MIC5323
High PSRR Low Noise 300mA µCap
Ultra-Low Dropout LDO Regulator
MicroLeadFrame and MLF are trademarks of Amkor, 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
November 2011 1 M9999-110311B
General Description
The MIC5323 is a high-performance, 300mA LDO regula-
tor, offering extremely high PSRR and very low noise while
consuming low ground current.
Ideal for battery operated applications, the MIC5323
features 2% accuracy, extremely low dropout voltage
(120mV @ 300mA), and low ground current at light load
(typically 90µA). When disabled, the MIC5323 typically
consumes less than 1µA.
The MIC5323 is a µCap design operating with small
ceramic output capacitors for stability, thereby reducing
required board space and component cost.
The MIC5323 is available in fixed output voltages and
adjustable output voltages in the super compact
6-pin 2mm × 2mm Thin MLF® and thin SOT-23-5 package.
Additional voltage options are available. Contact Micrel
marketing.
Data sheets and support documentation can be found on
Micrel’s web site at www.micrel.com.
Features
Ultra low dropout voltage of 120mV @ 300mA
Input voltage range: 2.65 to 5.5V
Stable with ceramic output capacitor
300mA guaranteed output current
Low output noise — 20µVrms
High PSRR, up to 80dB @1kHz
Less than 30µs turn-on time with CBYP = 0.1µF
High output accuracy: ±2.0% over temperature
Thermal shutdown protection
Current limit protection
6-pin 2mm × 2mm Thin MLF® package
Thin SOT-23-5 package
Applications
Cellular phones
Notebook and Tablet Computers
Fiber optic modules
Portable electronics
Instrumentation Systems
Audio Codec power supplies
Typical Application
Power Supply Rejection Ratio
(C
BYP
= 0.1µF)
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06
FREQUENCY (Hz)
PSRR (dB)
V
IN
= V
OUT
+ 1V
V
OUT
= 1.8V
I
OUT
= 1mA
I
OUT
= 100mA
I
OUT
= 300mA
Micrel, Inc. MIC5323
November 2011 2 M9999-110311B
Ordering Information
Part Number(1) Marking(2) Voltage Junction
Temp. Range(2) Package(3)
MIC5323-1.8YMT 23G 1.8V –40°C to +125°C 6-Pin 2mm x 2mm Thin MLF®
MIC5323-2.8YMT 23M 2.8V –40°C to +125°C 6-Pin 2mm x 2mm Thin MLF®
MIC5323-3.3YMT 23S 3.3V –40°C to +125°C 6-Pin 2mm x 2mm Thin MLF®
MIC5323YMT 23A ADJ –40°C to +125°C 6-Pin 2mm x 2mm Thin MLF®
MIC5323-1.8YD5 2318 1.8V –40°C to +125°C Thin SOT23-5
MIC5323-2.8YD5 2328 2.8V –40°C to +125°C Thin SOT23-5
MIC5323-3.3YD5 2333 3.3V –40°C to +125°C Thin SOT23-5
Notes:
1. For other output voltage and/or temperature options, contact Micrel marketing.
2. Underbar/Overbar symbols may not be to scale.
3. Pin 1 identifier for 2x2 Thin MLF® is “▲” symbol.
Micrel, Inc. MIC5323
November 2011 3 M9999-110311B
Pin Configuration
MIC5323-x.xYMT (Fixed) 6-Pin 2mm x 2mm Thin MLF® (MT)
(Top View)
MIC5323YMT (Adjustable) 6-Pin 2mm x 2mm Thin MLF® (MT)
(Top View)
MIC5323-x.xYD5 (Fixed)TSOT-23-5 (D5)
(Top View)
Pin Description
Pin Number
Thin MLF®-6
Adjustable
Pin Number
Thin MLF®-6
Fixed
Pin Number
TSOT23-5
Fixed
Pin
Name
Pin Description
1 1 3 EN
Enable Input: Active High. High = on, low = off. Do not leave
floating.
2 2 2 GND Ground.
