MIC4451 - Micrel

MIC4451/4452
12A-Peak Low-Side MOSFET Driver
Bipolar/CMOS/DMOS Process
General Description
Features
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 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.
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.
• 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 VS
• Low supply current 450µA with logic 1 input
• Low output impedance: 1.0Ω
• Output voltage swing to within 25mV of GND or VS
• Low equivalent input capacitance (typ.): 7pF
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
VS
0.3mA
MIC4451
INVERTING
0.1mA
OUT
IN
2kΩ
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
October 2011
M9999-103111-B
Micrel Inc.
MIC4451/4452
Ordering Information
Part Number
Temperature Range
Package
Configuration
MIC4451YN
−40°C to +85°C
8-Pin Plastic DIP
Inverting
MIC4451BM
MIC4451YM
−40°C to +85°C
8- Pin SOIC
Inverting
−
MIC4451ZT
0°C to +70°C
5- Pin TO-220
Inverting
−
MIC4452YN
−40°C to +85°C
8- Pin Plastic DIP
Non-Inverting
MIC4452BM
MIC4452YM
−40°C to +85°C
8- Pin SOIC
Non-Inverting
−
MIC4452ZT
0°C to +70°C
5- Pin TO-220
Non-Inverting
−
MIC4452VM
−40°C to +125°C
8- Pin SOIC
Non-Inverting
Standard
Pb-Free
−
Pin Configurations
VS 1
8 VS
IN 2
7 OUT
NC 3
6 OUT
GND 4
5 GND
5
4
3
2
1
OUT
GND
VS
GND
IN
Pin Description
Pin Number
T0-220-5
1
2, 4
3, TAB
5
October 2011
Pin Number
DIP, SOIC
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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MIC4451/4452
Absolute Maximum Ratings(1, 2)
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(θJC) ........................................... 10°C/W
Supply Voltage ..............................................................20V
Input Voltage .................................... VS + 0.3V to GND −5V
Input Current (VIN > VS) .................................................5mA
Power Dissipation, TAMBIENT ≤ 25°C
PDIP ..................................................................960mW
SOIC ................................................................1040mW
5-Pin TO-220 ............................................................2W
Power Dissipation, TCASE ≤ 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(10s) ............................................ 300°C
Electrical Characteristics(3)
(TA = 25oC, with 4.5V ≤ VS ≤ 18V unless otherwise specified.)
Symbol
Parameter
Condition
Min.
Typ.
2.4
1.3
Max.
Units
Input
VIH
Logic 1 Input Voltage
VIL
Logic 0 Input Voltage
VIN
Input Voltage Range
IIN
Input Current
VOH
VOL
1.1
V
0.8
V
−5
VS + .3
V
0 ≤ VIN ≤ VS
−10
10
μA
High Output Voltage
See Figure 1
VS −.025
Low Output Voltage
See Figure 1
Output
RO
Output Resistance,
Output High
V
V
IOUT = 10mA, VS = 18V
0.6
1.5
Ω
1.5
Ω
RO
Output Resistance, Output Low
IOUT = 10mA, VS = 18V
0.8
IPK
Peak Output Current
VS = 18V (See Figure 6)
12
IDC
Continuous Output Current
IR
0.025
Latch-up Protection
Duty Cycle ≤ 2%
Withstand Reverse Current
t ≤ 300μs
A
2
A
>1500
mA
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
VIN = 3V
0.4
1.5
mA
VIN = 0V
80
150
μA
Power Supply
IS
Power Supply Current
VS
Operating Input Voltage
October 2011
4.5
3
V
M9999-103111-B
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
VIL
Logic 0 Input Voltage
VIN
Input Voltage Range
IIN
Input Current
VOH
2.4
V
0.8
V
−5
VS + .3
V
0 ≤ VIN ≤ VS
−10
10
μA
High Output Voltage
See Figure 1
VS − .025
VOL
Low Output Voltage
See Figure 1
RO
Output Resistance, Output High
Output
RO
Output Resistance,
Output Low
V
0.025
V
IOUT = 10mA, VS = 18V
2.2
Ω
IOUT = 10mA, VS = 18V
2.2
Ω
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
VIN = 3V
3
mA
VIN = 0V
0.4
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.
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MIC4451/4452
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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MIC4451/4452
Typical Characteristics
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MIC4451/4452
Typical Characteristics Curves (Continued)
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MIC4451/4452
Applications Information
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 VS supply, however,
current will flow into the input lead. The input currents
can be as high as 30mA p-p (6.4mARMS) with the input.
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 1kΩ resistor.
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 0.05Ω 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.
October 2011
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.
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MIC4451/4452
+18
Resistive Load Power Dissipation
Dissipation caused by a resistive load can be calculated
as:
WIMA
MKS-2
1 µF
5.0V
1
8
6, 7
TEK CURRENT
PROBE 6302
PL = I2 RO D
18 V
MIC4451
0V
5
0.1µF
0.1µF
4
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)
0V
2,500 pF
POLYCARBONATE
12 AMPS
LOGIC
GROUND
300 mV
POWER
GROUND
PC TRACE RESISTANCE = 0.05Ω
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:
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 (PL)
•
Quiescent power dissipation (PQ)
•
Transition power dissipation (PT)
E = 1/2 C V2
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:
PL = f C (VS)2
Calculation of load power dissipation differs depending
on whether the load is capacitive, resistive or inductive.
where:
f = Operating Frequency
C = Load Capacitance
VS = Driver Supply Voltage
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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:
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:
PD = PL + PQ + PT
PL1 = I2 RO D
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.
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 ≤ 3.0mA. Quiescent power can therefore
be found from:
RO = Output resistance of a driver in Ωs.
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
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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MIC4451/4452
Package Information
PIN 1
DIMENSIONS:
INCH (MM)
0.380 (9.65)
0.370 (9.40)
0.255 (6.48)
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)
0.100 (2.54)
0.0375 (0.952)
0.380 (9.65)
0.320 (8.13)
8-Pin Plastic DIP (N)
0.026 (0.65)
MAX)
PIN 1
0.157 (3.99)
0.150 (3.81)
DIMENSIONS:
INCHES (MM)
0.050 (1.27)
TYP
0.064 (1.63)
0.045 (1.14)
0.197 (5.0)
0.189 (4.8)
0.020 (0.51)
0.013 (0.33)
0.0098 (0.249)
0.0040 (0.102)
0°–8°
SEATING
PLANE
45°
0.010 (0.25)
0.007 (0.18)
0.050 (1.27)
0.016 (0.40)
0.244 (6.20)
0.228 (5.79)
8-Pin SOIC (M)
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MIC4451/4452
Package Information (Continued)
5-Pin TO-220 (T)
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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 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
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
indemnify Micrel for any damages resulting from such use or sale.
© 1998 Micrel, Incorporated.
October 2011
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