MIC39300/39301/39302
3A, Low-Voltage Low-Dropout Regulator
**See Thermal Load Current Section
Super eta PNP is a registered trademark of Micrel, Inc.
StrongARM is a trademark of Advanced RISC Machines, Ltd
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
General Description
The MIC39300, MIC39301 and MIC39302 are 3.0A low-
dropout linear voltage regulators that provide a low
voltage, high-current output with a minimum of external
components. Utilizing Micrel’s proprietary Super eta
PNP® pass element, the MIC39300/1/2 offers extremely
low dropout (typically 385mV at 3.0A) and low ground
current (typically 36mA at 3.0A).
The MIC39300/1/2 is ideal for PC add-in cards that need
to convert from standard 3.3V to 2.5V or 2.5V to 1.8V. A
guaranteed maximum dropout voltage of 500mV over all
operating conditions allows the MIC39300/1/2 to provide
2.5V from a supply as low as 3V, and 1.8V from a supply
as low as 2.5V. The MIC39300/1/2 also has fast transient
response for heavy switching applications. The device
requires only 47µF of output capacitance to maintain
stability and achieve fast transient response.
The MIC39300/1/2 is fully protected with overcurrent
limiting, thermal shutdown, reversed-battery protection,
reversed-leakage protection, and reversed-lead insertion.
The MIC39301 offers a TTL-logic compatible enable pin
and an error flag that indicates under voltage and over
current conditions. Offered in fixed voltages, the
MIC39300/1 comes in the TO-220 and TO-263 (D2Pak)
packages and is an ideal upgrade to older, NPN-based
linear voltage regulators. The MIC39302 adjustable option
allows programming the output voltage anywhere between
1.24V and 15.5V and is offered in a 5-Pin, TO-263 (D2Pak)
package.
Features
• 3.0A minimum guaranteed output current
• 550mV maximum dropout voltage over temperature
• Ideal for 3.0V to 2.5V conversion
• Ideal for 2.5V to 1.8V conversion
• 1% initial accuracy
• Low ground current
• Current limiting and Thermal shutdown
• Reversed-battery protection
• Reversed-leakage protection
• Fast transient response
• TO-263 (D2Pak) and TO-220 packaging
• TTL/CMOS compatible enable pin (MIC39301/2 only)
• Error flag output (MIC39301 only)
• Adjustable output (MIC39302 only)
Applications
• LDO linear regulator for PC add-in cards
• High-efficiency linear power supplies
• SMPS post regulator
• Multimedia and PC processor supplies
• Low-voltage microcontrollers
• StrongARM™ processor supply
_________________________________________________________________________________________________________________________
Typical Application
MIC39300
MIC39301
MIC39302 Adjustable Output Application
(*See Minimum Load Current Section)
Micrel, Inc. MIC39300/39301/39302
October 2009 2 M9999-102309-A
Ordering Information
Part Number
Standard RoHS Compliant*
Voltage Junction Temp
Range Package
MIC39300-1.8BT MIC39300-1.8WT 1.8V –40°C to +125°C 3-Pin TO-220
MIC39300-1.8BU MIC39300-1.8WU 1.8V –40°C to +125°C 3-Pin TO-263
MIC39300-2.5BT MIC39300-2.5WT 2.5V –40°C to +125°C 3-Pin TO-220
MIC39300-2.5BU MIC39300-2.5WU 2.5V –40°C to +125°C 3-Pin TO-263
MIC39301-1.8BT MIC39301-1.8WT 1.8V –40°C to +125°C 5-Pin TO-220
MIC39301-1.8BU MIC39301-1.8WU 1.8V –40°C to +125°C 5-Pin TO-263
MIC39301-2.5BT MIC39301-2.5WT 2.5V –40°C to +125°C 5-Pin TO-220
MIC39301-2.5BU MIC39301-2.5WU 2.5V –40°C to +125°C 5-Pin TO-263
— MIC39302WU Adjustable –40°C to +125°C 5-Pin TO-263
Note:
* RoHS compliant with ‘high-melting solder’ exemption.
Micrel, Inc. MIC39300/39301/39302
October 2009 3 M9999-102309-A
Pin Configur ation
MIC39300-x.xBT
TO-220-3 (T) MIC39300-x.xBU
TO-263-3 (U)
MIC39301-x.xBT
TO-220-5 (T) MIC39301-x.xBU
TO-263-5 (D2Pak) (U)
MIC39302WU
TO-263-5 (D2Pak) (U)
Pin Description
Pin
Number
MIC39300
Pin
Number
MIC39301
Pin
Number
MIC39302 Pin Name Pin Function
— 1 1 EN
Enable (Input): TTL/CMOS compatible input. Logic high = enable; logic low
or open = shutdown.
1 2 2 IN Unregulated Input: +16V maximum supply.
2, TAB 3, TAB 3, TAB GND Ground: Ground pin and TAB are internally connected.
3 4 4 OUT Regulator Output
— 5
—
FLG Error Flag (Ouput): Open-collector indicates an output fault condition.
Active low.
— —
5
ADJ Adjustable Regulator Feedback Input: Connect to the resistor voltage
divider that is placed from OUT to GND in order to set the output voltage.
