mic49200 Micrel Semiconductor, mic49200 Datasheet - Page 11

• Manufacturer Part Number: mic49200
• Description: Mic49200 2a Low Voltage Ldo With Dual Input Voltages
• Manufacturer: Micrel Semiconductor

January 2006
The heat sink may be significantly reduced in
applications where the maximum input voltage is
known and large compared with the dropout voltage.
Use a series input resistor to drop excessive voltage
and distribute the heat between this resistor and the
regulator.
MIC49200 allow significant reductions in regulator
power dissipation and the associated heat sink
without
technique is employed, a capacitor of at least 1µF is
needed directly between the input and regulator
ground. Refer to “
and examples on thermal design and heat sink
specification.
Minimum Load Current
The MIC49200, unlike most other high current
regulators, does not require a minimum load to
maintain output voltage regulation.
compromising
The
Application Note 9
low-dropout
performance.
properties
” for further details
When
of
this
the
11
Adjustable Regulator Design
The
programming the output voltage anywhere between
0.9V and 5V. Two resistors are used. The resistor
value between V
exceed 10kΩ. Larger values can cause instability. The
resistor values are calculated by:
Where V
Enable
The fixed output voltage versions of the MIC49200
feature an active high enable input (EN) that allows
on-off control of the regulator. Supply currents reduce
to “zero” when the device is in shutdown, with only
microamperes of leakage current. The EN input has
TTL/CMOS compatible thresholds for simple logic
interfacing. EN may be directly tied to V
up to the maximum supply voltage.
MIC49200
OUT
is the desired output voltage.
V
OUT
OUT
adjustable
and the adjust pin should not
=
0.9
⎛
⎜ ⎜
⎝
R
R
2
1
+
1
⎞
⎟ ⎟
⎠
version
[phone]
M9999-011306
IN
and pulled
allows