MIC5235. General Description. Features. Applications. Typical Application. Ultra-Low Quiescent Current, 150mA µcap LDO Regulator

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1 MIC535 Ultra-Low Quiescent Current, 5mA µcap LDO Regulator General Description The MIC535 is a 5mA highly accurate, low dropout regulator with high input voltage and ultra-low ground current. This combination of high voltage and low ground current makes the MIC535 ideal for USB and portable electronics applications, using -cell, -cell or 3-cell Li-Ion battery inputs. A µcap LDO design, the MIC535 is stable with either ceramic or tantalum output capacitor. It only requires a.µf capacitor for stability. Features of the MIC535 includes enable input, thermal shutdown, current limit, reverse battery protection, and reverse leakage protection. Available in fixed and adjustable output voltage versions, the MIC535 is offered in the IttyBitty SOT-3-5 package with a junction temperature range of 4 C to +5 C. Features Wide input voltage range:.3v to 4V Ultra low ground current: 8 Low dropout voltage: 3 at 5mA High output accuracy: ±.% over temperature µcap: stable with ceramic or tantalum capacitors Excellent line and load regulation specifications Zero shutdown current Reverse battery protection Reverse leakage protection Thermal shutdown and current limit protection IttyBitty SOT-3-5 package Adjustable output from.4v-v Applications USB power supply Cellular phones Keep-alive supply in notebook and portable computers Logic supply for high-voltage batteries Automotive electronics Battery powered systems Typical Application 4 C IN =.µf V IN MIC535BM R R V OUT =.8V C OUT =.µf ceramic I = I OUT = ma I OUT = I OUT = Ultra-Low Current Adjustable Regulator Application Ground Current vs. Input Voltage IttyBitty is a registered trademark of Micrel, Inc Micrel Inc. 8 Fortune Drive San Jose, CA 953 USA tel + (48) fax + (48) May 8 M

2 MIC535 Ordering Information Part Number Marking Codes Standard Pb-Free Standard Pb-Free* Voltage** Junction Temp. Range Package MIC535-.5BM5 MIC535-.5YM5 L5 L5.5V 4 to +5 C 5-Pin SOT-3 MIC535-.8BM5 MIC535-.8YM5 L8 L8.8V 4 to +5 C 5-Pin SOT-3 MIC535-.5BM5 MIC535-.5YM5 L5 L5.5V 4 to +5 C 5-Pin SOT-3 MIC535-.7BM5 MIC535-.7YM5 L7 L7.7V 4 to +5 C 5-Pin SOT-3 MIC535-3.BM5 MIC535-3.YM5 L3 L3 3.V 4 to +5 C 5-Pin SOT-3 MIC BM5 MIC YM5 L33 L33 3.3V 4 to +5 C 5-Pin SOT-3 MIC535-5.BM5 MIC535-5.YM5 L5 L5 5.V 4 to +5 C 5-Pin SOT-3 MIC535BM5 MIC535YM5 LAA LAA Adj. 4 to +5 C 5-Pin SOT-3 * Under bar symbol (_) may not be to scale. ** Contact factory regarding availability for voltages not listed. Pin Configuration 3 IN 3 IN Lxx Lxx Lxx Lxx 4 5 NC OUT SOT-3-5 (Fixed) 4 5 ADJ OUT SOT-3-5 (Adjustable) Pin Description Pin Number Pin Name Pin Function IN Supply Input. Ground. 3 Enable (Input): Logic low = shutdown; logic high = enable. 4 NC (fixed) No Connect. ADJ (adj.) Adjust (Input): Feedback input. Connect to resistive voltage-divider network. 5 OUT Regulator Output. May 8 M

