MIC2169B_10 Datasheet, PDF (10/25 Pages) Micrel Semiconductor – 500kHz PWM Synchronous Buck Control IC

Micrel, Inc.
The following graphs are used to determine the
maximum gate charge that can be driven with respect to
supply voltage and ambient temperature. Figure 2 shows
the power dissipation in the driver for different values of
gate charge.
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
0
12Vin
5Vin
20
40
60
80 100
GATE CHARGE (nC)
Figure 2. Power Dissipation vs. Total Gate Charge
Figure 3 shows the maximum allowable power
dissipation vs ambient temperature. For a given total
gate charge, the maximum operating ambient
temperature can be found by using the two graphs.
140
120
100
80
60
40
20
0
0.0
MSOP
ePAD
MSOP
0.2 0.4 0.6 0.8 1.0 1.2
POWER DISSIPATION (W)
Figure 3. Maximum Ambient Temperature vs.
Power Dissipation
MIC2169B
Figures 4 and 5 show the increase in junction and case
temperature for a given power dissipation.
60
50
40
MSOP
30
20
ePAD
MSOP
10
0
0.0 0.2 0.4 0.6 0.8 1.0 1.2
POWER DISSIPATION (W)
Figure 4. Case Temperature Rise vs.
Power Dissipation
120
100
MSOP
80
60
ePAD
MSOP
40
20
0
0.0 0.2 0.4 0.6 0.8 1.0 1.2
POWER DISSIPATION (W)
Figure 5. Junction Temperature Rise vs.
Power Dissipation
April 2010
10
M9999-041210-B