MICREL MIC5219

MIC5219
Micrel
MIC5219
500mA-Peak Output LDO Regulator
General Description
Features
The MIC5219 is an efficient linear voltage regulator with high
peak output current capability, very low dropout voltage, and
better than 1% output voltage accuracy. Dropout is typically
10mV at light loads and less than 500mV at full load.
• 500mA Output current capability
• SOT-23-5 package - 500mA peak
• MSOP-8 package - 500mA continuous
• Low 500mV maximum dropout voltage at full load
• Extremely tight load and line regulation
• Tiny SOT-23-5 and MM8™ power MSOP-8 package
• Ultra-low-noise output
• Low temperature coefficient
• Current and thermal limiting
• Reversed-battery protection
• CMOS/TTL-compatible enable/shutdown control
• Near-zero shutdown current
The MIC5219 is designed to provide a peak output current for
startup conditions where higher inrush current is demanded.
It features a 500mA peak output rating. Continuous output
current is limited only by package and layout.
The MIC5219 can be enabled or shut down by a CMOS or
TTL compatible signal. When disabled, power consumption
drops nearly to zero. Dropout ground current is minimized to
help prolong battery life. Other key features include reversedbattery protection, current limiting, overtemperature shutdown, and low noise performance with an ultra-low-noise
option.
The MIC5219 is available in adjustable or fixed output voltages in space-saving SOT-23-5 and MM8™ 8-lead power
MSOP packages. For higher power requirements see the
MIC5209 or MIC5237.
Applications
•
•
•
•
•
•
Laptop, notebook, and palmtop computers
Cellular telephones and battery-powered equipment
Consumer and personal electronics
PC Card VCC and VPP regulation and switching
SMPS post-regulator/dc-to-dc modules
High-efficiency linear power supplies
Typical Applications
MIC5219-5.0BMM
ENABLE
SHUTDOWN
VIN 6V
VOUT 5V
2.2µF
tantalum
1
8
2
7
3
6
4
5
MIC5219-3.3BM5
VIN 4V
1
5
2
ENABLE
SHUTDOWN
3
4
VOUT 3.3V
2.2µF
tantalum
470pF
470pF
5V Ultra-Low-Noise Regulator
3.3V Ultra-Low-Noise Regulator
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com
April 2001
1
MIC5219
MIC5219
Micrel
Ordering Information
Part Number
Marking
Volts
Junction Temp. Range
Package
MIC5219-3.0BMM
—
3.0V
–40°C to +125°C
MSOP-8
MIC5219-3.3BMM
—
3.3V
–40°C to +125°C
MSOP-8
MIC5219-3.6BMM
—
3.6V
–40°C to +125°C
MSOP-8
MIC5219-5.0BMM
—
5.0V
–40°C to +125°C
MSOP-8
MIC5219BMM
—
Adj.
–40°C to +125°C
MSOP-8
MIC5219-2.5BM5
LG25
2.5V
–40°C to +125°C
SOT-23-5
MIC5219-2.6BM5
LG26
2.6V
–40°C to +125°C
SOT-23-5
MIC5219-2.7BM5
LG27
2.7V
–40°C to +125°C
SOT-23-5
MIC5219-2.8BM5
LG28
2.8V
–40°C to +125°C
SOT-23-5
MIC5219-2.9BM5
LG29
2.9V
–40°C to +125°C
SOT-23-5
MIC5219-3.0BM5
LG30
3.0V
–40°C to +125°C
SOT-23-5
MIC5219-3.1BM5
LG31
3.1V
–40°C to +125°C
SOT-23-5
MIC5219-3.3BM5
LG33
3.3V
–40°C to +125°C
SOT-23-5
MIC5219-3.6BM5
LG36
3.6V
–40°C to +125°C
SOT-23-5
MIC5219-5.0BM5
LG50
5.0V
–40°C to +125°C
SOT-23-5
MIC5219BM5
LGAA
Adj.
–40°C to +125°C
SOT-23-5
Other voltages available. Consult Micrel for details.