3 Absolute Maximum Ratings () Input Supply Voltage... V to 38V Enable Input Voltage....3V to 38V Power Dissipation...Internally Limited Junction Temperature... 4 C to +5 C Storage Temperature C to +5 C ESD Rating (3) Operating Ratings () MIC535 Input Supply Voltage....3V to 4V Enable Input Voltage... V to 4V Junction Thermal... 4 C to +5 C Package Thermal Resistance SOT-3-5 (θ JA )...35 C/W Electrical Characteristics (4) T A = 5 C with V IN = V OUT + V; I OUT =, Bold values indicate 4 C<T J <+5 C; unless otherwise specified. Parameter Condition Min Typ Max Units Output Voltage Accuracy Variation from nominal V OUT.. Line Regulation V IN = V OUT + V to 4V.4 % Load Regulation Load = to 5mA.5 % Dropout Voltage I OUT = I OUT = 5mA I OUT = ma I OUT = 5mA Reference Voltage..4.5 V Ground Current I OUT = I OUT = 5mA I OUT = ma I OUT = 5mA ma ma ma Ground Current in Shutdown V.6V; V IN = 4V. Short Circuit Current V OUT = V 35 5 ma Output Leakage, Load = 5Ω; V IN = 5V. Reverse Polarity Input Enable Input Input Low Voltage Regulator OFF.6 V Input High Voltage Regulator ON. V Enable Input Current V =.6V; Regulator OFF V =.V; Regulator ON V = 4V; Regulator ON Notes:. Exceeding the absolute maximum rating may damage the device.. The device is not guaranteed to function outside its operating rating. 3. Devices are ESD sensitive. Handling precautions recommended. Human body model,.5k in series with pf. 4. Specification for packaged product only % % May 8 3 M

4 MIC535 Typical Characteristics PSRR (db) OUTPUT VOLTAGE (V) Power Supply Rejection Ratio I LOAD = 5mA.. FREQUCY (khz) Dropout Characteristics I LOAD = I LOAD = 75mA I LOAD = 5mA I LOAD = ma vs. Input Voltage I OUT = ma I OUT = ma I OUT = I OUT = DROPOUT VOLTAGE () Dropout Voltage vs. Output Current OUTPUT CURRT (ma) vs. Output Current V IN =4V OUTPUT CURRT (ma) I LOAD = 75mA vs. Input Voltage I OUT =5mA I OUT = 75mA DROPOUT VOLTAGE () GROUND CURRT (ma) Dropout Voltage I OUT = 5mA vs. Output Current V IN = V V IN =4V V IN = 4V OUTPUT CURRT () I LOAD = 5mA vs. Input Voltage I OUT = ma I OUT = I OUT = May 8 4 M

5 MIC535 Typical Characteristics (continued) INPUT CURRT (ma) Input Current vs. Supply Voltage V =5V R LOAD =3 - - SUPPLY VOLTAGE (V) OUTPUT VOLTAGE (V) Output Voltage I LOAD = SHORT CIRCUIT CURRT (ma) Short Circuit Current V IN =4V mA ma V IN = 4V V OUT = 3V C OUT = 4.7µF ceramic May 8 5 M

6 MIC535 Functional Diagram IN OUT ABLE.4V V REF Block Diagram Fixed Output Voltage IN OUT ABLE R.4V V REF ADJ R Block Diagram Adjustable Output Voltage May 8 6 M

