Micrel, Inc.

MIC5219

MIC5219
500mA-Peak Output LDO Regulator

General Description Features

The MIC5219 is an efficient linear voltage regulator with high • 500mA output current capability
peak output current capability, very-low-dropout voltage, and SOT-23-5 package - 500mA peak
better than 1% output voltage accuracy. Dropout is typically 2mm×2mm MLF® package - 500mA continuous
10mV at light loads and less than 500mV at full load. 2mm×2mm Thin MLF® package - 500mA
The MIC5219 is designed to provide a peak output current for continuous
start-up conditions where higher inrush current is demanded. MSOP-8 package - 500mA continuous
It features a 500mA peak output rating. Continuous output • Low 500mV maximum dropout voltage at full load
current is limited only by package and layout. • Extremely tight load and line regulation
• Tiny SOT-23-5 and MM8™ power MSOP-8 package
The MIC5219 can be enabled or shut down by a CMOS or
• Ultra-low-noise output
TTL compatible signal. When disabled, power consumption
• Low temperature coefficient
drops nearly to zero. Dropout ground current is minimized to
• Current and thermal limiting
help prolong battery life. Other key features include reversed-
• Reversed-battery protection
battery protection, current limiting, overtemperature shutdown,
• CMOS/TTL-compatible enable/shutdown control
and low noise performance with an ultra-low-noise option.
• Near-zero shutdown current
The MIC5219 is available in adjustable or fixed output volt-
ages in the space-saving 6-pin (2mm × 2mm) MLF®, 6-pin Applications
(2mm × 2mm) Thin MLF® SOT‑23‑5 and MM8® 8‑pin power • Laptop, notebook, and palmtop computers
MSOP packages. For higher power requirements see the • Cellular telephones and battery-powered equipment
MIC5209 or MIC5237. • Consumer and personal electronics
All support documentation can be found on Micrel’s web site • PC Card VCC and VPP regulation and switching
at www.micrel.com. • SMPS post-regulator/DC-to-DC modules
• High-efficiency linear power supplies

Typical Applications
MIC5219-5.0BMM
ENABLE 1 8
SH U TD OWN
2 7
MIC5219-3.3BM5
VIN 6V 1 5
3 6 VIN 4V VOUT3.3V
VOUT5V 2
4 5
2.2µF
ENABLE 3 4 tantalum
2.2µF SH U TD OWN
tantalum 470pF
470pF

5V Ultra-Low-Noise Regulator 3.3V Ultra-Low-Noise Regulator

VIN VOUT VIN VOUT

MIC5219-x.xYML MIC5219YMT
ENABLE +
ENABLE
EN COUT EN 1 6 R1
SHUTDOWN 1 6 CBYP SHUTDOWN
2.2µF
(optional) 2 5
2 5

3 4
3 4 R2
470pF

Ultra-Low-Noise Regulator (Fixed) Ultra-Low-Noise Regulator (Adjustable)

MM8 is a registered trademark of Micrel, Inc.

MicroLeadFrame and MLF are registered trademarks of Amkor Technology, 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

