MIC5323
High PSRR Low Noise 300mA µCap
Ultra-Low Dropout LDO Regulator
General Description
The MIC5323 is a high-performance, 300mA LDO regulator, 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
(CBYP = 0.1µF)
0
-10
IOUT = 300mA
PSRR (dB)
-20
-30
-40
-50
-60
IOUT = 100mA
IOUT = 1mA
-70
-80
VIN = VOUT + 1V
-90
VOUT = 1.8V
-100
1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06
FREQUENCY (Hz)
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
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M9999-110311B
Micrel, Inc.
MIC5323
Ordering Information
Part Number(1)
Marking(2)
MIC5323-1.8YMT
Voltage
Junction
Temp. Range(2)
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
(3)
Package
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.
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Micrel, Inc.
MIC5323
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
1
1
2
2
Pin
Name
Pin Description
3
EN
Enable Input: Active High. High = on, low = off. Do not leave
floating.
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.
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MIC5323
Absolute Maximum Ratings (1)
Operating Ratings (2)
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
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
Ouput Voltage Accuracy
Variation from nominal VOUT, IOUT = 100µA to 300mA
–2.0
Line Regulation
VIN = VOUT +1V to 5.5V
Load Regulation
IOUT = 100µA to 300mA
Dropout Voltage
IOUT = 50mA, VOUT > 2.8V
20
35
mV
IOUT = 150mA, VOUT > 2.8V
60
85
mV
IOUT = 300mA, VOUT > 2.8V
120
170
mV
(6)
Typ
Max
Units
+2.0
%
0.02
0.3
%/V
0.1
0.5
%
IOUT = 50mA, VOUT =< 2.8V
25
45
mV
IOUT = 150mA, VOUT =< 2.8V
75
110
mV
IOUT = 300mA, VOUT =< 2.8V
150
220
mV
IOUT = 0 to 300mA
90
150
µA
Ground Pin Current in
Shutdown
VEN = 0V
0.5
2
µA
Ripple Rejection
f = 1kHz; COUT = 2.2µF ceramic; CBYP = 0.1µF
80
Ground Pin Current
(7)
f = 10kHz; COUT = 2.2µF ceramic; CBYP = 0.1µF
65
350
Current Limit
VOUT = 0V
Output Voltage Noise
COUT =2.2µF, CBYP = 0.1µF, 10Hz to 100kHz
20
Turn-On Time
COUT = 2.2µF; CBYP= 0.1µF; IOUT = 300mA
30
Enable Input Voltage
Logic Low
600
dB
900
mA
µVrms
150
µs
0.2
V
1.2
Logic High
Enable Input Current
dB
V
VIL ≤ 0.2V
0.01
1
µA
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.
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MIC5323
Typical Characteristics
Power Supply Rejection Ratio
(CBYP=1µF)
0
0
0
-10
-10
PSRR (dB)
-30
IOUT = 100mA
-40
-50
IOUT = 1mA
-60
IOUT = 300mA
-20
-30
IOUT = 100mA
-40
-50
IOUT = 1mA
-60
-30
IOUT = 100mA
-40
-50
IOUT = 1mA
-60
-70
-70
-80
VIN = V OUT + 1V
-80
VIN = VOUT + 1V
-80
VIN = VOUT + 1V
-90
VOUT = 1.8V
-90
VOUT = 1.8V
-90
VOUT = 1.8V
-100
1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06
FREQUENCY (Hz)
FREQUENCY (Hz)
Ground Current vs.
Input Voltage
110
-100
1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06
-100
1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06
FREQUENCY (Hz)
Ground Current vs.
