MIC4452BM Micrel Inc, MIC4452BM Datasheet - Page 9

• Manufacturer Part Number: MIC4452BM
• Description: IC DRIVER MOSF 12A LO SIDE 8SOIC
• Manufacturer: Micrel Inc

Specifications of MIC4452BM

• Rise Time: 20ns
• Mounting Type: Surface Mount
• Configuration: Low-Side
• Input Type: Non-Inverting
• Delay Time: 15ns
• Current - Peak: 12A
• Number Of Configurations: 1
• Number Of Outputs: 1
• Voltage - Supply: 4.5 V ~ 18 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 8-SOIC (3.9mm Width)
• Device Type: MOSFET
• Driver Case Style: SOIC
• No. Of Pins: 8
• Peak Output High Current, Ioh: 12A
• Supply Voltage Min: 4.5V
• Peak Reflow Compatible (260 C): No
• Number Of Drivers: 1
• Driver Configuration: Non-Inverting
• Driver Type: Low Side
• Input Logic Level: CMOS/TTL
• Fall Time: 50ns
• Propagation Delay Time: 60ns
• Operating Supply Voltage (max): 18V
• Peak Output Current: 12mA
• Power Dissipation: 1.04W
• Output Resistance: 0.8Ohm
• Operating Supply Voltage (min): 4.5V
• Turn Off Delay Time: 80fs
• Turn On Delay Time (max): 40ps
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 8
• Package Type: SOIC
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• High Side Voltage - Max (bootstrap): -
• Lead Free Status / RoHS Status: Not Compliant, Contains lead / RoHS non-compliant

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
current will flow into the input lead. The input currents
can be as high as 30mA p-p (6.4mA
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.
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.
Micrel Inc.
January 2011
RMS
S
supply, however,
) with the input.
9
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:
•
•
•
Calculation of load power dissipation differs depending
on whether the load is capacitive, resistive or inductive.
GROUND
GROUND
Figure 5. Switching Time Degradation Due to Negative
POWER
LOGIC
Load Power Dissipation (P
Quiescent power dissipation (P
Transition power dissipation (P
0 V
5.0V
0.1µF
300 mV
+18
MIC4451
1
4
12 AMPS
8
5
Feedback
PC TRACE RESISTANCE = 0.05Ω
6, 7
WIMA
MKS-2
1 µF
L
TEK CURRENT
0.1µF
)
PROBE 6302
T
Q
)
)
MIC4451/4452
M9999-011811
2,500 pF
POLYCARBONATE
18 V
0 V