MIC5209
500mA Low-Noise LDO Regulator
Intel is a registered trademark of Intel Corporation.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
July 15, 2014
Revision 3.1
General Description
The MIC5209 is an efficient linear voltage regulator with
very low dropout voltage, typically 10mV at light loads and
less than 500mV at full load, with better than 1% output
voltage accuracy
Designed especially for hand-held, battery-powered
devices, the MIC5209 features low ground current to help
prolong battery life. An enable/shutdown pin on SO-8 and
TO-263- 5 versions can further improve battery life with
near-zero shutdown current.
Key features include reversed-battery protection, current
limiting, overtemperature shutdown, ultra-low-noise
capability (SO-8 and TO-263-5 versions), and availability
in thermally-efficient packaging. The MIC5209 is available
in adjustable or fixed output voltages.
Datasheets and support documentation are available on
Micrel’s web site at: www.micrel.com.
Features
Output voltage range: 1.8V 5V
Meets Intel® Slot 1 and Slot 2 requirements
Guaranteed 500mA output over the full operating
temperature range
Low 500mV maximum dropout voltage at full load
Extremely tight load and line regulation
Thermally-efficient surface-mount package
Low temperature coefficient
Current and thermal limiting
Reversed-battery protection
No-load stability
1% output accuracy
Ultra-low-noise capability in SO-8 and TO-263-5
Ultra-small 3mm × 3mm DFN package
Applications
Pentium II Slot 1 and Slot 2 support circuits
Laptop, notebook, and palmtop computers
Cellular telephones
Consumer and personal electronics
SMPS post-regulator/DC-to-DC modules
High-efficiency linear power supplies
Typical Application
3.3V Nominal Input Slot 1 Power Supply
Ultra-Low Noise 5V Regulator
Micrel, Inc.
MIC5209
July 15, 2014
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Ordering Information
Part Number
Voltage
Junction Temperature Range
Package
Pb-Free
MIC5209-2.5BS
2.5V
-40°C to +125°C
SOT-223
MIC5209-2.5YS
2.5V
-40°C to +125°C
SOT-223
X
MIC5209-3.0BS
3.0V
-40°C to +125°C
SOT-223
MIC5209-3.0YS
3.0V
-40°C to +125°C
SOT-223
X
MIC5209-3.3BS
3.3V
-40°C to +125°C
SOT-223
MIC5209-3.3YS
3.3V
-40°C to +125°C
SOT-223
X
MIC5209-3.6BS
3.6V
-40°C to +125°C
SOT-223
MIC5209-3.6YS
3.6V
-40°C to +125°C
SOT-223
X
MIC5209-4.2BS
4.2V
-40°C to +125°C
SOT-223
MIC5209-4.2YS
4.2V
-40°C to +125°C
SOT-223
X
MIC5209-5.0BS
5.0V
-40°C to +125°C
SOT-223
MIC5209-5.0YS
5.0V
-40°C to +125°C
SOT-223
X
MIC5209-1.8BM(1)
1.8V
-0°C to +125°C
SOIC-8
MIC5209-1.8YM(1)
1.8V
-0°C to +125°C
SOIC-8
X
MIC5209-2.5BM
2.5V
-40°C to +125°C
SOIC-8
MIC5209-2.5YM
2.5V
-40°C to +125°C
SOIC-8
X
MIC5209-3.0BM
3.0V
-40°C to +125°C
SOIC-8
MIC5209-3.0YM
3.0V
-40°C to +125°C
SOIC-8
X
MIC5209-3.3BM
3.3V
-40°C to +125°C
SOIC-8
MIC5209-3.3YM
3.3V
-40°C to +125°C
SOIC-8
X
MIC5209-3.6BM
3.6V
-40°C to +125°C
SOIC-8
MIC5209-3.6YM
3.6V
-40°C to +125°C
SOIC-8
X
MIC5209-5.0BM
5.0V
-40°C to +125°C
SOIC-8
MIC5209-5.0YM
5.0V
-40°C to +125°C
SOIC-8
X
MIC5209BM
Adjustable (2.5V 5.0V)
-40°C to +125°C
SOIC-8
MIC5209YM
Adjustable (2.5V 5.0V)
-40°C to +125°C
SOIC-8
X
MIC5209-1.8YU(1)
1.8V
-0°C to +125°C
TO-263-5
X
MIC5209-2.5BU
2.5V
-40°C to +125°C
TO-263-5
MIC5209-2.5YU
2.5V
-40°C to +125°C
TO-263-5
X
Note:
1. Contact Micrel for availability.
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MIC5209
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Ordering Information (Continued)
Part Number
Voltage
Junction Temperature Range
Package
Pb-Free
MIC5209-3.0BU
3.0V
-40°C to +125°C
TO-263-5
MIC5209-3.0YU
3.0V
-40°C to +125°C
TO-263-5
X
MIC5209-3.3BU
3.3V
-40°C to +125°C
TO-263-5
MIC5209-3.3YU
3.3V
-40°C to +125°C
TO-263-5
X
MIC5209-3.6BU
3.6V
-40°C to +125°C
TO-263-5
MIC5209-3.6YU
3.6V
-40°C to +125°C
TO-263-5
X
MIC5209-5.0BU
5.0V
-40°C to +125°C
TO-263-5
MIC5209-5.0YU
5.0V
-40°C to +125°C
TO-263-5
X
MIC5209BU
Adjustable (2.5V 5.0V)
-40°C to +125°C
TO-263-5
MIC5209YU
Adjustable (2.5V 5.0V)
-40°C to +125°C
TO-263-5
X
MIC5209YML
Adjustable (2.5V 5.0V)
40°C to +125°C
8-Pin DFN
X
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MIC5209
July 15, 2014
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Pin Configuration
MIC5209-x.xBS
SOT-223
Fixed Voltages
MIC5209YML
8-Pin 3mm × 3mm DFN
Adjustable Voltages
MIC5209-x.xBM
SO-8
Fixed Voltages
MIC5209-x.xBU
TO-263-5
Fixed Voltages
MIC5209BM
SO-8
Adjustable Voltages
MIC5209BU
TO-263-5
Adjustable Voltages
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MIC5209
July 15, 2014
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Pin Description
Pin Number
8-Pin DFN
Pin Number
SOT-223
Pin Number
SO-8
Pin Number
TO-263-5
Pin Name
Pin Function
1, 2
1
2
2
IN
Supply Input.
7
2, TAB
5 8
3
GND
Ground: SOT-223 Pin 2 and TAB are internally
connected. SO-8 Pins 5 through 8 are internally
connected.
3, 4
3
3
4
OUT
Regulator Output: Pins 3 and 4 must be tied
together.
8
1
1
EN
Enable (Input): CMOS-compatible control input.
Logic High = Enable; Logic Low = Shutdown.
4 (Fixed)
5 (Fixed)
BYP
Reference Bypass: Connect external 470pF
capacitor to GND to reduce output noise. Can be
left open. For 1.8V or 2.5V operation, see
Application Information.
6
4 (Adjustable)
5 (Adjustable)
ADJ
Adjust (Input): Feedback input. Connect to
resistive voltage-divider network.
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MIC5209
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Absolute Maximum Ratings(2)
Supply Voltage (VIN) ....................................... 20V to +20V
Power Dissipation (PD). .......................... Internally Limited(4)
Junction Temperature (TJ)
All Except 1.8V ................................... 40C to +125C
1.8V Only ................................................ 0C to +125C
Lead Temperature (soldering, 5s) .............................. 260°C
Storage Temperature (TS) ......................... 65°C to +150C
Operating Ratings(3)
Supply Voltage (VIN) ...................................... +2.5V to +16V
Output Voltage (VOUT) Range ......................... +1.8V to 5.0V
Junction Temperature (TJ)
2.5V 5.0V ......................................... –40°C to +125°C
1.8V VOUT 2.5V .................................. 0C to +125C
Package Thermal Resistance .................................... Note 4
Electrical Characteristics
VIN = VOUT + 1V, COUT = 4.7µF, IOUT = 100µA; TJ = 25°C, bold values indicate –40°C TJ +125°C, except 0C TJ +125C
for 1.8V VOUT 2.5V, unless noted.
Symbol
Parameter
Condition
Min.
Typ.
Max.