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Micrel, Inc. MIC5219

Ordering Information
Part Number Marking
Standard Pb-Free Standard Pb-Free* Volts Temp. Range Package
MIC5219-2.5BMM MIC5219-2.5YMM — — 2.5V –40°C to +125°C MSOP-8
MIC5219-2.85BMM MIC5219-2.85YMM — — 2.85V –40°C to +125°C MSOP-8
MIC5219-3.0BMM MIC5219-3.0YMM — — 3.0V –40°C to +125°C MSOP-8
MIC5219-3.3BMM MIC5219-3.3YMM — — 3.3V –40°C to +125°C MSOP-8
MIC5219-3.6BMM MIC5219-3.6YMM — — 3.6V –40°C to +125°C MSOP-8
MIC5219-5.0BMM MIC5219-5.0YMM — — 5.0V –40°C to +125°C MSOP-8
MIC5219BMM MIC5219YMM — — Adj. –40°C to +125°C MSOP-8
MIC5219-2.5BM5 MIC5219-2.5YM5 LG25 LG25 2.5V –40°C to +125°C SOT-23-5
MIC5219-2.6BM5 MIC5219-2.6YM5 LG26 LG26 2.6V –40°C to +125°C SOT-23-5
MIC5219-2.7BM5 MIC5219-2.7YM5 LG27 LG27 2.7V –40°C to +125°C SOT-23-5
MIC5219-2.8BM5 MIC5219-2.8YM5 LG28 LG28 2.8V –40°C to +125°C SOT-23-5
MIC5219-2.8BML MIC5219-2.8YML G28 G28 2.8V –40°C to +125°C 6-Pin 2×2 MLF®
MIC5219-2.85BM5 MIC5219-2.85YM5 LG2J LG2J 2.85V –40°C to +125°C SOT-23-5
MIC5219-2.9BM5 MIC5219-2.9YM5 LG29 LG29 2.9V –40°C to +125°C SOT-23-5
MIC5219-3.1BM5 MIC5219-3.1YM5 LG31 LG31 3.1V –40°C to +125°C SOT-23-5
MIC5219-3.0BM5 MIC5219-3.0YM5 LG30 LG30 3.0V –40°C to +125°C SOT-23-5
MIC5219-3.0BML MIC5219-3.0YML G30 G30 3.0V –40°C to +125°C 6-Pin 2×2 MLF®
MIC5219-3.3BM5 MIC5219-3.3YM5 LG33 LG33 3.3V –40°C to +125°C SOT-23-5
MIC5219-3.3BML MIC5219-3.3YML G33 G33 3.3V –40°C to +125°C 6-Pin 2×2 MLF®
MIC5219-3.6BM5 MIC5219-3.6YM5 LG36 LG36 3.6V –40°C to +125°C SOT-23-5
MIC5219-5.0BM5 MIC5219-5.0YM5 LG50 LG50 5.0V –40°C to +125°C SOT-23-5
MIC5219BM5 MIC5219YM5 LGAA LGAA Adj. –40°C to +125°C SOT-23-5
MIC5219YMT GAA Adj. –40°C to +125°C 6-Pin 2x2 Thin MLF®**
MIC5219-5.0YMT G50 5.0V –40°C to +125°C 6-Pin 2x2 Thin MLF®**
Other voltages available. Consult Micrel for details.
* Over/underbar may not be to scale. ** Pin 1 identifier = ▲.

Pin Configuration
EN 1 8 GND E N GND IN
3 2 1
IN 2 EN 1 6 BYP
7 GND
OUT 3 6 GND GND 2 5 NC L Gx x
BYP 4 5 GND IN 3 4 OUT 4 5

BYP OUT

MIC5219-x.xBMM / MM8® / MSOP-8 MIC5219-x.xBML MIC5219-x.xBM5 / SOT-23-5

Fixed Voltages 6-Pin 2mm × 2mm MLF® (ML) Fixed Voltages
(Top View) (Top View) (Top View)

EN 1 8 GND E N GND IN
3 2 1
IN 2 7 GND EN 1 6 NC Part
Identification
OUT 3 6 GND GND 2 5 ADJ
LGAA
BYP 4 5 GND 4 5
IN 3 4 OUT
ADJ OUT

MIC5219YMM / MIC5219BMM MIC5219YMT MIC5219BM5 / SOT-23-5

MM8® MSOP-8 6-Pin 2mm × 2mm Thin MLF® (MT) Adjustable Voltage
Adjustable Voltage (Top View) (Top View)
(Top View)

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Micrel, Inc. MIC5219
Pin Description
Pin No. Pin No. Pin No. Pin Name Pin Function
MLF-6 MSOP-8 SOT-23-5
TMLF-6
3 2 1 IN Supply Input.
2 5–8 2 GND Ground: MSOP-8 pins 5 through 8 are internally connected.
4 3 5 OUT Regulator Output.
1 1 3 EN Enable (Input): CMOS compatible control input. Logic high = enable; logic
low or open = shutdown.
6 4 (fixed) 4 (fixed) BYP Reference Bypass: Connect external 470pF capacitor to GND to reduce
output noise. May be left open.
5(NC) 4 (adj.) 4 (adj.) ADJ Adjust (Input): Feedback input. Connect to resistive voltage-divider network.
EP — — GND Ground: Internally connected to the exposed pad. Connect externally to
GND pin.

