MIC29310/29312 Micrel MIC29310/29312 3A Fast-Response LDO Regulator General Description Features The MIC29310 and MIC29312 are low cost versions of MIC29300 family low-dropout (LDO) regulators. Manufactured on Micrel’s proprietary Super beta PNP™ process, the MIC29310/2 is a 3A LDO regulator with very low-dropout voltage (600mV over the full load) and low ground current. Along with a total accuracy of ±2% (over temperature, line and load regulation) these regulators feature very fast transient recovery from input voltage surges and output load current changes. The MIC29310 is available in fixed 3.3V and 5V outputs voltages; the MIC29312 has an adjustable output which can be set by two external resistors to a voltage between 1.24V to 15V. In addition, all versions are fully protected against overcurrent faults, reversed input polarity, reversed lead insertion, and overtemperature operation. A TTL logic enable (EN) pin is available in the MIC29312 to shutdown the regulator. When not used, the device can be set to continuous operation by connecting EN to the input (IN). The MIC29310/2 is available in the standard 3- and 5-pin TO-220 and TO-263 packages with an operating junction temperature range of 0°C to +125°C. • • • • • • • • Low cost versions of MIC29300 family Fast transient response 3A current over full temperature range 600mV dropout voltage at full load Low ground current Accurate 1% guaranteed tolerance “Zero” current shutdown mode (MIC29312) Fixed voltage and adjustable versions Applications • • • • • • Processor peripheral and I/O supplies PC add-in cards High-efficiency “green” computer systems High-efficiency linear power supplies High-efficiency switching supply post regulator Battery-powered equipment For applications requiring even lower dropout voltage, input voltage greater than 16V, or an error flag, see the MIC29300/29301/29302/ 29303. Typical Application MIC29312 On Off VIN MIC29310-x.x IN VOUT OUT EN R1* VOUT VIN OUT ADJ IN GND R2* GND V OUT = 1.240 R1 +1 R2 * For best performance, total series resistance (R1 + R2) should be small enough to pass the minimum regulator load current of 10mA. Fixed Regulator Configuration Adjustable Regulator Configuration Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com November 2006 1 MIC29310/29312 MIC29310/29312 Micrel Ordering Information Part Number Voltage Junction Temperature Range Package MIC29310-3.3WT 3.3V 0°C to +125°C TO-220 MIC29310-3.3BU MIC29310-3.3WU 3.3V 0°C to +125°C TO-263 MIC29310-5.0BT MIC29310-5.0WT 5.0V 0°C to +125°C TO-220 MIC29310-5.0BU MIC29310-5.0WU 5.0V 0°C to +125°C TO-263 MIC29312BT MIC29312WT Adj. 0°C to +125°C TO-220 MIC29312BU MIC29312WU Adj. 0°C to +125°C TO-263 Standard RoHS Compliant(1) MIC29310-3.3BT Note: 1. RoHS compliant with “high-melting solder” exemption. Pin Configuration TAB TAB 3 OUT 2 GND 1 IN OUT 2 GND 1 IN MIC29310-x.xBU/WU TO-263-3 (U) MIC29310-x.xBT/WT TO-220-3 (T) 5 4 3 2 1 TAB 5 ADJ 4 OUT 3 GND 2 IN 1 EN TAB 3 ADJ OUT GND IN EN MIC29312-x.xBU/WU TO-263-5 (U) MIC29312-x.xBT/WT TO-220-5 (T) Pin Description Pin Number MIC29310 Pin Number MIC29312 Pin Name Pin Function 1 EN Enable (Input): Active-high, logic-level enable/shutdown control. 1 2 IN Unregulated Input: +16V maximum supply. 2, TAB 3, TAB GND Ground: Ground pin and TAB are internally connected. 3 4 OUT Regulator Output 5 ADJ Ouput Voltage Adjust: 1.24V feedback from external resistive divider. Absolute Maximum Ratings (Note 1) Operating Ratings (Note 2) Input Voltage (VIN) ..........................................–20V to +20V Power Dissipation (PD) ............................. Internally Limited Storage Temperature Range (TS) ............. –65°C to +150°C Lead Temperature (soldering, 5 sec.) ........................ 