MIC29302A 3A Fast-Response LDO Regulator General Description Features The MIC29302A is a high-current, low-cost, low-dropout voltage regulator which 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, low dropout-critical systems, where their dropout voltage 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 which can be set by two external resistors to a voltage between 1.24V to 15V. In addition, the device is fully protected against over current 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. Data sheets and support documentation can be found on Micrel’s web site 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 lost-regulator for switching supply _________________________________________________________________________________________________________________________ Typical Application Dropout Voltage vs. Output Current ⎛ R1 ⎞ VOUT = 1.242 × ⎜ + 1⎟ ⎝ 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) MIC29302A Adjustable Output Regulator 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 August 2011 M9999-080411-A 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 5-Pin TO-263 (D2Pak) 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 Name 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. August 2011 INPUT: Unregulated input, +2.8V to +16V maximum 2 M9999-080411-A Micrel, Inc. MIC29302A Absolute Maximum Ratings(1) Operating Ratings(2) Input Supply Voltage (VIN)(1) ........................... –20V to +20V Enable Input Voltage (VEN)................................ –0.3V to VIN Lead Temperature (soldering, 5sec.)......................... 260°C Power Dissipation .....................................Internally Limited Storage Temperature Range ....................–65°C to +150°C ESD Rating all pins(3) 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 −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 = 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(7) en, Output Noise Voltage (10Hz to 100kHz CL = 10µF IL = 100mA CL = 33 µF 260 Ground Pin Current in Shutdown Input Voltage VIN = 16V 32 (6) ΔVOUT = −1% Dropout Voltage mV Ground Current Ground Current August 2011 3 4 400 3 mA 150 A µV (rms) µA M9999-080411-A 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 (8) 1.215 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 = 8V 2 VEN = 0.8V Regulator Output Current in Shutdown 30 75 Enable Pin Input Current V µA 4 10 (10) 20 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, 1.5k 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 3.3Vregulator or use 6V for a 5V regulator. Employ pulse testing procedure for current limit. 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. August 2011 4 M9999-080411-A 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) 50.0 40.0 30.0 20.0 V OUT = 1.8V IOUT = 3A 1.245 1.240 1.235 10.0 0 1.230 0.0 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 LOAD REGULATION (%) 42 40 4 8 12 12 16 10 V OUT = 1.8V IOUT = 10mA to 3A 0.200 0.100 V OUT = 0V 8 6 4 2 0.000 0 8 Short-Circuit Current vs. Input Voltage 0.300 ILOAD = 10mA 44 4 INPUT VOLTAGE (V) CURRENT LIMIT (A) DROPOUT VOLTAGE (mV) 500 ADJ PIN CURRENT (nA) Adjust Pin Voltage vs. Input Voltage 16 0 0 INPUT VOLTAGE (V) 4 8 12 16 INPUT VOLTAGE (V) Enable Pin Current vs. Input Voltage 0 4 8 12 16 INPUT VOLTAGE (V) Output Voltage vs. Input Voltage 20.00 1.243 15.00 OUTPUT VOLTAGE (V) ENABLE PIN CURRENT (µA) VOUT = 1.24V IOUT = 10mA 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) August 2011 16 0 4 8 12 16 INPUT VOLTAGE (V) 5 M9999-080411-A Micrel, Inc. MIC29302A Typical Characteristics (Continued) Enable Bias Current vs. Temperature (B06) GND Pin Current vs. Temperature 600 EN PIN CURRENT (nA) IOUT = 750mA 6.00 4.00 2.00 VIN = VEN = 8V 25 VOUT = 2.5V IOUT = 10mA 20 15 10 5 0.00 -25 0 25 50 75 100 125 IOUT = 3A 500 400 300 IOUT = 1.5A 200 VIN = 4.2V 100 0 0 -50 -50 -25 0 25 50 75 100 -50 125 -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 VIN = 4.2V CURRENT LIMIT (A) IOUT = 750mA 300 200 100 100 125 100 125 1.243 4.250 ADJ PIN VOLTAGE (V) GROUND CURRENT (mA) VIN =4.2V VOUT = 1.8V 8.00 DROPOUT VOLTAGE (mV) 30 10.00 DROPOUT VOLTAGE (mV) Dropout Voltage vs. Temperature 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) August 2011 100 125 -50 -25 0 25 50 75 100 125 TEMPERATURE (°C) 6 M9999-080411-A Micrel, Inc. MIC29302A Typical Characteristics (Continued) 500 V IN = 3V DROPOUT VOLTAGE (mV) V ADJ = 0V ADJUSTABLE OPTION 400 300 200 100 VIN = 4.2V 400 VADJ = 0V 300 200 100 0.5 1.0 1.5 2.0 2.5 0.0 3.0 0.5 1.0 Line Regulation vs. Output Current GROUND CURRENT (mA) LINE REGULATION (%) 0.1 0.0 V IN = 4.2V to 16V V OUT = 1.8V -0.2 0.5 1.0 1.5 2.0 2.5 V IN =3.3V V OUT = 1.8V IOUT = 10mA COUT = 22µF 1 10 FREQUENCY (kHz) August 2011 100 1.0 1000 1.5 2.0 2.5 3.0 Output Noise