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Micrel, Inc. MIC5219

Absolute Maximum Ratings(1) Operating Ratings(2)

Supply Input Voltage (VIN)...............................–20V to +20V Supply Input Voltage (VIN)............................. +2.5V to +12V
Power Dissipation (PD).............................. Internally Limited Enable Input Voltage (VEN)....................................0V to VIN
Junction Temperature (TJ)......................... –40°C to +125°C Junction Temperature (TJ)......................... –40°C to +125°C
Storage Temperature (TS)......................... –65°C to +150°C Package Thermal Resistance............................ see Table 1
Lead Temperature (Soldering, 5 sec.)........................ 260°C

Electrical Characteristics(3)
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 1 %
–2 2 %
ΔVOUT/ΔT Output Voltage Note 4 40
ppm/°C
Temperature Coefficient
ΔVOUT/VOUT Line Regulation VIN = VOUT + 1V to 12V 0.009 0.05 %/V
0.1
ΔVOUT/VOUT Load Regulation IOUT = 100µA to 500mA, Note 5 0.05 0.5 %
0.7
VIN – VOUT Dropout Voltage(6) IOUT = 100µA 10 60 mV
80
IOUT = 50mA 115 175 mV
250
IOUT = 150mA 175 300 mV
400
IOUT = 500mA 350 500 mV
600
IGND Ground Pin Current(7, 8) VEN ≥ 3.0V, IOUT = 100µA 80 130 µA
170
VEN ≥ 3.0V, IOUT = 50mA 350 650 µA
900
VEN ≥ 3.0V, IOUT = 150mA 1.8 2.5 mA
3.0
VEN ≥ 3.0V, IOUT = 500mA 12 20 mA
25
Ground Pin Quiescent Current(8) VEN ≤ 0.4V 0.05 3 µA
VEN ≤ 0.18V 0.10 8 µA
PSRR Ripple Rejection f = 120Hz 75 dB
ILIMIT Current Limit VOUT = 0V 700 1000 mA
ΔVOUT/ΔPD Thermal Regulation Note 9 0.05 %/W
eno Output Noise(10) IOUT = 50mA, COUT = 2.2µF, CBYP = 0 500 nV/ Hz
IOUT = 50mA, COUT = 2.2µF, CBYP = 470pF 300 nV/ Hz
ENABLE Input
VENL Enable Input Logic-Low Voltage VEN = logic low (regulator shutdown) 0.4 V
0.18
VEN = logic high (regulator enabled) 2.0 V
IENL Enable Input Current VENL ≤ 0.4V 0.01 –1 µA
VENL ≤ 0.18V 0.01 –2 µA
IENH VENH ≥ 2.0V 2 5 20 µA
25

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Micrel, Inc. MIC5219
Notes:
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.
2. The device is not guaranteed to function outside its operating rating.
3. Specification for packaged product only.
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 100µA to 500mA. 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 differen-
tial.
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. VEN is the voltage externally applied to devices with the EN (enable) input pin.
9. 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 regu-
lation effects. Specifications are for a 500mA load pulse at VIN = 12V for t = 10ms.
10. CBYP is an optional, external bypass capacitor connected to devices with a BYP (bypass) or ADJ (adjust) pin.

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Micrel, Inc. MIC5219

Typical Characteristics

Power Supply Power Supply Power Supply

Rejection Ratio Rejection Ratio Rejection Ratio
0 0 0
V IN = 6V V IN = 6V V IN = 6V
V OUT = 5V V OUT = 5V V OUT = 5V
-20 -20 -20

-40 -40 -40

-60 -60 -60

-80 IOUT = 100µA -80 IOUT = 1mA -80 IOUT = 100mA

C OUT = 1µF C OUT = 1µF C OUT = 1µF
-100 -100 -100
10 1E+2
1E+1 1k 1E+4
100 1E+3 10k 1E+5 1M 1E+7
100k 1E+6 10M 10 1E+2
1E+1 1k 1E+4
100 1E+3 10k 1E+5 1M 1E+7
100k 1E+6 10M 10 1E+2
1E+1 1k 1E+4
100 1E+3 10k 1E+5 1M 1E+7
100k 1E+6 10M
FREQUENCY (Hz) FREQUENCY (Hz) FREQUENCY (Hz)

