MIC4421AYM-TR [MICROCHIP]
9A BUF OR INV BASED MOSFET DRIVER, PDSO8;
| 型号： | MIC4421AYM-TR |
| 厂家： | 
MICROCHIP |
| 描述： | 9A BUF OR INV BASED MOSFET DRIVER, PDSO8 驱动 CD 光电二极管 接口集成电路 驱动器 |
| 文件： | 总12页 (文件大小：365K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
MIC4421A/4422A
9A Peak Low-Side MOSFET Driver
Bipolar/CMOS/DMOS Process
General Description
Features
MIC4421A and MIC4422A MOSFET drivers are rugged,
efficient, and easy to use. The MIC4421A is an inverting
driver, while the MIC4422A is a non-inverting driver.
High peak-output current: 9A Peak (typ.)
Wide operating range: 4.5V to 18V (typ.)
Minimum pulse width: 50ns
Both versions are capable of 9A (peak) output and can
drive the largest MOSFETs with an improved safe
operating margin. The MIC4421A/4422A 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.
Latch-up proof: fully isolated process is inherently
immune to any latch-up
Input will withstand negative swing of up to 5V
High capacitive load drive: 47,000pF
Low delay time: 15ns (typ.)
Logic high input for any voltage from 2.4V to VS
Low equivalent input capacitance: 7pF (typ.)
Low supply current: 500µA (typ.)
MIC4421A/4422A drivers can replace three or more
discrete components, reducing PCB area requirements,
simplifying product design, and reducing assembly cost.
Output voltage swing to within 25mV of GND or VS
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.
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
Data sheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
___________________________________________________________________________________________________________
Typical Application
Low-Side Power Switch
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
M9999-080112
August 2012
Micrel, Inc.
MIC4421A/4422A
Ordering Information
Part Number
MIC4421AXM*
MIC4421AYM
MIC4421AZM
MIC4421AYN
MIC4421AZN
Configuration
Inverting
Temperature Range
–55° to +125°C
–40° to +85°C
0° to +70°C
Package
8-Pin SOIC
8-Pin SOIC
8-Pin SOIC
8-Pin PDIP
8-Pin PDIP
5-Pin TO-220
8-Pin SOIC
8-Pin SOIC
8-Pin SOIC
8-Pin PDIP
8-Pin PDIP
5-Pin TO-220
Inverting
Inverting
Inverting
–40° to +85°C
0° to +70°C
Inverting
MIC4421AZT
Inverting
0° to +70°C
MIC4422AXM*
MIC4422AYM
MIC4422AZM
MIC4422AYN
MIC4422AZN
Non-Inverting
Non-Inverting
Non-Inverting
Non-Inverting
Non-Inverting
Non-Inverting
–55° to +125°C
–40° to +85°C
0° to +70°C
–40° to +85°C
0° to +70°C
MIC4422AZT
0° to +70°C
* Special order. Contact factory.
Pin Configuration
8-Pin PDIP (N)
8-Pin SOIC (M)
5-Pin TO-220 (T)
Pin Description
Pin Number
Pin Number
DIP, SOIC
Pin Name
Pin Name
Control Input.
TO-220-5
2
1
2, 4
3, TAB
5
IN
GND
VS
4, 5
1, 8
6, 7
3
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.
OUT
NC
—
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MIC4421A/4422A
Absolute Maximum Ratings(1)
Operating Ratings(2)
Supply Voltage (VS)......................................................+20V
Control Input Voltage (VIN). ............. VS + 0.3V to GND – 5V
Control Input Current (VIN > VS). .................................50mA
Power Dissipation, TA < +25°C(4)
PDIP (JA) ........................................................1478mW
SOIC (JA)..........................................................767mW
TO-220 (JA)........................................................1756W
Lead Temperature (soldering, 10sec.)....................... 300°C
Storage Temperature (Ts) .........................–65°C to +150°C
ESD Rating(3)..................................................................2kV
Supply Voltage (VS)....................................... +4.5V to +18V
Ambient Temperature (TA)
X Version ............................................–55°C to +125°C
Y Version ..............................................–40°C to +85°C
Z Version ..................................................0°C to +70°C
Junction Temperature (TJ) ......................................... 150°C
Package Thermal Resistance(4)
PDIP (JA) .......................................................84.6°C/W
SOIC (JA).....................................................163.0°C/W
TO-220 (JA)....................................................71.2°C/W
PDIP (JC) .......................................................41.2°C/W
SOIC (JC).......................................................38.8°C/W
TO-220 (JC) .....................................................6.5°C/W
Electrical Characteristics
TA = 25°C with 4.5V ≤ VS ≤ 18V, bold values indicate for X Version: –55°C< TA < +125°C, for Y Version: –40°C< TA <
+85°C, and for Z Version: 0°C< TA < +70°C, unless noted.
