MIC5216-3.2BMM Micrel Inc, MIC5216-3.2BMM Datasheet - Page 10

• Manufacturer Part Number: MIC5216-3.2BMM
• Description: IC REG LDO 500MA 1% 3.2V 8-MSOP
• Manufacturer: Micrel Inc

Specifications of MIC5216-3.2BMM

• Regulator Topology: Positive Fixed
• Voltage - Output: 3.2V
• Voltage - Input: Up to 12V
• Voltage - Dropout (typical): 0.3V @ 500mA
• Number Of Regulators: 1
• Current - Output: 500mA
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-MSOP, Micro8™, 8-uMAX, 8-uSOP,
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Current - Limit (min): -

With an output current of 500mA and a three-volt drop
across the MIC5216-xxBMM, the maximum duty cycle is
27.4%.
Applications also call for a set nominal current output
with a greater amount of current needed for short
durations. This is a tricky situation, but it is easily
remedied. Calculate the average power dissipation for
each current section, then add the two numbers giving
the total power dissipation for the regulator. For
example, if the regulator is operating normally at 50mA,
but for 12.5% of the time it operates at 500mA output,
the total power dissipation of the part can be easily
determined. First, calculate the power dissipation of the
device at 50mA. We will use the MIC5216-3.3BM5 with
5V input voltage as our example.
Micrel, Inc.
March 2007
% Duty Cycle Max = 27.4%
P
. 0
455mW
D
274
× 50mA = (5V – 3.3V) × 50mA + 5V × 650µA
a. 25
a. 25
=
⎛
⎜
⎝
=
%Duty
⎛
⎜
⎝
°
°
C Ambient
C Ambient
%Duty
100
Figure 1. MIC5216-x.xBM5 (SOT-23-5) on Minimum Recommended Footprint
100
Cycle
Cycle
Figure 2. MIC5216-x.xBM5 (SOT-23-5) on 1-inch
⎞
⎟
⎠
⎞
⎟
⎠
1.66W
b. 50
b. 50
°
°
C Ambient
C Ambient
10
However, this is continuous power dissipation, the actual
on-time for the device at 50mA is (100%-12.5%) or
87.5% of the time, or 87.5% duty cycle. Therefore, P
must be multiplied by the duty cycle to obtain the actual
average power dissipation at 50mA.
The power dissipation at 500mA must also be
calculated.
This number must be multiplied by the duty cycle at
which it would be operating, 12.5%.
P
P
P
P
P
P
P
D
D
D
D
D
D
D
× 50mA = 173mW
× 50mA = 0.875 × 173mW
× 50mA = 151mW
× 500mA = (5V – 3.3V) 500mA + 5V × 20mA
× 500mA = 950mW
× = 0.125mA × 950mW
× = 119mW
2
Copper Cladding
c. 85
c. 85
°
°
C Ambient
C Ambient
M9999-032307
MIC5216
D