MIC5239
Low Quiescent Current 500mA µCap
LDO Regulator
MLF and MicroLeadFrame is a registered trademark of Amkor Technologies
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (
408
) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
December 2007
M9999-121007
General Description
The MIC5239 is a low quiescent current, µCap low-dropout
regulator. With a maximum operating input voltage of 30V
and a quiescent current of 23µA, it is ideal for supplying
keep-alive power in systems with high voltage batteries.
Capable of 500mA output, the MIC5239 has a dropout
voltage of only 350mV. It can provide high output current
for applications such as USB.
As a µCap LDO, the MIC5239 is stable with either a
ceramic or a tantalum output capacitor. It only requires a
3.3µF output capacitor for stability.
The MIC5239 includes a logic compatible enable input and
an undervoltage error flag indicator. Other features of the
MIC5239 include thermal shutdown, current limit, overvolt-
age shutdown, reverse-leakage protection, and reverse-
battery protection.
Available in the thermally enhanced SOIC-8, MSOP-8 and
SOT-223, the MIC5239 comes in fixed 1.5V, 1.8V, 2.5V,
3.0V, 3.3V and 5.0V, and adjustable voltages. For other
output voltages, contact Micrel.
All support documentation can be found on Micrel’s web
site at: www.micrel.com.
Features
• Ultra-low quiescent current (I
Q
= 23µA @I
O
= 100µA)
• Continuous 500mA output current
• Wide input range: 2.3V to 30V
• Low dropout voltage: 350mV @500mA
• ±1.0% initial output accuracy
• Stable with ceramic or tantalum output capacitor
• Logic compatible enable input
• Low output voltage error flag indicator
• Overcurrent protection
• Thermal shutdown
• Reverse-leakage protection
• Reverse-battery protection
• High-power SOIC-8, MSOP-8 and SOT-223 packages
Applications
• USB power supply
• Keep-alive supply in notebook and portable personal
computers
• Logic supply from high voltage batteries
• Automotive electronics
• Battery-powered systems
___________________________________________________________________________________________________________
Typical Application
I
GND
= 23µA
V
OUT
3.0V/100µA
V
IN
30V IN
MIC5239
EN
OUT
GND
FLG
Regulator with Low I
O
and Low I
Q
40
35
30
25
20
15
10 914
19 24 29
4
I
OUT
= 1mA
I
OUT
= 10µA
I
OUT
= 100µA
Ground Current vs. Input Voltage
Micrel MIC5239
December 2007 2 M9999-121007
Ordering Information
Part Number
Standard Pb-Free Voltage
(1)
Junction Temp. Range Package
MIC5239-1.5BM MIC5239-1.5YM 1.5V –40°C to +125°C 8-pin SOIC
MIC5239-1.5BMM MIC5239-1.5YMM 1.5V –40°C to +125°C 8-pin MSOP
MIC5239-1.5BS MIC5239-1.5YS 1.5V –40°C to +125°C SOT-223
MIC5239-1.8BM MIC5239-1.8YM 1.8V –40°C to +125°C 8-pin SOIC
MIC5239-1.8BMM MIC5239-1.8YMM 1.8V –40°C to +125°C 8-pin MSOP
MIC5239-1.8BS MIC5239-1.8YS 1.8V –40°C to +125°C SOT-223
MIC5239-2.5BM MIC5239-2.5YM 2.5V –40°C to +125°C 8-pin SOIC
MIC5239-2.5BMM MIC5239-2.5YMM 2.5V –40°C to +125°C 8-pin MSOP
MIC5239-2.5BS MIC5239-2.5YS 2.5V –40°C to +125°C SOT-223
MIC5239-3.0BM MIC5239-3.0YM 3.0V –40°C to +125°C 8-pin SOIC
MIC5239-3.0BMM MIC5239-3.0YMM 3.0V –40°C to +125°C 8-pin MSOP
MIC5239-3.0BS MIC5239-3.0YS 3.0V –40°C to +125°C SOT-223
MIC5239-3.3BM MIC5239-3.3YM 3.3V –40°C to +125°C 8-pin SOIC
MIC5239-3.3BMM MIC5239-3.3YMM 3.3V –40°C to +125°C 8-pin MSOP
MIC5239-3.3BS MIC5239-3.3YS 3.3V –40°C to +125°C SOT-223
MIC5239-5.0BM MIC5239-5.0YM 5.0V –40°C to +125°C 8-pin SOIC
MIC5239-5.0BMM MIC5239-5.0YMM 5.0V –40°C to +125°C 8-pin MSOP
MIC5239-5.0BS MIC5239-5.0YS 5.0V –40°C to +125°C SOT-223
MIC5239BM MIC5239YM ADJ –40°C to +125°C 8-pin SOIC
MIC5239BMM MIC5239YMM ADJ –40°C to +125°C 8-pin MSOP
Note:
1. Other Voltages available. Contact Micrel for details.
Micrel MIC5239
December 2007 3 M9999-121007
Pin Configuration
SOIC-8 (M) SOT-223 (S) SOIC-8 (M)
MSOP-8(MM) MSOP-8(MM)
(Fixed) (Adj)
Pin Description
Pin Number
MSOP/SOIC
Pin Number
SOT-223
Pin Name Pin Function
2 (fixed) — FLG Error FLAG (Output): Open-collector output is active low when the output
is out of regulation due to insufficient input voltage or excessive load. An
external pull-up resistor is required.
2 (adj) — ADJ Adjustable Feedback Input: Connect to voltage divider network.
3 1 IN Power Supply Input.
4 3 OUT Regulated Output.
1 — EN Enable (input): Logic low = shutdown; logic high = enabled.
5–8 2 GND Ground: Pins 5, 6, 7, and 8 are internally connected in common via the
leadframe.
Micrel MIC5239
December 2007 4 M9999-121007
Absolute Maximum Ratings(1)
Supply Voltage (V
IN
) ...................................... –20V to +32V
Enable Input Voltage (V
EN
)............................ –0.3V to +32V
Power Dissipation (P
D
)
(3)
...........................Internally Limited
Junction Temperature (T
J
) ........................–40°C to +125°C
Storage Temperature (T
S
).........................–65°C to +150°C
Lead Temperature (soldering, 5 sec.)........................ 260°C
ESD Rating
(4)
SOT-23-3L ............................................................... 2kV
MSOP-8L .............................................................. 1.5kV
Operating Ratings(2)
Supply Voltage (V
IN
).......................................... 2.3V to 30V
Enable Input Voltage (V
EN
)................................... 0V to 30V
Junction Temperature (T
J
) ........................ –40°C to +125°C
Package Thermal Resistance
MSOP (
JA
)....................................................... 80°C/W
SOT-223 (
JA
)................................................... 50°C/W
Electrical Characteristics(5)
V
IN
= V
OUT
+ 1V; V
EN
2.0V; I
OUT
= 100µA; T
J
= 25°C, bold values indicate –40°C T
J
+125°C; unless noted.
Symbol Parameter Condition Min Typ Max Units
V
OUT
Output Voltage Accuracy Variation from nominal V
OUT
–1
–2 1
2
%
%
V
OUT
/V
OUT
Line Regulation V
IN
= V
OUT
+1V to 30V 0.06 0.5 %
V
OUT
/V
OUT
Load Regulation I
OUT
= 100µA to 500mA
(6)
15 30 mV
I
OUT
= 100µA 50 mV
I
OUT
= 150mA 260
350
400
mV
mV
V Dropout Voltage
(7)
I
OUT
= 500mA 350 mV
V
EN
2.0V, I
OUT
= 100µA 23
40
45
µA
µA
V
EN
2.0V, I
OUT
= 150mA 1.3 5 mA
I
GND
Ground Pin Current
V
EN
2.0V, I
OUT
= 500mA 8.5 15 mA
I
GND(SHDN)
Ground Pin Shutdown V
EN
0.6V, V
IN
= 30V 0.1 1 µA
I
SC
Short Circuit Current V
OUT
= 0V 850 1200 mA
e
n
Output Noise 10Hz to 100kHz, V
OUT
= 3.0V, C
L
= 3.3µF 160 µVrms
FLAG Output
Low Threshold % of V
OUT
94 % V
FLG
High Threshold % of V
OUT
95 %
V
OL
FLAG Output Low Voltage V
IN
= V
OUT(nom)
– 0.12V
OUT
, I
OL
= 200µA 150 mV
I
LEAK
FLAG Output Leakage V
OH
= 30V 0.1 µA
Enable Input
V
IL
Input Low Voltage regulator off 0.6 V
V
IH
Input High Voltage regulator on 2.0
V
V
EN
= 0.6V, regulator off –1.0
–2.0 0.01 1.0
2.0
µA
µA
V
EN
= 2.0V, regulator on 0.15
1.0
2.0
µA
µA
I
IN
Enable Input Current
V
EN
= 30V, regulator on 0.5
2.5
5.0
µA
µA
Micrel MIC5239
December 2007 5 M9999-121007
Notes:
1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating rating.
