Freelance Electronics Components Distributor
Closed Dec 25th-26th
800-300-1968
We Stock Hard to Find Parts

MIC29301-5.0WT

Part # MIC29301-5.0WT
Description LDO Regulator Pos 5V 3A Automotive 5-Pin(5+Tab) TO-220
Category RECTIFIER
Availability In Stock
Qty 2
Qty Price
1 + $1.93957
Manufacturer Available Qty
Micrel
Date Code: 0621
  • Shipping Freelance Stock: 2
    Ships Immediately



Technical Document


DISCLAIMER: The information provided herein is solely for informational purposes. Customers must be aware of the suitability of this product for their application, and consider that variable factors such as Manufacturer, Product Category, Date Codes, Pictures and Descriptions may differ from available inventory.

Micrel, Inc. MIC29150/29300/29500/29750
May 2010 16
M9999-050510-B
Functional Diagram
Micrel, Inc. MIC29150/29300/29500/29750
May 2010 17
M9999-050510-B
Application Information
The MIC29150/29300/29500/29750 are high
performance low-dropout voltage regulators suitable for
all moderate to high-current voltage regulator
applications. Their 350mV to 425mV typical dropout
voltage at full load make them especially valuable in
battery powered systems and as high efficiency noise
filters in “post-regulator” applications. Unlike older NPN-
pass transistor designs, where the minimum dropout
voltage is limited by the base-emitter voltage drop and
collector-emitter saturation voltage, dropout performance
of the PNP output of these devices is limited merely by
the low V
CE
saturation voltage.
A trade-off for the low-dropout voltage is a varying base
driver requirement. But Micrel’s Super ßeta PNP
®
process reduces this drive requirement to merely 1% of
the load current.
The MIC29150/29300/29500/29750 family of regulators
are fully protected from damage due to fault conditions.
Current limiting is provided. This limiting is linear; output
current under overload conditions is constant. Thermal
shutdown disables the device when the die temperature
exceeds the 125°C maximum safe operating
temperature. Transient protection allows device (and
load) survival even when the input voltage spikes
between –20V and +60V. When the input voltage
exceeds about 35V to 40V, the over voltage sensor
temporarily disables the regulator. The output structure
of these regulators allows voltages in excess of the
desired output voltage to be applied without reverse
current flow. MIC29xx1 and MIC29xx2 versions offer a
logic level ON/OFF control: when disabled, the devices
draw nearly zero current.
An additional feature of this regulator family is a common
pinout: a design’s current requirement may change up or
down yet use the same board layout, as all of these
regulators have identical pinouts.
MIC29XXX
OUT
V
OU
T
IN
GND
V
IN
Figure 3. Linear regulators require only two capacitors for
operation.
Thermal Design
Linear regulators are simple to use. The most
complicated design parameters to consider are thermal
characteristics. Thermal design requires the following
application-specific parameters:
Maximum ambient temperature, T
A
Output Current, I
OUT
Output Voltage, V
OUT
Input Voltage, V
IN
First, we calculate the power dissipation of the regulator
from these numbers and the device parameters from this
datasheet.
(
)
OUTINOUTD
V V1.01IP
=
Where the ground current is approximated by 1% of I
OUT
.
Then the heat sink thermal resistance is determined with
this formula:
()
CSJC
D
AJMAX
SA
P
TT
θ+θ
=θ
Where T
JMAX
125°C and θ
CS
is between 0 and 2°C/W.
The heat sink may be significantly reduced in
applications where the minimum input voltage is known
and is 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. The low-dropout properties of Micrel Super
ßeta PNP
®
regulators allow very significant reductions in
regulator power dissipation and the associated heat sink
without compromising performance. When this technique
is employed, a capacitor of at least 0.1µF is needed
directly between the input and regulator ground.
Please refer to Application Note 9 and Application Hint
17 for further details and examples on thermal design
and heat sink specification.
With no heat sink in the application, calculate the