Symbol
Parameter
Condition
Min
4.5
Typ
Max
18
Units
Power Supply
VS
IS
Operating Input Voltage
V
0.5
50
1.5
3
mA
mA
High Output Quiescent Current VIN = 3V (MIC4422A), VIN = 0 (MIC4421A)
150
200
µA
µA
Low Output Quiescent Current
VIN = 0V (MIC4422A), VIN = 3V (MIC4421A)
Input
VIH
Logic 1 Input Voltage
Logic 0 Input Voltage
Input Voltage Range
Input Current
See Figure 3
See Figure 3
3.0
2.1
1.5
V
V
VIL
0.8
VS+0.3
10
VIN
–5
V
IIN
0V ≤ VIN ≤ VS
–10
µA
Output
VOH
VOL
High Output Voltage
Low Output Voltage
See Figure 1
See Figure 1
VS+.025
V
V
0.025
Output Resistance,
Output High
0.6
0.8
1.0
3.6
Ω
Ω
IOUT = 10mA, VS = 18V
RO
Output Resistance,
Output Low
1.7
2.7
Ω
Ω
IOUT = 10mA, VS = 18V
VS = 18V (See Figure 8)
IPK
IDC
Peak Output Current
9
2
A
A
Continuous Output Current
Latch-Up Protection
Withstand Reverse Current
Duty Cycle ≤ 2%
t ≤ 300µs(5)
>1500
mA
IR
Switching Time(5)
20
24
15
75
120
ns
ns
tR
Rise Time
Test Figure 1, CL = 10,000pF
Test Figure 1, CL = 10,000pF
Test Figure 1
75
120
ns
ns
tF
Fall Time
68
80
ns
ns
tD1
Delay Time
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MIC4421A/4422A
Symbol
Parameter
Condition
Min
Typ
Max
Units
Switching Time(5) continued
35
60
80
ns
ns
tD2
Delay Time
Test Figure 1
tPW
fmax
Minimum Input Pulse Width
Maximum Input Frequency
See Figure 1 and Figure 2.
See Figure 1 and Figure 2.
50
1
ns
MHz
Notes:
1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating rating.
3. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5kΩ in series with 100pF.
4. Minimum footprint.
5. Guaranteed by design.
Test Circuit
Figure 1. Inverting Driver Switching Time
Figure 2. Non-Inverting Driver Switching Time
Control Input Behavior
Figure 3. Input Hysteresis
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MIC4421A/4422A
Typical Characteristics
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MIC4421A/4422A
Typical Characteristics (continued)
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Micrel, Inc.
MIC4421A/4422A
Functional Diagram
Figure 4. MIC4421A/22A Block Diagram
which must sink 0.4mA from the two current sources.
The higher current through Q1 causes a larger drain-to-
source voltage drop across Q1. A slightly higher control
voltage is required to pull the input of the first inverter
down to its threshold.
Functional Description
Refer to the functional diagram.
The MIC4422A is a non-inverting driver. A logic high on
the IN produces gate drive output. The MIC4421A is an
inverting driver. A logic low on the IN produces gate
drive output. The output is used to turn on an external N-
channel MOSFET.
Q2 turns off after the first inverter output goes high. This
reduces the current through Q1 to 0.1mA. The lower
current reduces the drain-to-source voltage drop across
Q1. A slightly lower control voltage will pull the input of
the first inverter up to its threshold.
Supply
VS (supply) is rated for +4.5V to +18V. External
capacitors are recommended to decouple noise.
Drivers
The second (optional) inverter permits the driver to be
manufactured in inverting and non-inverting versions.
Input
IN (control) is a TTL-compatible input. IN must be forced
high or low by an external signal. A floating input will
cause unpredictable operation.
The last inverter functions as a driver for the output
MOSFETs Q3 and Q4.
A high input turns on Q1, which sinks the output of the
0.1mA and the 0.3mA current source, forcing the input of
the first inverter low.
Output
OUT is designed to drive a capacitive load. VOUT (output
voltage) is either approximately the supply voltage or
approximately ground, depending on the logic state
applied to IN.
Hysteresis
The control threshold voltage, when IN is rising, is
slightly higher than the control threshold voltage when
CTL is falling.