Pin Configuration
EN 1
8
GND
IN 2
7
GND
OUT 3
6
GND
BYP 4
5
GND
EN GND IN
3
IN 2
4
5
BYP
OUT
MIC5219-x.xBM5
SOT-23-5
Fixed Voltages
8
GND
7
GND
EN GND IN
3
OUT 3
6
GND
ADJ 4
5
GND
2
1
Part
Identification
LGAA
MIC5219BMM
MM8™ MSOP-8
Adjustable Voltage
MIC5219
1
LGxx
MIC5219-x.xBMM
MM8™ MSOP-8
Fixed Voltages
EN 1
2
4
5
ADJ
OUT
MIC5219BM5
SOT-23-5
Adjustable Voltage
2
April 2001
MIC5219
Micrel
Pin Description
Pin No.
MSOP-8
Pin No.
SOT-23-5
Pin Name
Pin Function
2
1
IN
Supply Input
5–8
2
GND
Ground: MSOP-8 pins 5 through 8 are internally connected.
3
5
OUT
Regulator Output
1
3
EN
Enable (Input): CMOS compatible control input. Logic high = enable; logic
low or open = shutdown.
4 (fixed)
4 (fixed)
BYP
Reference Bypass: Connect external 470pF capacitor to GND to reduce
output noise. May be left open.
4 (adj.)
4 (adj.)
ADJ
Adjust (Input): Feedback input. Connect to resistive voltage-divider network.
April 2001
3
MIC5219
MIC5219
Micrel
Absolute Maximum Ratings
Operating Ratings
Supply Input Voltage (VIN) ............................ –20V to +20V
Power Dissipation (PD) ............................ Internally Limited
Junction Temperature (TJ) ....................... –40°C to +125°C
Lead Temperature (Soldering, 5 sec.) ...................... 260°C
Supply Input Voltage (VIN) ........................... +2.5V to +12V
Enable Input Voltage (VEN) .................................. 0V to VIN
Junction Temperature (TJ) ....................... –40°C to +125°C
Package Thermal Resistance ......................... see Table 1
Electrical Characteristics
VIN = VOUT + 1.0V; COUT = 4.7µF, IOUT = 100µA; TJ = 25°C, bold values indicate –40°C ≤ TJ ≤ +125°C; unless noted.
Symbol
Parameter
Conditions
VOUT
Output Voltage Accuracy
variation from nominal VOUT
∆VOUT/∆T
Output Voltage
Temperature Coefficient
Note 2
∆VOUT/VOUT
Line Regulation
VIN = VOUT + 1V to 12V
0.009
0.05
0.1
%/V
∆VOUT/VOUT
Load Regulation
IOUT = 100µA to 500mA Note 3
0.05
0.5
0.7
%
VIN – VOUT
Dropout Voltage, Note 4
IOUT = 100µA
10
60
80
mV
IOUT = 50mA
115
175
250
mV
IOUT = 150mA
175
300
400
mV
IOUT = 500mA
350
500
600
mV
VEN ≥ 3.0V, IOUT = 100µA
80
130
170
µA
VEN ≥ 3.0V, IOUT = 50mA
350
650
900
µA
VEN ≥ 3.0V, IOUT = 150mA
1.8
2.5
3.0
mA
VEN ≥ 3.0V, IOUT = 500mA
12
20
25
mA
VEN ≤ 0.4V
0.05
3
µA
VEN ≤ 0.18V
0.10
8
µA
IGND
Ground Pin Current, Notes 5, 6
Ground Pin Quiescent Current,
Note 6
Min
Typical
–1
–2
Max
Units
1
2
%
%
40
ppm/°C
PSRR
Ripple Rejection
f = 120Hz
75
dB
ILIMIT
Current Limit
VOUT = 0V
700
∆VOUT/∆PD
Thermal Regulation
Note 7
0.05
%/W
eno
Output Noise
IOUT = 50mA, COUT = 2.2µF, CBYP = 0
500
nV/ Hz
IOUT = 50mA, COUT = 2.2µF, CBYP = 470pF
300
nV/ Hz
1000
mA
ENABLE Input
VENL
Enable Input Logic-Low Voltage
VEN = logic low (regulator shutdown)
VEN = logic high (regulator enabled)
IENL
IENH
MIC5219
Enable Input Current
0.4
0.18
2.0
V
V
VENL ≤ 0.4V
0.01
–1
µA
VENL ≤ 0.18V
0.01
–2
µA
5
20
25
µA
VENH ≥ 2.0V
2
4
April 2001
MIC5219
Micrel
Note 1:
Absolute maximum ratings indicate limits beyond which damage to the component may occur. Electrical specifications do not apply when
operating the device outside of its operating ratings. The maximum allowable power dissipation is a function of the maximum junction
temperature, TJ(max), the junction-to-ambient thermal resistance, θJA, and the ambient temperature, TA. The maximum allowable power
dissipation at any ambient temperature is calculated using: 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. See Table 1 and the “Thermal Considerations”
section for details.