Power Supply Power Supply Power Supply Ripple Rejection

Rejection Ratio Rejection Ratio vs. Voltage Drop
0 0 60
V IN = 6V V IN = 6V
-20 V OUT = 5V -20 V OUT = 5V 50
1mA
40
-40 -40
30 10mA IOUT = 100mA
-60 -60
IOUT = 1mA 20
IOUT = 100µA
-80 C OUT = 2.2µF -80 C OUT = 2.2µF
10
C BYP = 0.01µF C BYP = 0.01µF C OUT = 1µF
-100 -100 0
10 1E+2
1E+1 1k 1E+4
100 1E+3 10k 1E+5 1M 1E+7
100k 1E+6 10M 10 1E+2
1E+1 1k 1E+4
100 1E+3 10k 1E+5 1M 1E+7
100k 1E+6 10M 0 0.1 0.2 0.3 0.4
FREQUENCY (Hz) FREQUENCY (Hz) VOLTAGE DROP (V)

Power Supply Ripple Rejection

vs. Voltage Drop Noise Performance Noise Performance
100 10 10
90 10mA, C OUT
= 1µF
80 1mA 1 1 100mA
70
60 0.1 0.1 10mA
50 IOUT = 100mA
40 10mA 0.01 0.01
30 V OUT = 5V 1mA
20 C OUT = 2.2µF 0.001 0.001 C OUT = 10µF
10 C BYP = 0.01µF V OUT = 5V electrolytic
0 0.0001 0.0001
0 0.1 0.2 0.3 0.4 10 1E+2
1E+1 1k 1E+4
100 1E+3 10k 1E+5
100k 1E+6
1M 1E+7
10M 10 1E+2
1E+1 1k 1E+4
100 1E+3 10k 1E+5
100k 1E+6
1M 1E+7
10M
VOLTAGE DROP (V) FREQUENCY (Hz) FREQUENCY (Hz)

Dropout Voltage Dropout Characteristics

Noise Performance vs. Output Current
10 400 3.5
I L =100µA
3.0
1
100mA 300
2.5
0.1 2.0
200
0.01 V 1.5 I =100mA
1mA L
OUT = 5V
C OUT = 10µF 1.0
100
0.001 electrolytic 10mA I =500mA
0.5 L
C BYP = 100pF
0.0001 0 0
10 1E+2
1E+1 1k 1E+4
100 1E+3 10k 1E+5
100k 1E+6
1M 1E+7
10M 0 100 200 300 400 500 0 1 2 3 4 5 6 7 8 9
FREQUENCY (Hz) OUTPUT CURRENT (mA) INPUT VOLTAGE (V)

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Micrel, Inc. MIC5219

Ground Current Ground Current Ground Current

vs. Output Current vs. Supply Voltage vs. Supply Voltage
12 25 3.0

10 2.5
20
8 2.0
15
6 1.5
10 IL =100 mA
4 1.0

2 5 0.5
IL =100µA
IL =500mA
0 0 0
0 100 200 300 400 500 0 1 2 3 4 5 6 7 8 9 0 2 4 6 8
OUTPUT CURRENT (mA) INPUT VOLTAGE (V) INPUT VOLTAGE (V)

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Micrel, Inc. MIC5219

Block Diagrams

IN OUT
VIN VOU T
COU T
BYP

CB Y P
(optional)

