Features. Applications V IN C IN

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1 3.A, Low-Voltage µcap LDO Regulator General Description The Micrel is a 3.A low-dropout linear voltage regulator that provides a low-voltage, high-current output with a minimum number of external components. It offers high precision, ultra-low-dropout (mv overtemperature), and low-ground current. The operates from an input of.5v to 6.V. It is designed to drive digital circuits requiring low-voltage at high currents (i.e., PLDs, DSP, microcontroller, etc.). It is available in fixed and adjustable output voltages. Fixed voltages include.5v,.8v,.5v and 3.3V. The adjustable version is capable of.v to 5.5V. Features of the LDO include thermal and current-limit protection, and reverse-current protection. Logic enable and error flag pins are available on the 5-pin version. Junction temperature range of the is from C to +5 C. For applications requiring input voltage greater than 6.V, see the MIC39x, MIC395x, MIC393x, and MIC39x LDOs. Data sheets and support documentation can be found on Micrel s web site at Features 3.A minimum guaranteed output current mv maximum dropout-voltage overtemperature Ideal for 3.V to.5v conversion Ideal for.5v to.8v,.65v, or.5v conversion Stable with ceramic or tantalum capacitor Wide input voltage range VIN:.5V to 6.V +.% initial output tolerance Fixed and adjustable output voltages: MIC373 3-pin fixed voltages MIC373 5-pin S-Pak or 8-pin e-pad SOIC fixed voltages with flag MIC373 5-pin adjustable voltage MIC pin e-pad SOIC adjustable voltage with flag Excellent line and load regulation specifications Thermal shutdown and current-limit protection Reverse-leakage protection Low profile S-Pak package Applications LDO linear regulator for low-voltage digital IC PC add-in cards High-efficiency linear power supplies SMPS post regulator Battery charger Typical Application V MIC373 IN = 3.V V OUT =.5V VIN VOUT V IN MIC373 VIN VOUT.3V GND 7µF, Ceramic C IN VEN ADJ GND R R 7µF, Ceramic Fixed.5V Regulator Adjustable Regulator Super ßeta PNP is a registered trademarks of Micrel Inc. 8 Fortune Drive San Jose, CA 953 USA tel + (8) 9-8 fax + (8) 7- October 9 M

2 MIC373 V IN = 3.V V OUT =.5V VIN VOUT C IN VEN GND FLG k Fixed.5 Regulator with Error Flag 7µF, Ceramic DROPOUT (mv) Dropout vs. Output Current 3 3.5V OUT 3.3V OUT OUTPUT CURRENT (A) Ordering Information Part number Standard RoHS Compliant* / Pb-Free Output Current Voltage Junction Temp. Range Package MIC373-.5BR MIC373-.5WR* 3.A.5V C to +5 C S-Pak-3 MIC BR MIC WR* 3.A.65V C to +5 C S-Pak-3 MIC373-.8BR MIC373-.8WR* 3.A.8V C to +5 C S-Pak-3 MIC373-.5BR MIC373-.5WR* 3.A.5V C to +5 C S-Pak-3 MIC BR MIC WR* 3.A 3.3V C to +5 C S-Pak-3 MIC373-.5YME 3.A.5V C to +5 C e-pad SOIC-8 MIC373-.5BR MIC373-.5WR* 3.A.5V C to +5 C S-Pak-5 MIC373-.8YME 3.A.8V C to +5 C e-pad SOIC-8 MIC373-.8BR MIC373-.8WR* 3.A.8V C to +5 C S-Pak-5 MIC373-.5YME 3.A.5V C to +5 C e-pad SOIC-8 MIC373-.5BR MIC373-.5WR* 3.A.5V C to +5 C S-Pak-5 MIC BR MIC WR* 3.A 3.3V C to +5 C S-Pak-5 MIC373BR MIC373WR* 3.A ADJ C to +5 C S-Pak-5 MIC373BU MIC373WU* 3.A ADJ C to +5 C TO-63-5 MIC3733YME 3.A ADJ C to +5 C e-pad SOIC-8 * RoHS compliant with high-melting solder exemption. October 9 M

