MIC22602 Datasheet, PDF (16/24 Pages) Micrel Semiconductor – 1MHz, 6A Integrated Switch High Efficiency Synchronous Buck Regulator

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.
VINÆ
VOUT
@6AÈ
0.7V
1.2V
1.8V
2.5V
3.3V
2.6V 3.3V 3.6V 4.5V 5.5V 5.5V
1.41
1.43
1.48
------
------
1.269
1.276
1.292
1.295
------
1.209
1.220
1.230
1.228
1.216
1.192
1.206
1.221
1.215
1.208
1.198
1.207
1.218
1.224
1.201
1.202
1.214
1.231
1.230
1.224
Table 1. Power Dissipation (W) for 6A output
• T_AMB is the Operating Ambient temperature.
MIC22602
Example:
The Evaluation board has two copper planes
contributing to an Rθ_JA of approximately 25°C/W. The
worst case Rθ_JC of the MLF 4x4 is 14^oC/W.
Rθ_JA = Rθ_JC + Rθ_CA
Rθ_JA = 14 + 25 = 39^oC/W
To calculate the junction temperature for a 50°C
ambient:
T_J = T_AMB+P_DISS . Rθ_JA
T_J = 50 + (1.5 x 39)
T_J = 109°C
This is below the maximum of 125°C.
October 2009
16
M9999-102809-A