MIC47300
3A, Low Voltage, Adjustable LDO
Regulator with Dual Input Supply
General Description
The MIC47300 is a high-bandwidth, low-dropout, 3A volt-
age regulator ideal for powering core voltages of low-
power microprocessors. The MIC47300 implements a dual
supply configuration allowing for very low output
impedance and very fast transient response.
The MIC47300 requires a bias input supply between 3V
and 6.5V for proper operation. The main input supply rail
operates from 1.4V to 6.5V that allows for adjustable
output voltages down to 0.9V.
The MIC47300 requires a minimum of 1µF output
capacitance for stability, and optimal operation is achieved
with small ceramic capacitors.
The MIC47300 is available in a 5-pin power D-Pak
package (TO-252) with an operating temperature range of
–40°C to +125°C.
Datasheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
Features
•
Input Voltage Range:
– V
IN
: 1.4V to 6.5V
– V
BIAS
: 3.0V to 6.5V
•
Stable with 1µF ceramic capacitor
•
±1% initial tolerance
•
Maximum dropout voltage (V
IN
–V
OUT
) of 400mV
over temperature
•
Adjustable output voltage down to 0.9V
•
Ultra fast transient response (Up to 10MHz bandwidth)
•
Excellent line and load regulation specifications
•
Power D-Pak package (TO-252)
•
Thermal shutdown and current-limit protection
•
Junction temperature range: –40°C to 125°C
Applications
•
•
•
•
•
•
Graphics processors
PC add-in cards
Microprocessor core voltage supply
Low voltage digital ICs
High efficiency linear power supplies
SMPS post regulators
__________________________________________________________________________________________
Typical Application*
Figure 1. Typical Application Circuit
*See Thermal Design Section
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
October 2009
M9999-102309-A
Micrel, Inc.
MIC47300
Ordering Information
Part Number
MIC47300WD*
Note:
* RoHs compliant with ‘high-melting solder’ exemption.
Output Current
3A
Voltage
Adjustable
Junction Temp. Range
–40° to +125°C
Package
5-Pin TO-252
Pin Configuration
5-Pin TO-252 D-Pak (D)
Pin Description
Pin Number
1
2
3
4
5
Pin Name
ADJ
BIAS
GND, TAB
IN
OUT
Pin Name
Adjustable Regulator Feedback Input: Connect to the resistor voltage divider that is
placed from OUT to GND in order to set the output voltage.
Input Bias Voltage: Voltage for powering all internal circuitry of the regulator with the
exception of the output power device.
Ground: TAB is also connected internally to the IC’s ground on D-Pak.
Input Voltage: Supplies the current to the output power device
Regulator Output: The output voltage is set by the resistor divider connected from OUT
to GND (with the divided connection tied to ADJ). A minimum value capacitor must be
used to maintain stability. See Applications Information.
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MIC47300
Absolute Maximum Ratings
(1)
Supply Voltage (V
IN
) .........................................................8V
Bias Supply Voltage (V
BIAS
)..............................................8V
Power Dissipation .....................................Internally Limited
ESD Rating
(3)
.................................................................. 2kV
Operating Ratings
(2)
Supply Voltage (V
IN
)......................................... 1.4V to 6.5V
Bias Supply Voltage (V
BIAS
)................................. 3V to 6.5V
Junction Temperature (T
J
) ..................–40°C
≤
T
J
≤
+125°C
Maximum Power Dissipation.....................................
Note 4
Package Thermal Resistance
TO-252 (θ
JC
) ........................................................3°C/W
TO-252 (θ
JA
).......................................................56°C/W
Electrical Characteristics
(5)
V
IN
= V
OUT
+ 1V, V
BIAS
= V
OUT
+ 2.1V,
I
OUT
= 10mA; T
A
= 25°C, bold values indicate –40°C≤ T
J
≤
+125°C, unless noted.
Symbol
V
LNREG
V
LDREG
V
DO
V
DO(BIAS)
I
GND
I
BIAS
I
LIM
T
SD
Parameter
Line Regulation
Load Regulation
Dropout Voltage (V
IN
-V
OUT
)
Dropout Voltage (V
BIAS
- V
OUT
)
Note 6
Ground Pin Current,
Note 7
Current thru V
BIAS
Current Limit
Thermal Shutdown
Thermal Shutdown Hysteresis
Reference (Adjust Pin)
V
ADJ
I
ADJ
Notes:
1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating rating.
3. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5kΩ in series with 100pF.
4. P
D(MAX)
= (T
J(MAX)
– T
A
) /
θ
JA
, where
θ
JA
, depends upon the printed circuit layout. See “Applications Information.”
5. Specification for packaged product only.
6. For V
OUT
≤1V,
V
BIAS
dropout specification does not apply due to a minimum 3V V
BIAS
input.
7. I
GND
= I
BIAS
+ (I
IN
– I
OUT
). At high loads, input current on V
IN
will be less than the output current, due to drive current being supplied by V
BIAS
.
Condition
V
IN
= V
OUT
+1V to 6.5V
I
OUT
= 10mA to A
I
OUT
= 1.5A
I
OUT
= 3A
I
OUT
= 3A
I
OUT
= 10mA
I
OUT
= 3A
I
OUT
= 10mA
I
OUT
= 3A
V
OUT
= 0V
Min
–0.1
Typ
0.01
0.2
105
230
1.24
25
25
20
50
6.5
168
10
Max
+0.1
0.5
200
400
2.1
Units
%/V
%
mV
mV
V
mA
mA
mA
mA
A
°C
°C
50
35
150
10
Reference Voltage
Adjust Pin Current
V
ADJ
= 1.2V
0.891
0.882
0.9
0.01
0.909
0.918
1
V
V
μA
October 2009
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M9999-102309-A
Micrel, Inc.
MIC47300
Typical Characteristics
October 2009
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M9999-102309-A
Micrel, Inc.
MIC47300
Typical Characteristics
(continued)
October 2009
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M9999-102309-A
嵌入式系统