3 3 1 VIN Supply Input.
4 4 5 VOUT Output Voltage.
5 – – ADJ
Adjust Input: Connect to external resistor voltage divider
network.
– 5 – NC No connection for fixed voltage parts.
6 6 4 BYP
Reference Bypass: Connect external 0.1µF capacitor to GND for
reduced output noise. May be left open.
EPAD EPAD – EPAD
Exposed Heatsink Pad: Connect to ground plane for
performance enhancement.
Micrel, Inc. MIC5323
November 2011 4 M9999-110311B
Absolute Maximum Ratings (1)
Supply Voltage (VIN)............................................... 0V to 6V
Enable Input Voltage (VEN)..................................... 0V to 6V
Power Dissipation (PD)........................... Internally Limited(3)
Junction Temperature (TJ) ........................–40°C to +125°C
Lead Temperature (soldering, 5sec.)......................... 260°C
Storage Temperature (Ts) .........................–65°C to +150°C
ESD Rating(4).................................................................. 2kV
Operating Ratings (2)
Supply voltage (VIN) ....................................... 2.65V to 5.5V
Enable Input Voltage (VEN)..................................... 0V to VIN
Junction Temperature (TJ) ........................ –40°C to +125°C
Junction Thermal Resistance
2mm x 2mm Thin MLF® 6 pin (θJA)....................93°C/W
TSOT-23-5 (θJA) ..............................................235°C/W
Electrical Characteristics (5)
VIN = VOUT + 1.0V; COUT = 2.2µF; IOUT = 100µA; TJ = 25°C, bold values indicate –40°C to +125°C, unless noted.
Parameter Condition Min Typ Max Units
Ouput Voltage Accuracy Variation from nominal VOUT, IOUT = 100µA to 300mA –2.0 +2.0 %
Line Regulation VIN = VOUT +1V to 5.5V 0.02 0.3 %/V
Load Regulation(6) IOUT = 100µA to 300mA 0.1 0.5 %
IOUT = 50mA, VOUT > 2.8V 20 35 mV
IOUT = 150mA, VOUT > 2.8V 60 85 mV
IOUT = 300mA, VOUT > 2.8V 120 170 mV
IOUT = 50mA, VOUT =< 2.8V 25 45 mV
IOUT = 150mA, VOUT =< 2.8V 75 110 mV
Dropout Voltage
IOUT = 300mA, VOUT =< 2.8V 150 220 mV
Ground Pin Current(7) IOUT = 0 to 300mA 90 150 µA
Ground Pin Current in
Shutdown
VEN = 0V 0.5 2 µA
f = 1kHz; COUT = 2.2µF ceramic; CBYP = 0.1µF 80 dB Ripple Rejection
f = 10kHz; COUT = 2.2µF ceramic; CBYP = 0.1µF 65 dB
Current Limit VOUT = 0V 350 600 900 mA
Output Voltage Noise COUT =2.2µF, CBYP = 0.1µF, 10Hz to 100kHz 20 µVrms
Turn-On Time COUT = 2.2µF; CBYP= 0.1µF; IOUT = 300mA 30 150 µs
Logic Low 0.2 V Enable Input Voltage
Logic High 1.2 V
VIL ≤ 0.2V 0.01 1 µA Enable Input Current
VIH ≥ 1.2V 0.01 1 µA
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 TA (ambient temperature) is PD(max) = (TJ(max) - TA) / θJA. Exceeding the maximum allowable
power dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown.
4. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5kΩ in series with 100pF.
5. Specification for packaged product only.
6. Regulation is measured at constant junction temperature using low duty cycle pulse testing, changes in output voltage due to heating effects
are covered by the thermal regulation specification.
7. Ground pin current is the regulator quiescent current. The total current drawn from the supply is the sum of the load current plus the ground
pin current.