7 Application Information Enable/Shutdown The MIC535 comes with an active-high enable pin that allows the regulator to be disabled. Forcing the enable pin low disables the regulator and sends it into a zero off-mode-current state. In this state, current consumed by the regulator goes nearly to zero. Forcing the enable pin high enables the output voltage. Input Capacitor The MIC535 has high input voltage capability up to 4V. The input capacitor must be rated to sustain voltages that may be used on the input. An input capacitor may be required when the device is not near the source power supply or when supplied by a battery. Small, surface mount, ceramic capacitors can be used for bypassing. Larger values may be required if the source supply has high ripple. Output Capacitor The MIC535 requires an output capacitor for stability. The design requires.µf or greater on the output to maintain stability. The design is optimized for use with low-esr ceramic chip capacitors. High ESR capacitors may cause high frequency oscillation. The maximum recommended ESR is 3Ω. The output capacitor can be increased without limit. Larger valued capacitors help to improve transient response. X7R/X5R dielectric-type ceramic capacitors are recommended because of their temperature performance. X7R-type capacitors change capacitance by 5% over their operating temperature range and are the most stable type of ceramic capacitors. Z5U and Y5V dielectric capacitors change value by as much as 5% and 6% respectively over their operating temperature ranges. To use a ceramic chip capacitor with Y5V dielectric, the value must be much higher than a X7R ceramic capacitor to ensure the same minimum capacitance over the equivalent operating temperature range. No-Load Stability The MIC535 will remain stable and in regulation with no load unlike many other voltage regulators. This is especially important in CMOS RAM keep-alive applications. Thermal Considerations The MIC535 is designed to provide 5mA of continuous current in a very small package. 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 junction-to-ambient thermal resistance of the device and the following basic equation: P D(MAX) T = J(MAX) θ JA T A MIC535 T J(MAX) is the maximum junction temperature of the die, 5 C, and T A is the ambient operating temperature. θ JA is layout dependent; Table shows examples of the junction-to-ambient thermal resistance for the MIC535. Package θ JA Recommended Minimum Footprint SOT C Table. SOT-3-5 Thermal Resistance The actual power dissipation of the regulator circuit can be determined using the equation: P D = (V IN V OUT )I OUT + V IN I Substituting P D(MAX) for P D and solving for the operating conditions that are critical to the application will give the maximum operating conditions for the regulator circuit. For example, when operating the MIC535-3.BM5 at 5 C with a minimum footprint layout, the maximum input voltage for a set output current can be determined as follows: 5 C 5 C P D(MAX) = 35 C/W P D(MAX) = 39mW The junction-to-ambient (θ JA ) thermal resistance for the minimum footprint is 35 C/W, from Table. It is important that the maximum power dissipation not be exceeded to ensure proper operation. Since the MIC535 was designed to operate with high input voltages, careful consideration must be given so as not to overheat the device. With very high input-to-output voltage differentials, the output current is limited by the total power dissipation. Total power dissipation is calculated using the following equation: P D = (V IN V OUT )I OUT + V IN I Due to the potential for input voltages up to 4V, ground current must be taken into consideration. If we know the maximum load current, we can solve for the maximum input voltage using the maximum power dissipation calculated for a 5 C ambient, 39. P D(MAX) = (V IN V OUT )I OUT + V IN x I 39mW = (V IN 3V)5mA + V IN x.8ma Ground pin current is estimated using the typical characteristics of the device. 769mW = V IN (5.8mA) V IN = 5.3V For higher current outputs only a lower input voltage will work for higher ambient temperatures. Assuming a lower output current of ma, the maximum input voltage can be recalculated: May 8 7 M

8 39mW = (V IN 3V)mA + V IN x.ma 379mW = V IN x.ma V IN = 8.8V Maximum input voltage for a ma load current at 5 C ambient temperature is 8.8V, utilizing virtually the entire operating voltage range of the device. Adjustable Regulator Application The MIC535BM5 can be adjusted from.4v to V by using two external resistors (Figure ). The resistors set the output voltage based on the following equation: V OUT = V REF R + R MIC535 Where V REF =.4V. Feedback resistor R should be no larger than 3kΩ. V IN MIC535BM5 IN OUT.µF ADJ. R R V OUT Figure. Adjustable Voltage Application.µF May 8 8 M

9 MIC535 Package Information SOT-3-5 (M5) MICREL, INC. 8 FORTUNE DRIVE SAN JOSE, CA 953 USA TEL + (48) FAX + (48) 474- WEB 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 a Purchaser s own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. 3 Micrel, Incorporated. May 8 9 M