MIC5205
150mA Low-Noise LDO Regulator
Xxxxx is a trademark of Micrel, Inc
Xxxxx 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 2006
M9999-020806
(408) 955-1690
General Description
The MIC5205 is an efficient linear voltage regulator with
ultra low-noise output, very low dropout voltage (typically
17mV at light loads and 165mV at 150mA), and very low
ground current (600⎧A at 100mA output). The MIC5205
offers better than 1% initial accuracy.
Designed especially for hand-held, battery-powered
devices, the MIC5205 includes a CMOS or TTL compatible
enable/shutdown control input. When shut down, power
consumption drops nearly to zero. Regulator ground
current increases only slightly in dropout, further
prolonging battery life.
Key MIC5205 features include a reference bypass pin to
improve its already excellent low-noise performance,
reversed-battery protection, current limiting, and
overtemperature shutdown.
The MIC5205 is available in fixed and adjustable output
voltage versions in a small SOT-23-5 package.
For low-dropout regulators that are stable with ceramic
output capacitors, see the
µ
Cap MIC5245/6/7 family.
Data sheets and support documentation can be found on
Micrel’s web site at www.micrel.com.
Features
• Ultra-low-noise output
• High output voltage accuracy
• Guaranteed 150mA output
• Low quiescent current
• Low dropout voltage
• Extremely tight load and line regulation
• Very low temperature coefficient
• Current and thermal limiting
• Reverse-battery protection
• “Zero” off-mode current
• Logic-controlled electronic enable
Applications
• Cellular telephones
• Laptop, notebook, and palmtop computers
• Battery-powered equipment
• PCMCIA V
CC
and V
PP
regulation/switching
• Consumer/personal electronics
• SMPS post-regulator/dc-to-dc modules
• High-efficiency linear power supplies
___________________________________________________________________________________________________________
Typical Application
Ultra-Low-Noise Regulator Application
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Ordering Information
Part Number Marking
Standard Pb-Free Standard Pb-Free
(1)
Accuracy Voltage Temperature Package
MIC5205BM5 MIC5205YM5 LBAA KBAA 1% Adj –40°C to +125°C SOT-23-5
MIC5205-2.5BM5 MIC5205-2.5YM5 LB25 KB25 1% 2.5V –40°C to +125°C SOT-23-5
MIC5205-2.7BM5 MIC5205-2.7YM5 LB27 KB27 1% 2.7V –40°C to +125°C SOT-23-5
MIC5205-2.8BM5 MIC5205-2.8YM5 LB28 KB28 1% 2.8V –40°C to +125°C SOT-23-5
MIC5205-2.85BM5 MIC5205-2.85YM5 LB2J KB2J 1% 2.85V –40°C to +125°C SOT-23-5
MIC5205-2.9BM5 MIC5205-2.9YM5 LB29 KB29 1% 2.9V –40°C to +125°C SOT-23-5
MIC5205-3.0BM5 MIC5205-3.0YM5 LB30 KB30 1% 3.0V –40°C to +125°C SOT-23-5
MIC5205-3.1BM5 MIC5205-3.1YM5 LB31 KB31 1% 3.1V –40°C to +125°C SOT-23-5
MIC5205-3.2BM5 MIC5205-3.2YM5 LB32 KB32 1% 3.2V –40°C to +125°C SOT-23-5
MIC5205-3.3BM5 MIC5205-3.3YM5 LB33 KB33 1% 3.3V –40°C to +125°C SOT-23-5
MIC5205-3.6BM5 MIC5205-3.6YM5 LB36 KB36 1% 3.6V –40°C to +125°C SOT-23-5
MIC5205-3.8BM5 MIC5205-3.8YM5 LB38 KB38 1% 3.8V –40°C to +125°C SOT-23-5
MIC5205-4.0BM5 MIC5205-4.0YM5 LB40 KB40 1% 4.0V –40°C to +125°C SOT-23-5
MIC5205-5.0BM5 MIC5205-5.0YM5 LB50 KB50 1% 5.0V –40°C to +125°C SOT-23-5
Note:
1. Underbar (_) symbol may not be to scale.
Pin Configuration
MIC5205-x.xBM5/YM5 MIC5205BM5/YM5
Fixed Voltages Adjustable Voltages
Pin Description
MIC5205-x.x
(fixed)
MIC5205
(adjustable) Pin Name Pin Function
1 1 IN Supply Input
2 2 GND Ground
3 3 EN
Enable/Shudown (Input): CMOS compatible input. Logic high = enable, logic low
or open = shutdown
4 BYP
Reference Bypass: Connect external 470pF capacitor to GND to reduce output
noise. May be left open.
