MIC37300/01/02/03
3.0A, Low-Voltage µCap LDO Regula tor
Super ßeta PNP is a registered trademark of Micrel, Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
February
24, 2015
Revision 2.0
General Description
The Micrel MIC37300/01/02/03 is a 3.0A low-dropout
linear voltage regulator that provides a low voltage, high
current output with a minimum number of external
components. It offers high precision, ultra-low dropout
(500mV over temperature), and low ground current.
The MIC37300/01/02/03 operates from an input of 2.25V
to 6.0V. I t is desi gned to dr ive digital circuits r equiring low-
voltage at high currents (i.e., PLDs, DSP, microcontroller,
etc.). It is available in fixed and adjustable output voltages.
Fixed voltages include 1.5V, 1.8V, 2.5V, and 3.3V. The
adjustable version is capable of 1.24V to 5.5V.
Features of the MIC37300/01/02/03 LDO include thermal
and current-l imit protec tio n, and rev er se-c ur rent pr otection.
Logic enable and error flag pins are available on the 5-pin
version.
Junction temperature range of the MIC37300/01/02/03 is
from –40°C to +125°C.
For applications requiring input voltage greater than 6.0V,
see the MIC3910x, MIC3915x, MIC3930x, and MIC3950x
LDOs.
Datasheets and support documentation are available on
Micrel’s webs ite at : www.micrel.com.
Features
• 3.0A minimum guaranteed output current
• 500mV maximum dropout voltage over temperature
− Ideal for 3.0V to 2.5V conversion
− Ideal for 2.5V to 1.8V, 1.65V, or 1.5V conversion
• Stable with ceramic or tantalum capacitor
• Wide input voltage range
− VIN: 2.25V to 6.0V
• +1.0% initial output tolerance
• Fixed and adjustable output v oltages:
− MIC37300: 3-pin S-Pak fixed voltages
− MIC37301: 5-pin S-Pak or 8-pin ePad SOIC fixed
voltages with flag
− MIC37302: 5-pin adjus tab le voltage
− MIC37303: 8-pin eP ad SOIC, DFN adjustable voltage
with flag
• Excellent line and load regulation specifications
• Thermal-shutdown and current-limit protection
• Reverse-leakage protec ti on
• Low profile S-Pak package
Applications
• LDO linear regulator for low-voltage digital IC
• PC add-in cards
• High-efficiency linear power supplies
• SMPS post regulator
• Battery charger
Typical Application
Fixed 2.5 Regulator
Adjustable Regulator
Micrel, Inc.
MIC37300/01/02/03
February
24, 2015 2 Revision 2.0
Ordering Information
Part number Enable Voltage Flag Junction
Temperature
Range Package
RoHS Compliant
(1)
/
Pb-Free
MIC37300-1.5WR(1) No 1.5V No –40°C to +125°C S-Pak-3
MIC37300-1.65WR(1) No 1.65V No –40°C to +125°C S-Pak-3
MIC37300-1.8WR
(1)
No 1.8V No –40°C to +125°C S-Pak-3
MIC37300-2.5WR
(1)
No 2.5V No –40°C to +125°C S-Pak-3
MIC37300-3.3WR(1) No 3.3V No –40°C to +125°C S-Pak-3
MIC37301-1.5YME Yes 1.5V Yes –40°C to +125°C ePad SOIC-8
MIC37301-1.5WR(1) Yes 1.5V Yes –40°C to +125°C S-Pak-5
MIC37301-1.8YME Yes 1.8V Yes –40°C to +125°C ePad SOIC-8
MIC37301-1.8WR
(1)
Yes 1.8V Yes –40°C to +125°C S-Pak-5
MIC37301-2.5YME Yes 2.5V Yes –40°C to +125°C ePad SOIC-8
MIC37301-2.5WR(1) Yes 2.5V Yes –40°C to +125°C S-Pak-5
MIC37301-3.3WR(1) Yes 3.3V Yes –40°C to +125°C S-Pak-5
MIC37302WR(1) Yes ADJ No –40°C to +125°C S-Pak-5
MIC37302WU(1) Yes ADJ No –40°C to +125°C TO-263-5
MIC37303YME Yes ADJ Yes –40°C to +12 5°C ePad SOIC-8
MIC37303YML Yes ADJ Yes –40°C to +125°C 3mm × 3mm DFN
Note:
1. RoHS-com pl i ant with ‘hi gh-m elti ng solder’ exempt i on.
Micrel, Inc.