junction temperature to determine the maximum power
dissipation that will be allowed before exceeding the
maximum junction temperature of the MIC29152. The
maximum power allowed can be calculated using the
thermal resistance (θ
JA
) of the D-Pak adhering to the
following criteria for the PCB design: 2 oz. copper and
100mm
2
copper area for the MIC29152.
For example, given an expected maximum ambient
temperature (T
A
) of 75°C with V
IN
= 3.3V, V
OUT
= 2.5V,
and I
OUT
= 1.5A, first calculate the expected P
D
using
Equation (1);
P
D
=(3.3V–2.5V)1.5A–(3.3V)(0.016A)=1.1472W
Next, calcualte the junction temperature for the expected
power dissipation.
T
J
=(θ
JA
×P
D
)+T
A
=(56°C/W×1.1472W)+75°C=139.24°C
Now determine the maximum power dissipation allowed
that would not exceed the IC’s maximum junction
temperature (125°C) without the useof a heat sink by
P
D(MAX)
=(T
J(MAX)
–T
A
)/θ
JA
=(125°C–75°C)/(56°C/W) =0.893W
Micrel, Inc. MIC29150/29300/29500/29750
May 2010 18
M9999-050510-B
Capacitor Requirements
For stability and minimum output noise, a capacitor on
the regulator output is necessary. The value of this
capacitor is dependent upon the output current; lower
currents allow smaller capacitors. The
MIC29150/29300/29500/29750 regulators are stable
with the following minimum capacitor values at full load:
Device Full Load Capacitor
MIC29150...............................................10µF
MIC29300...............................................10µF
MIC29500...............................................10µF
MIC29750...............................................22µF
This capacitor need not be an expensive low ESR type:
aluminum electrolytics are adequate. In fact, extremely
low ESR capacitors may contribute to instability.
Tantalum capacitors are recommended for systems
where fast load transient response is important.
Where the regulator is powered from a source with a
high AC impedance, a 0.1µF capacitor connected
between Input and GND is recommended. This capacitor
should have good characteristics to above 250kHz.
Minimum Load Current
The MIC29150–29750 regulators are specified between
finite loads. If the output current is too small, leakage
currents dominate and the output voltage rises. The
following minimum load current swamps any expected
leakage current across the operating temperature range:
Device Minimum Load
MIC29150................................................5mA
MIC29300................................................7mA
MIC29500..............................................10mA
MIC29750..............................................10mA
Adjustable Regulator Design
R1
R2
V
IN
V
OUT
MIC29152BT
22µF
10µF
Figure 4. Adjustable Regulator with Resistors
The adjustable regulator versions, MIC29xx2 and
MIC29xx3, allow programming the output voltage
anywhere between 1.25V and the 25V. Two resistors are
used. The resistor values are calculated by:
×= 1
1.240
V
RR
OUT
21
where V
OUT
is the desired output voltage. Figure 4 shows
component definition. Applications with widely varying
load currents may scale the resistors to draw the
minimum load current required for proper operation (see
“Minimum Load Current” section).
Error Flag
MIC29xx1 and MIC29xx3 versions feature an Error Flag,
which looks at the output voltage and signals an error
condition when this voltage drops 5% below its expected
value. The error flag is an open-collector output that
pulls low under fault conditions. It may sink 10mA. Low
output voltage signifies a number of possible problems,
including an overcurrent fault (the device is in current
limit) and low input voltage. The flag output is inoperative
during overtemperature shutdown conditions.
Enable Input
MIC29xx1 and MIC29xx2 versions feature an enable
(EN) input that allows ON/OFF control of the device.
Special design allows “zero” current drain when the
device is disabled—only microamperes of leakage
current flows. The EN input has TTL/CMOS compatible
thresholds for simple interfacing with logic, or may be
directly tied to 30V. Enabling the regulator requires
approximately 20µA of current.
PREVIOUS12345678NEXT