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Micrel, Inc.
MIC5219
MIC5219
500mA-Peak Output LDO Regulator
General Description
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. The MIC5219 is designed to provide a peak output current for start-up 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 the space-saving 6-pin (2mm x 2mm) MLF(R), 6-pin (2mm x 2mm) Thin MLF(R) SOT-23-5 and MM8(R) 8-pin power MSOP packages. For higher power requirements see the MIC5209 or MIC5237. All support documentation can be found on Micrel's web site at www.micrel.com.
Features
* 500mA output current capability SOT-23-5 package - 500mA peak 2mmx2mm MLF(R) package - 500mA continuous 2mmx2mm Thin MLF(R) package - 500mA continuous MSOP-8 package - 500mA continuous * Low 500mV maximum dropout voltage at full load * Extremely tight load and line regulation * Tiny SOT-23-5 and MM8TM 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
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
ENABLE SH U TD OWN 1 2 3 4
MIC5219-5.0BMM
8 7 6 5
VIN 6V
MIC5219-3.3BM5 VIN 4V
ENABLE SH U TD OWN 1 2 3 4 5
VOUT5V 2.2F tantalum
VOUT3.3V 2.2F tantalum 470pF
470pF
5V Ultra-Low-Noise Regulator
VIN
ENABLE SHUTDOWN
3.3V Ultra-Low-Noise Regulator
VOUT
VIN
ENABLE SHUTDOWN
MIC5219-x.xYM L
1 2 3 6 5 4
MIC5219YMT
1 2 3 6 5 4
VOUT R1 + 2.2F
EN
CBYP
COUT
EN
(optional)
470pF
R2
Ultra-Low-Noise Regulator (Fixed)
MM8 is a registered trademark of Micrel, Inc. MicroLeadFrame and MLF are registered trademarks of Amkor Technology, Inc..
Ultra-Low-Noise Regulator (Adjustable)
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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MIC5219
Part Number Marking Standard -- -- -- -- -- -- -- LG25 LG26 LG27 LG28 G28 LG2J LG29 LG31 LG30 G30 LG33 G33 LG36 LG50 LGAA Pb-Free* -- -- -- -- -- -- -- LG25 LG26 LG27 LG28 G28 LG2J LG29 LG31 LG30 G30 LG33 G33 LG36 LG50 LGAA GAA G50 Volts 2.5V 2.85V 3.0V 3.3V 3.6V 5.0V Adj. 2.5V 2.6V 2.7V 2.8V 2.8V 2.85V 2.9V 3.1V 3.0V 3.0V 3.3V 3.3V 3.6V 5.0V Adj. Adj. 5.0V Temp. Range -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C Package MSOP-8 MSOP-8 MSOP-8 MSOP-8 MSOP-8 MSOP-8 MSOP-8 SOT-23-5 SOT-23-5 SOT-23-5 SOT-23-5 6-Pin 2x2 MLF(R) SOT-23-5 SOT-23-5 SOT-23-5 SOT-23-5 6-Pin 2x2 MLF(R) SOT-23-5 6-Pin 2x2 MLF(R) SOT-23-5 SOT-23-5 SOT-23-5 6-Pin 2x2 Thin MLF(R)** 6-Pin 2x2 Thin MLF(R)**
Ordering Information
Standard MIC5219-2.5BMM MIC5219-2.85BMM MIC5219-3.0BMM MIC5219-3.3BMM MIC5219-3.6BMM MIC5219-5.0BMM MIC5219BMM MIC5219-2.5BM5 MIC5219-2.6BM5 MIC5219-2.7BM5 MIC5219-2.8BM5 MIC5219-2.8BML MIC5219-2.85BM5 MIC5219-2.9BM5 MIC5219-3.1BM5 MIC5219-3.0BM5 MIC5219-3.0BML MIC5219-3.3BM5 MIC5219-3.3BML MIC5219-3.6BM5 MIC5219-5.0BM5 MIC5219BM5 Pb-Free MIC5219-2.5YMM MIC5219-2.85YMM MIC5219-3.0YMM MIC5219-3.3YMM MIC5219-3.6YMM MIC5219-5.0YMM MIC5219YMM MIC5219-2.5YM5 MIC5219-2.6YM5 MIC5219-2.7YM5 MIC5219-2.8YM5 MIC5219-2.8YML MIC5219-2.85YM5 MIC5219-2.9YM5 MIC5219-3.1YM5 MIC5219-3.0YM5 MIC5219-3.0YML MIC5219-3.3YM5 MIC5219-3.3YML MIC5219-3.6YM5 MIC5219-5.0YM5 MIC5219YM5 MIC5219YMT MIC5219-5.0YMT
Other voltages available. Consult Micrel for details. * Over/underbar may not be to scale. ** Pin 1 identifier = .
