MIC29302A 3A Fast-Response LDO Regulator General Description Features The MIC29302A is a high-current, low-cost, low-dropout voltage regulator that uses Micrel's proprietary Super βeta ® PNP process with a PNP pass element. The 3A LDO regulator features 450mV (full load) dropout voltage and very low ground current. Designed for high-current loads, these devices also find applications in lower current, lowdropout critical systems, where their dropout voltages and ground current values are important attributes. Along with a total accuracy of ±2% (over temperature, line, and load regulation) the regulator features very fast transient recovery from input voltage surges and output load current changes. The MIC29302A has an adjustable output that can be set by two external resistors to a voltage between 1.24V and 15V. In addition, the device is fully protected against overcurrent faults, reversed input polarity, reversed lead insertion, and overtemperature operation. A TTL logic enable (EN) pin is available in the MIC29302A to shutdown the regulator. When not used, the device can be set to continuous operation by connecting EN to the input (IN). The MIC29302A is available in the standard and 5-pin TO-263 and TO-252 packages with an operating junction temperature range of −40°C to +125°C. Datasheets and support documentation can be found on Micrel’s website at: www.micrel.com. • High-current capability − 3A over full temperature range • Low-dropout voltage of 450mV at full load • Low ground current • Accurate 1% guaranteed tolerance • Extremely fast transient response • Zero-current shutdown mode • Error flag signals output out-of-regulation • Adjustable output voltage • Packages: TO-263-5L and TO-252-5L Applications • • • • • • • Processor peripheral and I/O supplies High-efficiency “green” computer systems Automotive electronics High-efficiency linear lower supplies Battery-powered equipment PC add-in cards High-efficiency post-regulator for switching supply _________________________________________________________________________________________________________________________ Typical Application Dropout Voltage vs. Output Current R1 + 1 VOUT = 1.242 × R2 DROPOUT VOLTAGE (mV) 500 VIN = 3.3V 400 TA = 25ºC VADJ = 0V 300 200 100 0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 OUTPUT CURRENT (A) Super ßeta PNP is a registered trademark of Micrel, 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 October 3, 2014 Revision 2.0 Micrel, Inc. MIC29302A Ordering Information Part Number Voltage Junction Temperature Range Package MIC29302AWU Adjustable –40°C to +125°C 5-Pin TO-263 MIC29302AWD Adjustable –40°C to +125°C 5-Pin TO-252 Pin Configuration 2 5-Pin TO-263 (D Pak) Adjustable Voltage (U) MIC29302AWU 5-Pin TO-252 (D-Pak) Adjustable Voltage (D) MIC29302AWD Pin Description Pin Number TO-263 Pin Number TO-252 Pin Name 1 1 EN Pin Function Enable (Input): Active-high CMOS compatible control input. Do not float. 2 2 IN 3, TAB 3, TAB GND GND: TAB is also connected internally to the IC’s ground on both packages. 4 4 OUT OUTPUT: The regulator output voltage 5 5 ADJ Feedback Voltage: 1.24V feedback from external resistor divider. October 3, 2014 INPUT: Unregulated input, +3V to +16V maximum 2 Revision 2.0 Micrel, Inc. MIC29302A Absolute Maximum Ratings(1) Operating Ratings(2) (1) Input Supply Voltage (VIN) ........................... –20V to +20V Enable Input Voltage (VEN) ................................ –0.3V to VIN Lead Temperature (soldering, 5 sec.) ........................ 