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MIC5219
Micrel
MIC5219
500mA-Peak Output LDO Regulator Final
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 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 MM8TM 8-lead power MSOP packages. For higher power requirements see the MIC5209 or MIC5237.
Features
* 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 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
MIC5219-5.0BMM
ENABLE SHUTDOWN 1 2 3 4 8 7 6 5
MIC5219-3.3BM5 VIN 4V
ENABLE SHUTDOWN 1 2 3 4 5
VIN 6V VOUT 5V 2.2F tantalum
VOUT 3.3V 2.2F tantalum 470pF
470pF
5V Ultra-Low-Noise Regulator
3.3V Ultra-Low-Noise Regulator
MM8 is a trademark of Micrel, Inc. Micrel, Inc. * 1849 Fortune Drive * San Jose, CA 95131 * USA * tel + 1 (408) 944-0800 * fax + 1 (408) 944-0970 * http://www.micrel.com
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MIC5219
MIC5219
Micrel
Ordering Information
Part Number MIC5219-2.85BMM MIC5219-3.0BMM MIC5219-3.3BMM MIC5219-3.6BMM MIC5219-5.0BMM MIC5219BMM MIC5219YMM MIC5219-2.5BM5 MIC5219-2.6BM5 MIC5219-2.7BM5 MIC5219-2.8BM5 MIC5219-2.85BM5 MIC5219-2.9BM5 MIC5219-3.1BM5 MIC5219-3.0BM5 MIC5219-3.3BM5 MIC5219-3.6BM5 MIC5219-5.0BM5 MIC5219BM5 Marking -- -- -- -- -- -- -- LG25 LG26 LG27 LG28 LG2J LG29 LG31 LG30 LG33 LG36 LG50 LGAA Volts 2.85V 3.0V 3.3V 3.6V 5.0V Adj. Adj. 2.5V 2.6V 2.7V 2.8V 2.85V 2.9V 3.1V 3.0V 3.3V 3.6V 5.0V Adj. Junction 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 Package MSOP-8 MSOP-8 MSOP-8 MSOP-8 MSOP-8 MSOP-8 MSOP-8 Lead-Free 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 SOT-23-5 SOT-23-5 SOT-23-5
Other voltages available. Consult Micrel for details.
Pin Configuration
EN 1 IN 2 OUT 3 BYP 4 8 7 6 5 GND GND GND GND
4
EN GND IN
3 2 1
LGxx
5
BYP
OUT
MIC5219-x.xBMM MM8TM MSOP-8 Fixed Voltages
EN 1 IN 2 OUT 3 ADJ 4 8 7 6 5 GND GND GND GND
MIC5219-x.xBM5 SOT-23-5 Fixed Voltages
EN GND IN
3 2 1
LGAA
4 5
Part Identification
ADJ
OUT
MIC5219YMM MIC5219BMM MM8TM MSOP-8 Adjustable Voltage
MIC5219BM5 SOT-23-5 Adjustable Voltage
MIC5219
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MIC5219
Micrel
Pin Description
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 IN GND OUT EN BYP ADJ Pin Function 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.