Bandgap
VRef.
REF

EN

Current Limit
Thermal Shutdown
MIC5219-x.xBM5/M/YMT
GND

Ultra-Low-Noise Fixed Regulator

IN OUT
VIN VOU T
R1 COU T

R2 CB Y P
Bandgap (optional)
VRef.
REF

EN

Current Limit
Thermal Shutdown
MIC5219BM5/MM/YMT
GND

Ultra-Low-Noise Adjustable Regulator

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Micrel, Inc. MIC5219

Applications Information Thermal Considerations

The MIC5219 is designed for 150mA to 200mA output current The MIC5219 is designed to provide 200mA of continuous
applications where a high current spike (500mA) is needed for current in two very small profile packages. Maximum power
short, start-up conditions. Basic application of the device will dissipation can be calculated based on the output current and
be discussed initially followed by a more detailed discussion the voltage drop across the part. To determine the maximum
of higher current applications. power dissipation of the package, use the thermal resistance,
junction-to-ambient, of the device and the following basic
Enable/Shutdown
equation.
Forcing EN (enable/shutdown) high (>2V) enables the
regulator. EN is compatible with CMOS logic. If the enable/
P D (max ) =
( T (max ) − T )
J A
shutdown feature is not required, connect EN to IN (supply
θ JA
input). See Figure 5.
Input Capacitor TJ(max) is the maximum junction temperature of the die,
125°C, and TA is the ambient operating temperature. θJA
A 1µF capacitor should be placed from IN to GND if there is
is layout dependent; Table 1 shows examples of thermal
more than 10 inches of wire between the input and the AC
resistance, junction-to-ambient, for the MIC5219.
filter capacitor or if a battery is used as the input.
Package θJA Recommended θJA 1" Square θJC
Output Capacitor Minimum Footprint 2oz. Copper
An output capacitor is required between OUT and GND to MM8® (MM) 160°C/W 70°C/W 30°C/W
prevent oscillation. The minimum size of the output capacitor
SOT-23-5 (M5) 220°C/W 170°C/W 130°C/W
is dependent upon whether a reference bypass capacitor is
used. 1µF minimum is recommended when CBYP is not used 2×2 MLF® (ML) 90°C/W — —
(see Figure 5). 2.2µF minimum is recommended when CBYP 2×2 Thin
is 470pF (see Figure 6). For applications < 3V, the output MLF® (MT) 90°C/W — —
capacitor should be increased to 22µF minimum to reduce Table 1. MIC5219 Thermal Resistance
start-up overshoot. Larger values improve the regulator’s
The actual power dissipation of the regulator circuit can be
transient response. The output capacitor value may be in-
determined using one simple equation.
creased without limit.
PD = (VIN – VOUT) IOUT + VIN IGND
The output capacitor should have an ESR (equivalent series
resistance) of about 1Ω or less and a resonant frequency Substituting PD(max) for PD and solving for the operating
above 1MHz. Ultra-low-ESR capacitors could cause oscilla- conditions that are critical to the application will give the
tion and/or underdamped transient response. Most tantalum maximum operating conditions for the regulator circuit. For
or aluminum electrolytic capacitors are adequate; film types example, if we are operating the MIC5219-3.3BM5 at room
will work, but are more expensive. Many aluminum electro- temperature, with a minimum footprint layout, we can deter-
lytics have electrolytes that freeze at about –30°C, so solid mine the maximum input voltage for a set output current.
tantalums are recommended for operation below –25°C.
At lower values of output current, less output capacitance is P D (max ) =
(125 °C − 25°C )
needed for stability. The capacitor can be reduced to 0.47µF 220°C / W
for current below 10mA, or 0.33µF for currents below 1mA. PD(max) = 455mW
No-Load Stability The thermal resistance, junction-to-ambient, for the minimum
The MIC5219 will remain stable and in regulation with no load footprint is 220°C/W, taken from Table 1. The maximum power
(other than the internal voltage divider) unlike many other dissipation number cannot be exceeded for proper opera-
voltage regulators. This is especially important in CMOS tion of the device. Using the output voltage of 3.3V, and an
RAM keep-alive applications. output current of 150mA, we can determine the maximum
Reference Bypass Capacitor input voltage. Ground current, maximum of 3mA for 150mA
of output current, can be taken from the “Electrical Charac-
BYP is connected to the internal voltage reference. A 470pF
teristics” section of the data sheet.
capacitor (CBYP) connected from BYP to GND quiets this
reference, providing a significant reduction in output noise 455mW = (VIN – 3.3V) × 150mA + VIN × 3mA
(ultra-low-noise performance). CBYP reduces the regulator 455mW = (150mA) × VIN + 3mA × VIN – 495mW
phase margin; when using CBYP, output capacitors of 2.2µF 950mW = 153mA × VIN
or greater are generally required to maintain stability.
VIN = 6.2VMAX
The start-up speed of the MIC5219 is inversely proportional
Therefore, a 3.3V application at 150mA of output current
to the size of the reference bypass capacitor. Applications
can accept a maximum input voltage of 6.2V in a SOT-23-5
requiring a slow ramp-up of output voltage should consider
package. For a full discussion of heat sinking and thermal
larger values of CBYP. Likewise, if rapid turn-on is necessary,
effects on voltage regulators, refer to the “Regulator Ther-
consider omitting CBYP.
mals” section of Micrel’s Designing with Low-Dropout Voltage
Regulators handbook.