260°C ESD, Note 3 Input Voltage (VIN) ........................................ +2.3V to +16V Junction Temperature (TJ) ............................ 0°C to +125°C Package Thermal Resistance TO-263 (θJC) ......................................................... 2°C/W TO-220 (θJC) ......................................................... 2°C/W TO-220 (θJA) ....................................................... 55°C/W MIC29310/29312 2 November 2006 MIC29310/29312 Micrel Electrical Characteristics(Note 11) TJ = 25°C, bold values indicate 0°C ≤ TJ ≤ +125°C; unless noted Parameter Condition Output Voltage 10mA ≤ IO ≤ IFL, (VOUT + 1V) ≤ VIN ≤ 8V, Note 4 Max Units 2 % Line Regulation IO = 10mA, (VOUT + 1V) ≤ VIN ≤ 16V Load Regulation VIN = VOUT + 1V, 10mA ≤ IOUT ≤ IFULL LOAD, Notes 4, 8 0.06 0.5 % 0.2 1 % ΔVO / ΔT ppm/°C Output Voltage Temperature Coefficient, Note 8 20 100 Dropout Voltage ΔVOUT = –1%, Note 5 IO = 100mA IO = 750mA IO = 1.5A IO = 3A 80 220 330 600 200 Ground Current Min IO = 750mA, VIN = VOUT + 1V IO = 1.5A IO = 3A IGNDDO Ground Pin Current at Dropout VIN = 0.5V less than specified VOUT. IOUT = 10mA Current Limit VOUT = 0V, Note 6 3.0 Minimum Load Current en, Output Noise Voltage (10Hz to 100kHz) IL = 100mA Typ –2 1000 20 5 15 60 150 mA mA mA 2 3 mA 10 mA 3.8 A 7 CL = 10µF CL = 33µF mV mV mV mV 400 260 µVRMS µVRMS Reference (MIC29312 only) Reference Voltage 10mA ≤ IO ≤ IFL, VOUT + 1V ≤ VIN ≤ 8V, Note 4 1.215 Adjust Pin Bias Current Reference Voltage ppm/°C Temperature Coefficient 40 Note 9 1.265 VMAX 80 120 nA nA 20 Adjust Pin Bias Current Temperature Coefficient 0.1 nA/°C Enable Input (MIC29312 only) Input Logic Voltage Enable Pin Input Current Regulator Output Current in Shutdown Note 1. low (off) high (on) 0.8 V V 2.4 VEN = VIN 15 30 75 µA µA VEN = 0.8V – 2 4 µA µA Note 10 10 20 µA µA Exceeding the absolute maximum rating may damage the device. Note 2. The device is not guaranteed to function outside its operating rating. Note 3. Devices are ESD sensitive. Handling precautions recommended. Note 4: Full Load current is defined as 3A for the MIC29310/29312. For testing, VOUT is programmed to 5V. Note 5: Dropout voltage is defined as the input-to-output differential when the output voltage drops to 99% of its nominal value with VOUT + 1V applied to VIN. Note 6: For this test, VIN is the larger of 8V or VOUT + 3V. Note 7: Ground pin current is the regulator quiescent current. The total current drawn from the source is the sum of the load current plus the ground pin current. Note 8: Output voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range. Note 9: VREF ≤ VOUT ≤ (VIN – 1V), 2.4V ≤ VIN ≤ 16V, 10mA < IL ≤ IFL, TJ ≤ TJ(max). Note 10: VEN ≤ 0.8V and VIN ≤ 8V, VOUT = 0. Note 11: Specification for packaged product only. November 2006 3 MIC29310/29312 MIC29310/29312 Micrel Block Diagram IN OUT *EN Bias On/Off O.V. ILIMIT 16V Reference Feedback ADJ* Thermal Shutdown GND MIC29310/29312 MIC29310/29312 * MIC29312 only. 4 November 2006 MIC29310/29312 Micrel Typical Characteristics MIC29312 Line Transient Response with 3A Load, 100F Output Capacitance VIN = VOUT + 1V EN OUT IN ADJ GND 0.1µF 49.9k 1% INPUT VOLTAGE VOUT 3.525V nominal MIC29312 93.1k 1% 4 × 330µF AVX TPSE337M006R0100 tantalum 6.525V 4.525V 200s/division OUTPUT VOLTAGE VOUT load (not shown):Intel® Power Validato r MIC29312 Load Transient Response Test Circuit +20mV 3.525V –20mV MIC29312 Load Transient Response (See Test Circuit Schematic) OUTPUT VOLTAGE 6.525V 4.525V LOAD CURRENT 3.525V –20mV DROPOUT VOLTAGE (V) 0.60 MIC2931x Dropout Voltage vs. Output Current 1 0.50 0.40 0.30 0.20 0.10 