4 ADJ
Adjust (Input): Adjustable regulator feedback input. Connect to resistor voltage
divider.
5 5 OUT Regulator Ouput
Micrel MIC5205
February 2006 3
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Absolute Maximum Ratings
(1)
Supply Input Voltage (V
IN
).............................. –20V to +20V
Enable Input Voltage (V
EN
)............................. –20V to +20V
Power Dissipation (P
D
) .................Internally Limited, Note 3
Lead Temperature (soldering, 5 sec.)........................ 260°C
Junction Temperature (T
J
) ........................–40°C to +125°C
Storage Temperature (T
S
).........................–65°C to +150°C
Operating Ratings
(2)
Input Voltage (V
IN
)......................................... +2.5V to +16V
Enable Input Voltage (V
EN
).....................................0V to V
IN
Junction Temperature (T
J
) ........................ –40°C to +125°C
Thermal Resistance, SOT-23-5 (θ
JA
) ........................ Note 3
Electrical Characteristics
(4)
V
IN
= V
OUT
+ 1V; I
L
= 100µA; C
L
= 1.0µF; V
EN
≥ 2.0V; T
J
= 25°C, bold values indicate –40°C ≤ T
J
≤
+125°C; unless noted.
Symbol Parameter Condition Min Typ Max Units
V
O
Output Voltage Accuracy variations from specified V
OUT
–1
–2
1
2
%
%
∆V
O
/∆T Output Voltage Temperature
Coefficient
Note 4 40 ppm/°C
∆V
O
/V
O
Line Regulation V
IN
= V
OUT
+ 1V to 16V 0.004 0.012
0.05
%/V
%/V
∆V
O
/V
O
Load Regulation I
L
= 0.1mA to 150mA, Note 5 0.02 0.2
0.5
%
%
V
IN
– V
O
Dropout Voltage, Note 6 I
L
= 100µA
I
L
= 50mA
I
L
= 100mA
I
L
= 150mA
10
110
140
165
50
70
150
230
250
300
275
350
mV
mV
mV
mV
mV
mV
mV
mV
I
GND
Quiescent Current V
EN
≤ 0.4V (shutdown)
V
EN
≤ 0.18V (shutdown)
0.01 1
5
µA
µA
I
GND
Ground Pin Current, Note 7 V
EN
≥ 2.0V, I
L
= 100µA
I
L
= 50mA
I
L
= 100mA
I
L
= 150mA
80
350
600
1300
125
150
600
800
1000
1500
1900
2500
µA
µA
µA
µA
µA
µA
µA
µA
PSRR Ripple Rejection Frequency = 100Hz, I
L
= 100µA 75 dB
I
LIMIT
Current Limit V
OUT
= 0V 320 500 mA
∆V
O
/∆P
D
Thermal Regulation Note 8 0.05 %/W
e
NO
Output Noise I
L
= 50mA, C
L
= 2.2µF, 470pF from BYP to
GND
260 H
z
nV/
ENABLE Input
V
IL
Enable Input Logic-Low Voltage regulator shutdown 0.4
0.18
V
V
V
IH
Enable Input Logic-High
Voltage
regulator enabled 2.0 V
I
IL
I
IH
Enable Input Current V
IL
≤ 0.4V
V
IL
≤ 0.18V
V
IL
= 2.0V
V
IL
= 2.0V
2
0.01
5
–1
–2
20
25
µA
µA
µA
µA
Micrel MIC5205
February 2006 4
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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 at 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 MIC5205-xxBM5 (all
versions) is 220°C/W mounted on a PC board (see “Thermal Considerations” section for further details).
4. Output voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range.
5. Regulation is measured at constant junction temperature using low duty cycle pulse testing. Parts are tested for load regulation in the load range
from 0.1mA to 150mA. Changes in output voltage due to heating effects are covered by the thermal regulation specification.
6. 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.
7. 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.
8, 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 150mA load pulse at V
IN
= 16V for t = 10ms.
Micrel MIC5205
February 2006 5
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Typical Characteristics
Micrel MIC5205
February 2006 6
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(408) 955-1690
Typical Characteristics
Micrel MIC5205
February 2006 7
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(408) 955-1690
Block Diagrams
Ultra-Low-Noise Fixed Regulator
Ultra-Low-Noise Adjustable Regulator
Micrel MIC5205
February 2006 8
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Application Information
Enable/Shutdown
Forcing EN (enable/shutdown) high (> 2V) enables the
regulator. EN is compatible with CMOS logic gates.
If the enable/shutdown feature is not required, connect
EN (pin 3) to IN (supply input, pin 1). See Figure 1.
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.