Note 2:
Output voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range.
Note 3:
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.
Note 4:
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.
Note 5:
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.
Note 6:
VEN is the voltage externally applied to devices with the EN (enable) input pin.
Note 7:
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 500mA load pulse at VIN = 12V for t = 10ms.
Note 8:
CBYP is an optional, external bypass capacitor connected to devices with a BYP (bypass) or ADJ (adjust) pin.
April 2001
5
MIC5219
MIC5219
Micrel
Typical Characteristics
Power Supply
Rejection Ratio
-40
-60
-80
-60
-80
-60
-60
IOUT = 100µA
COUT = 2.2µF
CBYP = 0.01µF
-100
1k 1E+4
1E+1
10k 1E+5
1M 1E+7
10M
10 1E+2
100k 1E+6
100 1E+3
FREQUENCY (Hz)
Power Supply Ripple Rejection
vs. Voltage Drop
Power Supply Ripple Rejection
vs. Voltage Drop
10mA
IOUT = 100mA
20
10
COUT = 1µF
0
0.1
0.2
0.3
VOLTAGE DROP (V)
0.4
Noise Performance
10
100
90
10mA, COUT = 1µF
80
1
1mA
70
60
IOUT = 100mA
50
40
10mA
30
20
10
0
Noise Performance
COUT = 2.2µF
CBYP = 0.01µF
0
0.1
0.2
0.3
VOLTAGE DROP (V)
0.1
0.01
0.001
0.4
VOUT = 5V
0.0001
1E+1
10 1E+2
1k 1E+4
100 1E+3
10k 1E+5
100k 1E+6
1M 1E+7
10M
FREQUENCY (Hz)
Dropout Voltage
vs. Output Current
Noise Performance
10
400
10
1
1
0.1
10mA
0.01
VOUT = 5V
COUT = 10µF
electrolytic
1mA
0.0001
1E+1
1k 1E+4
10 1E+2
1M 1E+7
10k 1E+5
100k 1E+6
10M
100 1E+3
FREQUENCY (Hz)
NOISE (µV/√Hz)
100mA
100mA
0.1
0.01
1mA
VOUT = 5V
COUT = 10µF
0.001
electrolytic
10mA
CBYP = 100pF
0.0001
1E+1
1k 1E+4
10 1E+2
1M 1E+7
10k 1E+5
100k 1E+6
10M
100 1E+3
FREQUENCY (Hz)
6
DROPOUT VOLTAGE (mV)
30
IOUT = 100mA
COUT = 2.2µF
CBYP = 0.01µF
-100
1k 1E+4
1E+1
10k 1E+5
1M 1E+7
10M
10 1E+2
100k 1E+6
100 1E+3
FREQUENCY (Hz)
NOISE (µV/√Hz)
RIPPLE REJECTION (dB)
RIPPLE REJECTION (dB)
1mA
-60
-80
-100
1k 1E+4
1E+1
10k 1E+5
1M 1E+7
10M
10 1E+2
100k 1E+6
100 1E+3
FREQUENCY (Hz)
40
-40
IOUT = 1mA
COUT = 2.2µF
CBYP = 0.01µF
-80
50
VIN = 6V
VOUT = 5V
-20
PSRR (dB)
PSRR (dB)
PSRR (dB)
0
-40
60
NOISE (µV/√Hz)
Power Supply
Rejection Ratio
VIN = 6V
VOUT = 5V
-20
-40
MIC5219
-100
1k 1E+4
1E+1
10k 1E+5
1M 1E+7
10M
10 1E+2
100k 1E+6
100 1E+3
FREQUENCY (Hz)
0
-80
IOUT = 100mA
COUT = 1µF
Power Supply
Rejection Ratio
VIN = 6V
VOUT = 5V
-20
0.001
-60
-80
-100
1k 1E+4
1E+1
10k 1E+5
1M 1E+7
10M
10 1E+2
100k 1E+6
100 1E+3
FREQUENCY (Hz)
0
0
-40
IOUT = 1mA
COUT = 1µF
Power Supply
Rejection Ratio
VIN = 6V
VOUT = 5V
-20
-40
IOUT = 100µA
COUT = 1µF
-100
1k 1E+4
1E+1
10k 1E+5
1M 1E+7
10M
10 1E+2
100k 1E+6
100 1E+3
FREQUENCY (Hz)
0
VIN = 6V
VOUT = 5V
-20
PSRR (dB)
-20
PSRR (dB)
0
VIN = 6V
VOUT = 5V
Power Supply
Rejection Ratio
PSRR (dB)
0
Power Supply
Rejection Ratio
300
200
100
0
0
100 200 300 400 500
OUTPUT CURRENT (mA)
April 2001
MIC5219
Micrel
Dropout Characteristics
Ground Current
vs. Output Current
3.0
12
I =100µA
L
GROUND CURRENT (mA)
OUTPUT VOLTAGE (V)
3.5
2.5
2.0
1.5
I =100mA
L
1.0
I =500mA
