MIC5219BMM [MICREL]
500mA-Peak Output LDO Regulator; 值为500mA的峰值输出LDO稳压器型号: | MIC5219BMM |
厂家: | MICREL SEMICONDUCTOR |
描述: | 500mA-Peak Output LDO Regulator |
文件: | 总12页 (文件大小:120K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
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.
• Guaranteed 500mA-peak output over the full operating
temperature range
• 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
TheMIC5219isdesignedtoprovideapeakoutputcurrentfor
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
helpprolongbatterylife.Otherkeyfeaturesincludereversed-
battery protection, current limiting, overtemperature shut-
down, and low noise performance with an ultra-low-noise
option.
Applications
• Laptop, notebook, and palmtop computers
• Cellular telephones and battery-powered equipment
• Consumer and personal electronics
The MIC5219 is available in adjustable or fixed output volt-
ages in space-saving SOT-23-5 and MM8™ 8-lead power
MSOP packages. For higher power requirements see the
MIC5209 or MIC5237.
• PC Card V and V regulation and switching
• SMPS post-regulator/dc-to-dc modules
• High-efficiency linear power supplies
CC
PP
Typical Applications
MIC5219-5.0BMM
1
2
3
4
8
7
6
5
ENABLE
SHUTDOWN
MIC5219-3.3BM5
1
2
3
5
VIN 6V
VOUT 5V
VIN 4V
VOUT 3.3V
2.2µF
tantalum
4
ENABLE
SHUTDOWN
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
July 2000
1
MIC5219
MIC5219
Micrel
Ordering Information
Part Number
Marking
—
Volts
3.0V
3.3V
3.6V
5.0V
Adj.
Junction Temp. Range
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
–40°C to +125°C
Package
MSOP-8
MSOP-8
MSOP-8
MSOP-8
MSOP-8
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
SOT-23-5
MIC5219-3.0BMM
MIC5219-3.3BMM
MIC5219-3.6BMM
MIC5219-5.0BMM
MIC5219BMM
—
—
—
—
MIC5219-2.6BM5
MIC5219-2.7BM5
MIC5219-2.8BM5
MIC5219-2.9BM5
MIC5219-3.0BM5
MIC5219-3.3BM5
MIC5219-3.6BM5
MIC5219-5.0BM5
MIC5219BM5
LG26
LG27
LG28
LG29
LG30
LG33
LG36
LG50
LGAA
2.6V
2.7V
2.8V
2.9V
3.0V
3.3V
3.6V
5.0V
Adj.
Other voltages available. Consult Micrel for details.
Pin Configuration
EN GND IN
EN
IN
GND
GND
GND
GND
1
2
3
4
8
7
6
5
3
2
1
LGxx
OUT
BYP
4
5
BYP
OUT
MIC5219-x.xBMM
MM8™ MSOP-8
Fixed Voltages
MIC5219-x.xBM5
SOT-23-5
Fixed Voltages
EN GND IN
EN
IN
GND
GND
GND
GND
1
2
3
4
8
7
6
5
3
2
1
Part
Identification
LGAA
OUT
ADJ
4
5
ADJ
OUT
MIC5219BMM
MM8™ MSOP-8
Adjustable Voltage
MIC5219BM5
SOT-23-5
Adjustable Voltage
Pin Description
Pin No.
Pin No.
Pin Name
Pin Function
MSOP-8
SOT-23-5
2
5–8
3
1
2
5
3
IN
Supply Input
GND
OUT
EN
Ground: MSOP-8 pins 5 through 8 are internally connected.
Regulator Output
1
Enable (Input): CMOS compatible control input. Logic high = enable; logic
low or open = shutdown.
4 (fixed)
4 (adj.)
4 (fixed)
4 (adj.)
BYP
ADJ
Reference Bypass: Connect external 470pF capacitor to GND to reduce
output noise. May be left open.
Adjust (Input): Feedback input. Connect to resistive voltage-divider network.