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Absolute Maximum Ratings(1)
Supply Voltage (VIN)....................................... –20V to +20V
Enable Voltage (VEN)....................................................+20V
Storage Temperature (TS)................–65°C to +150°C Lead
Temperature (soldering, 5 sec.)................................. 260°C
ESD Rating................................................................ Not e 3
Operating Ratings(2)
Supply Voltage (VIN)...................................... +2.5V to +16V
Enable Voltage (VEN)....................................................+16V
Maximum Power Dissipation (PD(max)) ....................... Note 4
Junction Temperature (TJ) ........................ –40°C to +125°C
Package Thermal Resistance
TO-263 (θJC) ........................................................2°C/W
TO-220 (θJC) ........................................................2°C/W
Electrical Characteristics(5)
TJ = 25°C, bold values indicate –40°C TJ +125°C, unless noted.
Symbol Parameter Condition Min Typ Max Units
VOUT Output Voltage 10mA
10mA IOUT 3A, VOUT + 1V VIN 8V
–1
–2
1
2
%
%
Line Regulation IOUT = 10mA, VOUT + 1V VIN 8V 0.06 0.5 %
Load Regulation VIN = VOUT + 1V, 10mA IOUT 3A 0.2 1 %
VOUT/T
Output Voltage Temp.
Coefficient
Note 6
20 100 ppm/°C
IOUT = 100mA, VOUT = –1% 65 200 mV
IOUT = 750mA, VOUT = –1% 185 mV
IOUT = 1.5A, VOUT = –1% 250 mV
VDO Dropout Voltage
Note 7, Note 10
IOUT = 3A, VOUT = –1% 385 550 mV
IOUT = 750mA, VIN = VOUT + 1V 10 20 mA
IOUT = 1.5A, VIN = VOUT + 1V 17 mA
IGND Ground Current
Note 8
IOUT = 3A, VIN = VOUT + 1V 45 mA
IGND(do) Dropout Ground Pin Current VIN VOUT(nominal) – 0.5V, IOUT = 10mA 6 mA
IOUT(lim) Current Limit VOUT = 0V, VIN = VOUT + 1V 4.5 A
Enable Input (MIC39301)
VEN Enable Input Voltage logic low (off) 0.8 V
logic high (on) 2.5 V
IIN Enable Input Current VEN = 2.5V 15 30
75
µA
µA
V
EN = 0.8V 2 µA
4 µA
IOUT(shdn) Shutdown Output Current Note 9 10
20 µA
Flag Output (MIC39301)
IFLG(leak) Output Leakage Current VOH = 16V 0.01 1
2
µA
µA
VFLG(do) Output Low Voltage VIN = 2.50V, IOL, = 250µA, Note 10 220 300
400
mV
mV
VFLG Low Threshold % of VOUT 93 %
High Threshold % of VOUT 99.2 %
Hysteresis 1 %
Micrel, Inc. MIC39300/39301/39302
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Symbol Parameter Condition Min Typ Max Units
Reference (Adju st Pin) – MIC39302 only
1.228 1.240 1.252 V VADJ Reference Voltage 1.215
1.265 V
VTC Reference Voltage Temp.
Coefficient
Note 11 20 ppm/°C
40 80 nA IADJ Adjust Pin Bias Current
120 nA
ITC Adjust Pin Bias Current Temp.
Coefficient
0.1 nA/°C
Notes:
1. Exceeding the absolute maximum ratings may damage the device.
2. The device is not guaranteed to function outside its operating rating.
3. Devices are ESD sensitive. Handling precautions recommended.
4. PD(max) = (TJ(max) – TA) ÷ JA, where JA depends upon the printed circuit layout. See “Applications Information.”
5. Specification for packaged product only.
6. Output voltage temperature coefficient is VOUT(worst case) ÷ (TJ(max) – TJ(min)) where TJ(max) is +125°C and TJ(min) is –40°C.
7. VDO = VIN – VOUT when VOUT decreases to 99% of its nominal output voltage with VIN = VOUT + 1V. For output voltages below 2.5V, dropout voltage
is the input-to-output voltage differential with the minimum input voltage being 2.5V. Minimum input operating voltage is 2.5V.
8. IGND is the quiescent current. IIN = IGND + IOUT.
9. VEN 0.8V, VIN 8V, and VOUT = 0V
10. For a 1.8V device, VIN = 2.5V.
11. Thermal regulation is defined as the change in output voltage at a time t after a change in power dissipation is applied, excluding load or line
regulation effects. Specifications are for a 200mA load pulse at VIN = 8V for t = 10ms.
Micrel, Inc. MIC39300/39301/39302
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Typical Characteristics
Micrel, Inc. MIC39300/39301/39302
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Typical Characteristics (cont)
Micrel, Inc. MIC39300/39301/39302
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Functional Characteristics
Micrel, Inc. MIC39300/39301/39302
October 2009 9 M9999-102309-A
Functional Diagram
Micrel, Inc. MIC39300/39301/39302
October 2009 10 M9999-102309-A
Application Information
The MIC39300/1/2 are high-performance, low-dropout
voltage regulators suitable for moderate to high-current
voltage regulator applications. Its 550mV dropout
voltage at full load makes it especially valuable in
battery-powered systems and as a high-efficiency noise
filter in post-regulator applications. Unlike older NPN-
pass transistor designs, where the minimum dropout
voltage is limited by the base-to-emitter voltage drop and
collector-to-emitter saturation voltage, dropout
performance of the PNP output of these devices is
limited only by the low VCE saturation voltage.