L
0.5
0
0
1
2 3 4 5 6 7 8
INPUT VOLTAGE (V)
10
8
6
4
2
0
0
9
Ground Current
vs. Supply Voltage
Ground Current
vs. Supply Voltage
April 2001
3.0
GROUND CURRENT (mA)
GROUND CURRENT (mA)
25
20
15
10
5
0
0
100 200 300 400 500
OUTPUT CURRENT (mA)
IL=500mA
1 2 3 4 5 6 7 8
INPUT VOLTAGE (V)
2.5
2.0
1.5
1.0
0.5
0
0
9
7
IL=100 mA
IL=100µA
2
4
6
INPUT VOLTAGE (V)
8
MIC5219
MIC5219
Micrel
Block Diagrams
VIN
OUT
IN
VOUT
COUT
BYP
CBYP
(optional)
Bandgap
Ref.
V
REF
EN
Current Limit
Thermal Shutdown
MIC5219-x.xBM5/MM
GND
Ultra-Low-Noise Fixed Regulator
VIN
OUT
IN
VOUT
R1
R2
Bandgap
Ref.
V
REF
COUT
CBYP
(optional)
EN
Current Limit
Thermal Shutdown
MIC5219BM5/MM [adj.]
GND
Ultra-Low-Noise Adjustable Regulator
MIC5219
8
April 2001
MIC5219
Micrel
Thermal Considerations
The MIC5219 is designed to provide 200mA of continuous
current in two very small profile packages. 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 thermal resistance,
junction-to-ambient, of the device and the following basic
equation.
Applications Information
The MIC5219 is designed for 150mA to 200mA output current
applications where a high current spike (500mA) is needed
for short, startup conditions. Basic application of the device
will be discussed initially followed by a more detailed discussion of higher current applications.
Enable/Shutdown
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). See Figure 5.
Input Capacitor
PD(max) =
θ JA
TJ(MAX) is the maximum junction temperature of the die,
125°C, and TA is the ambient operating temperature. θJA is
layout dependent; table 1 shows examples of thermal resistance, junction-to-ambient, for the MIC5219.
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
θJA Recommended θJA 1" Square
Minimum Footprint 2 oz. Copper
Package
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 5). 2.2µF minimum is recommended when CBYP
is 470pF (see Figure 6). For applications <3V, the output
capacitor should be increased to 22µF minimum to reduce
start-up overshoot. Larger values improve the regulator’s
transient response. The output capacitor value may be increased without limit.
The output capacitor should have an ESR (equivalent series
resistance) of about 5Ω or less and a resonant frequency
above 1MHz. Ultra-low-ESR capacitors could cause oscillation and/or underdamped transient response. Most tantalum
or aluminum electrolytic capacitors are adequate; film types
will work, but are more expensive. Many aluminum electrolytics have electrolytes that freeze at about –30°C, so solid
tantalums are recommended for operation below –25°C.
At lower values of output current, less output capacitance is
needed for stability. The capacitor can be reduced to 0.47µF
for current below 10mA or 0.33µF for currents below 1mA.
θJC
MM8™ (MM)
160°C/W
70°C/W
30°C/W
SOT-23-5 (M5)
220°C/W
170°C/W
130°C/W
Table 1. MIC5219 Thermal Resistance
The actual power dissipation of the regulator circuit can be
determined using one simple equation.