Micrel, Inc. MIC5323
November 2011 5 M9999-110311B
Typical Characteristics
Power Supply Rejection Ratio
(C
BYP
=1µF)
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06
FREQUENCY (Hz)
PSRR (dB)
V
IN
= V
OUT
+ 1V
V
OUT
= 1.8V
I
OUT
= 1mA
I
OUT
= 100mA
I
OUT
= 300mA
Power Supply Rejection Ratio
(C
BYP
= 0.1µF)
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06
FREQUENCY (Hz)
PSRR (dB)
V
IN
= V
OUT
+ 1V
V
OUT
= 1.8V
I
OUT
= 1mA
I
OUT
= 100mA
I
OUT
= 300mA
Power Supply Rejection Ratio
(C
BYP
= 0.01µF)
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06
FREQUENCY (Hz)
PSRR (dB)
V
IN
= V
OUT
+ 1V
V
OUT
= 1.8V
I
OUT
= 1mA
I
OUT
= 100mA
I
OUT
= 300mA
Ground Current vs.
Input Voltage
50
60
70
80
90
100
110
2.5 3.0 3.5 4.0 4.5 5.0 5.5
INPUT VOLTAGE (V)
GROUND CURRENT (µA)
I
OUT
= 300mA
I
OUT
= 100µA
I
OUT
= 100mA
V
OUT
= 1.8V
Ground Current vs.
Output Current
50
60
70
80
90
100
110
0 50 100 150 200 250 300
OUTPUT CURRENT (mA)
GROUND CURRENT (µA)
V
IN
= V
OUT
+ 1V
V
OUT
= 1.8V
Ground Current vs.
Temperature
50
60
70
80
90
100
110
-40-200 20406080100120
TEMPERATURE (°C)
GROUND CURRENT (µA)
I
OUT
= 300mA
I
OUT
= 100mA
I
OUT
= 100µA
V
IN
= V
OUT
+ 1V
V
OUT
= 1.8V
Output Voltage vs.
Input Voltage
1.5
2.0
2.5
3.0
3.5
2.5 3.0 3.5 4.0 4.5 5.0 5.5
INPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
I
OUT
= 300mA
I
OUT
= 100µA
I
OUT
= 150mA
V
OUT
= 2.8V
Current Limit vs.
Input Voltage
100
200
300
400
500
600
700
800
2.5 3.0 3.5 4.0 4.5 5.0 5.5
INPUT VOLTAGE (V)
CURRENT LIMIT (mA)
V
OUT
= 1.8V
Dropout Voltage vs.
Output Current
0
20
40
60
80
100
120
140
160
0 50 100 150 200 250 300
OUTPUT CURRENT (mA)
DROPOUT (mV)
V
OUT
= 2.8V
Micrel, Inc. MIC5323
November 2011 6 M9999-110311B
Dropout Voltage vs.
Temperature
0
20
40
60
80
100
120
140
160
-40-20 0 2040 6080100120
TEMPERATURE (°C)
DROPOUT (mV)
I
OUT
= 300mA
I
OUT
= 100mA
I
OUT
= 200mA
I
OUT
= 10mA V
OUT
= 2.8V
Output Voltage vs.
Temperature
1.700
1.725
1.750
1.775
1.800
1.825
1.850
1.875
1.900
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
OUTPUT VOLTAGE (V)
V
IN
= 5.5V
V
OUT
= 1.8V
I
OUT
= 100µ
A
Output Noise
Spectral Density
0.001
0.010
0.100
1.000
10.000
1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06
FREQUENCY (Hz)
NOISE µV/√Hz
V
IN
= V
OUT
+ 1V
V
OUT
= 1.8V
C
BYP
= 0.01µF
Noise (10Hz-100kHz) = 18.7µV
Output Noise
Spectral Density
0.001
0.010
0.100
1.000
10.000
1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06
FREQUENCY (Hz)
NOISE µV/√Hz
VIN = VOUT + 1V
VOUT = 1.8V
CBYP = 0.1µF
Noise (10Hz-100kHz) = 18.7µV
Output Noise
Spectral Density
0.001
0.010
0.100
1.000
10.000
1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06
FREQUENCY (Hz)
NOISE µV/√Hz
VIN = VOUT + 1V
VOUT = 1.8V
CBYP = 1µF
Noise (10Hz-100kHz) = 18µV
Micrel, Inc. MIC5323
November 2011 7 M9999-110311B
Functional Characteristics
Micrel, Inc. MIC5323
November 2011 8 M9999-110311B
Functional Diagram
MIC5323 Block Diagram – Fixed
MIC5323 Block Diagram – Adjustable
Micrel, Inc. MIC5323
November 2011 9 M9999-110311B
Application Information
Enable/Shutdown
The MIC5323 comes with an active high enable pin that
allows the regulator to be disabled. Forcing the enable
pin low disables the regulator and sends it into a “zero”
off mode current state. In this state, current consumed
by the regulator goes nearly to zero. Forcing the enable
pin high enables the output voltage. The active high
enable pin uses CMOS technology, and the enable pin
cannot be left floating; a floating enable pin may cause
an indeterminate state on the output.