MIC37300/01/02/03
February
24, 2015 3 Revision 2.0
Pin Configuration
S-PAK-5 (R)
(Top View)
S-PAK-3 (R)
(Top View)
TO-263-5 (U)
(Top View)
e-Pad SOIC-8 (ME)
(Top View)
3mm × 3mm DFN (ML)
(Top View)
Pin Description
Pin Number
S-PAK-5
TO-263-5
Pin Number
S-PAK-3
Pin Number
ePad SOIC-8
DFN Pin Name Pin Function
1 — 2 EN Enable input: CMOS-compatible input. Logic HIGH = enable;
Logic LOW = shutdown. Do not leave floating.
2 1 3, 4 VIN Input voltage that supplies current to the output power device.
3 2 1 GND Ground: TAB is connected to gr ound .
4 3 5, 6, 7 (Fixed) VOUT Regulator output.
5, 6 (Adj.)
5 (Fixed) — 8 FLG Error flag (output): Open collector output. Active LOW indicates
an output fault condition.
5 (Adj.) — 7 (Adj.) ADJ Adjustable regulator feedb ac k input : Connect to resistor voltage
driver.
— — EP ePad Connect to GND for best thermal performance.
5 FLG/ADJ
4 VOUT
3 GND
2VIN
1 EN
1GND
EN
VIN
VIN
8FLG
VOUT/ADJ
VOUT
VOUT
7
6
5
2
3
4
Micrel, Inc.
MIC37300/01/02/03
February
24, 2015 4 Revision 2.0
Absolute Maximum Ratings(2)
Supply Voltage (VIN) ...................................................... 6.5V
Enable Input Voltage (VEN)(4) ......................................... 6.5V
Power Dissip ati on (PD)(4) ........................... Interna ll y Lim ited
Junction Temperature (TJ) ..................–40°C ≤ TJ ≤ +125°C
Storage Temperature (TS) ...................–65°C ≤ TJ ≤ +150°C
Lead Temperature (soldering, 10s) ............................ 260°C
ESD Rating(5) .................................................................. 2kV
Operating Ratings(3)
Supply Voltage (VIN) ................................ 2.25V to 6.0V
Enable Input Voltage (VEN) ........................... 0V to 6.0V
Junction Temperature (TJ) ........... –40°C ≤ TJ ≤ +125°C
Package Thermal Resistance
S-Pak (θJC) ................................................ 5.5°C/W
TO-263-5 (θJC) .......................................... 6.3°C/W
ePad SOIC-8 (θJC) ..................................... 16°C/W
3mm × 3mm DFN (θJC) .............................. 29°C/W
Electrical Characteristics(6)
TA = 25°C with VIN = VOUT + 1V; VEN = VIN; IL = 10mA; bold values indicat e –40°C < TJ < +125°C, unle ss noted.
Parameter Condition Min. Typ. Max. Units
Output Voltage Accuracy IL = 1 0mA -1 +1 %
10mA < IOUT < IL(max), VOUT + 1 ≤ VIN ≤ 6V -2 +2 %
Output Voltage Line Regulation VIN = VOUT + 1.0V to 6.0V; IL = 10mA 0.02 0.5 %
Output Voltage Load Regulation IL = 10mA to 3A 0.2 1 %
VIN – VOUT Dropout Voltage(7)
IL = 1.5A
(ePad SOIC-8, DFN) 175 350
400 mV
IL = 3A
(ePad SOIC-8, DFN) 300 500
550
mV
Ground Pin Current(8) IL = 3A 27 40
50 mA
mA
Ground Pin Current in Shutdown VIL ≤ 0.5V, VIN = VOUT +1V 1.0 5 µA
Current Limit VOUT = 0V 4.75 6.5 A
Start-Up Time VEN = VIN, IOUT = 10mA, COUT = 47µF 170 500 µs
Notes:
2. Exceeding the absolute maximum rating may damage the device.
3. The device is not guarant eed to function outside its operat i ng rating.
4. PD(max) = (T J(max) – TA)/θJA, where θJA, depends upon the printed circuit layout. S ee “Application Information.”
5. Devices are ESD sensitive. Handling precautions recommended.
6. Specific at i on for packaged product only.
7. VDO = VIN – VOUT when VOUT decreases to 98% of its nominal output voltage with VIN = VOUT + 1V. For output voltages below 1.75, dropout voltage
specificat i on does not apply due to a minimum input operating voltage of 2.25V.
8. IGND is the quiescent current. IIN = IGND + IOUT.
Micrel, Inc.