Reference Bypass Capacitor
BYP (reference bypass) is connected to the internal
voltage reference. A 470pF capacitor (C
BYP
) connected
from BYP to GND quiets this reference, providing a
significant reduction in output noise. C
BYP
reduces the
regulator phase margin; when using C
BYP
, output
capacitors of 2.2µF or greater are generally required to
maintain stability.
The start-up speed of the MIC5205 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 C
BYP
.
Likewise, if rapid turn-on is necessary, consider omitting
C
BYP
.
If output noise is not a major concern, omit C
BYP
and
leave BYP open.
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. 1.0µF minimum is recommended
when C
BYP
is not used (see Figure 2). 2.2µF minimum is
recommended when C
BYP
is 470pF (see Figure 1).
Larger values improve the regulator’s transient
response. The output capacitor value may be increased
without limit.
The output capacitor should have an ESR (effective
series resistance) of about 5Ω or less 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 required for output stability. The capacitor
can be reduced to 0.47⎧F for current below 10mA or
0.33µF for currents below 1mA.
No-Load Stability
The MIC5205 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.
Thermal Considerations
The MIC5205 is designed to provide 150mA of
continuous current in a very small package. Maximum
power dissipation can be calculated based on the output
current and the voltage drop across the part. To
determine the maximum power dissipation of the
package, use the junction-to-ambient thermal resistance
of the device and the following basic equation:
(
)
JA
AJ(max)
D(max)
θ
TT
P−
=
T
J(max)
is the maximum junction temperature of the die,
125°C, and T
A
is the ambient operating temperature. θ
JA
is layout dependent; Table 1 shows examples of
junction-toambient thermal resistance for the MIC5205.
Package θJA
Recommended
Minimum
Footprint
θJA Square
Copper Clad
θJC
SOT-23-5(M5) 220°C/W 170°C/W 130°C/W
Table 1. SOT-23-5 Thermal Resistance
The actual power dissipation of the regulator circuit can
be determined using the equation:
P
D
= (V
IN
– V
OUT
) I
OUT
+ V
IN
I
GND
Substituting P
D(max)
for P
D
and solving for the operating
conditions that are critical to the application will give the
maximum operating conditions for the regulator circuit.
For example, when operating the MIC5205-3.3BM5 at
room temperature with a minimum footprint layout, the
maximum input voltage for a set output current can be
determined as follows:
(
)
455mWP
C/W220
C25C125
P
D(max)
D(max)
=
°
°−°
=
The junction-to-ambient thermal resistance for the
minimum footprint is 220°C/W, from Table 1. The
maximum power dissipation must not be exceeded for
proper operation. Using the output voltage of 3.3V and
an output current of 150mA, the maximum input voltage
can be determined. From the Electrical Characteristics
table, the maximum ground current for 150mA output
current is 2500µA or 2.5mA.
455mW = (V
IN
– 3.3V) 150mA + V
IN
·2.5mA
455mW = V
IN
×150mA – 495mW + V
IN
·2.5mA
950mW = V
IN
×152.5mA
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MIC5205
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V
IN(max)
= 6.23V
Therefore, a 3.3V application at 150mA of output current
can accept a maximum input voltage of 6.2V in a SOT-
23-5 package. 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.
Fixed Regulator Applications
Figure 1. Ultra-Low-Noise Fixed Voltage Application
Figure 1 includes a 470pF capacitor for low-noise
operation and shows EN (pin 3) connected to IN (pin 1)
for an application where enable/shutdown is not
required. C
OUT
= 2.2µF minimum.
Figure 2. Low-Noise Fixed Voltage Application
Figure 2 is an example of a low-noise configuration
where C
BYP
is not required. C
OUT
= 1µF minimum.
Adjustable Regulator Applications
The MIC5205BM5 can be adjusted to a specific output
voltage by using two external resistors (Figure 3). The
resistors set the output voltage based on the following
equation:
⎟
⎠
⎞
⎜
⎝
⎛+×= 1
R1
R2
1.242VV
OUT
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 and have a different V
OUT
equation.
Resistor values are not critical because ADJ (adjust) has
a high input impedance, but for best results use resistors
of 470kΩ or less. A capacitor from ADJ to ground
provides greatly improved noise performance.
Figure 3. Ultra-Low-Noise
Adjustable Voltage Application
Figure 3 includes the optional 470pF noise bypass
capacitor from ADJ to GND to reduce output noise.
Dual-Supply Operation
When used in dual supply systems where the regulator
load is returned to a negative supply, the output voltage
must be diode clamped to ground.
Micrel
MIC5205
February 2006 10
M9999-020806
(408) 955-1690
Package Information
SOT-23-5 (M5)
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
reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical impla
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.
can nt
© 2004 Micrel, Incorporated.