vs. Frequency V IN = 4.2V 50 40 30 20 0.5 1.0 1.5 2.0 2.5 3.0 Noise Spectral Density 100 10 1 VIN =3.3V 0.1 VOUT = 1.8V IOUT = 3A 0.01 10 80 0.1 0.5 OUTPUT CURRENT (A) V OUT = 1.8V 0.0 RIPPLE REJECTION (dB) RIPPLE REJECTION (dB) 60 COUT = 47µF 0.001 0.01 0.1 80 60 50 30 20 VIN =3.3V VOUT = 1.8V IOUT = 1.5A COUT = 22µF 10 0 0.01 0.1 1 10 FREQUENCY (kHz) 7 100 10 100 1000 Ripple Rejection (IOUT = 3A) vs. Frequency 70 40 1 FREQUENCY (kHz) Gain (dB) Gain (dB) 40 0 0.01 0.0 3.0 Ripple Rejection (IOUT = 1.5A) vs. Frequency 50 10 2.5 OUTPUT CURRENT (A) 60 20 2.0 1000 Ripple Rejection (IOUT = 10mA) vs. Frequency 70 30 1.5 0 3.0 OUTPUT CURRENT (A) 80 1.238 GND Pin Current vs. Output Current 70 0.2 0.0 1.240 OUTPUT CURRENT (A) OUTPUT CURRENT (A) -0.1 V OUT = 1.8V 1.242 OUTPUT NOISE (µV/√Hz) 0.0 V IN = 4.2V 1.244 1.236 0 0 Adjust Pin Voltage vs. Output Current 1.246 RIPPLE REJECTION (dB) DROPOUT VOLTAGE (mV) 500 Dropout Voltage vs. Output Current ADJ PIN VOLTAGE (V) Dropout Voltage vs. Output Current 1000 Gain (dB) 70 60 50 40 VIN =3.3V 30 IOUT = 3A 20 VOUT = 1.8V COUT = 22µF 10 0 0.01 0.1 1 10 100 1000 FREQUENCY (kHz) M9999-080411-A Micrel, Inc. MIC29302A Functional Characteristics Figure 2. MIC29302A Load Transient Response Test Circuit August 2011 8 M9999-080411-A Micrel, Inc. MIC29302A Functional Diagram August 2011 9 M9999-080411-A 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 offer a logic level ON/OFF control: when disabled, the devices draw nearly zero current. PD = IOUT (1.02VIN − VOUT ) Where the ground current is approximated by 2% of IOUT. Then the heat sink thermal resistance is determined with this formula: − TA T θ SA = JMAX − (θ JC + θ CS ) PD where: TJMAX ≤ 125°C and θCS is between 0 and 2°C/W. The heat sink 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 heat sink 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 heat sink specification. With no heat sink 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: 2 oz. copper and 100mm2 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 = 1.5A, first calculate the expected PD using: Figure 3. 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 August 2011 PD = (3.3V − 2.5V ) × 3A − (3.3V ) × (0.016A ) = 2.3472W 10 M9999-080411-A 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 heat sink 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 4 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 4. 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. August 2011 11 M9999-080411-A Micrel, Inc. MIC29302A Evaluation Board Schematic August 2011 12 M9999-080411-A Micrel, Inc. MIC29302A Bill of Materials Item Part Number C2012X5R0J106K C1 C2,C3 C5 Manufacturer TDK GRM2196R60J106K Murata(2) 08056D106KAT2A Vishay(3) B45196H4106K309 Kemet TR3C106K020C0450 Vishay EEU-FM1C102 Description Qty. (1) 10µF, 6.3V, Ceramic Capacitor, X5R, 0805 1 10µF, 20V, Tantalum Capacitor, 2312 2 1000µF, 16V, Elect Capacitor, through hole, 10X20-case 1 100µF, 20V, Tantalum Capacitor, 2917 1 (4) (3) Panasonic(5) T495D107K016ATE125 Kemet(4) TR3D107K016C0125 Vishay(3) R1 CRCW06031K00FKTA Vishay(3) 1K, Resistor, 1%, 0603 1 R2 Open (CRCW06031002FRT1) Vishay(3) 10K, Resistor, 1%, 0603 1 R3 CRCW06038061FRT1 Vishay(3) 8.06K, Resistor, 1%, 0603 1 CRCW06034751FRT1 (3) 4.75K, Resistor, 1%, 0603 1 (3) C6 R4 Vishay R5 CRCW06033241FRT1 Vishay 3.24K, Resistor, 1%, 0603 1 R6 CRCW06031911RFRT1 Vishay(3) 1.91k, Resistor, 1%, 0603 1 0Ω, Resistor, 1%, 0603 1 R7 CRCW06030000FKTA (3) Vishay (3) R8 CRCW060350R0FRT1 Vishay 50Ω, Resistor, 1%, 0603 1 U1 MIC29302AWU Micrel(6) 3A Fast-Response LDO Regulator 1 Notes: 1. TDK: www.tdk.com. 2. Murata: www.murata.com. 3. Vishay: www.vishay.com. 4. Kemet: www.kemet.com. 5. Panasonic.: www.panasonic.com. 6. Micrel, Inc.: www.micrel.com. August 2011 13 M9999-080411-A Micrel, Inc. MIC29302A PCB Layout Recommendations MIC29302A Evaluation Board Top Layer MIC29302A Evaluation Board Top Silk August 2011 14 M9999-080411-A Micrel, Inc. MIC29302A PCB Layout Recommendations (Continued) MIC29302A Evaluation Board Bottom Layer MIC29302A Evaluation Board Bottom Silk August 2011 15 M9999-080411-A Micrel, Inc. MIC29302A Package Information 5-Pin TO-263 (U) August 2011 16 M9999-080411-A Micrel, Inc. MIC29302A Package Information (Continued) 5-Pin TO-252 (D) August 2011 17 M9999-080411-A Micrel, Inc. MIC29302A Recommended Landing Pattern 5-Pin TO-263 (U) August 2011 18 M9999-080411-A Micrel, Inc. MIC29302A Recommended Landing Pattern (Continued) 5-Pin TO-252 (D) August 2011 19 M9999-080411-A 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 makes no representations or warranties with respect to the accuracy or completeness of the information furnished in this data sheet. 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. August 2011 20 M9999-080411-A