MIC5250 Ver la hoja de datos (PDF) - Micrel
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MIC5250 Datasheet PDF : 12 Pages
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MIC5250
Since the total power dissipation allowable is 325mW, the
maximum power dissipation of the second regulator is limited
to:
PD(max) = PD(reg1) + PD(reg2)
325mW = 180.4mW + PD(reg2)
PD(reg2) = 144.6mW
The maximum output current of the second regulator can be
calculated using the same equations but solving for the
output current (ground current is constant over load and
simplifies the equation):
( ) PD(reg2) = VIN −VOUT IOUT +VIN IGND
144.6mW = (4.2V − 3.0V)IOUT + 4.2V × 100µA
IOUT = 120.5mA
The second output is limited to 120mA due to the total power
dissipation of the system when operating at 60°C ambient
temperature.
Fixed Regulator Applications
MIC5250-3.3BMM
OUTA 10
VINA
9 INA BYPA 1
2 ENA GNDA 3
VINB
7 INB
5 ENB
OUTB 8
BYPB 4
GNDB 6
Micrel
0.01µF
3.3V
1µF
0.01µF
3.3V
1µF
Figure 1. Ultra-Low-Noise Dual 3.3V Application
Figure 1 includes 0.01µF capacitors for low-noise operation
and shows EN (pin 3) connected to IN (pin 1) for an applica-
tions where enable/shutdown is not required. COUT = 1µF
minimum.
MIC5250-3.3BMM
OUTA 10
3.3V
VINA
9 INA BYPA 1
1µF
2 ENA GNDA 3
VINB
7 INB OUTB 8
3.3V
5 ENB BYPB 4
1µF
GNDB 6
Figure 2. Low-Noise Fixed Voltage Application
Figure 2 is an example of a low-noise configuration where
CBYP is not required. COUT = 1µF minimum.
Dual-Supply Operation
When used in dual supply systems where the regulator load
is returned to a negative supply, the output voltage must be
diode clamped to ground.
June 2003
9
MIC5250
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