0.00 0 1 2 OUTPUT CURRENT (A) November 2006 3 3.525V –20mV 1ms/division IOUT = 3A COUT =10F DROPOUT VOLTAGE (mV) OUTPUT VOLTAGE 200s/division +20mV 3A 200mA 0mA MIC2931x Dropout Voltage vs. Temperature 0.8 0.6 0.4 ILOAD = 3A 0.2 0 -60 -30 0 30 60 90 120 150 TEMPERATURE (°C) 5 MIC29310-3.3 Dropout Characteristics 5.0 OUTPUT VOLTAGE (V) INPUT VOLTAGE MIC29312 Line Transient Response with 3A Load, 10F Output Capacitance +20mV IOUT = 3A COUT = 100F 4.0 ILOAD = 10mA 3.0 2.0 ILOAD = 3A 1.0 0.0 0 2 4 INPUT VOLTAGE (V) 6 MIC29310/29312 MIC29310/29312 20 2.0 1.0 0.0 -60 -30 0 30 60 90 120 150 TEMPERATURE (°C) 40 30 20 10 0 40 ENABLE CURRENT (µA) OUTPUT VOLTAGE (V) 50 0 1 2 OUTPUT CURRENT (A) 3 30 25 20 VEN = 5V 15 10 VEN = 2V 5 0 -60 -30 0 30 60 90 120 150 TEMPERATURE (°C) 10 IOUT = 1.5A 5 20 MIC2931x Ground Current vs. Temperature 80 IOUT = 3A 60 40 20 0 -60 -30 0 30 60 90 120 150 TEMPERATURE (°C) 0 -60 -30 0 30 60 90 120 150 TEMPERATURE (°C) MIC29310-3.3 Output Voltage vs. Temperature MIC2931x Short Circuit Current vs. Temperature 6 5 3 DEVICES 3.24 3.22 3.20 -60 -30 0 30 60 90 120 150 TEMPERATURE (°C) MIC29312 Enable Current vs. Temperaure 35 15 100 3.40 3.38 3.36 3.34 3.32 3.30 3.28 3.26 4 3 VOUT = 0V 2 1 0 -60 -30 0 30 60 90 120 150 TEMPERATURE (°C) MIC29312 Adjust Pin Current vs. Temperature 50 ADJUST PIN CURRENT (nA) GROUND CURRENT (mA) 60 MIC2931x Ground Current vs. Output Current MIC2931x Ground Current vs. Temperature -10 0 10 INPUT VOLTAGE (V) 10 40 30 ILOAD = 10mA 20 10 0 -60 -30 0 30 60 90 120 150 TEMPERATURE (°C) MIC2931x Output Impedance vs. Frequency 1 0.1 0.01 0.001 1x106 IOUT = 750mA 3.0 10 100x103 4.0 RLOAD = 100Ω -0.5 -20 10x103 5.0 2 4 6 8 INPUT VOLTAGE (V) 0.0 1x103 MIC2931x Ground Current vs. Temperature 0 0.5 100x100 10 1.0 10x100 6.0 2 4 6 8 INPUT VOLTAGE (V) 0 VOUT = 3.3V 1.5 CURRENT (A) 0 50 OUTPUT IMPEDANCE (Ω) 0.5 100 MIC2931x Ground Current vs. Input Voltage 2.0 GROUND CURRENT (mA) GROUND CURRENT (mA) 1.0 IOUT = 3A 150 GROUND CURRENT (mA) GROUND CURRENT (mA) IOUT = 10mA 1.5 0.0 MIC2931x Ground Current vs. Input Voltage 200 GROUND CURRENT (mA) MIC2931x Ground Current vs. Input Voltage 2.0 GROUND CURRENT (mA) Micrel FREQUENCY (Hz) MIC29310/29312 6 November 2006 MIC29310/29312 Micrel Applications Information PD = IOUT × (1.02VIN – VOUT) The MIC29310 and MIC29312 are high performance low-dropout voltage regulators suitable for all moderate to high-current voltage regulator applications. Their 600mV of dropout voltage at full load make them especially valuable in battery powered systems and as high efficiency noise filters in “post-regulator” applications. Unlike older NPN-pass 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 of these devices is limited merely by the low VCE saturation voltage. A trade-off for the low dropout voltage is a varying base drive requirement. But Micrel’s Super ßeta PNP™ process reduces this drive requirement to merely 2% to 5% of the load current. MIC29310/312 regulators are fully protected from damage due to fault conditions. Current limiting is provided. This limiting is linear; output current under overload conditions is constant. Thermal shutdown disables the device when the die temperature exceeds the maximum safe operating temperature. Transient protection allows device (and load) survival even when the input voltage spike above and below nominal. The output structure of these regulators allows voltages in excess of the desired output voltage to be applied without reverse current flow. The MIC29312 version offers a logic level ON/OFF control: when disabled, the devices draw nearly zero current. An additional feature of this regulator family is a common pinout: a design’s current requirement may change up or down yet use the same board layout, as all of Micrel’s high-current Super ßeta PNP™ regulators have identical pinouts. Where the ground current is approximated by 2% of IOUT. Then the heat sink thermal resistance is determined with this formula: TJ MAX – TA θSA = —————— – (θJC + θCS) PD Where TJ MAX ≤ 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 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 Super ßeta 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 for further details and examples on thermal design and heat sink specification. 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. MIC29310/2 regulators are stable with a minimum capacitor value of 10µF 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. Where the regulator is powered from a source with a high AC impedance, a 0.1µF capacitor connected between Input and GND is recommended. This capacitor should have good characteristics to above 250kHz. Transient Response and 5V to 3.3V Conversion The MIC29310/2 have excellent response to variations in input voltage and load current. By virtue of their low dropout voltage, these devices do 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. Minimum Load Current The MIC29310/2 regulators are specified between finite loads. If the output current is too small, leakage currents dominate VOUT IN OUT GND Figure 3. The MIC29310 regulator requires only two capacitors for operation. 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, TA • Output Current, IOUT • Output Voltage, VOUT • Input Voltage, VIN First, we calculate the power dissipation of the regulator from these numbers and the device parameters from this datasheet. November 2006 7 MIC29310/29312 MIC29310/29312 Micrel VOUT R1 = R2 × ( –—— – 1 ) 1.240 and the output voltage rises. A 10mA minimum load current is necessary for proper regulation. Adjustable Regulator Design Where VO is the desired output voltage. 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 the table below). Enable Input The MIC29312 version 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. Figure 4. Adjustable Regulator with Resistors The adjustable regulator version, MIC29312, allows programming the output voltage anywhere between 1.25V and the 15V maximum operating rating of the family. Two resistors are used. Resistors can be quite large, up to 1MΩ, because of the very high input impedance and low bias current of the sense comparator. The resistor values are calculated by: Resistor Value Table for the MIC29312 Adjustable Regulator Voltage 2.85 2.9 3.0 3.1 3.15 3.3 3.45 3.6 3.8 4.0 4.1 Standard (Ω) R1 100k 100k 100k 100k 100k 100k 100k 100k 100k 100k 100k R2 76.8k 75.0k 69.8k 66.5k 64.9k 60.4k 56.2k 52.3k 48.7k 45.3k 43.2k Min. Load (Ω) R1 162 165 174 187 191 205 221 237 255 274 287 R2 124 124 124 124 124 124 124 124 124 124 124 Note: This regulator has a minimum load requirement. “Standard” values assume the load meets this requirement. “Minimum Load” values are calculated to draw 10mA and allow regulation with an open load (the minimum current drawn from the load may be zero). MIC29310/29312 8 November 2006 MIC29310/29312 Micrel Package Information 3-Pin TO-220 (T) 3-Pin TO-263 (U) November 2006 9 MIC29310/29312 MIC29310/29312 Micrel 5-Pin TO-220 (T) 5-Pin TO-263 (U) MIC29310/29312 10 November 2006 MIC29310/29312 November 2006 Micrel 11 MIC29310/29312 MIC29310/29312 Micrel 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 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 at Purchaser’s own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. © 2005 Micrel, Incorporated. MIC29310/29312 12 November 2006