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MIC5219
MIC5219
Micrel
Absolute Maximum Ratings
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
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
VIN = VOUT + 1.0V; COUT = 4.7F, IOUT = 100A; TJ = 25C, bold values indicate -40C TJ +125C; unless noted. Symbol VOUT VOUT/T VOUT/VOUT VOUT/VOUT VIN - VOUT Parameter Output Voltage Accuracy Output Voltage Temperature Coefficient Line Regulation Load Regulation Dropout Voltage, Note 4 Conditions variation from nominal VOUT Note 2 VIN = VOUT + 1V to 12V IOUT = 100A to 500mA Note 3 IOUT = 100A IOUT = 50mA IOUT = 150mA IOUT = 500mA IGND Ground Pin Current, Notes 5, 6 VEN 3.0V, IOUT = 100A VEN 3.0V, IOUT = 50mA VEN 3.0V, IOUT = 150mA VEN 3.0V, IOUT = 500mA Ground Pin Quiescent Current, Note 6 PSRR ILIMIT VOUT/PD eno Ripple Rejection Current Limit Thermal Regulation Output Noise VEN 0.4V VEN 0.18V f = 120Hz VOUT = 0V Note 7 IOUT = 50mA, COUT = 2.2F, CBYP = 0 IOUT = 50mA, COUT = 2.2F, CBYP = 470pF ENABLE Input VENL Enable Input Logic-Low Voltage VEN = logic low (regulator shutdown) VEN = logic high (regulator enabled) IENL IENH Enable Input Current VENL 0.4V VENL 0.18V VENH 2.0V 2 2.0 0.01 0.01 5 -1 -2 20 25 0.4 0.18 V V A A A Min -1 -2 40 0.009 0.05 10 115 175 350 80 350 1.8 12 0.05 0.10 75 700 0.05 500 300 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 Typical Max 1 2 Units % % ppm/C %/V % mV mV mV mV A A mA mA A A dB mA %/W
nV/ Hz nV/ Hz
MIC5219
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MIC5219
Note 1:
Micrel
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. Output voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range. 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. 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. 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. VEN is the voltage externally applied to devices with the EN (enable) input pin. 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. CBYP is an optional, external bypass capacitor connected to devices with a BYP (bypass) or ADJ (adjust) pin.
Note 2: Note 3: Note 4: Note 5: Note 6: Note 7: Note 8:
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MIC5219
MIC5219
Micrel
Typical Characteristics
Power Supply Rejection Ratio
0 -20 PSRR (dB) -40 -60 -80 IOUT = 100A COUT = 1F VIN = 6V VOUT = 5V PSRR (dB) 0 -20 -40 -60 -80 IOUT = 1mA COUT = 1F
Power Supply Rejection Ratio
VIN = 6V VOUT = 5V PSRR (dB) 0 -20 -40 -60 -80
Power Supply Rejection Ratio
VIN = 6V VOUT = 5V
IOUT = 100mA COUT = 1F
-100 1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7 10 100 1k 10k 100k 1M 10M FREQUENCY (Hz)
-100 1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7 10 100 1k 10k 100k 1M 10M FREQUENCY (Hz)
-100 1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7 10 100 1k 10k 100k 1M 10M FREQUENCY (Hz)
Power Supply Rejection Ratio
0 -20 PSRR (dB) -40 -60 -80 IOUT = 100A COUT = 2.2F CBYP = 0.01F VIN = 6V VOUT = 5V PSRR (dB) 0 -20 -40 -60 -80
Power Supply Rejection Ratio
0 VIN = 6V VOUT = 5V PSRR (dB) -20 -40 -60 -80
Power Supply Rejection Ratio
VIN = 6V VOUT = 5V
IOUT = 1mA COUT = 2.2F CBYP = 0.01F
-100 1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7 10 100 1k 10k 100k 1M 10M FREQUENCY (Hz)
-100 1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7 10 100 1k 10k 100k 1M 10M FREQUENCY (Hz)
-100 1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7 10 100 1k 10k 100k 1M 10M FREQUENCY (Hz)
IOUT = 100mA COUT = 2.2F CBYP = 0.01F
60 RIPPLE REJECTION (dB) 50 40 30 20 10 0