Input Capacitor
The MIC5323 is a high performance, high bandwidth
device. Therefore, it requires a well-bypassed input
supply for optimal performance. A 2.2µF capacitor is
required from the input-to-ground to provide stability.
Low ESR ceramic capacitors provide optimal perform-
ance using a minimum amount of space. Additional high
frequency capacitors, such as small valued NPO
dielectric type capacitors, help filter out high-frequency
noise, and are a good practice in any RF based circuit.
Output Capacitor
The MIC5323 requires an output capacitor of 2.2µF or
greater to maintain stability. The design is optimized for
use with low ESR ceramic chip capacitors. High ESR
capacitors may cause high frequency oscillation. The
output capacitor can be increased, but performance has
been optimized for a 2.2µF ceramic output capacitor,
and it does not improve significantly with larger
capacitance.
X7R/X5R dielectric type ceramic capacitors are recom-
mended because of their temperature performance. X7R
type capacitors change capacitance by 15% over their
operating temperature range, making them the most
stable type of ceramic capacitors. Z5U and Y5V
dielectric capacitors 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.
Bypass Capacitor
A capacitor can be placed from the noise bypass pin to
ground to reduce output voltage noise. The capacitor
bypasses the internal reference. A 0.1µF capacitor is
recommended for applications that require low noise
outputs. The bypass capacitor can be increased, further
reducing noise and improving PSRR. Turn-on time
increases slightly with respect to bypass capacitance. A
unique, quick-start circuit allows the MIC5323 to drive a
large capacitor on the bypass pin without significantly
slowing turn on time. Refer to the Typical Characteristics
section for performance with different bypass capacitors.
No Load Stability
Unlike many other voltage regulators, the MIC5323 will
remain stable and in regulation with no load. This is
especially important in CMOS RAM keep alive
applications.
Adjustable Regulator Application
Adjustable regulators use the ratio of two resistors to
multiply the reference voltage to produce the desired
output voltage. The MIC5323 can be adjusted from
1.25V to 5.5V by using two external resistors (Figure 1).
The resistors set the output voltage based on the
following equation:
1.25V=
REF
V
R2
R1
+1
REF
V=
OUT
V
Figure 1. Adjustable Voltage Application
Micrel, Inc. MIC5323
November 2011 10 M9999-110311B
Thermal Considerations
The MIC5323 is designed to provide 300mA of
continuous current in a very small package. Maximum
ambient operating temperature can be calculated based
on the output current and the voltage drop across the
part. Given that the input voltage is 3.3V, the output
voltage is 2.8V and the output current = 300mA.
The actual power dissipation of the regulator circuit can
be determined using the equation:
P
D = (VIN – VOUT) IOUT + VIN IGND
Because this device is CMOS and the ground current is
typically <100µA over the load range, the power
dissipation contributed by the ground current is < 1%
and can be ignored for this calculation.