MIC37300/01/02/03
February
24, 2015 5 Revision 2.0
Electrical Characteristics(6) (Continued)
TA = 25°C with VIN = VOUT + 1V; VEN = VIN; IL = 10mA; bold values indicat e –40°C < TJ < +125°C, unle ss noted.
Parameter Condition Min. Typ. Max. Units
Enable Input
Enable Input Threshold Regulator enable 2.25 V
Regulator shutdown 0.8
Enable Pin Input Current VIL ≤ 0.8V (Regul ator shut dow n) 2
4
µA
VIH ≥ 2.25V (Regulator enable) 1 15 30
75 µA
Flag Output
IFLG(LEAK) VOH = 6V 1
2 µA
VFLG(LO) VIN = 2.25V, IOL = 250µA(9) 210 400
500
mV
VFLG
Low Threshold, % of VOUT below nominal 93
% Hysteresis 2
High Threshold, % of VOUT below nominal 99.2
MIC37302 Only
Reference Voltage 1.228
1.215 1.240 1.252
1.265 V
Adjust Pin Bias Current 40 80
120 nA
Note:
9. For a 2.5V device, VIN = 2.250V (device is in dropout).
Micrel, Inc.
MIC37300/01/02/03
February
24, 2015 6 Revision 2.0
Typical Characteris tics
Micrel, Inc.
MIC37300/01/02/03
February
24, 2015 7 Revision 2.0
Typical Characteristics (Continued)
Micrel, Inc.
MIC37300/01/02/03
February
24, 2015 8 Revision 2.0
Functional Characteristics
Micrel, Inc.
MIC37300/01/02/03
February
24, 2015 9 Revision 2.0
Applications Information
The MIC37300/01/02/03 is a high-performance low-
dropout voltage regulator suitable for moderate to
high-current regulator applications. Its 500m V dropout
voltage at full load and over temperature makes it
especially valuable in battery-powered systems and
as high-efficiency noise filters in post-regulator
applications. Unlike older NPN-pass transistor
designs, where the minim um dropout v olt age is lim ited
by the based-to-emitter voltage drop and collector-to-
emitter saturation voltage, dropout perfor mance of the
PNP output of these devices is limited only b y the lo w
VCE saturation voltage.
A trade-off for the low dropout voltage is a varying
base drive requirement. Micrel’s Super ßeta PNP®
process reduces this drive requirement to only 2% to
5% of the load current.
The MIC37300/01/02/03 regulator is fully protected
from damage due to fault conditions. Current-limiting
is provided. This limiting is linear; output current
during overload conditions is constant. Thermal
shutdown disables the device when the die
temperature exceeds the maximum safe operating
temperature. The output structure of these regulators
allows voltages in excess of the desired output
voltage to be applied without reverse current flow.
Thermal Design
Linear regulators are simple to use. The most
complicated design parameters to consider are
thermal characteristics. Thermal design requires the
following app l icati on-specific parameters:
• Maximum ambient temperature (TA)
• Output current (IOUT)
• Output voltage (VOUT)
• Input voltage (VIN)
• Ground current (IGND)
First, calculate the power dissipation of the regulator
from these numbers and the device parameters from
this datasheet (Equation 1):
PD = (VIN – VOUT) IOUT + VIN IGND Eq. 1
where the ground current is approximated by using
numbers from the “Electrical Characteristics” or
“Typical Characteristics.”
Then the heat sink thermal resistance is determined
with Equation 2:
θSA = ((TJ(max) – TA)/PD) – (θJC + θCS) Eq. 2
where TJ(max) <125°C and θCS is between 0°C/W 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’s Super ßeta PNP regulators allow significant
reductions in regulator power dissipation and the
associated heat sink without compromising
performance. When this technique is employed, a
capacitor of at least 1.0µF is needed direct ly between
the input and regulator ground.
Output Capacitor
The MIC37300/01/02/03 requires an output capacitor
for stable operation. As a µCap LDO, the
MIC37300/01/02/03 can operate with ceramic output
capacitors as long as the amount of capacitance is
47µF or greater. For values of output capacitance
lower than 47µF, the recommended ESR range is
200mΩ to 2Ω. The minimum value of output
capacitance recommended for the MIC37300 is 10µF.
For 47µF or greater, the ESR range recommended is
less than 1Ω. Ultra-low ESR, ceramic capacitors are
recommended for output capacitance of 47µF or
greater to help improve transient response and noise
reduction at high frequency. X7R/X5R dielectric-type
ceramic capacitors are recommended because of
their temperature performance. X7R-type capacitors
change capacitance by 15% over their operating
temperature range and are the most stable type of
ceramic capacitors. Z5U an d Y5V die lectric c apac itors
change value by as much as 50% and 60%,
respectively, over their operating temperature ranges.