Power Supply Ripple Rejection vs. Voltage Drop
RIPPLE REJECTION (dB)
Power Supply Ripple Rejection vs. Voltage Drop
100 90 80 70 60 50 40 30 20 10 0 IOUT = 100mA 10mA COUT = 2.2F CBYP = 0.01F 0 0.1 0.2 0.3 VOLTAGE DROP (V) 0.4 1mA NOISE (V/Hz) 10
Noise Performance
10mA, COUT = 1F 1 0.1 0.01 0.001 VOUT = 5V 0.0001 1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7 10 100 1k 10k 100k 1M 10M FREQUENCY (Hz)
1mA
10mA
IOUT = 100mA
COUT = 1F 0 0.1 0.2 0.3 VOLTAGE DROP (V) 0.4
Noise Performance
10 1 NOISE (V/Hz) 0.1 0.01 0.001 VOUT = 5V COUT = 10F electrolytic 1mA 100mA NOISE (V/Hz) 10mA 10 1 0.1
Noise Performance
DROPOUT VOLTAGE (mV)
Dropout Voltage vs. Output Current
400
100mA
300
200
0.0001 1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7 10 100 1k 10k 100k 1M 10M FREQUENCY (Hz)
1mA VOUT = 5V COUT = 10F 0.001 electrolytic 10mA CBYP = 100pF 0.0001 1E+1 1E+2 1E+3 1E+4 1E+5 1E+6 1E+7 10 100 1k 10k 100k 1M 10M FREQUENCY (Hz)
0.01
100
0 0
100 200 300 400 500 OUTPUT CURRENT (mA)
MIC5219
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MIC5219
Micrel
Dropout Characteristics
3.5 OUTPUT VOLTAGE (V) 3.0 2.5 2.0 1.5 1.0 0.5 0 0 1 I =500mA L 2345678 INPUT VOLTAGE (V) 9 I =100mA L GROUND CURRENT (mA) I =100A L 12 10 8 6 4 2 0 0
Ground Current vs. Output Current
100 200 300 400 500 OUTPUT CURRENT (mA)
Ground Current vs. Supply Voltage
25 GROUND CURRENT (mA) GROUND CURRENT (mA) 20 15 10 5 0 0 IL=500mA 12345678 INPUT VOLTAGE (V) 3.0 2.5 2.0 1.5 1.0 0.5 0 0
Ground Current vs. Supply Voltage
IL=100 mA
IL=100A 2 4 6 INPUT VOLTAGE (V) 8
9
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MIC5219
MIC5219
Micrel
Block Diagrams
VIN
IN BYP
OUT
VOUT COUT
CBYP (optional) Bandgap Ref. VREF EN Current Limit Thermal Shutdown MIC5219-x.xBM5/MM GND
Ultra-Low-Noise Fixed Regulator
VIN
IN
OUT R1
VOUT COUT
R2 Bandgap Ref. VREF EN Current Limit Thermal Shutdown MIC5219BM5/MM [adj.] GND
CBYP (optional)
Ultra-Low-Noise Adjustable Regulator
MIC5219
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November 2002
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 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 5 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.
PD(max) =
(TJ(max) - TA )
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 MM8TM (MM) SOT-23-5 (M5) JA Recommended JA 1" Square Minimum Footprint 2 oz. Copper 160C/W 220C/W 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. 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) =
(125C
- 25C) 220C/W
PD(max) = 455mW 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 455mW = (150mA) x VIN + 3mA x VIN - 495mW 950mW = 153mA x VIN 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.
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MIC5219
MIC5219
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. 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.
Micrel
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. % DC Avg.PD = V - VOUT IOUT + VIN IGND 100 IN
PD(max) =
(TJ(max) - TA )
JA
Assuming a 25C room temperature, we have a maximum power dissipation number of
PD(max) =
(125C
- 25C) 220C/W
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 VOUT = 5V IGND = 20mA 455mW = (VIN - 5V) 500mA + VIN x 20mA 2.995W = 520mA x VIN 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 10
(
)
% DC 455mW = (8V - 5V) 500mA + 8V x 20mA 100 % Duty Cycle 455mW = 1.66W 100 0.274 = % 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 x 50mA = (5V - 3.3V) x 50mA + 5V x 650A PD x 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.