MIC5219
2
July 2000
MIC5219
Micrel
Absolute Maximum Ratings
Operating Ratings
Supply Input Voltage (V ) ............................ –20V to +20V
Supply Input Voltage (V ) ........................... +2.5V to +12V
IN
IN
Power Dissipation (P ) ............................ Internally Limited
Enable Input Voltage (V ) .................................. 0V to V
D
EN
IN
Junction Temperature (T ) ....................... –40°C to +125°C
Junction Temperature (T ) ....................... –40°C to +125°C
J
J
Lead Temperature (Soldering, 5 sec.) ...................... 260°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
Min Typical Max
Units
VOUT
Output Voltage Accuracy
variation from nominal VOUT
–1
–2
1
2
%
%
∆VOUT/∆T
Output Voltage
Temperature Coefficient
Note 2
40
0.009
0.05
10
ppm/°C
%/V
%
∆VOUT/VOUT Line Regulation
VIN = VOUT + 1V to 12V
IOUT = 100µA to 500mA Note 3
IOUT = 100µA
0.05
0.1
∆VOUT/VOUT Load Regulation
0.5
0.7
VIN – VOUT
Dropout Voltage, Note 4
60
80
mV
mV
mV
mV
µA
IOUT = 50mA
115
175
350
80
175
250
IOUT = 150mA
300
400
I
OUT = 500mA
500
600
IGND
Ground Pin Current, Notes 5, 6
VEN ≥ 3.0V, IOUT = 100µA
VEN ≥ 3.0V, IOUT = 50mA
VEN ≥ 3.0V, IOUT = 150mA
VEN ≥ 3.0V, IOUT = 500mA
130
170
350
1.8
650
900
µA
2.5
3.0
mA
mA
12
20
25
Ground Pin Quiescent Current,
Note 6
V
EN ≤ 0.4V
0.05
0.10
75
3
8
µA
µA
V
EN ≤ 0.18V
PSRR
ILIMIT
Ripple Rejection
Current Limit
f = 120Hz
dB
VOUT = 0V
700
0.05
500
300
1000
mA
∆VOUT/∆PD
eno
Thermal Regulation
Output Noise
Note 7
%/W
nV/ Hz
nV/ Hz
IOUT = 50mA, COUT = 2.2µF, CBYP = 0
IOUT = 50mA, COUT = 2.2µF, CBYP = 470pF
ENABLE Input
VENL
Enable Input Logic-Low Voltage
VEN = logic low (regulator shutdown)
VEN = logic high (regulator enabled)
0.4
0.18
V
2.0
2
V
IENL
Enable Input Current
VENL ≤ 0.4V
VENL ≤ 0.18V
VENH ≥ 2.0V
0.01
0.01
5
–1
–2
µA
µA
µA
IENH
20
25
July 2000
3
MIC5219
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, T
, the junction-to-ambient thermal resistance, θ , and the ambient temperature, T . The maximum allowable power
J(max)
JA
A
dissipation at any ambient temperature is calculated using: P
= (T
– T ) ÷ θ . Exceeding the maximum allowable power dissipa-
D(max)
J(max)
A
JA
tion 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:
V
is the voltage externally applied to devices with the EN (enable) input pin.
EN
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 V = 12V for t = 10ms.
IN
Note 8:
C
is an optional, external bypass capacitor connected to devices with a BYP (bypass) or ADJ (adjust) pin.
