MIC22200 Datasheet, PDF (16/22 Pages) Micrel Semiconductor – 2A Integrated Switch Synchronous Buck Regulator with Frequency Programmable from 800kHz to 4MHz

Micrel, Inc.
Rθ_JA is a combination of junction-to-case thermal
resistance (Rθ_JC) and case-to-ambient thermal
resistance (Rθ_CA), since thermal resistance of the solder
connection from the ePAD to the PCB is negligible; Rθ_CA
is the thermal resistance of the ground plane to ambient,
so Rθ_JA = Rθ_JC + Rθ_CA.
VOUT
@2A
1
1.2
1.8
2.5
3.3
VIN
3V
0.86822
0.87796
0.93972
0.91848
—
VIN
3.5V
0.81512
0.8247
0.86722
0.90504
—
VIN
4V
0.7836
0.79362
0.82568
0.85466
0.8764
VIN
4.5V
0.77014
0.77956
0.8095
0.83296
0.842
VIN
5V
0.76194
0.76842
0.80076
0.81846
0.8326
Table 3. Power Dissipation (W) for 2A Output
MIC22200
T_A is the Operating Ambient temperature.
Example:
To calculate the junction temperature for a 50°C
ambient:
T_J = T_A + P_DI . Rθ_JA
T_J = 50 + 0.8 x 40
T_J = 82°C
This is below the maximum of 125°C.
V_OUT
1.1V
1.3V
1.8V
4.2V
L
3.3µH
1.5µH
2.2µH
1.5µH
C_OUT
2 x 47µF
2 x 47µF
2 x 47µF
2 x 47µF
C_COMP
100pF
100pF
100pF
100pF
V_IN = 5V
R_COMP
5k Ω
5k Ω
5k Ω
20k Ω
C_FF
N.U.
1nF
1nF
1nF
R_FF
4.7k Ω
4.7k Ω
4.7k Ω
4.7k Ω
C_FB
100pF
100pF
100pF
100pF
R_FB
8.2k Ω
5.49k Ω
3.0k Ω
953 Ω
Table 4. Compensation Selection
Figure 14. Table 4 Schematic Reference
December 2010
16
M9999-120310-C