260°C Power Dissipation ..................................... Internally Limited Storage Temperature Range .................... –65°C to +150°C (3) ESD Rating all pins Operating Junction Temperature .............. −40°C to +125°C Operating Input Voltage ....................................... 3V to 16V Package Thermal Resistance TO-263 (θJC)......................................................... 3°C/W TO-252 (θJC)......................................................... 3°C/W TO-252 (θJA) ...................................................... 35°C/W TO-263 (θJA) ....................................................... 28°C/W Electrical Characteristics(4) VIN = 4.2V; IOUT = 100mA; TA = 25°C, bold values indicate −40°C≤ TJ ≤ +125°C, unless noted. Parameter Condition Min. Typ. Max. Units 2 % Output Voltage (5) −2 Output Voltage Accuracy 100mA ≤ IOUT ≤3A, (VOUT + 1V) ≤ VIN ≤ 16V Line Regulation IOUT = 100mA, (VOUT + 1V) ≤ VIN ≤ 16V 0.1 0.5 % Load Regulation VIN = VOUT + 1V, 100mA ≤ IOUT ≤ 3A 0.2 1 % IOUT = 100mA 80 200 IOUT = 750mA 220 IOUT = 1.5A 275 IOUT = 2.0A 375 630 IOUT = 2.5A 430 720 IOUT = 3A 450 800 IOUT = 750mA, VIN = VOUT + 1V 5 20 IOUT = 1.5A 15 IOUT = 3A 60 IGRNDDO Ground Pin Current @ Dropout VIN = 0.5V less than specified VOUT × IOUT = 10mA 2 Current Limit VOUT = 0V en, Output Noise Voltage (10Hz to 100kHz CL = 10µF 400 IL = 100mA CL = 33µF 260 Ground Pin Current in Shutdown Input Voltage VIN = 16V 32 Dropout Voltage (6) mV Ground Current Ground Current (7) 3 4 mA 150 A µVRMS µA Notes: 1. Exceeding the absolute maximum rating may damage the device. 2. The device is not guaranteed to function outside its operating rating. 3. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5kΩ in series with 100pF. 4. Specification for packaged product only 5. Output voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature change. 6. Dropout voltage is defined as the input-to-output differential when output voltage drops to 99% of its normal value with VOUT + 1V applied to VIN. 7. VIN =VOUT (nominal) + 1V. For example, use VIN = 4.3V for a 3.3V regulator or use 6V for a 5V regulator. Employ pulse testing procedure for current limit. October 3, 2014 3 Revision 2.0 Micrel, Inc. MIC29302A Electrical Characteristics(4) (Continued) VIN = 4.2V; IOUT = 10mA; TA = 25°C, bold values indicate −40°C≤ TJ ≤ +125°C, unless noted. Reference Reference Voltage 1.215 Note 8 1.267 40 Adjust Pin Bias Current 120 V nA ENABLE Input Input Logic Voltage 0.8 Low (OFF) 2.4 High (ON) 15 VEN = 4.2V 2 VEN = 0.8V Regulator Output Current in Shutdown 30 75 Enable Pin Input Current V µA 4 10 Note 10 20 µA Notes: 8. VREF ≤ VOUT ≤ VIN -1, 3V ≤ VOUT ≤ 16V, 10mA ≤ IL ≤ IFL, TJ ≤ TJmax. 9. Thermal regulation is defined as the change in the output voltage at a time T after a change in power dissipation is applied, excluding load or line regulation effects. Specifications are for a 250mA load pulse at VIN = 16V (a 4W pulse) for T = 10ms. 10. VEN ≤ 0.8V, VIN ≤ 16V and VOUT = 0V. October 3, 2014 4 Revision 2.0 Micrel, Inc. MIC29302A Typical Characteristics GND Pin Current vs. Input Voltage Dropout Voltage vs. Input Voltage 70.0 400 IOUT = 3A 300 200 IOUT = 1.0A 100 1.250 IOUT = 3A 60.0 ADJ PIN VOLTAGE (V) GROUND CURRENT (mA) 500 DROPOUT VOLTAGE (mV) Adjust Pin Voltage vs. Input Voltage 50.0 40.0 30.0 20.0 VOUT = 1.8V IOUT = 3A 1.245 1.240 1.235 10.0 0 4 8 12 16 0 4 8 12 INPUT VOLTAGE (V) INPUT VOLTAGE (V) Adjust Pin Current vs. Input Voltage Load Regulation vs. Input Voltage 46 0 16 42 40 4 8 12 12 16 10 VOUT = 