PD = (VIN – VOUT) IOUT + VIN IGND
Substituting PD(MAX) for PD and solving for the operating
conditions that are critical to the application will give the
maximum operating conditions for the regulator circuit. For
example, if we are operating the MIC5219-3.3BM5 at room
temperature, with a minimum footprint layout, we can determine the maximum input voltage for a set output current.
PD(max) =
(125°C
– 25°C)
220°C/W
PD(max) = 455mW
The thermal resistance, junction-to-ambient, for the minimum footprint is 220°C/W, taken from table 1. The maximum
power dissipation number cannot be exceeded for proper
operation of the device. Using the output voltage of 3.3V, and
an output current of 150mA, we can determine the maximum
input voltage. Ground current, maximum of 3mA for 150mA
of output current, can be taken from the Electrical Characteristics section of the data sheet.
No-Load Stability
The MIC5219 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.
455mW = (VIN – 3.3V) × 150mA + VIN × 3mA
455mW = (150mA) × VIN + 3mA × VIN – 495mW
950mW = 153mA × VIN
Reference Bypass Capacitor
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). CBYP reduces the regulator
phase margin; when using CBYP, output capacitors of 2.2µF
or greater are generally required to maintain stability.
The start-up speed of the MIC5219 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.
April 2001
(TJ(max) – TA )
VIN = 6.2VMAX
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.
9
MIC5219
MIC5219
Micrel
Peak Current Applications
The MIC5219 is designed for applications where high startup currents are demanded from space constrained regulators. This device will deliver 500mA start-up current from a
SOT-23-5 or MM8 package, allowing high power from a very
low profile device. The MIC5219 can subsequently provide
output current that is only limited by the thermal characteristics of the device. You can obtain higher continuous currents
from the device with the proper design. This is easily proved
with some thermal calculations.
Figures 3 and 4 show safe operating regions for the MIC5219x.xBMM, the power MSOP package part. These graphs
show three typical operating regions at different temperatures. The lower the temperature, the larger the operating
region. The graphs were obtained in a similar way to the
graphs for the MIC5219-x.xBM5, taking all factors into consideration and using two different board layouts, minimum
footprint and 1" square copper PC board heat sink. (For
further discussion of PC board heat sink characteristics, refer
to Application Hint 17, “Designing PC Board Heat Sinks”.)
The information used to determine the safe operating regions
can be obtained in a similar manner to that used in determining typical power dissipation, already discussed. Determining the maximum power dissipation based on the layout is the
first step, this is done in the same manner as in the previous
two sections. Then, a larger power dissipation number
multiplied by a set maximum duty cycle would give that
maximum power dissipation number for the layout. This is
best shown through an example. If the application calls for 5V
at 500mA for short pulses, but the only supply voltage
available is 8V, then the duty cycle has to be adjusted to
determine an average power that does not exceed the
maximum power dissipation for the layout.
If we look at a specific example, it may be easier to follow. The
MIC5219 can be used to provide up to 500mA continuous
output current. First, calculate the maximum power dissipation of the device, as was done in the thermal considerations
section. Worst case thermal resistance (θJA = 220°C/W for
the MIC5219-x.xBM5), will be used for this example.
PD(max) =
(TJ(max) – TA )
θ JA
Assuming a 25°C room temperature, we have a maximum
power dissipation number of
PD(max) =
(125°C
– 25°C)
220°C/W
 % DC 
Avg.PD = 
 V – VOUT IOUT + VIN IGND
 100  IN
(
PD(max) = 455mW
Then we can determine the maximum input voltage for a fivevolt regulator operating at 500mA, using worst case ground
current.
PD(max) = 455mW = (VIN – VOUT) IOUT + VIN IGND
IOUT = 500mA
 % DC 
455mW = 
 (8V – 5V) 500mA + 8V × 20mA
 100 
 % Duty Cycle 
455mW = 
 1.66W


100
VOUT = 5V
IGND = 20mA
0.274 =
455mW = (VIN – 5V) 500mA + VIN × 20mA
2.995W = 520mA × VIN
% Duty Cycle
100
% Duty Cycle Max = 27.4%
With an output current of 500mA and a three-volt drop across
the MIC5219-xxBMM, the maximum duty cycle is 27.4%.