3. The maximum allowable power dissipation of any T
A
(ambient temperature) is P
D
(max) = (T
J
(max) – T
A
) ÷
JA
. Exceeding the maximum
allowable power dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown. The
JA
of the MIC5239-
x.xBMM (all versions) is 80°C/W, the MIC5239-x.xBM (all versions) is 63°C/W, and the MIC5239-x.xBS (all versions) is 50°C/W mounted on a
PC board, see “Thermal Characteristics” for further details.
4. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.
5. Specification for packaged product only.
6. Regulation is measured at constant junction temperature using pulse testing with a low duty-cycle. Changes in output voltage due to heating
effects are covered by the specification for thermal regulation.
7. Dropout voltage is defined as the input to output differential at which the output voltage drops 2% below its nominal value measured at 1.0V
differential.
Micrel MIC5239
December 2007 6 M9999-121007
Typical Characteristics
(V
OUT
= 3V)
Micrel MIC5239
December 2007 7 M9999-121007
Typical Characteristics (continued)
(V
OUT
= 3V)
0
20
40
60
80
100
120
-20 -10 0 10
)Am(TNERRUCTUPNI
SUPPLY VOLTAGE (V)
Input Current
V
EN
= 5V
R
LOAD
= 30
Functional Characteristics
Micrel MIC5239
December 2007 8 M9999-121007
Functional Diagram
Block Diagram — Fixed Voltages
Block Diagram — Adjustable Voltages
Micrel MIC5239
December 2007 9 M9999-121007
Application Information
The MIC5239 provides all of the advantages of the
MIC2950: wide input voltage range, and reversed-
battery protection, with the added advantages of
reduced quiescent current and smaller package.
Additionally, when disabled, quiescent current is reduced
to 0.1µA.
Enable
A low on the enable pin disables the part, forcing the
quiescent current to less than 0.1µA. Thermal shutdown
and the error flag are not functional while the device is
disabled. The maximum enable bias current is 2µA for a
2.0V input. An open-collector pull-up resistor tied to the
input voltage should be set low enough to maintain 2V
on the enable input. Figure 1 shows an open-collector
output driving the enable pin through a 200k pull-up
resistor tied to the input voltage.
In order to avoid output oscillations, slow transitions from
low-to-high should be avoided.
C
V
V
5V
V
IN
MIC5239
EN
200
k
200k
OUT
GND
FLG
Figure 1. Remote Enable
Input Capacitor
An input capacitor may be required when the device is
not near the source power supply or when supplied by a
battery. Small, surface mount ceramic capacitors can be
used for bypassing. Larger values may be required if the
source supply has high ripple.
Output Capacitor
The MIC5239 has been designed to minimize the effect
of the output capacitor ESR on the closed loop stability.
As a result, ceramic or film capacitors can be used at the
output. Figure 2 displays a range of ESR values for a
10µF capacitor. Virtually any 10µF capacitor with an
ESR less than 3.4 is sufficient for stability over the
entire input voltage range. Stability can also be
maintained throughout the specified load and line
conditions with 4.7µF film or ceramic capacitors.
Figure 2. Output Capacitor ESR
Error Detection Comparator Output
The FLAG pin is an open-collector output which goes
low when the output voltage drops 5% below it’s
internally programmed level. It senses conditions such
as excessive load (current limit), low input voltage, and
over temperature conditions. Once the part is disabled
via the enable input, the error flag output is not valid.
Overvoltage conditions are not reflected in the error flag
output. The error flag output is also not valid for input
voltages less than 2.3V.
The error output has a low voltage of 400mV at a current
of 200µA. In order to minimize the drain on the source
used for the pull-up, a value of 200k to 1M is
suggested for the error flag pull-up. This will guarantee a
maximum low voltage of 0.4V for a 30V pull-up potential.
An unused error flag can be left unconnected.