1.8V IOUT = 10mA to 3A 0.200 0.100 VOUT = 0V 8 6 4 2 0 0.000 0 8 Short-Circuit Current vs. Input Voltage CURRENT LIMIT (A) 44 4 INPUT VOLTAGE (V) 0.300 ILOAD = 10mA LOAD REGULATION (%) ADJ PIN CURRENT (nA) 1.230 0.0 0 16 0 INPUT VOLTAGE (V) 4 8 12 16 Enable Pin Current vs. Input Voltage 0 4 8 12 16 INPUT VOLTAGE (V) INPUT VOLTAGE (V) Output Voltage vs. Input Voltage 20.00 1.243 OUTPUT VOLTAGE (V) ENABLE PIN CURRENT (µA) VOUT = 1.24V IOUT = 10mA 15.00 10.00 VOUT = 1.8V IOUT = 10mA 5.00 VEN = VIN 1.242 1.241 1.240 0.00 0 4 8 12 INPUT VOLTAGE (V) October 3, 2014 16 0 4 8 12 16 INPUT VOLTAGE (V) 5 Revision 2.0 Micrel, Inc. MIC29302A Typical Characteristics (Continued) GND Pin Current vs. Temperature Dropout Voltage vs. Temperature Enable Bias Current vs. Temperature 10.00 600 30 6.00 4.00 2.00 20 15 10 5 0 0.00 -50 -25 0 25 50 75 100 IOUT = 3A 500 400 300 IOUT = 1.5A 200 VIN = 4.2V 100 0 -50 125 -25 0 25 50 75 100 125 -50 -25 0 25 50 75 TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE (°C) Dropout Voltage vs. Temperature Short-Circuit Current vs. Temperature Adjust Pin Voltage vs. Temperature 400 IOUT = 750mA 200 100 ADJ PIN VOLTAGE (V) VIN = 4.2V 300 100 125 100 125 1.243 4.250 CURRENT LIMIT (A) DROPOUT VOLTAGE (mV) VIN = VEN = 8V VOUT = 2.5V IOUT = 10mA 25 IOUT = 750mA DROPOUT VOLTAGE (mV) VOUT = 1.8V 8.00 EN PIN CURRENT (nA) GROUND CURRENT (mA) VIN =4.2V 4.000 3.750 VIN = 4.2V 1.240 VIN =4.2V 1.238 VOUT = 1.8V IOUT = 10mA VOUT = 0V IOUT = 100mA 0 3.500 -50 -25 0 25 50 75 100 125 1.235 -50 -25 0 25 50 75 TEMPERATURE (°C) TEMPERATURE (°C) Adjust Pin Current vs. Temperature Line Regulation vs. Temperature 100 125 -50 -25 0 25 50 75 TEMPERATURE (°C) 0.5 80 LINE REGULATION (%/V) ADJ PIN CURRENT (nA) VIN = 3V to 16V 60 40 VIN = 4.2V 20 ILOAD = 10mA 0 VOUT = 1.8V 0.4 IOUT = 10mA 0.3 0.2 0.1 0.0 -50 -25 0 25 50 75 TEMPERATURE (°C) October 3, 2014 100 125 -50 -25 0 25 50 75 100 125 TEMPERATURE (°C) 6 Revision 2.0 Micrel, Inc. MIC29302A Typical Characteristics (Continued) Dropout Voltage vs. Output Current Dropout Voltage vs. Output Current 1.246 500 VADJ = 0V ADJUSTABLE OPTION 400 300 200 100 VIN = 4.2V 400 VADJ = 0V 300 200 1.0 1.5 2.0 2.5 0.0 3.0 0.5 1.0 GROUND CURRENT (mA) 0.1 0.0 VIN = 4.2V to 16V VOUT = 1.8V 1.5 2.0 2.5 60 VIN = 4.2V 50 40 30 20 0.5 1.0 1.5 2.0 3.0 VIN =3.3V VOUT = 1.8V IOUT = 10mA COUT = 22µF 0.1 1 10 FREQUENCY (kHz) October 3, 2014 100 1000 3.0 1 VIN =3.3V 0.1 VOUT = 1.8V IOUT = 3A 0.01 COUT = 47µF 0.1 VIN =3.3V VOUT = 1.8V IOUT = 1.5A COUT = 22µF 10 0 0.01 0.1 1 10 FREQUENCY (kHz) 7 100 1000 Gain (dB) 50 20 100 80 60 30 10 Ripple Rejection (IOUT = 3A) vs. Frequency 70 40 1 FREQUENCY (kHz) RIPPLE REJECTION (dB) 40 2.5 10 0.001 0.01 Gain (dB) RIPPLE REJECTION (dB) RIPPLE REJECTION (dB) 2.5 80 Gain (dB) 50 2.0 Noise Spectral Density 100 Ripple Rejection (IOUT = 1.5A) vs. Frequency 60 1.5 Output Noise vs. Frequency OUTPUT CURRENT (A) 70 0 0.01 1.0 OUTPUT CURRENT (A) VOUT = 1.8V 0.0 80 10 0.5 1000 Ripple Rejection (IOUT = 10mA) vs. Frequency 20 0.0 3.0 0 3.0 OUTPUT CURRENT (A) 30 2.5 10 -0.2 1.0 2.0 70 0.2 0.5 1.5 GND Pin Current vs. Output Current Line Regulation vs. Output Current 0.0 1.240 OUTPUT CURRENT (A) OUTPUT CURRENT (A) -0.1 1.242 OUTPUT NOISE (µV/√Hz) 0.5 VOUT = 1.8V 1.236 0 0.0 VIN = 4.2V 1.244 1.238 100 0 LINE REGULATION (%) ADJ PIN VOLTAGE (V) VIN = 3V DROPOUT VOLTAGE (mV) DROPOUT VOLTAGE (mV) 500 Adjust Pin Voltage vs. Output Current 1000 70 60 50 40 VIN =3.3V VOUT = 1.8V 30 20 IOUT = 3A COUT = 22µF 10 0 0.01 0.1 1 10 100 1000 FREQUENCY (kHz) Revision 2.0 Micrel, Inc. MIC29302A Functional Characteristics Figure 1. MIC29302A Load Transient Response Test Circuit October 3, 2014 8 Revision 2.0 Micrel, Inc. MIC29302A Functional Diagram October 3, 2014 9 Revision 2.0 Micrel, Inc. MIC29302A First, we calculate the power dissipation of the regulator from these numbers and the device parameters from this datasheet: Application Information The MIC29302A is a high-performance, low-dropout voltage regulator suitable for all moderate to high-current voltage regulation applications. Its 450mV typical dropout voltage at full load makes it especially valuable in battery-powered systems and as high efficiency noise filters in post-regulator applications. Unlike older NPNpass transistor designs, where the minimum dropout voltage is limited by the base-emitter voltage drop and collector-emitter saturation voltage, dropout performance of the PNP output is limited merely by the low VCE saturation voltage. A trade-off for the low-dropout voltage is a varying base ® driver requirement. But Micrel’s Super ßeta PNP process reduces this drive requirement to merely 1% of the load current. The MIC29302A regulator is fully protected from damage due to fault conditions. Current limiting is linear; output current under overload conditions is constant. Thermal shutdown disables the device when the die temperature exceeds the +125°C maximum safe operating temperature. The output structure of the regulators allows voltages in excess of the desired output voltage to be applied without reverse current flow. The MIC29302A offers a logic-level ON/OFF control. When disabled, the device draws nearly zero current. PD = IOUT (1.02VIN − VOUT ) Where the ground current is approximated by 2% of IOUT. Then the heatsink thermal resistance is determined with this formula: θ SA = where: TJMAX ≤ 125°C and θCS is between 0°C/W and 2°C/W. The heatsink may be significantly reduced in applications where the minimum input voltage is known and is large compared to the dropout voltage. A series input resistor can be used to drop excessive voltage and distribute the heat between this resistor and the regulator. The low-dropout properties of Micrel Super ® βeta PNP regulators allow very significant reductions in regulator power dissipation and the associated heatsink without compromising performance. When this technique is employed, a capacitor of at least 0.1µF is needed directly between the input and regulator ground. Please refer to Application Note 9 and Application Hint 17 on Micrel’s website (www.micrel.com) for further details and examples on thermal design and heatsink specification. With no heatsink in the application, calculate the junction temperature to determine the maximum power dissipation that will be allowed before exceeding the maximum junction temperature of the MIC29302A. The maximum power allowed can be calculated using the thermal resistance (θJA) of the D-Pak (TO252) adhering to the following criteria for the PCB design: 2oz. copper 2 and 100mm copper area for the MIC29302A. For example, given an expected maximum ambient temperature (TA) of 75°C with VIN = 3.3V, VOUT = 2.5V, and IOUT = 3A, first calculate the expected PD using: Figure 2. Linear Regulators Require Only Two Capacitors for Operation Thermal Design Linear regulators are simple to use. The most complicated set of design parameters to consider are thermal characteristics. Thermal design requires the following application-specific parameters: • Maximum ambient temperature, TA • Output Current, IOUT • Output Voltage, VOUT • Input Voltage, VIN October 3, 2014 TJMAX − TA − (θ JC + θ CS ) PD PD = (3.3V − 2.5V ) × 3A − (3.3V ) × (0.016A ) = 2.3472W 10 Revision 2.0 Micrel, Inc. MIC29302A Next, calcualte the junction temperature for the expected power dissipation: For best performance the total resistance (R1+R2) should be small enough to pass the minimum regulator load current of 10mA. TJ = (θJA×PD) + TA = (35°C/W × 2.3472W) + 75°C = 157.15°C Adjustable Regulator Design The output voltage can be programmed anywhere between 1.25V and the 15V. Two resistors are used. The resistor values are calculated by: Now determine the maximum power dissipation allowed that would not exceed the IC’s maximum junction temperature (125°C) without the use of a heatsink by: V R1 = R 2 × OUT − 1 1.240 PD(MAX) = (TJ(MAX) – TA) / θJA = (125°C – 75°C) / (35°C/W) = 1.428W where VOUT is the desired output voltage. Capacitor Requirements For stability and minimum output noise, a capacitor on the regulator output is necessary. The value of this capacitor is dependent upon the output current; lower currents allow smaller capacitors. The MIC29302A is stable with a 10μF capacitor at full load. This capacitor need not be an expensive low-ESR type; aluminum electrolytics are adequate. In fact, extremely low-ESR capacitors may contribute to instability. Tantalum capacitors are recommended for systems where fast load transient response is important. When the regulator is powered from a source with high AC impedance, a 0.1µF capacitor connected between input and GND is recommended. Figure 3 shows component definition. Applications with widely varying load currents may scale the resistors to draw the minimum load current required for proper operation (see “Minimum Load Current” section). Transient Response and 5V to 3.3V Conversion The MIC29302A has excellent response to variations in input voltage and load current. By virtue of its low dropout voltage, the device does not saturate into dropout as readily as similar NPN-based designs. A 3.3V output Micrel LDO will maintain full speed and performance with an input supply as low as 4.2V, and will still provide some regulation with supplies down to 3.8V, unlike NPN devices that require 5.1V or more for good performance and become nothing more than a resistor under 4.6V of input. Micrel’s PNP regulators provide superior performance in “5V to 3.3V” conversion applications than NPN regulators, especially when all tolerances are considered. Figure 3. Adjustable Regulator with Resistors Enable Input MIC29302A features an enable (EN) input that allows ON/OFF control of the device. Special design allows “zero” current drain when the device is disabled—only microamperes of leakage current flows. The EN input has TTL/CMOS compatible thresholds for simple interfacing with logic, or may be directly tied to VIN. Enabling the regulator requires approximately 20µA of current into the EN pin. Minimum Load Current The MIC29302A regulator operates within a specified load range. If the output current is too small, leakage currents dominate and the output voltage rises. A minimum load current of 10mA is necessary for proper regulation and to swamp any expected leakage current across the operating temperature range. October 3, 2014 11 Revision 2.0 Micrel, Inc. MIC29302A Evaluation Board Schematic October 3, 2014 12 Revision 2.0 Micrel, Inc. MIC29302A Bill of Materials Item C1 C2,C3 C5 Part Number C2012X5R1E106K Manufacturer (11) TDK Qty. 10µF, 25V, Ceramic