BYP
MIC5219
4
July 2000
MIC5219
Micrel
Typical Characteristics
Power Supply
Rejection Ratio
Power Supply
Rejection Ratio
Power Supply
Rejection Ratio
0
0
-20
0
-20
VIN = 6V
VIN = 6V
VOUT = 5V
VIN = 6V
OUT = 5V
V
OUT = 5V
V
-20
-40
-40
-40
-60
-60
-60
IOUT = 100mA
OUT = 1µF
-80
-80
-80
IOUT = 100µA
OUT = 1µF
IOUT = 1mA
OUT = 1µF
C
C
C
-100
-100
-100
1E+11E+21E1+k311E0+k41E+51E1M+6 E+7
1E+11E+21E1+k311E0+k41E+51E1M+6 E+7
1E+11E+21E1+k311E0+k41E+51E1M+6 E+7
10 100 100k
10M
10 100
100k
10M
10 100
100k
10M
FREQUENCY (Hz)
FREQUENCY (Hz)
FREQUENCY (Hz)
Power Supply
Rejection Ratio
Power Supply
Rejection Ratio
Power Supply
Rejection Ratio
0
0
0
VIN = 6V
OUT = 5V
VIN = 6V
OUT = 5V
VIN = 6V
VOUT = 5V
V
V
-20
-40
-20
-40
-20
-40
-60
-60
-60
IOUT = 1mA
IOUT = 100µA
IOUT = 100mA
COUT = 2.2µF
BYP = 0.01µF
-80
-80
-80
COUT = 2.2µF
BYP = 0.01µF
COUT = 2.2µF
BYP = 0.01µF
C
C
C
-100
-100
-100
1E+11E+21E1+k311E0+k41E+51E1M+6 E+7
1E+11E+21E1+k311E0+k41E+51E1M+6 E+7
1E+11E+21E1+k311E0+k41E+51E1M+6 E+7
10 100 100k
10M
10 100
100k
10M
10 100
100k
10M
FREQUENCY (Hz)
FREQUENCY (Hz)
FREQUENCY (Hz)
Power Supply Ripple Rejection
vs. Voltage Drop
Power Supply Ripple Rejection
vs. Voltage Drop
Noise Performance
60
100
10
1
90
80
70
60
50
40
30
20
10
0
10mA, COUT = 1µF
50
40
30
20
10
0
1mA
1mA
0.1
IOUT = 100mA
10mA
IOUT = 100mA
0.01
0.001
0.0001
10mA
COUT = 2.2µF
CBYP = 0.01µF
COUT = 1µF
VOUT = 5V
0
0.1
0.2
0.3
0.4
0
0.1
0.2
0.3
0.4
1E+11E+21E+31E+41E+51E+61E+7
10
1k
100
10k 100k 1M 10M
VOLTAGE DROP (V)
VOLTAGE DROP (V)
FREQUENCY (Hz)
Dropout Voltage
vs. Output Current
Noise Performance
Noise Performance
10
1
10
1
400
300
200
100
0
100mA
100mA
0.1
10mA
0.1
0.01
0.001
0.0001
0.01
0.001
0.0001
1mA
VOUT = 5V
OUT = 10µF
electrolytic
BYP = 100pF
VOUT = 5V
OUT = 10µF
electrolytic
1mA
C
C
10mA
C
0
100 200 300 400 500
OUTPUT CURRENT (mA)
1E+11E+21E+31E+4 E+51E+61E+7
1E+11E+21E+31E+4 E+51E+61E+7
10
100
10
1k 10k 100k 1M 10M
100
FREQUENCY (Hz)
1k 10k 100k 1M 10M
FREQUENCY (Hz)
July 2000
5
MIC5219
MIC5219
Micrel
Dropout Characteristics
Ground Current
vs. Output Current
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
12
10
8
I
=100µA
L
6
I =100mA
L
4
I =500mA
L
2
0
0
1
2
3
4
5
6
7
8
9
0
100 200 300 400 500
OUTPUT CURRENT (mA)
INPUT VOLTAGE (V)
Ground Current
vs. Supply Voltage
Ground Current
vs. Supply Voltage
25
20
15
10
5
3.0
2.5
2.0
1.5
1.0
0.5
0
I =100 mA
L
I =100µA
I =500mA
L
L
0
0
1
2
3
4
5
6
7
8
9
0
2
4
6
8
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
MIC5219
6
July 2000
MIC5219
Micrel
Block Diagrams
OUT
IN
VOUT
COUT
VIN
BYP
CBYP
(optional)
Bandgap
Ref.
EN
Current Limit
Thermal Shutdown
MIC5219-x.xBM5/MM
GND
Ultra-Low-Noise Fixed Regulator
OUT
IN
VOUT
COUT
VIN
R1
R2
CBYP
(optional)
Bandgap
Ref.