NOT
VALID
NOT
VALID
VALID ERROR
Error FLAG
Output
Input
Voltage
Output
Voltage
4.75V
0V
0V
5V
1.3V
Figure 3. Error FLAG Output Timing
Thermal Shutdown
The MIC5239 has integrated thermal protection. This
feature is only for protection purposes. The device
should never be intentionally operated near this
temperature as this may have detrimental effects on the
life of the device. The thermal shutdown may become
inactive while the enable input is transitioning from a
high to a low. When disabling the device via the enable
pin, transition from a high to low quickly. This will insure
that the output remains disabled in the event of a
thermal shutdown.
Micrel MIC5239
December 2007 10 M9999-121007
Current Limit
Figure 4 displays a method for reducing the steady state
short-circuit current. The duration that the supply
delivers current is set by the time required for the error
flag output to discharge the 4.7µF capacitor tied to the
enable pin. The off time is set by the 200k resistor as it
recharges the 4.7µF capacitor, enabling the regulator.
This circuit reduces the short-circuit current from 800mA
to 40mA while allowing for regulator restart once the
short is removed.
C
OUT
V
OUT
V
IN
5V
V
ERR
IN
MIC5239
EN
200k
1N4148
200k
4.7µF
OUT
GND
SHUTDOWN
ENABLE
FLG
Figure 4. Remote Enable with Short-Circuit
Current Foldback
Thermal Characteristics
The MIC5239 is a high input voltage device, intended to
provide 500mA of continuous output current in two very
small profile packages. The power MSOP-8 allows the
device to dissipate about 50% more power than their
standard equivalents.
Power MSOP-8 Thermal Characteristics
One of the secrets of the MIC5239’s performance is its
power MSOP-8 package featuring half the thermal
resistance of a standard MSOP-8 package. Lower
thermal resistance means more output current or higher
input voltage for a given package size.
Lower thermal resistance is achieved by joining the four
ground leads with the die attach paddle to create a
single piece electrical and thermal conductor. This
concept has been used by MOSFET manufacturers for
years, proving very reliable and cost effective for the
user.
Thermal resistance consists of two main elements,
JC
(junction-to-case thermal resistance) and
CA
(case-to-
ambient
thermal resistance). See Figure 5.
JC
is the
resistance
from the die to the leads of the package.
CA
is the resistance
from the leads to the ambient air and it
includes
CS
(case-to-sink
thermal resistance) and
SA
(sink-to-ambient thermal resistance).
Figure 5. Thermal Resistance
Using the power MSOP-8 reduces the
JC
dramatically
and allows the user to reduce
CA
. The total thermal
resistance,
JA
(junction-to-ambient thermal resistance)
is the limiting factor in calculating the maximum power
dissipation capability of the device. Typically, the power
MSOP-8 has a
JC
of 80°C/W, this is significantly lower
than the standard MSOP-8 which is typically 200°C/W.
CA
is reduced because pins 5 through 8 can now be
soldered directly to a ground plane which significantly
reduces the case-to-sink thermal resistance and sink to
ambient thermal resistance.
Low-dropout linear regulators from Micrel are rated to a
maximum junction temperature of 125°C. It is important
not to exceed this maximum junction temperature during
operation of the device. To prevent this maximum
junction temperature from being exceeded, the
appropriate ground plane heatsink must be used.
2
Figure 6. Copper Area vs. Power-MSOP
Power Dissipation (∆T
JA
)
Figure 6 shows copper area versus power dissipation
with each trace corresponding to a different temperature
rise above ambient.
From these curves, the minimum area of copper
necessary for the part to operate safely can be
determined. The maximum allowable temperature rise
must be calculated to determine operation along which
curve.
Micrel MIC5239
December 2007 11 M9999-121007
T = T
J
(max) – T
A
(max)
T
J
(max) = 125°C
T
A
(max) = maximum ambient operating
temperature
For example, the maximum ambient temperature is
50°C, the T is determined as follows:
T = 125°C – 50°C
T = 75°C
Using Figure 6, the minimum amount of required copper
can be determined based on the required power
dissipation. Power dissipation in a linear regulator is
calculated as follows:
P
D
= (V
IN
– V
OUT
) I
OUT
+ V
IN
× I
GND
If we use a 3V output device and a 28V input at
moderate output current of 25mA, then our power
dissipation is as follows:
P
D
= (28V – 3V) × 25mA + 28V 250µA
P
D
= 625mW + 7mW
P
D
= 632mW
From Figure 6, the minimum amount of copper required
to operate this application at a T of 75°C is 110mm
2
.