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MIC5219
Micrel
10 100mA
10
10
VOLTAGE DROP (V)
VOLTAGE DROP (V)
6 4 2 0 400mA
200mA 300mA
6 200mA 4 300mA 2 0 400mA 0 20 500mA 40 60 80 DUTY CYCLE (%) 100
VOLTAGE DROP (V)
8
8
100mA
8 6 4 2 500mA 0 400mA 0 20
100mA
200mA 300mA
500mA 0 20 40 60 80 DUTY CYCLE (%) 100
40 60 80 DUTY CYCLE (%)
100
a. 25C Ambient
b. 50C Ambient
c. 85C Ambient
Figure 1. MIC5219-x.xBM5 (SOT-23-5) on Minimum Recommended Footprint
10 100mA
10
10 100mA
VOLTAGE DROP (V)
VOLTAGE DROP (V)
VOLTAGE DROP (V)
8 6 4 2 0 400mA 500mA 0 20 40 60 80 DUTY CYCLE (%) 100 200mA 300mA
8 6 4 2 0 400mA 500mA 0 20
8 100mA 6 200mA 4 2 0 300mA
200mA 300mA
400mA 0
40 60 80 DUTY CYCLE (%)
100
500mA 20 40 60 80 DUTY CYCLE (%)
100
a. 25C Ambient
b. 50C Ambient
c. 85C Ambient
Figure 2. MIC5219-x.xBM5 (SOT-23-5) on 1-inch2 Copper Cladding
10 100mA
10 100mA
10
VOLTAGE DROP (V)
VOLTAGE DROP (V)
6 4 400mA 2
200mA 300mA
6 4 2 0 400mA
VOLTAGE DROP (V)
8
8 200mA 300mA
8 6
100mA
200mA 4 2 400mA 0 0 500mA 20 40 60 80 DUTY CYCLE (%) 100 300mA
500mA 0 0 20 40 60 80 DUTY CYCLE (%) 100 0 20
500mA 40 60 80 DUTY CYCLE (%) 100
a. 25C Ambient
b. 50C Ambient
c. 85C Ambient
Figure 3. MIC5219-x.xBMM (MSOP-8) on Minimum Recommended Footprint
10
200mA
10
10 200mA 100mA
VOLTAGE DROP (V)
VOLTAGE DROP (V)
6 4 2 0 400mA
300mA
VOLTAGE DROP (V)
8
8 6 4 2 0 400mA
8 6 4 2 0 400mA 500mA 200mA 300mA
300mA
500mA
500mA
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 November 2002 11 MIC5219
MIC5219
PD x 50mA = 0.875 x 173mW PD x 50mA = 151mW The power dissipation at 500mA must also be calculated. PD x 500mA = (5V - 3.3V) 500mA + 5V x 20mA PD x 500mA = 950mW This number must be multiplied by the duty cycle at which it would be operating, 12.5%. PD x = 0.125 x 950mW PD x = 119mW 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) = 151mW + 119mW PD(total) = 270mW 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
VIN MIC5219-x.x IN EN OUT BYP GND 1F VOUT
Micrel
VIN MIC5219-x.x IN EN OUT BYP GND 470pF 2.2F VOUT
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
VIN MIC5219 IN EN OUT ADJ GND R1 1F R2 VOUT
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 VOUT = 1.242V + 1 R1 Although ADJ is a high-impedance input, for best performance, R2 should not exceed 470k.
VIN MIC5219 IN EN OUT ADJ GND 470pF R1 2.2F R2 VOUT
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.
MIC5219
12
November 2002
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)
0.012 (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) 3.02 (0.119) 2.80 (0.110) 1.30 (0.051) 0.90 (0.035) 10 0 0.15 (0.006) 0.00 (0.000) 0.20 (0.008) 0.09 (0.004)
0.50 (0.020) 0.35 (0.014)
0.60 (0.024) 0.10 (0.004)
SOT-23-5 (M5)
MICREL INC.
TEL
1849 FORTUNE DRIVE SAN JOSE, CA 95131
FAX
USA
+ 1 (408) 944-0800
+ 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. (c) 2002 Micrel Incorporated
November 2002
13
MIC5219

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