EN
Current Limit
Thermal Shutdown
MIC5219BM5/MM [adj.]
GND
Ultra-Low-Noise Adjustable Regulator
July 2000
7
MIC5219
MIC5219
Micrel
Thermal Considerations
Applications Information
The MIC5219 is designed to provide 200mA of continuous
current in two very small profile packages. Maximum power
dissipationcanbecalculatedbasedontheoutputcurrentand
the voltage drop across the part. To determine the maximum
powerdissipationofthepackage,usethethermalresistance,
junction-to-ambient, of the device and the following basic
equation.
TheMIC5219isdesignedfor150mAto200mAoutputcurrent
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 discus-
sion of higher current applications.
Enable/Shutdown
Forcing EN (enable/shutdown) high (> 2V) enables the regu-
lator. EN is compatible with CMOS logic. If the enable/
shutdown feature is not required, connect EN to IN (supply
input). See Figure 5.
T
– TA
(
)
J(max)
PD
=
(max)
θJA
T
is the maximum junction temperature of the die,
Input Capacitor
J(MAX)
125°C, and T is the ambient operating temperature. θ is
layout dependent; table 1 shows examples of thermal resis-
tance, junction-to-ambient, for the MIC5219.
A
JA
A 1µF capacitor should be placed from IN to GND if there is
morethan10inchesofwirebetweentheinputandtheacfilter
capacitor or if a battery is used as the input.
Package
θJA Recommended θJA 1" Square
Minimum Footprint 2 oz. Copper
θJC
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 C
(see Figure 5). 2.2µF minimum is recommended when C
MM8™ (MM)
160°C/W
220°C/W
70°C/W
30°C/W
SOT-23-5 (M5)
170°C/W
130°C/W
is not used
BYP
Table 1. MIC5219 Thermal Resistance
BYP
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 in-
creased without limit.
The actual power dissipation of the regulator circuit can be
determined using one simple equation.
P = (V – V
) I
+ V I
IN GND
D
IN
OUT OUT
Substituting P
for P and solving for the operating
D(MAX)
D
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 deter-
mine the maximum input voltage for a set output current.
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 oscilla-
tion and/or underdamped transient response. Most tantalum
or aluminum electrolytic capacitors are adequate; film types
willwork, butaremoreexpensive. Manyaluminumelectrolyt-
ics have electrolytes that freeze at about –30°C, so solid
tantalums are recommended for operation below –25°C.
125°C – 25°C
(
)
P
=
D(max)
220°C/W
= 455mW
P
D(max)
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.
The thermal resistance, junction-to-ambient, for the mini-
mum footprint is 220°C/W, taken from table 1. The maximum
power dissipation number cannot be exceeded for proper
operationofthedevice. Usingtheoutputvoltageof3.3V, 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 Character-
istics section of the data sheet.
No-Load Stability
TheMIC5219willremainstableandinregulationwithnoload
(other than the internal voltage divider) unlike many other
voltage regulators. This is especially important in CMOS
RAM keep-alive applications.
Reference Bypass Capacitor
455mW = (V – 3.3V) × 150mA + V × 3mA
IN
IN
BYP is connected to the internal voltage reference. A 470pF
455mW = (150mA) × V + 3mA × V – 495mW
IN
IN
capacitor (C
) connected from BYP to GND quiets this
BYP
950mW = 153mA × V
IN
reference, providing a significant reduction in output noise
V
= 6.2V
MAX
IN
(ultra-low-noise performance). C
reduces the regulator
BYP
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
effectsonvoltageregulators, refertotheRegulatorThermals
sectionofMicrel’sDesigningwithLow-DropoutVoltageRegu-
lators handbook.
phase margin; when using C
or greater are generally required to maintain stability.
, output capacitors of 2.2µF
BYP
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 C
consider omitting C
. Likewise, if rapid turn-on is necessary,
.