Capacitor, X5R, 0805 1 10µF, 20V, Tantalum Capacitor, 2312 2 1000µF, 25V, Elect Capacitor, through hole, 10X22-case 1 100µF, 20V, Tantalum Capacitor, 2917 1 (12) B45196H4106K309 Kemet TR3C106K020C0450 Vishay EEU-FM1E102 Description (13) Panasonic (14) T495D107K016ATE125 Kemet TR3D107K016C0125 Vishay R1 CRCW06031K00FKTA Vishay 1k, Resistor, 1%, 0603 1 R2 Open (CRCW06031002FRT1) Vishay 10k, Resistor, 1%, 0603 1 R3 CRCW06038061FRT1 Vishay 8.06k, Resistor, 1%, 0603 1 R4 CRCW06034751FRT1 Vishay 4.75k, Resistor, 1%, 0603 1 R5 CRCW06033241FRT1 Vishay 3.24k, Resistor, 1%, 0603 1 R6 CRCW06031911RFRT1 Vishay 1.91k, Resistor, 1%, 0603 1 R7 CRCW06030000FKTA Vishay 0Ω, Resistor, 1%, 0603 1 R8 CRCW060350R0FRT1 Vishay 50Ω, Resistor, 1%, 0603 1 3A Fast-Response LDO Regulator 1 C6 U1 MIC29302AWU (15) Micrel Notes: 11. TDK: www.tdk.com. 12. Kemet: www.kemet.com. 13. Vishay: www.vishay.com. 14. Panasonic.: www.panasonic.com. 15. Micrel, Inc.: www.micrel.com. October 3, 2014 13 Revision 2.0 Micrel, Inc. MIC29302A PCB Layout Recommendations MIC29302A Evaluation Board Top Layer MIC29302A Evaluation Board Top Silk October 3, 2014 14 Revision 2.0 Micrel, Inc. MIC29302A PCB Layout Recommendations (Continued) MIC29302A Evaluation Board Bottom Layer MIC29302A Evaluation Board Bottom Silk October 3, 2014 15 Revision 2.0 Micrel, Inc. MIC29302A Package Information(16) 5-Pin TO-263 (U) Note: 16. Package information is correct as of the publication date. For updates and most current information, go to www.micrel.com. October 3, 2014 16 Revision 2.0 Micrel, Inc. MIC29302A Package Information (Continued) 5-Pin TO-252 (D) October 3, 2014 17 Revision 2.0 Micrel, Inc. MIC29302A 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 Micrel, Inc. is a leading global manufacturer of IC solutions for the worldwide high performance linear and power, LAN, and timing & communications markets. The Company’s products include advanced mixed-signal, analog & power semiconductors; high-performance communication, clock management, MEMs-based clock oscillators & crystal-less clock generators, Ethernet switches, and physical layer transceiver ICs. Company customers include leading manufacturers of enterprise, consumer, industrial, mobile, telecommunications, automotive, and computer products. Corporation headquarters and state-of-the-art wafer fabrication facilities are located in San Jose, CA, with regional sales and support offices and advanced technology design centers situated throughout the Americas, Europe, and Asia. Additionally, the Company maintains an extensive network of distributors and reps worldwide. Micrel makes no representations or warranties with respect to the accuracy or completeness of the information furnished in this datasheet. This information is not intended as a warranty and Micrel does not assume responsibility for its use. Micrel reserves the right to change circuitry, specifications and descriptions at any time without notice. No license, whether express, implied, arising by estoppel or otherwise, to any intellectual property rights is granted by this document. Except as provided in Micrel’s terms and conditions of sale for such products, Micrel assumes no liability whatsoever, and Micrel disclaims any express or implied warranty relating to the sale and/or use of Micrel products including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright, or other intellectual property right. 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. © 2011 Micrel, Incorporated. October 3, 2014 18 Revision 2.0