Applications also call for a set nominal current output with a
greater amount of current needed for short durations. This is
a tricky situation, but it is easily remedied. Calculate the
average power dissipation for each current section, then add
the two numbers giving the total power dissipation for the
regulator. For example, if the regulator is operating normally
at 50mA, but for 12.5% of the time it operates at 500mA
output, the total power dissipation of the part can be easily
determined. First, calculate the power dissipation of the
device at 50mA. We will use the MIC5219-3.3BM5 with 5V
input voltage as our example.
PD × 50mA = (5V – 3.3V) × 50mA + 5V × 650µA
2.955W
= 5.683V
520mA
Therefore, to be able to obtain a constant 500mA output
current from the 5219-5.0BM5 at room temperature, you
need extremely tight input-output voltage differential, barely
above the maximum dropout voltage for that current rating.
You can run the part from larger supply voltages if the proper
precautions are taken. Varying the duty cycle using the
enable pin can increase the power dissipation of the device
by maintaining a lower average power figure. This is ideal for
applications where high current is only needed in short
bursts. Figure 1 shows the safe operating regions for the
MIC5219-x.xBM5 at three different ambient temperatures
and at different output currents. The data used to determine
this figure assumed a minimum footprint PCB design for
minimum heat sinking. Figure 2 incorporates the same
factors as the first figure, but assumes a much better heat
sink. A 1" square copper trace on the PC board reduces the
thermal resistance of the device. This improved thermal
resistance improves power dissipation and allows for a larger
safe operating region.
VIN(max) =
MIC5219
)
PD × 50mA = 173mW
However, this is continuous power dissipation, the actual
on-time for the device at 50mA is (100%-12.5%) or 87.5% of
the time, or 87.5% duty cycle. Therefore, PD must be
multiplied by the duty cycle to obtain the actual average
power dissipation at 50mA.
10
April 2001
MIC5219
Micrel
10
10
10
6
200mA
4
300mA
400mA
2
8
100mA
6
200mA
4
300mA
2
400mA
500mA
0
0
20
40
60
80
DUTY CYCLE (%)
0
100
VOLTAGE DROP (V)
8
VOLTAGE DROP (V)
VOLTAGE DROP (V)
100mA
0
20
500mA
40
60
80
DUTY CYCLE (%)
8
6
4
200mA
300mA
2 500mA
0
100
100mA
400mA
0
20
40
60
80
DUTY CYCLE (%)
100
a. 25°C Ambient
b. 50°C Ambient
c. 85°C Ambient
Figure 1. MIC5219-x.xBM5 (SOT-23-5) on Minimum Recommended Footprint
10
10
10
6
200mA
300mA
4
400mA
2
8
100mA
6
200mA
4
300mA
2
400mA
500mA
0
0
20
40
60
80
DUTY CYCLE (%)
0
100
VOLTAGE DROP (V)
8
VOLTAGE DROP (V)
VOLTAGE DROP (V)
100mA
500mA
0
20
40
60
80
DUTY CYCLE (%)
8
100mA
6
200mA
4
2
0
100
300mA
400mA
0
500mA
20
40
60
80
DUTY CYCLE (%)
100
a. 25°C Ambient
b. 50°C Ambient
c. 85°C Ambient
Figure 2. MIC5219-x.xBM5 (SOT-23-5) on 1-inch2 Copper Cladding
10
10
10
100mA
200mA
6
300mA
4
400mA
2
8
6
200mA
300mA
4
400mA
2
500mA
0
0
20
VOLTAGE DROP (V)
8
VOLTAGE DROP (V)
VOLTAGE DROP (V)
100mA
500mA
40
60
80
DUTY CYCLE (%)
0
100
0
20
40
60
80
DUTY CYCLE (%)
8
6
200mA
300mA
4
2
400mA
0
100
100mA
0
500mA
20
40
60
80
DUTY CYCLE (%)
100
a. 25°C Ambient
b. 50°C Ambient
c. 85°C Ambient
Figure 3. MIC5219-x.xBMM (MSOP-8) on Minimum Recommended Footprint
10
8
300mA
6
400mA
4
500mA
2
10
100mA
200mA
8
6
VOLTAGE DROP (V)
200mA
VOLTAGE DROP (V)
VOLTAGE DROP (V)
10
300mA
400mA
4
500mA
2
8
200mA
6
300mA
4
400mA
2
500mA
0
0
20
40
60
80
DUTY CYCLE (%)
100
0
0
20
40
60
80
DUTY CYCLE (%)
100
0
0
20
40
60
80
DUTY CYCLE (%)
100
a. 25°C Ambient
b. 50°C Ambient
c. 85°C Ambient
Figure 4. MIC5219-x.xBMM (MSOP-8) on 1-inch2 Copper Cladding
April 2001
11
MIC5219
MIC5219
Micrel
PD × 50mA = 0.875 × 173mW
PD × 50mA = 151mW
MIC5219-x.x
VIN
IN
EN
The power dissipation at 500mA must also be calculated.