Pin Configuration
EN 1 IN 2 OUT 3 BYP 4 8 GND 7 GND 6 GND 5 GND
EN 1 GND 2 IN 3 6 BYP 5 NC 4 OUT
4
E N GND IN
3 2 1
L Gx x
5
BYP
OUT
MIC5219-x.xBMM / MM8(R) / MSOP-8 Fixed Voltages (Top View)
EN 1 IN 2 OUT 3 BYP 4 8 GND 7 GND 6 GND 5 GND
MIC5219-x.xBML 6-Pin 2mm x 2mm MLF(R) (ML) (Top View)
MIC5219-x.xBM5 / SOT-23-5 Fixed Voltages (Top View)
E N GND IN
EN 1 GND 2 IN 3
6 NC 5 ADJ 4 OUT
3
2
1
LGAA
4 5
Part Identification
ADJ
OUT
MIC5219YMM / MIC5219BMM MM8(R) MSOP-8 Adjustable Voltage (Top View) June 2009
MIC5219YMT 6-Pin 2mm x 2mm Thin MLF(R) (MT) (Top View) 2
MIC5219BM5 / SOT-23-5 Adjustable Voltage (Top View)
M0371-061809
Micrel, Inc.
MIC5219
Pin No. MSOP-8 2 5-8 3 1 4 (fixed) 4 (adj.) -- Pin No. SOT-23-5 1 2 5 3 4 (fixed) 4 (adj.) -- Pin Name Pin Function
Pin Description
Pin No. MLF-6 TMLF-6 3 2 4 1 6 5(NC) EP
IN GND OUT EN BYP ADJ GND
Supply Input. Ground: MSOP-8 pins 5 through 8 are internally connected. Regulator Output. Enable (Input): CMOS compatible control input. Logic high = enable; logic low or open = shutdown. 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. Ground: Internally connected to the exposed pad. Connect externally to GND pin.
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MIC5219
Absolute Maximum Ratings(1)
Supply Input Voltage (VIN) ..............................-20V to +20V Power Dissipation (PD) ............................. Internally Limited Junction Temperature (TJ) ........................ -40C to +125C Storage Temperature (TS) ........................ -65C to +150C Lead Temperature (Soldering, 5 sec.) ....................... 260C
Operating Ratings(2)
Supply Input Voltage (VIN) ............................ +2.5V to +12V Enable Input Voltage (VEN)....................................0V to VIN Junction Temperature (TJ) ........................ -40C to +125C Package Thermal Resistance........................... see Table 1
Electrical Characteristics(3)
Symbol VOUT VOUT/T ppm/C VOUT/VOUT VOUT/VOUT VIN - VOUT VIN = VOUT + 1.0V; COUT = 4.7F, IOUT = 100A; TJ = 25C, bold values indicate -40C TJ +125C; unless noted. Parameter Conditions Min -1 -2 40 Output Voltage Accuracy Output Voltage Temperature Coefficient Line Regulation Load Regulation Dropout Voltage(6) VIN = VOUT + 1V to 12V IOUT = 100A to 500mA, Note 5 IOUT = 100A IOUT = 50mA IOUT = 150mA IOUT = 500mA IGND Ground Pin Current(7, 8) VEN 3.0V, IOUT = 100A VEN 3.0V, IOUT = 50mA VEN 3.0V, IOUT = 150mA VEN 3.0V, IOUT = 500mA Ground Pin Quiescent Current(8) PSRR VOUT/PD ILIMIT Ripple Rejection Current Limit Thermal Regulation Output Noise(10) VEN 0.4V f = 120Hz Note 9 0.009 0.05 10 115 175 350 80 350 1.8 12 0.05 0.10 75 700 0.05 500 300 0.4 0.18 2.0 0.01 0.01 2 5 -1 -2 20 25 1000 0.05 0.1 0.5 0.7 60 80 175 250 300 400 500 600 130 170 650 900 2.5 3.0 20 25 3 8 %/V % mV mV mV mV A A mA mA A A dB mA %/W
nV/ Hz nV/ Hz
Typical
Max 1 2
Units % %
variation from nominal VOUT Note 4
VEN 0.18V
VOUT = 0V IOUT = 50mA, COUT = 2.2F, CBYP = 0
eno
ENABLE Input VENL Enable Input Logic-Low Voltage
IOUT = 50mA, COUT = 2.2F, CBYP = 470pF VEN = logic low (regulator shutdown) VEN = logic high (regulator enabled) VENL 0.18V VENH 2.0V VENL 0.4V
V V A A A
IENL IENH
Enable Input Current
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Notes:
MIC5219