3 Pin Configuration S-PAK-5 (R) S-PAK-3 (R) 5 FLG/ADJ VOUT 3 GND VIN EN GND EN VIN VIN 3 8 FLG 7 VOUT/ADJ 6 VOUT 5 VOUT TO-63-5 (U) e-pad SOIC-8 (ME) Pin Description Pin Number S-PAK-5 TO-63-5 Pin Number S-PAK-3 Pin Number e-pad SOIC-8 Pin Name Pin Function EN Enable Input : CMOS compatible input. Logic high = enable; Logic low = shutdown. 3, VIN Input voltage which supplies current to the output power device. 3 GND Ground: TAB is connected to ground. 3 5, 6, 7 (Fixed) 5, 6 (Adj.) VOUT Regulator Output. 5 (Fixed) 8 FLG Error Flag (Output): Open collector output. Active-low indicates an output fault condition. 5 (Adj.) 7 ADJ Adjustable Regulator Feedback Input: Connect to resistor voltage driver. October 9 3 M

4 Absolute Maximum Ratings () Supply Voltage (V IN ) V Enable Input Voltage (V EN ) (3) V Power Dissipation (P D ) (3)... Internally Limited Junction Temperature (T J )... C T J +5 C Storage Temperature (T S ) C T J + C Lead Temperature (soldering, 5sec)...6 C ESD Rating ()...kv Operating Ratings () Supply Voltage (V IN )...5V to 6.V Enable Input Voltage (V EN )...V to 6.V Junction Temperature (T J )... C T J +5 C Package Thermal Resistance S-Pak (θ JC )... C/W TO-63-5 (θ JC )... C/W e-pad SOIC-8 (θ JC )... C/W Electrical Characteristics (5) T A = 5 C with V IN = V OUT + V; V EN = V IN ; I L = ma; bold values indicate C < T J < +5 C, unless noted. Parameter Conditions Min Typ Max Units Output Voltage Accuracy I L = ma - + % ma < I OUT < I L(max), V OUT + V IN 6V - + % Output Voltage Line Regulation V IN = V OUT +.V to 6.V; I L = ma..5 % Output Voltage Load Regulation I L = ma to 3A. % V IN V OUT Dropout Voltage (6) I L =.5A (e-pad SOIC-8) I L = 3A (e-pad SOIC-8) Ground Pin Current (7) I L = 3A 7 Ground Pin Current in Shutdown V IL.5V, V IN = V OUT +V. 5 µa Current Limit V OUT = V A Start-up Time V EN = V in, I OUT = ma, = 7µF 7 µs Enable Input Enable Input Threshold Regulator enable.5 V Regulator shutdown.8 V Enable pin Input Current V IL.8V (Regulator shutdown) V IH.5V (Regulator enable) Flag Output I FLG(LEAK) V OH = 6V V FLG(LO) V IN =.5V, I OL = µa (8) V FLG Low Threshold, % of VOUT below nominal 93 % Hysteresis % High Threshold, % of VOUT below nominal 99. % MIC373 Only Reference Voltage Adjust Pin Bias Current 8 mv mv ma ma µa µa µa µa µa µa mv mv V V na na October 9 M

5 Notes:. Exceeding the absolute maximum rating may damage the device.. The device is not guaranteed to function outside its operating rating. 3. P D(max) = (T J(max) T A ) / θ JA, where θ JA, depends upon the printed circuit layout. See Applicatins Information.. Devices are ESD sensitive. Handling precautions recommended. 5. Specification for packaged product only. 6. V DO = V IN V OUT when V OUT decreases to 98% of its nominal output voltage with V IN = V OUT + V. For output voltages below.75, dropout voltage specification does not apply due to a minimum input operating voltage of.5v. 7. I GND is the quiescent current. I IN = I GND + I OUT. 8. For a.5v device, V IN =.V (device is in dropout). October 9 5 M