Units
VOUT
Output Voltage Accuracy
Variation from nominal VOUT
1
1
%
2
2
VOUT/T
Output Voltage Temperature Co-Efficient
Note 5
40
ppm/C
VOUT/ VOUT
Line Regulation
VIN = VOUT + 1V to 16V
0.009
0.05
%/V
0.1
Load Regulation
IOUT = 100µA to 500mA(6)
0.05
0.5
%
0.7
VIN VOUT
Dropout Voltage(7)
IOUT = 100µA
10
60
mV
80
IOUT = 50mA
115
175
250
IOUT = 150mA
165
300
400
IOUT = 500mA
350
500
600
Notes:
2. Exceeding the absolute maximum ratings may damage the device.
3. The device is not guaranteed to function outside its operating ratings.
4. The maximum allowable power dissipation at any TA (ambient temperature) is calculated using: PD(MAX) = (TJ(MAX) – TA) JA. Exceeding the maximum
allowable power dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown. See Table 1 and the “Thermal
Considerations” sub-section in Application Information for details.
5. Output voltage temperature coefficient is the worst case voltage change divided by the total temperature range.
6. Regulation is measured at constant junction temperature using low duty cycle pulse testing. Parts are tested for load regulation in the load range
from 100µA to 500mA. Changes in output voltage due to heating effects are covered by the thermal regulation specification.
7. Dropout voltage is defined as the input to output differential at which the output voltage drops 2% below its nominal value measured at 1V
differential.
8. Ground pin current is the regulator quiescent current plus pass transistor base current. The total current drawn from the supply is the sum of the load
current plus the ground pin current.
9. VEN is the voltage externally applied to devices with the EN (enable) input pin. [SO-8 (M) and TO-263-5 (U) packages only.]
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MIC5209
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Electrical Characteristics (Continued)
VIN = VOUT + 1V, COUT = 4.7µF, IOUT = 100µA; TJ = 25°C, bold values indicate –40°C TJ +125°C, except 0C TJ +125C
for 1.8V VOUT 2.5V, unless noted.
Symbol
Parameter
Condition
Min.
Typ.
Max.
Units
IGND
Ground Pin Current(8, 9)
VEN 3.0V, IOUT = 100µA
80
130
µA
170
VEN 3.0V, IOUT = 50mA
350
650
900
VEN 3.0V, IOUT = 150mA
1.8
2.5
mA
3.0
VEN 3.0V, IOUT = 500mA
8
20
25
IGND
Ground Pin Quiescent Current(9)
VEN 0.4V (Shutdown)
0.05
3
µA
VEN 0.18V (Shutdown)
0.10
8
PSRR
Ripple Rejection
f = 120Hz
75
dB
ILIMIT
Current Limit
VOUT = 0V
700
900
mA
1000
VOUT/PD
Thermal Regulation
Note 10
0.05
%/W
eNO
Output Noise(11)
VOUT = 2.5V, IOUT = 50mA
COUT = 2.2µF, CBYP = 0
500
nV √Hz
IOUT = 50mA, COUT = 2.2µF
CBYP = 470pF
300
VENL
Enable Input Logic-Low Voltage
VEN = Logic Low
(Regulator Shutdown)
0.4
V
0.18
VEN = Logic High
(Regulator Enabled)
2.0
IENL
Enable Input Current
VENL 0.4V
0.01
1
µA
VENL 0.18V
0.01
2
IENH
VENH 2.0V
5
20
µA
25
VENH 16V
30
50
Notes:
10. Thermal regulation is 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 500mA load pulse at V N = 16V for t = 10ms.
11. CBYP is an optional, external bypass capacitor connected to devices with a BYP (bypass) or ADJ (adjust) pin. [SO-8 (M) and TO-263-5 (U) packages
only].
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MIC5209
July 15, 2014
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Block Diagrams
Low-Noise Fixed Regulator (SOT-223 Version Only)
Ultra-Low-Noise Fixed Regulator
Ultra-Low-Noise Adjustable Regulator
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MIC5209
July 15, 2014
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Typical Characteristics
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MIC5209
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Typical Characteristics (Continued)
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MIC5209
July 15, 2014
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Application Information
Enable Shutdown
Enable is available only on devices in the SO-8 (M) and
TO-263-5 (U) packages.
Forcing EN (enable/shutdown) high (> 2V) enables the
regulator. EN is compatible with CMOS logic. If the
enable/shutdown feature is not required, connect EN to
IN (supply input).
Input Capacitor
A 1µF capacitor should be placed from IN to GND if there
is more than 10 inches of wire between the input and the
AC filter capacitor or if a battery is used as the input.
Output Capacitor
An output capacitor is required between OUT and GND
to prevent oscillation. The minimum size of the output
capacitor is dependent upon whether a reference bypass
capacitor is used. 1µF minimum is recommended when
CBYP is not used (see Figure 1). 2.2µF minimum is
recommended when CBYP is 470pF (see Figure 2).