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Micrel, Inc. MIC5219
Peak Current Applications xBMM, the power MSOP package part. These graphs show
The MIC5219 is designed for applications where high start-up three typical operating regions at different temperatures. The
currents are demanded from space constrained regulators. lower the temperature, the larger the operating region. The
This device will deliver 500mA start-up current from a SOT- graphs were obtained in a similar way to the graphs for the
23-5 or MM8 package, allowing high power from a very low MIC5219-x.xBM5, taking all factors into consideration and
profile device. The MIC5219 can subsequently provide output using two different board layouts, minimum footprint and 1"
current that is only limited by the thermal characteristics of square copper PC board heat sink. (For further discussion
the device. You can obtain higher continuous currents from of PC board heat sink characteristics, refer to “Application
the device with the proper design. This is easily proved with Hint 17, Designing PC Board Heat Sinks” .)
some thermal calculations. The information used to determine the safe operating regions
If we look at a specific example, it may be easier to follow. can be obtained in a similar manner such as determining
The MIC5219 can be used to provide up to 500mA continuous typical power dissipation, already discussed. Determining
output current. First, calculate the maximum power dissipa- the maximum power dissipation based on the layout is the
tion of the device, as was done in the thermal considerations first step, this is done in the same manner as in the previous
section. Worst case thermal resistance (θJA = 220°C/W for two sections. Then, a larger power dissipation number multi-
the MIC5219-x.xBM5), will be used for this example. plied by a set maximum duty cycle would give that maximum
power dissipation number for the layout. This is best shown
P D (max ) =
( T (max ) − T )
J A through an example. If the application calls for 5V at 500mA
θ JA for short pulses, but the only supply voltage available is
8V, then the duty cycle has to be adjusted to determine an
Assuming a 25°C room temperature, we have a maximum average power that does not exceed the maximum power
power dissipation number of dissipation for the layout.

P D (max ) =
(125 °C − 25°C )
 % DC 
220 °C / W Avg.P D =  ( )
 V – V OUT I OUT + V IN I GND
 100  IN
PD(max) = 455mW  % DC 
Then we can determine the maximum input voltage for a 455mW =   (8V – 5V ) 500mA + 8V × 20mA
 100 
5-volt regulator operating at 500mA, using worst case ground
current.  % Duty Cycle 
455mW =   1.66W
PD(max) = 455mW = (VIN – VOUT) IOUT + VIN IGND  100 
IOUT = 500mA % Duty Cycle
0.274 =
VOUT = 5V 100
IGND = 20mA % Duty Cycle Max = 27.4%
455mW = (VIN – 5V) 500mA + VIN × 20mA With an output current of 500mA and a three-volt drop across
2.995W = 520mA × VIN the MIC5219-xxBMM, the maximum duty cycle is 27.4%.
2.955W Applications also call for a set nominal current output with a
VIN (max ) = = 5.683V greater amount of current needed for short durations. This is a
520mA tricky situation, but it is easily remedied. Calculate the average
Therefore, to be able to obtain a constant 500mA output cur- power dissipation for each current section, then add the two
rent from the 5219-5.0BM5 at room temperature, you need numbers giving the total power dissipation for the regulator.
extremely tight input-output voltage differential, barely above For example, if the regulator is operating normally at 50mA,
the maximum dropout voltage for that current rating. but for 12.5% of the time it operates at 500mA output, the
You can run the part from larger supply voltages if the proper total power dissipation of the part can be easily determined.
precautions are taken. Varying the duty cycle using the en- First, calculate the power dissipation of the device at 50mA.
able pin can increase the power dissipation of the device by We will use the MIC5219-3.3BM5 with 5V input voltage as
maintaining a lower average power figure. This is ideal for our example.
applications where high current is only needed in short bursts. PD × 50mA = (5V – 3.3V) × 50mA + 5V × 650µA
Figure 1 shows the safe operating regions for the MIC5219-x. PD × 50mA = 173mW
xBM5 at three different ambient temperatures and at differ-
However, this is continuous power dissipation, the actual
ent output currents. The data used to determine this figure
on‑time for the device at 50mA is (100%-12.5%) or 87.5%
assumed a minimum footprint PCB design for minimum heat
of the time, or 87.5% duty cycle. Therefore, PD must be mul-
sinking. Figure 2 incorporates the same factors as the first
tiplied by the duty cycle to obtain the actual average power
figure, but assumes a much better heat sink. A 1" square cop-
dissipation at 50mA.
per 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.
Figures 3 and 4 show safe operating regions for the MIC5219-x.