A trade-off for the low dropout voltage is a varying base
drive requirement. Micrel’s Super eta PNP® process
reduces this drive requirement to only 2% to 5% of the
load current.
The MIC39300/1/2 regulators are 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. Transient
protection allows device (and load) survival even when
the input voltage spikes above and below nominal. 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 four application-
specific parameters:
• Maximum ambient temperature (TA)
• Output Current (IOUT)
• Output Voltage (VOUT)
• Input Voltage (VIN)
• Ground Current (IGND)
Calculate the power dissipation of the regulator from
these numbers and the device parameters from this
datasheet, where the ground current is taken from the
data sheet.
P
D = (VIN – VOUT) IOUT + VIN × IGND
The heat sink thermal resistance is determined by:
()
CSJC
D
A(max)J
SA P
TT θ+θ−
−
=θ
where TJ(max) 125°C and 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
eta 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 1.0F is needed
directly between the input and regulator ground.
Refer to “Application Note 9” for further details and
examples on thermal design and heat sink specification.
Figure 1. Capacitor Requirements
Output Capacitor
The MIC39300/1/2 requires an output capacitor to
maintain stability and improve transient response.
Proper capacitor selection is important to ensure proper
operation. The MIC39300/1/2 output capacitor selection
is dependent upon the ESR (equivalent series
resistance) of the output capacitor to maintain stability.
When the output capacitor is 47F or greater, the output
capacitor should have less than 1 of ESR. This will
improve transient response as well as promote stability.
Ultralow ESR capacitors, such as ceramic chip
capacitors may promote instability. These very low ESR
levels may cause an oscillation and/or underdamped
transient response. A low-ESR solid tantalum capacitor
works extremely well and provides good transient
response and stability over temperature. Aluminum
electrolytics can also be used, as long as the ESR of the
capacitor is < 1.
The value of the output capacitor can be increased
without limit. Higher capacitance values help to improve
transient response and ripple rejection and reduce
output noise.
Input Capacitor
An input capacitor of 1F or greater is recommended
when the device is more than 4 inches away from the
bulk ac supply capacitance, or when the supply is a
battery. Small, surface mount, ceramic chip capacitors
can be used for the bypassing. Larger values will help to
improve ripple rejection by bypassing the input to the
regulator, further improving the integrity of the output
voltage.
Micrel, Inc. MIC39300/39301/39302
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Transient Response and 3.3V to 2.5V and 2.5V to
1.8V Conversions
The MIC39300/1/2 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 47F 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 or 2.5V to
1.8V, the NPN-based regulators are already operating in
dropout, with typical dropout requirements of 1.2V or
greater. To convert down to 2.5V without operating in
dropout, NPN-based regulators require an input voltage
of 3.7V at the very least. The MIC39300/1 regulator will
provide excellent performance with an input as low as
3.0V or 2.5V. This gives the PNP-based regulators a
distinct advantage over older, NPN-based linear
regulators.
Minimum Load Current
The MIC39300/1/2 regulators are specified between
finite loads. If the output current is too small, leakage
currents dominate and the output voltage rises. A 10mA
minimum load current is necessary for proper regulation.
Error Flag
The MIC39301 version features an error flag circuit
which monitors the output voltage and signals an error
condition when the voltage drops 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.
When the error flag is not used, it is best to leave it
open. A pull-up resistor from FLG to either VIN or VOUT is
required for proper operation.
Enable Input
The MIC39301/2 features an enable input for on/off
control of the device. The enable input’s shutdown state
draws “zero” current (only microamperes of leakage).
The enable input is TTL/CMOS compatible for simple
logic interface, but can be connected to up to 20V. When
enabled, it draws approximately 15A.
Adjustable Regulator Design
Figure 2. Adjustable Regulator with Resistors
The MIC39302 allows programming the output voltage
anywhere between 1.24V and 15.5V. Two resistors are
used. The resistor values are calculated by:
⎟
⎟
⎠
⎞
⎜
⎜
⎝
⎛−×= 1
1.240
V
R2R1 OUT
Where VOUT is the desired output voltage. Figure 2
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).
Micrel, Inc. MIC39300/39301/39302
October 2009 12 M9999-102309-A
Package Information
3-Pin TO-220 (T)
5-Pin TO-220 (T)
Micrel, Inc. MIC39300/39301/39302
October 2009 13 M9999-102309-A
3-Pin TO-263 (U)
5-Pin TO-263 (U)
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
The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its
use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer.
Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product
can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant
into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A
Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk and Purchaser agrees to fully
indemnify Micrel for any damages resulting from such use or sale.
© 2009 Micrel, Incorporated.
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MIC39301-1.8WU-TR MIC39301-2.5WU-TR