Larger values improve the regulator’s transient response.
The output capacitor should have an ESR (equivalent
series resistance) of about 1Ω and a resonant frequency
above 1MHz. Ultra-low-ESR capacitors can cause a low
amplitude oscillation on the output and/or underdamped
transient response. Most tantalum or aluminum
electrolytic capacitors are adequate; film types will work,
but are more expensive. Since many aluminum
electrolytics have electrolytes that freeze at about –30°C,
solid tantalums are recommended for operation below
25°C.
At lower values of output current, less output capacitance
is needed for output stability. The capacitor can be
reduced to 0.47µF for current below 10mA or 0.33µF for
currents below 1mA.
No-Load Stability
The MIC5209 will remain stable and in regulation with no
load (other than the internal voltage divider) unlike many
other voltage regulators. This is especially important in
CMOS RAM keep-alive applications.
Reference Bypass Capacitor
BYP (reference bypass) is available only on devices in
SO-8 and TO-263-5 packages.
BYP is connected to the internal voltage reference. A
470pF capacitor (CBYP) connected from BYP to GND
quiets this reference, providing a significant reduction in
output noise (ultra-low-noise performance). Because CBYP
reduces the phase margin, the output capacitor should be
increased to at least 2.2µF to maintain stability.
The start-up speed of the MIC5209 is inversely
proportional to the size of the reference bypass capacitor.
Applications requiring a slow ramp-up of output voltage
should consider larger values of CBYP. Likewise, if rapid
turn-on is necessary, consider omitting CBYP.
If output noise is not critical, omit CBYP and leave BYP
open.
Thermal Considerations
The SOT-223 has a ground tab which allows it to
dissipate more power than the SO-8 (refer to the “Slot-1
Power Supply” sub-section for details). At 25°C ambient,
it will operate reliably at 2W dissipation with “worst-case”
mounting (no ground plane, minimum trace widths, and
FR4 printed circuit board).
Thermal resistance values for the SO-8 represent typical
mounting on a 1”-square, copper-clad, FR4 circuit board.
For greater power dissipation, SO-8 versions of the
MIC5209 feature a fused internal lead frame and die
bonding arrangement that reduces thermal resistance
when compared to standard SO-8 packages.
Table 1. MIC5209 Thermal Resistance
Package
JA
JC
SOT-223 (S)
50C/W
8C/W
SO-8 (M)
50C/W
20C/W
TO-263-5 (U)
2C/W
3mm × 3mm DFN (ML)
63C/W
2C/W
Multilayer boards with a ground plane, wide traces near
the pads, and large supply-bus lines will have better
thermal conductivity and will also allow additional power
dissipation.
For additional heat sink characteristics, refer to Micrel
Application Hint 17, Designing P.C. Board Heat Sinks,
included in Micrel’s Databook. For a full discussion of
heat sinking and thermal effects on voltage regulators,
refer to the “Regulator Thermals” section of Micrel’s
Designing with Low-Dropout Voltage Regulators
handbook.
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MIC5209
July 15, 2014
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Low-Voltage Operation
The MIC5209-1.8 and MIC5209-2.5 require special
consideration when used in voltage-sensitive systems.
They may momentarily overshoot their nominal output
voltages unless appropriate output and bypass capacitor
values are chosen.
During regulator power up, the pass transistor is fully
saturated for a short time, while the error amplifier and
voltage reference are being powered up more slowly from
the output (see Block Diagrams). Selecting larger output
and bypass capacitors allows additional time for the error
amplifier and reference to turn on and prevent overshoot.
To ensure that no overshoot is present when starting up
into a light load (100µA), use a 4.7µF output capacitance
and 470pF bypass capacitance. This slows the turn-on
enough to allow the regulator to react and keep the
output voltage from exceeding its nominal value. At
heavier loads, use a 10µF output capacitance and 470pF
bypass capacitance. Lower values of output and bypass
capacitance can be used, depending on the sensitivity of
the system.
Applications that can withstand some overshoot on the
output of the regulator can reduce the output capacitor
and/or reduce or eliminate the bypass capacitor.
Applications that are not sensitive to overshoot due to
power-on reset delays can use normal output and bypass
capacitor configurations.
Please note the junction temperature range of the
regulator output less than 2.5V (fixed and adjustable) is
0C to +125C.