6 Typical Characteristics PSRR (db) DROPOUT (mv) OUTPUT VOLTAGE (V) Power Supply Rejection Ratio V IN =.5V V OUT =.5V 3 I OUT =3A =7µF C IN =.. FREQUENCY (khz) Dropout vs. Tempetature 3 3.5V OUT TEMPERATURE( C) Dropout Characteristics (3.3V) ma Load 3A Load INPUT VOLTAGE (V) vs. Supply Voltage (.5V) A 3A A 3 5 PSRR (db) OUTPUT VOLTAGE (V) Power Supply Rejection Ratio V IN =.5V V OUT =.5V 3 I OUT =3A =µf C IN =.. FREQUENCY (khz) Dropout Characteristics (.5V).6 ma Load A Load INPUT VOLTAGE (V) vs. Output Current OUTPUT CURRENT (A) vs. Supply Voltage (.5V) ma. ma 3 5 DROPOUT (mv) OUTPUT VOLTAGE (V) Dropout vs. Output Current 3 3.5V OUT 3.3V OUT OUTPUT CURRENT (A) Dropout Characteristics (.5V) ma Load 3A Load INPUT VOLTAGE (V) vs. Supply Voltage (.5V) ma ma vs. Supply Voltage (.5V) A 3A A 3 5 October 9 6 M

7 Typical Characteristics (continued) SHORT CIRCUIT CURRENT (A) FLAG VOLTAGE (mv) vs. Supply Voltage (3.3V) ma ma V OUT I OUT =.5A Short-Circuit Current vs. Supply Voltage Flag Low Voltage Flag Current = µa SHORT CIRCUIT CURRENT (A) FLAG VOLTAGE (V) vs. Supply Voltage (3.3V) 3A A A V 35 OUT I OUT =3A Short-Circuit Current.5V IN Error Flag Pull-Up Resistor 6 Flag High (OK) 5 3 Flag Low (FAULT) V IN =5V.. OUTPUT VOLTAGE (V) FLAG VOLTAGE (V) ENABLE CURRENT (µa) v OUT.5 I OUT =ma Output Voltage.5V OUT Flag Voltage vs. Flag Current 5V IN.5V IN 3.3V IN FLAG CURRENT (ma) Enable Current.5V EN October 9 7 M

8 Functional Characteristics Load Transient Response Line Transient Response OUTPUT VOLTAGE (mv/div.) OUTPUT CURRENT (3A/div.) V IN = 3.3V V OUT =.5V = 7µF Ceramic TIME (µs/div.) 3A ma OUTPUT VOLTAGE (mv/div.) INPUT VOLTAGE (V/div.) = 7µF Ceramic TIME (µs/div.) 5V 3.3V Enable Transient Response OUTPUT VOLTAGE (V/div.) ENABLE VOLTAGE (V/div.) I OUT = 3A V IN = 3.3V = 7µF.5V TIME (µs/div.) October 9 8 M

9 Applications Information Enable/Shutdown The is a high-performance lowdropout voltage regulator suitable for moderate to high-current regulator applications. Its mv dropout voltage at full load and over-temperature makes it especially valuable in battery-powered systems and as high-efficiency noise filters in post-regulator applications. Unlike older NPN-pass transistor designs, there the minimum dropout voltage is limited by the based-to-emitter voltage drop and collector-toemitter saturation voltage, dropout performance of the PNP output of these devices is limited only by the low VCE saturation voltage. A trade-off for the low dropout voltage is a varying base drive requirement. Micrel s Super ßeta PNP process reduces this drive requirement to only % to 5% of the load current. The regulator is fully protected from damage due to fault conditions. Current limiting is provided. This limiting is linear; output current during overload conditions is constant. Thermal shutdown disables the device when the die temperature exceeds the maximum safe operating temperature. The output structure of these regulators allows voltages in excess of the desired output voltage to be applied without reverse current flow. Thermal Design Linear regulators are simple to use. The most complicated design parameters to consider are thermal characteristics. Thermal design requires the following application-specific parameters: Maximum ambient temperature (T A ) Output current (I OUT ) Output voltage (V OUT ) Input voltage (V IN ) Ground current (I GND ) First, calculate the power dissipation of the regulator from these numbers and the device parameters from this datasheet. P D = (V IN V OUT ) I OUT + V IN I GND where the ground current is approximated by using numbers from the Electrical Characteristics or Typical Characteristics. Then the heat sink thermal resistance is determined with this formula: θ SA = ((T J(max) T A )/ P D ) (θ JC + θ CS ) Where T J(max) < 5 C and θ CS is between C and C/W. The heat sink may be significantly reduced in applications where the minimum input voltage is known and is large compared with the dropout voltage. Use a series input resistor to drop excessive voltage and distribute the heat between this resistor and the regulator. The low-dropout properties of Micrel s Super ßeta PNP regulators allow significant reductions in regulator power dissipation and the associated heat sink without compromising performance. When this technique is employed, a capacitor of at least.µf is needed directly between the input and regulator ground. Refer to Application Note 9 for further details and examples on thermal design and heat sink applications. Output Capacitor The requires an output capacitor for stable operation. As a µcap LDO, the can operate with ceramic output capacitors as long as the amount of capacitance is 7µF or greater. For values of output capacitance lower than 7µF, the recommended ESR range is mω to Ω. The minimum value of output capacitance recommended for the MIC373 is µf. For 7µF or greater, the ESR range recommended is less than Ω. Ultra-low ESR, ceramic capacitors are recommended for output capacitance of 7µF or greater to help improve transient response and noise reduction at high frequency. 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 % and 6%, respectively, over their operating temperature ranges. To use a ceramic chip capacitor with Y5V dielectric, the value must be much higher than an X7R ceramic capacitor to ensure the same minimum capacitance over the equivalent operating temperature range. Input Capacitor An input capacitor of.µf or greater is recommended when the device is more than inches away from the bulk supply capacitance, or when the supply is a battery. Small, surface-mount chip capacitors can be used for the bypassing. The capacitor should be place within " of the device for optimal performance. Larger values will help to improve ripple rejection by bypassing the input to the regulator, further improving the integrity of the output voltage. October 9 9 M