If IN is high, and VS (supply) drops to zero, the output
will be floating (unpredictable).
When IN is low, Q2 is on, which applies the additional
0.3mA current source to Q1. Forcing IN high turns on Q1
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MIC4421A/4422A
To guarantee low supply impedance over a wide
frequency range, a parallel capacitor combination is
recommended for supply bypassing. Low inductance
ceramic disk capacitor 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.
Application 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 MIC4421A/4422A 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.
Grounding
The high current capability of the MIC4421A/4422A
demands careful PC board layout for best performance.
Since the MIC4421A 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 MIC4421A
input structure includes about 600mV of hysteresis to
ensure clean transitions and freedom from oscillation,
but attention to layout is still recommended.
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.
Figure 5 shows the feedback effect in detail. As the
MIC4421A input begins to go positive, the output goes
negative and several amperes of current flow in the
ground lead. As little as 0.05ꢀ of PC trace resistance
can produce hundreds of millivolts at the MIC4421A
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 MIC4421A
GND pins will ensure full logic drive to the input and
ensure fast output switching. Both of the MIC4421A
GND pins should, however, still be connected to power
ground.
Figure 5. Switching Time Due to Negative Feedback
Table 1. MIC4421A Maximum Operating Frequency
VS
Max Frequency
220kHz
18V
15V
10V
5V
300kHz
640kHz
2MHz
Conditions:
1. JA = 150°C/W
θ
2. TA = 25°C
3. CL = 10,000pF
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MIC4421A/4422A
Input Stage
example, the thermal resistance of the 8-pin plastic DIP
package, from the data sheet, is 84.6°C/W. In a 25°C
ambient, then, using a maximum junction temperature of
150°C, this package will dissipate 1478mW.
The input voltage level of the MIC4421A changes the
quiescent supply current. The N-Channel MOSFET input
stage transistor drives a 320µA current source load. With
a logic “1” input, the quiescent supply current is typically
500µA. Logic “0” input level signals reduce quiescent
current to 80µA typical.
Accurate power dissipation numbers can be obtained by
summing the three sources of power dissipation in the
device:
The MIC4421A/4422A input is designed to provide
600mV 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.
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.
Resistive Load Power Dissipation
The MIC4421A can be directly driven by the TL494,
SG1526/1527, SG1524, TSC170, MIC38C42, and
similar switch mode power supply integrated circuits. By
off loading the power-driving duties to the MIC4421A/
4422A, the power supply controller can operate at lower
dissipation. This can improve performance and reliability.
Dissipation caused by a resistive load can be calculated
as:
PL = I2 RO D
where:
I =
the current drawn by the load
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 MIC4421A/4422A however, and
it will not latch.
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).
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 1kꢀ resistor.
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:
Power Dissipation
E = 1/2 C V2
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
MIC4421A/4422A 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.
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
Load Capacitance
The supply current vs. frequency and supply current vs.
capacitive load characteristic curves aid in determining
C =
VS =
power dissipation calculations. Table
1
lists the
Driver Supply Voltage
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.
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:
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
P
L1 = I2 RO D
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MIC4421A/4422A
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:
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 + PT
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:
Definitions
CL =
D =
Load Capacitance in Farads.
PL = P L1 + P L2
Duty Cycle expressed as the fraction of time
the input to the driver is high.
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; logic high will result in a current
drain of ≤ 3.0mA.
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.
Quiescent power can therefore be found from:
PQ = VS [D IH + (1 – D) IL]
where:
ID =
Output current from a driver in Amps.
IH =
IL =
Quiescent current with input high
Quiescent current with input low
Fraction of time input is high (duty cycle)
Power supply voltage
PD =
PL =
Total power dissipated in a driver in Watts.
Power dissipated in the driver due to the
driver’s load in Watts.
D =
VS =
PQ =
PT =
Power dissipated in a quiescent driver in
Watts.
Transition Power Dissipation
Power dissipated in a driver when the output
changes states (“shoot-through current”) in
Watts.
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
RO =
Output resistance of a driver in Ohms.
VS = Power supply voltage to the IC in Volts.
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Micrel, Inc.
MIC4421A/4422A
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
0.380 (9.65)
0.320 (8.13)
0.018 (0.57)
0.100 (2.54)
0.130 (3.30)
0.0375 (0.952)
8-Pin Plastic DIP (N)
8-Pin SOIC (M)
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Micrel, Inc.
MIC4421A/4422A
5-Pin TO-220 (T)
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
The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its
use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer.
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.
© 2002 Micrel, Incorporated.
M9999-080112
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