June 2009 10 M0371-061809

Micrel, Inc. MIC5219

10 10 10
100mA
8 8 100mA 8 100mA

6 200mA 6 6
200mA
4 300mA 4 4 200mA
300mA
400mA 300mA
2 2 2 500mA
400mA
500mA 500mA 400mA
0 0 0
0 20 40 60 80 100 0 20 40 60 80 100 0 20 40 60 80 100
DUTY CYCLE (%) 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 10 10
100mA
8 8 100mA 8
100mA
6 200mA 6 6
200mA
200mA
4 300mA 4 4
300mA
400mA
2 2 400mA 2 400mA 300mA
500mA
500mA 500mA
0 0 0
0 20 40 60 80 100 0 20 40 60 80 100 0 20 40 60 80 100
DUTY CYCLE (%) DUTY CYCLE (%) DUTY CYCLE (%)
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 100mA
8 8 8 100mA

200mA
6 6 200mA 6
200mA
300mA
4 4 300mA 4 300mA
400mA
2 2 400mA 2
500mA 400mA
500mA
500mA
0 0 0
0 20 40 60 80 100 0 20 40 60 80 100 0 20 40 60 80 100
DUTY CYCLE (%) 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 10 10
200mA
100mA
200mA
8 8 8

300mA 200mA
6 6 6
300mA
400mA 400mA 300mA
4 4 4

500mA 400mA
2 2 500mA 2
500mA
0 0 0
0 20 40 60 80 100 0 20 40 60 80 100 0 20 40 60 80 100
DUTY CYCLE (%) DUTY CYCLE (%) DUTY CYCLE (%)
a. 25°C Ambient b. 50°C Ambient c. 85°C Ambient
Figure 4. MIC5219-x.xBMM (MSOP-8) on 1-inch2 Copper Cladding