To use a ceramic chip capacitor with Y5V dielectric,
the value must be much higher than an X7R ceramic
capacitor to ensure the same minimum capacitance
over the equivalent operating temperature range.
Micrel, Inc.
MIC37300/01/02/03
February
24, 2015 10 Revision 2.0
Input Capacitor
An input capacitor of 1.0µF or greater is
recommended when the device is m ore than 4 inches
away from the bulk supply capacitance, or when the
supply is a battery. Small, surface-mount chip
capacitors can be used for the bypassing. The
capacitor should be place within 1 inch of the device
for optimal performance. Larger values will help to
improve ripple rejection by bypassing the input to the
regulator, further improving the integrity of the output
voltage.
Transient Response and 3.3V to 2.5V, 2.5V to 1.8V
or 1.65V, or 2.5V to 1.5V Conversions
The MIC37300/01/02/03 has excellent transient
response to variations in input voltage and load
current. The device has been designed to respond
quickly to load current variations and input voltage
variations. Large output capacitors are not required to
obtain this performance. A standard 47µF output
capacitor, preferably tantalum, is all that is required.
Larger values help to improve performance even
further.
By virtue of its low-dropout voltage, this device does
not saturate into dropout as readily as similar NPN-
based designs. When converting from 3.3V to 2.5V,
2.5V to 1.8V or 1.65V, or 2.5V to 1.5V, the NPN-
based regulators are already operating in dropout,
with typical dropout requirements of 1.2V or greater.
To conver t down to 2.5V without operat ing in dropout ,
NPN-base d regu lat or s requ ir e an inpu t volta ge of 3.7V
at the very least. The MIC37300/01/02/03 regulator
will pro vid e ex cel lent p er f ormanc e with an inp ut as lo w
as 3.0V or 2.25V, respectively. This gives the PNP-
based regulators a distinct advantage over older,
NPN-based linear regulators.
Minimum Load Current
The MIC37300/01/02/03 regulator is specified
between finite loads. If the output current is too small,
then the leakage currents dominate and the output
voltage rises. A 10mA minimum load current is
necessary for proper operation. For adjustable
regulators, this can be accomplished by selecting the
feedback resistors to load the output with 10mA.
Error Flag
The MIC37301 and MIC37303 feature an error flag
circuit that monitors the output voltage and signals an
error condition when the voltage is 5% below the
nominal output voltage. The error flag is an open-
collector output that can sink 10mA during a fault
condition.
Low output voltage can be caused by a number of
problems, including an overcurrent fault (device in
current limit) or low input voltage. The flag is
inoperative during overtemperature shutdown.
Enable Input
The MIC373 01/02/03 also f eatures an en able input f or
on/off control of the device. Its shutdown state draws
“zero” current (only microamperes of leakage). The
enable i nput is T TL/CMOS compatib le for sim ple logic
interface, but can be connected up to VIN. When
enabled, it draws approximately 15µA.
Adjustable Regulator Design
Figure 1. Adjustable Regulator with Resistors
The MIC373 02 and MIC37 303 allow pro gramming the
output volt age anywhere b etween 1.24 V and the 5.5V
maximum operating rating of the family. Two resistors
are used. Resistors can be quite large, up to 1MΩ,
because of the very high input impedance and low
bias current of the sense comparator.
The resistor values are calculated b y:
−= 1
240.1
V
2R1R OUT
Eq. 3
where VOUT is the desired output voltage. Figure 1
shows component definition. Applications with widely
varying load currents may scale the resistors to draw
the minimum load current required for proper
operation.
IN R1 VOUT
VIN
COUT
R2
EN
OUT
ADJ
GND
MIC37302
ENABLE
SHUTDOWN
V1.240V 1R1
R2
OUT
=+
Micrel, Inc.
MIC37300/01/02/03
February
24, 2015 16 Revision 2.0
MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http://www.micrel.com
Micrel, Inc. is a leading global manufac turer of IC solutions f or the worldwide high pe rformance linear and power, LAN, and t iming & communications
markets. The Company’s products include advanced mixed
-signal, analog & power semiconductors; high-perform
ance communication, clock
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customers include leading manufacturers of enterprise, consumer, industrial, mobile, telecommunications, automotive, and computer products.
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is datash
eet. This
information is not intended as a warranty and Micrel does not assume responsibility for its use. Micrel reserves the right to change circuitry,
specifications and descriptions at any time without notice. No license, whether express, implied, arising by estoppel or otherwise, to any intellectual
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s are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a
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