Quick Method
Determine the power dissipation requirements for the
design along with the maximum ambient temperature at
which the device will be operated. Refer to Figure 7,
which shows safe operating curves for three different
ambient temperatures: 25°C, 50°C and 85°C. From
these curves, the minimum amount of copper can be
determined by knowing the maximum power dissipation
required. If the maximum ambient temperature is 50°C
and the power dissipation is as above, 639mW, the
curve in Figure 7 shows that the required area of copper
is 110mm
2
.
The
JA
of this package is ideally 80°C/W, but it will vary
depending upon the availability of copper ground plane
to which it is attached.
2
Figure 7. Copper Area vs. Power-MSOP
Power Dissipation (T
A
)
Figure 8. Copper Area vs. Power-SOIC
Power Dissipation (∆T
JA
)
2
Figure 9. Copper Area vs. Power-SOIC
Power Dissipation (T
A
)
The same method of determining the heatsink area used
for the power MSOP-8 can be applied directly to the
power SOIC-8. The same two curves showing power
dissipation versus copper area are reproduced for the
power SOIC-8 and they can be applied identically.
Power SOIC-8 Thermal Characteristics
The power SOIC-8 package follows the same idea as
the power MSOP-8 package, using four ground leads
with the die attach paddle to create a single-piece
electrical and thermal conductor, reducing thermal
resistance and increasing power dissipation capability.
Quick Method
Determine the power dissipation requirements for the
design along with the maximum ambient temperature at
which the device will be operated. Refer to Figure 9,
which shows safe operating curves for three different
ambient temperatures, 25°C, 50°C, and 85°C. From
these curves, the minimum amount of copper can be
determined by knowing the maximum power dissipation
required. If the maximum ambient temperature is 50°C,
and the power dissipation is 632mW, the curve in Figure
9 shows that the required area of copper is less than
100mm
2
, when using the power SOIC-8.
Micrel MIC5239
December 2007 12 M9999-121007
Adjustable Regulator Application
Figure 10. Adjustable Voltage Application
The MIC5239YM can be adjusted from 1.24V to 20V by
using two external resistors (Figure 10). The resistors
set the output voltage based on the following equation:
⎟
⎠
⎞
⎜
⎝
⎛+= R2
R1
1VV
REFOUT
Where V
REF
= 1.23V.
Feedback resistor R2 should be no larger than 300k.
Micrel MIC5239
December 2007 13 M9999-121007
Package Information
8-Pin MSOP (MM)
SOT-223 (S)
Micrel MIC5239
December 2007 14 M9999-121007
8-Pin SOIC (M)
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.
© 2003 Micrel, Incorporated.
Mouser Electronics
Authorized Distributor
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MIC5239-1.8YS MIC5239YMM MIC5239-3.3YS MIC5239-5.0YS MIC5239-5.0YS TR MIC5239-3.3YM MIC5239-
3.3YMM MIC5239-5.0YM MIC5239-5.0YMM MIC5239YM MIC5239-2.5YS MIC5239-1.5YM MIC5239-3.0YS
MIC5239-1.5YMM MIC5239-1.8YM MIC5239YM TR MIC5239-2.5YMM MIC5239-3.3YMM TR MIC5239-2.5YMM TR
MIC5239-1.5YS TR MIC5239-1.5YM TR MIC5239-1.8YS TR MIC5239-2.5YM MIC5239-3.0YMM MIC5239-1.8YMM
MIC5239YMM TR MIC5239-3.3YS TR MIC5239-3.3YM TR MIC5239-5.0YM TR MIC5239-3.0YS TR MIC5239-
2.5YS TR MIC5239-1.5YS MIC5239-3.0YMM TR MIC5239-2.5YM TR MIC5239-1.8YMM TR MIC5239-5.0YMM TR
MIC5239-1.8YM TR MIC5239-1.5YMM TR MIC5239-3.0YMM-TR MIC5239-1.5YS-TR MIC5239-3.3YM-TR MIC5239-
5.0YS-TR MIC5239-2.5YM-TR MIC5239-1.8YMM-TR MIC5239-1.8YM-TR MIC5239-1.5YM-TR MIC5239-2.5YMM-
TR MIC5239-2.5YS-TR MIC5239-3.3YMM-TR MIC5239-1.8YS-TR MIC5239-5.0YMM-TR MIC5239-3.0YS-TR
MIC5239-3.3YS-TR MIC5239YM-TR MIC5239-1.5YMM-TR MIC5239YMM-TR MIC5239-5.0YM-TR