June 2009 11 M0371-061809

Micrel, Inc. MIC5219
PD × 50mA = 0.875 × 173mW MIC5219-x.x
VIN VOU T
PD × 50mA = 151mW IN OUT
The power dissipation at 500mA must also be calculated. EN BYP
PD × 500mA = (5V – 3.3V) 500mA + 5V × 20mA GND 2.2µF
PD × 500mA = 950mW 470pF
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
PD × = 0.125 × 950mW
Figure 6 includes the optional 470pF noise bypass capacitor
PD × = 119mW between BYP and GND to reduce output noise. Note that the
The total power dissipation of the device under these condi- minimum value of COUT must be increased when the bypass
tions is the sum of the two power dissipation figures. capacitor is used.
PD(total) = PD × 50mA + PD × 500mA Adjustable Regulator Circuits
PD(total) = 151mW + 119mW MIC5219
VIN VOU T
PD(total) = 270mW IN OUT
The total power dissipation of the regulator is less than the EN ADJ R1
GND 1µF
maximum power dissipation of the SOT-23-5 package at room
temperature, on a minimum footprint board and therefore R2
would operate properly.
Multilayer boards with a ground plane, wide traces near the
pads, and large supply-bus lines will have better thermal Figure 7. Low-Noise Adjustable Voltage Regulator
conductivity.
Figure 7 shows the basic circuit for the MIC5219 adjustable
For additional heat sink characteristics, please refer to Mi- regulator. The output voltage is configured by selecting values
crel “Application Hint 17, Designing P.C. Board Heat Sinks”, for R1 and R2 using the following formula:
included in Micrel’s Databook. For a full discussion of heat
sinking and thermal effects on voltage regulators, refer to  R2 
V OUT = 1.242V  + 1
“Regulator Thermals” section of Micrel’s Designing with Low-  R1 
Dropout Voltage Regulators handbook. Although ADJ is a high-impedance input, for best performance,
Fixed Regulator Circuits R2 should not exceed 470kΩ.
MIC5219-x.x MIC5219
VIN VOU T VIN VOU T
IN OUT IN OUT
EN BYP EN ADJ R1
GND GND 2.2µF
1µF
R2
470pF

Figure 5. Low-Noise Fixed Voltage Regulator

Figure 8. Ultra-Low-Noise Adjustable Application
Figure 5 shows a basic MIC5219‑x.xBMX fixed-voltage regu-
lator circuit. A 1µF minimum output capacitor is required for Figure 8 includes the optional 470pF bypass capacitor from
basic fixed-voltage applications. ADJ to GND to reduce output noise.

June 2009 12 M0371-061809

Micrel, Inc. MIC5219

Package Information

8-Pin MSOP (MM)

SOT-23-5 (M5)

June 2009 13 M0371-061809

Micrel, Inc. MIC5219

6-Pin MLF® (ML)

6-Pin Thin MLF® (MT)

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 at Purchaser’s own risk and Purchaser agrees to fully indemnify
Micrel for any damages resulting from such use or sale.
© 2005 Micrel, Incorporated.

June 2009 14 M0371-061809

Mouser Electronics

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MIC5219-3.6YML TR MIC5219-3.3YMM MIC5219-5.0YMM MIC5219-3.0YMM MIC5219YMM MIC5219-2.5YMM
MIC5219-3.3YM5 TR MIC5219-5.0YM5 TR MIC5219YM5 TR MIC5219YMM TR MIC5219-2.5YMM TR MIC5219-
3.6YMM TR MIC5219-3.1YM5 TR MIC5219-2.85YM5 TR MIC5219-2.6YM5 TR MIC5219-3.3YMM TR MIC5219-
5.0YMT TR MIC5219-2.85YMM MIC5219-3.6YM5 TR MIC5219-3.6YMM MIC5219-2.7YM5 TR MIC5219-2.5YM5 TR
MIC5219-3.0YMM TR MIC5219-3.0YML TR MIC5219-2.9YM5 TR MIC5219-2.8YML TR MIC5219-5.0YMM TR
MIC5219-2.85YMM TR MIC5219-3.3YML TR MIC5219YMT TR MIC5219-2.8YM5 TR MIC5219-3.0YM5 TR
MIC5219-3.6YML-TR MIC5219-3.6YMM-TR MIC5219YM5-TR MIC5219-3.0YML-TR MIC5219YMM-TR MIC5219-
2.9YM5-TR MIC5219-3.1YM5-TR MIC5219-2.5YM5-TR MIC5219-2.6YM5-TR MIC5219-5.0YM5-TR MIC5219-
3.3YML-TR MIC5219-3.6YM5-TR MIC5219-2.7YM5-TR MIC5219-3.3YMM-TR MIC5219-2.5YMM-TR MIC5219-
2.8YM5-TR MIC5219-3.3YM5-TR MIC5219-5.0YMM-TR MIC5219-5.0YMT-TR MIC5219-3.0YM5-TR MIC5219YMT-
TR MIC5219-3.0YMM-TR MIC5219-2.85YMM-TR MIC5219-2.85YM5-TR MIC5219-2.8YML-TR MIC5219YM5-T5