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, JA, and the ambient temperature, TA. The maximum allowable power dissipation at any ambient temperature is calculated using: PD(max) = (TJ(max) - TA) / JA. 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 100A 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 differential. 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 regulation 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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Typical Characteristics
Power Supply Rejection Ratio
V IN = 6V V OUT = 5V
0 -20 -40 -60 -80
0 -20 -40 -60
Power Supply Rejection Ratio
V IN = 6V V OUT = 5V
0 -20 -40 -60
Power Supply Rejection Ratio
V IN = 6V V OUT = 5V
-100 10 100 1k 10k 100k 1M 10M 1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7 FREQUENCY (Hz)
IOUT = 100A C OUT = 1F
-80
-100 10 100 1k 10k 100k 1M 10M 1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7 FREQUENCY (Hz)
IOUT = 1mA C OUT = 1F
-80
IOUT = 100mA C OUT = 1F
-100 10 100 1k 10k 100k 1M 10M 1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7 FREQUENCY (Hz)
0 -20 -40 -60 -80
Power Supply Rejection Ratio
V IN = 6V V OUT = 5V
0 -20 -40 -60
Power Supply Rejection Ratio
V IN = 6V V OUT = 5V
60 50 40 30
Power Supply Ripple Rejection vs. Voltage Drop
1mA 10mA IOUT = 100mA
-100 10 100 1k 10k 100k 1M 10M 1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7 FREQUENCY (Hz)
IOUT = 100A C OUT = 2.2F C BYP = 0.01F
-80
IOUT = 1mA C OUT = 2.2F C BYP = 0.01F
20 10 0 C OUT = 1F 0 0.1 0.2 0.3 VOLTAGE DROP (V) 0.4
-100 10 100 1k 10k 100k 1M 10M 1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7 FREQUENCY (Hz)
100 90 80 70
Power Supply Ripple Rejection vs. Voltage Drop
1mA
10 1 0.1
Noise Performance
10mA, C
OUT
10 1 0.1 0.01 0.001
Noise Performance
= 1F 100mA 10mA
60 50 40 30 20 10 0
IOUT = 100mA 10mA C OUT = 2.2F C BYP = 0.01F 0 0.1 0.2 0.3 VOLTAGE DROP (V) 0.4 0.01 0.001 V OUT = 5V 0.0001 10 100 1k 10k 100k 1M 10M 1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7 FREQUENCY (Hz) V OUT = 5V C OUT = 10F electrolytic 1mA
0.0001 10 100 1k 10k 100k 1M 10M 1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7 FREQUENCY (Hz)
10 1 0.1
Noise Performance
Dropout Voltage vs. Output Current
400
3.5 3.0
Dropout Characteristics
I L =100A
100mA
300
2.5 2.0 1.5 1.0 0.5 I =500mA L 1 234567 INPUT VOLTAGE (V) 8 9 I =100mA L
200
0.01 V OUT = 5V C OUT = 10F 0.001 electrolytic C BYP = 100pF 1mA 10mA
100
0.0001 10 100 1k 10k 100k 1M 10M 1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7 FREQUENCY (Hz)
0
0
100 200 300 400 OUTPUT CURRENT (mA)
500
0 0
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MIC5219
Ground Current vs. Output Current
12 10 8 6 4 2 0 0 100 200 300 400 OUTPUT CURRENT (mA) 500 10 5 0 25 20 15
Ground Current vs. Supply Voltage
3.0 2.5 2.0 1.5 1.0 IL =500mA 0 1 234567 INPUT VOLTAGE (V) 8 9 0.5 0 0
Ground Current vs. Supply Voltage
IL =100 mA IL =100A 2 4 6 INPUT VOLTAGE (V) 8
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Block Diagrams
VIN
IN BYP
OUT
VOU T COU T
CB Y P (optional) Bandgap Ref. VR E F EN Current Limit Thermal Shutdown MIC5219-x.xBM5/M/YMT GND
Ultra-Low-Noise Fixed Regulator
VIN
IN
OUT R1
VOU T COU T
R2 Bandgap Ref. VR E F EN Current Limit Thermal Shutdown MIC5219BM5/MM/YMT GND
CB Y P (optional)
Ultra-Low-Noise Adjustable Regulator