PD × 500mA = (5V – 3.3V) 500mA + 5V × 20mA
BYP
GND
This number must be multiplied by the duty cycle at which it
would be operating, 12.5%.
PD × = 0.125 × 950mW
Figure 6. Ultra-Low-Noise Fixed Voltage Regulator
Figure 6 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.
PD × = 119mW
The total power dissipation of the device under these conditions is the sum of the two power dissipation figures.
PD(total) = PD × 50mA + PD × 500mA
Adjustable Regulator Circuits
PD(total) = 151mW + 119mW
PD(total) = 270mW
IN
EN
R1
1µF
Figure 7 shows the basic circuit for the MIC5219 adjustable
regulator. The output voltage is configured by selecting
values for R1 and R2 using the following formula:
 R2 
VOUT = 1.242V 
+ 1
 R1 
Although ADJ is a high-impedance input, for best performance, R2 should not exceed 470kΩ.
VOUT
VIN
OUT
BYP
GND
ADJ
GND
Figure 7. Low-Noise Adjustable Voltage Regulator
Fixed Regulator Circuits
EN
VOUT
OUT
R2
For additional heat sink characteristics, please 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
Regulator Thermals section of Micrel’s Designing with LowDropout Voltage Regulators handbook.
IN
MIC5219
VIN
The total power dissipation of the regulator is less than the
maximum power dissipation of the SOT-23-5 package at
room temperature, on a minimum footprint board and therefore would operate properly.
Multilayer boards with a ground plane, wide traces near the
pads, and large supply-bus lines will have better thermal
conductivity.
MIC5219-x.x
2.2µF
470pF
PD × 500mA = 950mW
VIN
VOUT
OUT
MIC5219
IN
EN
1µF
VOUT
OUT
ADJ
GND
470pF
R1
2.2µF
R2
Figure 5. Low-Noise Fixed Voltage Regulator
Figure 8. Ultra-Low-Noise Adjustable Application.
Figure 5 shows a basic MIC5219-x.xBMX fixed-voltage regulator circuit. A 1µF minimum output capacitor is required for
basic fixed-voltage applications.
MIC5219
Figure 8 includes the optional 470pF bypass capacitor from
ADJ to GND to reduce output noise.
12
April 2001
MIC5219
Micrel
Package Information
0.199 (5.05)
0.187 (4.74)
0.122 (3.10)
0.112 (2.84)
DIMENSIONS:
INCH (MM)
0.120 (3.05)
0.116 (2.95)
0.036 (0.90)
0.032 (0.81)
0.043 (1.09)
0.038 (0.97)
0.007 (0.18)
0.005 (0.13)
0.012 (0.30) R
0.012 (0.03)
0.0256 (0.65) TYP
0.008 (0.20)
0.004 (0.10)
5° MAX
0° MIN
0.012 (0.03) R
0.039 (0.99)
0.035 (0.89)
0.021 (0.53)
8-Pin MSOP (MM)
1.90 (0.075) REF
0.95 (0.037) REF
1.75 (0.069)
1.50 (0.059)
3.00 (0.118)
2.60 (0.102)
DIMENSIONS:
MM (INCH)
1.30 (0.051)
0.90 (0.035)
3.02 (0.119)
2.80 (0.110)
0.20 (0.008)
0.09 (0.004)
10°
0°
0.15 (0.006)
0.00 (0.000)
0.50 (0.020)
0.35 (0.014)
0.60 (0.024)
0.10 (0.004)
SOT-23-5 (M5)
MICREL INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131
TEL
+ 1 (408) 944-0800
FAX
+ 1 (408) 944-0970
WEB
USA
http://www.micrel.com
This information is believed to be accurate and reliable, however no responsibility is assumed by Micrel for its use nor for any infringement of patents or
other rights of third parties resulting from its use. No license is granted by implication or otherwise under any patent or patent right of Micrel Inc.
© 2000 Micrel Incorporated
April 2001
13
MIC5219