VS to ground. The transition power dissipation is
approximately:

PT = 2 f VS (A s)

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Package Information

PIN 1

DIMENSIONS:
INCH (MM)

0.380 (9.65) 0.255 (6.48)

0.370 (9.40) 0.245 (6.22)
0.135 (3.43)
0.125 (3.18) 0.300 (7.62)

0.013 (0.330
0.010 (0.254

0.018 (0.57) 0.130 (3.30) 0.380 (9.65)

0.320 (8.13)
0.100 (2.54) 0.0375 (0.952)

8-Pin Plastic DIP (N)

0.026 (0.65)
MAX) PIN 1

0.157 (3.99) DIMENSIONS:

0.150 (3.81) INCHES (MM)

0.020 (0.51)
0.013 (0.33)
0.050 (1.27)
TYP 0.0098 (0.249) 45
0.010 (0.25)
0.0040 (0.102) 0.007 (0.18)

0.197 (5.0) 08 0.050 (1.27)

0.064 (1.63) 0.189 (4.8) SEATING 0.016 (0.40)
0.045 (1.14) PLANE
0.244 (6.20)
0.228 (5.79)

8-Pin SOIC (M)

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Package Information (Continued)

5-Pin TO-220 (T)

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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 Micrels 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 reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant
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
Purchasers use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchasers own risk and Purchaser agrees to fully
indemnify Micrel for any damages resulting from such use or sale.

1998 Micrel, Incorporated.

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Mouser Electronics

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