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MIC5219 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, start-up 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 A 1F 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 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. 1F minimum is recommended when CBYP is not used (see Figure 5). 2.2F minimum is recommended when CBYP is 470pF (see Figure 6). For applications < 3V, the output capacitor should be increased to 22F 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 1 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 -30C, so solid tantalums are recommended for operation below -25C. At lower values of output current, less output capacitance is needed for stability. The capacitor can be reduced to 0.47F for current below 10mA, or 0.33F for currents below 1mA. 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. 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 2.2F 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.
P D (max ) =
( T (max ) - T )
J A
JA
TJ(max) is the maximum junction temperature of the die, 125C, and TA is the ambient operating temperature. JA is layout dependent; Table 1 shows examples of thermal resistance, junction-to-ambient, for the MIC5219.
Package MM8(R) (MM) SOT-23-5 (M5) 2x2 MLF(R) (ML) 2x2 Thin MLF(R) (MT) JA Recommended Minimum Footprint 160C/W 220C/W 90C/W 90C/W JA 1" Square 2oz. Copper 70C/W 170C/W -- -- JC 30C/W 130C/W -- --
Table 1. MIC5219 Thermal Resistance The actual power dissipation of the regulator circuit can be determined using one simple equation. 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 = (VIN - VOUT) IOUT + VIN IGND
P D (max ) =
(125 C - 25C )
220C / W
The thermal resistance, junction-to-ambient, for the minimum footprint is 220C/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. 455mW = (VIN - 3.3V) x 150mA + VIN x 3mA 950mW = 153mA x VIN 455mW = (150mA) x VIN + 3mA x VIN - 495mW
PD(max) = 455mW
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
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VIN = 6.2VMAX
June 2009
Micrel, Inc. Peak Current Applications The MIC5219 is designed for applications where high start-up currents are demanded from space constrained regulators. This device will deliver 500mA start-up current from a SOT23-5 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. 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 (JA = 220C/W for the MIC5219-x.xBM5), will be used for this example.
MIC5219 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 such as 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. % DC Avg.P D = V - V OUT I OUT + V IN I GND 100 IN
P D (max ) =
( T (max ) - T )
J A
JA
Assuming a 25C room temperature, we have a maximum power dissipation number of
P D (max ) =
(125 C - 25C )
220 C / W
(
)
Then we can determine the maximum input voltage for a 5-volt regulator operating at 500mA, using worst case ground current. PD(max) = 455mW = (VIN - VOUT) IOUT + VIN IGND IOUT = 500mA VOUT = 5V IGND = 20mA
PD(max) = 455mW
% DC 455mW = (8V - 5V ) 500mA + 8V x 20mA 100 % Duty Cycle 455mW = 1.66W 100 0.274 = % Duty Cycle 100 = 27.4%
% Duty Cycle Max
455mW = (VIN - 5V) 500mA + VIN x 20mA 2.995W = 520mA x VIN
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 x 50mA = 173mW PD x 50mA = (5V - 3.3V) x 50mA + 5V x 650A
VIN (max ) =
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. Figures 3 and 4 show safe operating regions for the MIC5219-x. June 2009 10
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.