P
D = (3.3V – 2.8V) × 300mA
P
D = 0.15W
To determine the maximum ambient operating
temperature of the package, use the junction-to-ambient
thermal resistance of the device and the following basic
equation:
JA
θ
AJ(max)
D(max)
TT
P-
Where TJ(max) is the maximum junction temperature,
125°C, and θJA represents the junction-to-ambient
thermal resistance, 93°C/W.
Substituting PD for PD(max) and solving for the ambient
operating temperature will give the maximum operating
conditions for the regulator circuit consuming PD watts.
The maximum power dissipation must not be exceeded
for proper operation.
For example, when operating the MIC5323-2.8YMT at
an input voltage of 3.3V and 300mA load with a
minimum footprint layout, the maximum ambient can be
solved for as follows:
C/W
-C25
W15. 93
T1
0A
C111
A
T
Therefore, a 2.8V application at 300mA of output current
can accept an ambient operating temperature of 111°C
in a 6 pin 2mm x 2mm Thin MLF® 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. This information can be found on Micrel's
website at:
http://www.micrel.com/_PDF/other/LDOBk_ds.pdf
Micrel, Inc. MIC5323
November 2011 11 M9999-110311B
Typical Application Circuit (Fixed Output)
Bill of Materials
Item Part Number Manufacturer Description Qty.
C1608X5R0J225K TDK(1)
C1 GRM188R60J225KE19D Murata(2) 1
C1608X5R0J225K TDK(1) C2
GRM188R60J225KE19D Murata(2)
Ceramic Capacitor, 2.2µF, 6.3V, X5R, Size 0603
1
C3 CL10B104KB8NNN Samsung(3) Ceramic Capacitor, 100nF, 50V, X5R, Size 0603 1
U1 MIC5323YMT Micrel, Inc.(4) 300mA Low Noise Ultra Low Dropout LDO 1
Notes:
1. TDK: www.tdk.com
2. Murata: www.murata.com
3. Samsung: www.samsungsem.com
4. Micrel, Inc.: www.micrel.com
Micrel, Inc. MIC5323
November 2011 12 M9999-110311B
Typical Application Circuit (Adjustable Output)
Bill of Materials
Item Part Number Manufacturer Description Qty.
C1608X5R0J225K TDK(1)
C1 GRM188R60J225KE19D Murata(2) 1
C1608X5R0J225K TDK(1) C2
GRM188R60J225KE19D Murata(2)
Ceramic Capacitor, 2.2µF, 6.3V, X5R, Size 0603
1
C3 CL10B104KB8NNN Samsung(3) Ceramic Capacitor, 100nF, 50V, X7R, Size 0603 1
R1 CRCW060312K1FKEA Vishay(4) Resistor, 10kΩ, 1%, 1/16W, Size 0603 1
R2 CRCW060312K1FKEA Vishay(4) Resistor, 10kΩ, 1%, 1/16W, Size 0603 1
U1 MIC5323YMT Micrel, Inc.(5) 300mA Low Noise Ultra Low Dropout LDO 1
Notes:
1. TDK: www.tdk.com
2. Murata: www.murata.com
3. Samsung: www.samsungsem.com
4. Vishay: www.vishay.com
5. Micrel, Inc.: www.micrel.com
Micrel, Inc. MIC5323
November 2011 13 M9999-110311B
Layout Recommendations
Top Layer
Bottom Layer
Micrel, Inc. MIC5323
November 2011 14 M9999-110311B
Package Information
6-Pin 2mm x 2mm Thin MLF® (MT)
5-Pin TSOT-23 (D5)
Micrel, Inc. MIC5323
November 2011 15 M9999-110311B
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.
© 2011 Micrel, Incorporated.
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 makes no representations or warranties with respect to the accuracy or completeness of the information furnished in this data sheet. 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
property rights is granted by this document. Except as provided in Micrel’s terms and conditions of sale for such products, Micrel assumes no liability
whatsoever, and Micrel disclaims any express or implied warranty relating to the sale and/or use of Micrel products including liability or warranties
relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right.
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.
© 2011 Micrel
,
Incor
p
orated.
Mouser Electronics
Authorized Distributor
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