10 Transient Response and 3.3V to.5v,.5v to.8v or.65v, or.5v to.5v Conversions The has excellent transient response to variations in input voltage and load current. The device has been designed to respond quickly to load current variations and input voltage variations. Large output capacitors are not required to obtain this performance. A standard 7µF output capacitor, preferably tantalum, is all that is required. Larger values help to improve performance even further. By virtue of its low-dropout voltage, this device does not saturate into dropout as readily as similar NPNbased designs. When converting from 3.3V to.5v,.5v to.8v or.65v, or.5v to.5v, the NPNbased regulators are already operating in dropout, with typical dropout requirements of.v or greater. To convert down to.5v without operating in dropout, NPN-based regulators require an input voltage of 3.7V at the very least. The regulator will provide excellent performance with an input as low as 3.V or.5v, respectively. This gives the PNPbased regulators a distinct advantage over older, NPN-based linear regulators. Minimum Load Current The regulator is specified between finite loads. If the output current is too small, leakage currents dominate and the output voltage rises. A ma minimum load current is necessary for proper operation. Error Flag The MIC373 and MIC3733 feature an error flag circuit that monitors the output voltage and signals an error condition when the voltage is 5% below the nominal output voltage. The error flag is an opencollector output that can sink ma during a fault condition. Low output voltage can be caused by a number of problems, including an overcurrent fault (device in current limit) or low input voltage. The flag is inoperative during overtemperature shutdown. Enable Input The MIC373//3 also features an enable input for on/off control of the device. Its shutdown state draws zero current (only microamperes of leakage). The enable input is TTL/CMOS compatible for simple logic interface, but can be connected up to VIN. When enabled, it draws approximately 5µA. Adjustable Regulator Design ENABLE SHUTDOWN V IN MIC373 IN OUT EN ADJ GND V.V R OUT = + R R R Figure. Adjustable Regulator with Resistors V OUT The MIC373 and MIC3733 allow programming the output voltage any-where between.v and the 5.5V maximum operating rating of the family. Two resistors are used. Resistors can be quite large, up to MΩ, because of the very high input impedance and low bias current of the sense comparator. The resistor values are calculated by: VOUT R = R. Where V OUT is the desired output voltage. Figure shows component definition. Applications with widely varying load currents may scale the resistors to draw the minimum load current required for proper operation (see above). October 9 M

11 Package Information θ θ θ θ θ3 θ θ θ3 θ θ 5-Pin TO-63-5 (U) 5-Pin S-PAK (R) October 9 M

12 3-Pin S-PAK (R) 8-Pin SOIC (ME) October 9 M

13 MICREL, INC. 8 FORTUNE DRIVE SAN JOSE, CA 953 USA TEL + (8) 9-8 FAX + (8) 7- 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. October 9 3 M