Output Current
90
80
IOUT = 100mA
IOUT = 100µA
70
60
VOUT = 1.8V
GROUND CURRENT (µA)
IOUT = 300mA
100
100
90
80
70
VIN = VOUT + 1V
60
VOUT = 1.8V
50
50
2.5
3.0
3.5
4.0
4.5
5.0
50
INPUT VOLTAGE (V)
100
150
200
250
IOUT = 150mA
IOUT = 300mA
1.5
3.5
4.0
4.5
INPUT VOLTAGE (V)
November 2011
VOUT = 1.8V
-40
800
160
700
140
600
500
400
300
-20
0
5.0
5.5
20
40
60
80
100 120
120
100
80
60
40
20
2.5
3.0
3.5
4.0
4.5
INPUT VOLTAGE (V)
5
5.0
VOUT = 2.8V
0
100
3.0
VIN = VOUT + 1V
60
Dropout Voltage vs.
Output Current
VOUT = 1.8V
2.5
70
TEMPERATURE (°C)
200
VOUT = 2.8V
IOUT = 100µA
IOUT = 100mA
300
DROPOUT (mV)
CURRENT LIMIT (mA)
2.5
2.0
80
Current Limit vs.
Input Voltage
IOUT = 100µA
3.0
IOUT = 300mA
90
OUTPUT CURRENT (mA)
Output Voltage vs.
Input Voltage
3.5
100
50
0
5.5
Ground Current vs.
Temperature
110
110
GROUND CURRENT (µA)
GROUND CURRENT (µA)
IOUT = 300mA
-20
PSRR (dB)
IOUT = 300mA
-70
OUTPUT VOLTAGE (V)
Power Supply Rejection Ratio
(CBYP = 0.01µF)
-10
-20
PSRR (dB)
Power Supply Rejection Ratio
(CBYP = 0.1µF)
5.5
0
50
100
150
200
250
300
OUTPUT CURRENT (mA)
M9999-110311B
Micrel, Inc.
MIC5323
Dropout Voltage vs.
Temperature
160
Output Voltage vs.
Temperature
1.900
IOUT = 300mA
1.875
IOUT = 200mA
100
80
IOUT = 100mA
60
40
IOUT = 10mA
20
-20
0
20
40
60
80
1.825
1.800
1.775
1.750
VIN = 5.5V
VOUT = 2.8V
1.725
0
-40
1.850
100 120
-40
0
20
40
60
80
100 120
Output Noise
Spectral Density
VIN = V OUT + 1V
VIN = V OUT + 1V
VOUT = 1.8V
VOUT = 1.8V
VOUT = 1.8V
CBY P = 0.01µF
CBY P = 0.1µF
CBY P = 1µF
0.100
0.010
1.000
0.100
0.010
Noise (10Hz-100kHz) = 18.7µV
0.001
1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06
FREQUENCY (Hz)
November 2011
Output Noise
Spectral Density
10.000
10.000
NOISE µV/√Hz
NOISE µV/√Hz
1.000
-20
TEMPERATURE (°C)
Output Noise
Spectral Density
VIN = VOUT + 1V
IOUT = 100µA
1.700
TEMPERATURE (°C)
10.000
V OUT = 1.8V
1.000
NOISE µV/√Hz
120
OUTPUT VOLTAGE (V)
DROPOUT (mV)
140
0.100
0.010
Noise (10Hz-100kHz) = 18.7µV
0.001
1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06
FREQUENCY (Hz)
6
Noise (10Hz-100kHz) = 18µV
0.001
1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06
FREQUENCY (Hz)
M9999-110311B
Micrel, Inc.
MIC5323
Functional Characteristics
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Micrel, Inc.
MIC5323
Functional Diagram
MIC5323 Block Diagram – Fixed
MIC5323 Block Diagram – Adjustable
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M9999-110311B
Micrel, Inc.
MIC5323
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.
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:
R1
V
= VREF 1 +
OUT
R2
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 performance 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.
VREF = 1.25V
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 recommended 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.
Figure 1. Adjustable Voltage Application
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
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MIC5323
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:
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:
PD = (VIN – VOUT) IOUT + VIN IGND
Because this device is CMOS and the ground current is
typically