Fixed Regulator Circuits
Figure 1 shows a basic MIC5209-x.xBM (SO-8) fixed-
voltage regulator circuit. See Figure 5 for a similar
configuration using the more thermally-efficient MIC5209-
x.xBS (SOT-223). A 1µF minimum output capacitor is
required for basic fixed- voltage applications.
Figure 1. Low-Noise Fixed Voltage Regulator
Figure 2 includes the optional 470pF noise bypass
capacitor between BYP and GND to reduce output noise.
Note that the minimum value of COUT must be increased
when the bypass capacitor is used.
Figure 2. Ultra-Low-Noise Fixed Voltage Regulator
Adjustable Regulator Circuits
The MIC5209BM/U can be adjusted to a specific output
voltage by using two external resistors (Figure 3). The
resistors set the output voltage based on the equation:
1R2R
1V242.1VOUT
Eq. 1
This equation is correct due to the configuration of the
bandgap reference. The bandgap voltage is relative to
the output, as seen in the block diagram. Traditional
regulators normally have the reference voltage relative to
ground; therefore, their equations are different from the
equation for the MIC5209BM/U.
Although ADJ is a high-impedance input and, for best
performance, R2 should not exceed 470kΩ.
Figure 3. Low-Noise Adjustable Voltage Regulator
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Figure 4 includes the optional 470pF bypass capacitor
from ADJ to GND to reduce output noise.
Figure 4. Ultra-Low-Noise Adjustable Application
Slot-1 Power Supply
Intel’s Pentium II processors have a requirement for a
2.5V ±5% power supply for a clock synthesizer and its
associated loads. The current requirement for the 2.5V
supply is dependent upon the clock synthesizer used, the
number of clock outputs, and the type of level shifter
(from core logic levels to 2.5V levels). Intel estimates a
“worst-case” load of 320mA.
The MIC5209 was designed to provide the 2.5V power
requirement for Slot-1 applications. Its guaranteed
performance of 2.5V ±3% at 500mA allows adequate
margin for all systems, and the dropout voltage of 500mV
means that it operates from a “worst-case” 3.3V supply
where the voltage can be as low as 3.0V.
Figure 5. Slot-1 Power Supply
A Slot-1 power supply (Figure 5) is easy to implement.
Only two capacitors are necessary, and their values are
not critical. CIN bypasses the internal circuitry and should
be at least 0.1µF. COUT provides output filtering,
improves transient response, and compensates the
internal regulator control loop. Its value should be at least
22µF. CIN and COUT can be increased as much as
desired.
Slot-1 Power Supply Power Dissipation
Powered from a 3.3V supply, the Slot-1 power supply
illustrated in Figure 5 has a nominal efficiency of 75%. At
the maximum anticipated Slot-1 load (320mA), the
nominal power dissipation is only 256mW.
The SOT-223 package has sufficient thermal
characteristics for wide design margins when mounted on
a single-layer copper-clad printed circuit board. The
power dissipation of the MIC5209 is calculated using the
voltage drop across the device output current plus supply
voltage ground current.
Considering “worst-case” tolerances, the power
dissipation could be as high as:
(VIN(MAX) VOUT(MAX)) × IOUT + VIN(MAX) × IGND
[(3.6V 2.375V) × 320mA] + (3.6V × 4mA)
PD = 407mW
Using the maximum junction temperature of 125°C and a
JC of 8°C/W for the SOT-223, 25°C/W for the SO-8, or
2°C/W for the TO-263 package, the following worst-case
heat-sink thermal resistance (SA) requirements are:
JCJASA
D
A)MAX(J
JA PTT
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MIC5209
July 15, 2014
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Table 2 and Figure 6 show that the Slot-1 power supply
application can be implemented with a minimum footprint
layout.
Table 2. Maximum Allowable Thermal Resistance
TA
40C
50C
60C
75C
JA (Limit)
209C/W
184C/W
160C/W
123C/W
SA SOT-223
201C/W
176C/W
152C/W
115C/W
SA SO-8
184C/W
159C/W
135C/W
98C/W
SA TO-263-5
207C/W
182C/W
158C/W
121C/W
Figure 6 shows the necessary copper pad area to obtain
specific heatsink thermal resistance (SA) values. The SA
values highlighted in Table 2 require much less than
500mm2 of copper and, per Figure 6, can be easily
accomplished with the minimum footprint.
Figure 6. PCB Heatsink Thermal Resistance
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MIC5209
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Package Information(12) (Continued)
8-Pin 3mm × 3mm DFN (ML)
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
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