M0371-061809
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MIC5219
10 100mA 8 6 4 2 0 400mA 500mA 0 20 40 60 80 DUTY CYCLE (%) 100 200mA 300mA
10 8 6 200mA 4 2 0 400mA 500mA 0 20 40 60 80 DUTY CYCLE (%) 100 300mA 100mA
10 8 6 4 2 500mA 0 400mA 0 20 40 60 80 DUTY CYCLE (%) 100 200mA 300mA 100mA
a. 25C Ambient
b. 50C Ambient
c. 85C Ambient
Figure 1. MIC5219-x.xBM5 (SOT-23-5) on Minimum Recommended Footprint
10 100mA 8 6 4 2 0 400mA 500mA 0 20 40 60 80 DUTY CYCLE (%) 100 200mA 300mA
10 8 6 4 2 0 400mA 500mA 0 20 40 60 80 DUTY CYCLE (%) 100 100mA 200mA 300mA
10 8 100mA 6 200mA 4 2 400mA 0 500mA 0 20 40 60 80 DUTY CYCLE (%) 100 300mA
a. 25C Ambient
b. 50C Ambient
c. 85C Ambient
Figure 2. MIC5219-x.xBM5 (SOT-23-5) on 1-inch2 Copper Cladding
10 100mA 8 6 4 400mA 2 500mA 0 0 20 40 60 80 DUTY CYCLE (%) 100 200mA 300mA
10 100mA 8 6 4 2 0 400mA 500mA 0 20 40 60 80 DUTY CYCLE (%) 100 200mA 300mA
10 8 6 200mA 4 2 400mA 0 500mA 0 20 40 60 80 DUTY CYCLE (%) 100 300mA 100mA
a. 25C Ambient
b. 50C Ambient
c. 85C Ambient
Figure 3. MIC5219-x.xBMM (MSOP-8) on Minimum Recommended Footprint
10 8 6 4 2 0 400mA
200mA
10 8 200mA
10 100mA 8 6 4 500mA 2 0 400mA 500mA 200mA 300mA
300mA
6 4 400mA
300mA
500mA
2 0
0
20
40 60 80 DUTY CYCLE (%)
100
0
20
40 60 80 DUTY CYCLE (%)
100
0
20
40 60 80 DUTY CYCLE (%)
100
a. 25C Ambient
b. 50C Ambient
c. 85C Ambient
Figure 4. MIC5219-x.xBMM (MSOP-8) on 1-inch2 Copper Cladding June 2009 11
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Micrel, Inc. PD x 50mA = 151mW PD x 50mA = 0.875 x 173mW
VIN MIC5219-x.x IN EN OUT BYP GND 470pF VOU T 2.2F
MIC5219
The power dissipation at 500mA must also be calculated. PD x 500mA = (5V - 3.3V) 500mA + 5V x 20mA This number must be multiplied by the duty cycle at which it would be operating, 12.5%. PD x = 0.125 x 950mW The total power dissipation of the device under these conditions is the sum of the two power dissipation figures. PD(total) = PD x 50mA + PD x 500mA PD(total) = 270mW PD(total) = 151mW + 119mW PD x = 119mW PD x 500mA = 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. Adjustable Regulator Circuits MIC5219 VIN IN OUT EN ADJ GND
VOU T R1 R2 1F
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. 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. Fixed Regulator Circuits MIC5219-x.x VIN IN OUT EN BYP GND
VOU T
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: R2 V OUT = 1.242V + 1 R1 Although ADJ is a high-impedance input, for best performance, R2 should not exceed 470k. MIC5219 VIN VOU T IN OUT R1 EN ADJ GND 2.2F
470pF R2
1F
Figure 5. Low-Noise Fixed Voltage Regulator Figure 5 shows a basic MIC5219-x.xBMX fixed-voltage regulator circuit. A 1F minimum output capacitor is required for basic fixed-voltage applications.
Figure 8. Ultra-Low-Noise Adjustable Application Figure 8 includes the optional 470pF bypass capacitor from ADJ to GND to reduce output noise.
June 2009
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Micrel, Inc.
MIC5219
Package Information
8-Pin MSOP (MM)
SOT-23-5 (M5)
June 2009
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Micrel, Inc.
MIC5219
6-Pin MLF(R) (ML)
6-Pin Thin MLF(R) (MT)
MICREL, INC.
tel
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. (c) 2005 Micrel, Incorporated.
+ 1 (408) 944-0800 fax + 1 (408) 474-1000 web http://www.micrel.com
2180 FORTUNE DRIVE SAN JOSE, CA 95131
USA
June 2009
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M0371-061809

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