BYP
BYP
MIC5219
8
July 2000
MIC5219
Micrel
Peak Current Applications
Figures3and4showsafeoperatingregionsfortheMIC5219-
x.xBMM, the power MSOP package part. These graphs
show three typical operating regions at different tempera-
tures. 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 con-
sideration and using two different board layouts, minimum
footprint and 1" square copper PC board heat sink. (For
furtherdiscussionofPCboardheatsinkcharacteristics, refer
to Application Hint 17, “Designing PC Board Heat Sinks”.)
The MIC5219 is designed for applications where high start-
up currents are demanded from space constrained regula-
tors. 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 characteris-
tics of the device. You can obtain higher continuous currents
from the device with the proper design. This is easily proved
with some thermal calculations.
Theinformationusedtodeterminethesafeoperatingregions
can be obtained in a similar manner to that used in determin-
ing typical power dissipation, already discussed. Determin-
ingthemaximumpowerdissipationbasedonthelayoutisthe
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
bestshownthroughanexample. Iftheapplicationcallsfor5V
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.
Ifwelookataspecificexample,itmaybeeasiertofollow. The
MIC5219 can be used to provide up to 500mA continuous
output current. First, calculate the maximum power dissipa-
tion of the device, as was done in the thermal considerations
section. Worst case thermal resistance (θ = 220°C/W for
JA
the MIC5219-x.xBM5), will be used for this example.
T
– TA
(
)
J(max)
PD
=
(max)
θJA
Assuming a 25°C room temperature, we have a maximum
power dissipation number of
125°C – 25°C
(
)
P
=
D(max)
220°C/W
= 455mW
% DC
Avg.PD =
455mW =
455mW =
0.274 =
V
– VOUT
I
+ VIN IGND
(
)
P
IN
OUT
D(max)
100
Then we can determine the maximum input voltage for a five-
volt regulator operating at 500mA, using worst case ground
current.
% DC
100
8V – 5V 500mA + 8V × 20mA
(
)
P
I
= 455mW = (V – V
) I
+ V I
IN GND
D(max)
IN
OUT OUT
% Duty Cycle
100
1.66W
= 500mA
OUT
V
= 5V
OUT
% Duty Cycle
100
I
= 20mA
GND
455mW = (V – 5V) 500mA + V × 20mA
IN
IN
% Duty Cycle Max = 27.4%
2.995W = 520mA × V
IN
With an output current of 500mA and a three-volt drop across
the MIC5219-xxBMM, the maximum duty cycle is 27.4%.
2.955W
V
=
= 5.683V
IN(max)
520mA
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.
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
resistanceimprovespowerdissipationandallowsforalarger
safe operating region.
P × 50mA = (5V – 3.3V) × 50mA + 5V × 650µA
D
P × 50mA = 173mW
D
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, P must be
D
multiplied by the duty cycle to obtain the actual average
power dissipation at 50mA.
July 2000
9
MIC5219
MIC5219
Micrel
10
8
10
8
10
8
100mA
100mA
100mA
200mA
6
6
6
200mA
200mA
4
4
4
300mA
300mA
300mA
400mA
20
2
2
2
500mA
400mA
400mA
20
500mA
40
500mA
40
DUTY CYCLE (%)
0
0
0
0
60
80
100
0
60
80
100
0
20
40
60
80
100
DUTY CYCLE (%)
DUTY CYCLE (%)
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
8
10
8
10
8
100mA
100mA
100mA
200mA
6
6
6
200mA
200mA
300mA
4
4
4
300mA
80
400mA
20
2
2
2
300mA
400mA
20
400mA
500mA
20 40
500mA
40 60
500mA
40 60
0
0
0
0
0
0
80
100
0
100
0
60
80
100
DUTY CYCLE (%)
DUTY CYCLE (%)
DUTY CYCLE (%)
a. 25°C Ambient
b. 50°C Ambient
c. 85°C Ambient
2
Figure 2. MIC5219-x.xBM5 (SOT-23-5) on 1-inch Copper Cladding
10
8
10
8
10
8
100mA
300mA
100mA
100mA
200mA
6
6
6
200mA
200mA
300mA
300mA
4
4
4
400mA
20
400mA
20
2
2
2
400mA
500mA
40 60
500mA
40
500mA
20 40
DUTY CYCLE (%)
0
0
0
80
100
0
60
80
100
0
60
80
100
DUTY CYCLE (%)
DUTY CYCLE (%)
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
10
8
10
8
200mA
300mA
100mA
200mA
300mA
200mA
6
6
6
400mA
300mA
400mA
4
4
4
400mA
20
500mA
2
2
500mA
2
500mA
40 60
0
0
0
20
40
60
80
100
0
20
40
60
80
100
0
80
100
DUTY CYCLE (%)
DUTY CYCLE (%)
DUTY CYCLE (%)
a. 25°C Ambient
b. 50°C Ambient
c. 85°C Ambient
2
Figure 4. MIC5219-x.xBMM (MSOP-8) on 1-inch Copper Cladding
MIC5219
10
July 2000
MIC5219
Micrel
MIC5219-x.x
P × 50mA = 0.875 × 173mW
D
VIN
VOUT
P × 50mA = 151mW
IN
OUT
BYP
GND
D
EN
The power dissipation at 500mA must also be calculated.
2.2µF
P × 500mA = (5V – 3.3V) 500mA + 5V × 20mA
D
470pF
P × 500mA = 950mW
D
This number must be multiplied by the duty cycle at which it
would be operating, 12.5%.
Figure 6. Ultra-Low-Noise Fixed Voltage Regulator
P × = 0.125 × 950mW
Figure 6 includes the optional 470pF noise bypass capacitor
between BYP and GND to reduce output noise. Note that the
D
P × = 119mW
D
minimum value of C
capacitor is used.
must be increased when the bypass
OUT
The total power dissipation of the device under these condi-
tions is the sum of the two power dissipation figures.
Adjustable Regulator Circuits
P
P
P
= P × 50mA + P × 500mA
D D
D(total)
D(total)
D(total)
MIC5219
= 151mW + 119mW
= 270mW
VIN
VOUT
1µF
IN
OUT
ADJ
GND
R1
R2
EN
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 there-
fore would operate properly.
Multilayer boards with a ground plane, wide traces near the
pads, and large supply-bus lines will have better thermal
conductivity.
Figure 7. Low-Noise Adjustable Voltage Regulator
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:
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 Low-
Dropout Voltage Regulators handbook.
R2
V
= 1.242V
+1
OUT
R1
Although ADJ is a high-impedance input, for best perfor-
Fixed Regulator Circuits
MIC5219-x.x
mance, R2 should not exceed 470kΩ.
MIC5219
VIN
VOUT
1µF
VIN
VOUT
IN
OUT
BYP
IN
OUT
ADJ
GND
R1
R2
EN
EN
GND
2.2µF
470pF
Figure 5. Low-Noise Fixed Voltage Regulator
Figure 8. Ultra-Low-Noise Adjustable Application.
Figure5showsabasicMIC5219-x.xBMXfixed-voltageregu-
lator circuit. A 1µF minimum output capacitor is required for
basic fixed-voltage applications.
Figure 8 includes the optional 470pF bypass capacitor from
ADJ to GND to reduce output noise.
July 2000
11
MIC5219
MIC5219
Micrel
Package Information
0.122 (3.10)
0.112 (2.84)
0.199 (5.05)
0.187 (4.74)
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)
0.012 (0.30) R
0.007 (0.18)
0.005 (0.13)
0.008 (0.20)
0.004 (0.10)
5° MAX
0° MIN
0.012 (0.03)
0.012 (0.03) R
0.039 (0.99)
0.0256 (0.65) TYP
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) 3.00 (0.118)
1.50 (0.059) 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 USA
TEL + 1 (408) 944-0800 FAX + 1 (408) 944-0970 WEB 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
MIC5219
12
July 2000
相关型号:
MIC5219YMTTR
ADJUSTABLE POSITIVE LDO REGULATOR, 0.6V DROPOUT, PDSO6, 2 X 2 MM, LEAD FREE, MLF-6
MICREL
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