MIC29510/29512 Micrel MIC29510/29512 5A Fast-Response LDO Regulator Preliminary Information General Description Features The MIC29510 and MIC29512 are high-current, high-accuracy, low-dropout voltage regulators featuring fast transient recovery from input voltage surges and output load current changes. These regulators use a PNP pass element that features Micrel’s proprietary Super ßeta PNP™ process. The MIC29510/2 is available in two versions: the three pin fixed output MIC29510 and the five pin adjustable output voltage MIC29512. All versions are fully protected against overcurrent faults, reversed input polarity, reversed lead insertion, overtemperature operation, and positive and negative transient voltage spikes. A TTL compatible enable (EN) control pin supports external on/off control. If on/off control is not required, the device may be continuously enabled by connecting EN to IN. The MIC29510/2 is available in the standard three and five pin TO-220 package with an operating junction temperature range of 0°C to +125°C. • • • • • • • Fast transient response 5A current capability 700mV dropout voltage at full load Low ground current Accurate 1% guaranteed tolerance “Zero” current shutdown mode (MIC29512) Fixed voltage and adjustable versions Applications • • • • • Pentium™ and Power PC™ processor supplies 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 MIC29500/ 29501/29502/29503. Ordering Information Part Number Temp. Range* Voltage Current Package MIC29510-3.3BT 0°C to +125°C 3.3V 5.0A TO-220-3 MIC29510-5.0BT 0°C to +125°C 5.0V 5.0A TO-220-3 MIC29512BT 0°C to +125°C Adj. 5.0A TO-220-5 * Junction Temperature Typical Application MIC29510 VIN OUT IN MIC29512 On Off VOUT EN OUT IN ADJ VOUT R1 VIN GND GND R2 R1 + 1 V OUT = 1. 240 R2 Fixed Regulator Configuration Adjustable Regulator Configuration 3-96 1997 MIC29510/29512 Micrel Pin Configuration 1 2 3 12345 MIC29510BT MIC29512BT On all devices, the Tab is grounded. Pin Description 3 3-Pin TO-220 (MIC29510) Pin Number Pin Name Pin Function 1 IN 2 GND Ground: Internally connected to tab (ground). 3 OUT Regulated Output Unregulated Input: +16V maximum supply. 5-Pin TO-220 (MIC29512) Pin Number Pin Name Pin Function 1 EN Enable (Input): Logic-level ON/OFF control. 2 IN Unregulated Input: +16V maximum supply. 3 GND Ground: Internally connected to tab (ground). 4 OUT Regulated Output 5 ADJ Output Voltage Adjust: 1.240V feedback from external resistive divider. Absolute Maximum Ratings Operating Ratings Input Supply Voltage (Note 1) ....................... –20V to +20V Power Dissipation .................................... Internally Limited Storage Temperature Range ................... –65°C to +150°C Lead Temperature (Soldering, 5 sec.) ...................... 260°C Operating Junction Temperature ................. 0°C to +125°C θJC (TO-220) ............................................................. 2°C/W θJA (TO-220) ........................................................... 55°C/W 1997 3-97 MIC29510/29512 Micrel Electrical Characteristics All measurements at TJ = 25°C unless otherwise noted. Bold values are guaranteed across the operating temperature range. Parameter Condition Max Units Output Voltage 10mA ≤ IO ≤ IFL, (VOUT + 1V) ≤ VIN ≤ 8V (Note 2) 2 % Line Regulation IO = 10mA, (VOUT + 1V) ≤ VIN ≤ 8V 0.06 0.5 % Load Regulation VIN = VOUT + 1V, 10mA ≤ IOUT ≤ IFULL LOAD (Notes 2, 6) 0.2 1 % ∆VO / ∆T Output Voltage Temperature Coefficient (Note 6) 20 100 ppm/°C Dropout Voltage ∆VOUT = – 1%, (Note 3) MIC29510/29512 IO = 100mA IO = 750mA IO = 1.5A IO = 3A IO = 5A 80 200 320 500 700 200 mV mV mV mV mV MIC29510/29512 IO = 750mA, VIN = VOUT + 1V IO = 1.5A IO = 3A IO = 5A 3 10 36 100 150 mA mA mA mA 2 3 mA Ground Current Min IGNDDO Ground Pin Current at Dropout VIN = 0.5V less than specified VOUT. IOUT = 10mA Current Limit MIC29510/29512 VOUT = 0V (Note 4) en, Output Noise Voltage (10Hz to 100kHz) IL = 100mA CL = 47µF Typ –2 5.0 1000 20 6.5 A 260 µVRMS Reference (MIC29512 only) Reference Voltage 10mA ≤ IO ≤ IFL, VOUT + 1V ≤ VIN ≤ 8V (Note 2) Adjust Pin Bias Current Reference Voltage Temperature Coefficient 1.215 40 (Note 7) Adjust Pin Bias Current Temperature Coefficient 3-98 1.265 VMAX 80 120 nA nA 20 ppm/°C 0.1 nA/°C 1997 MIC29510/29512 Micrel Parameter Conditions Min Low (Off) High (On) 2.4 Typical Max Units 0.8 V V Enable Input (MIC29512 only) Input Logic Voltage Enable (EN) Pin Input Current Regulator Output Current in Shutdown VEN = VIN 15 30 75 µA µA VEN = 0.8V – 2 4 µA µA (Note 8) 10 20 µA µA General Note: Devices are ESD sensitive. Handling precautions recommended. Note 1: The maximum continuous supply voltage is 16V. Note 2: Full Load current is defined as 5A for the MIC29510/29512. For testing, VOUT is programmed to 5V. Note 3: 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 4: For this test, VIN is the larger of 8V or VOUT + 3V. Note 5: 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 6: Output voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range. Note 7: VREF ≤ VOUT ≤ (VIN – 1 V), 2.4V ≤ VIN ≤ 16V, 10mA < IL ≤ IFL, TJ ≤ TJ MAX. Note 8: VEN ≤ 0.8V and VIN ≤ 8V, VOUT = 0. 3 Block Diagram OUT IN EN On/Off Bias O.V. ILIMIT 28V 16V Reference Feedback ADJ Thermal Shutdown GND 1997 3-99 MIC29510/29512 Micrel Typical Characteristics VOUT 3.525V nominal MIC29512 EN VIN = VOUT + 1V OUT IN OUTPUT VOLTAGE MIC29512 Load Transient Response (See Test Circuit Schematic) 0.1µF 93.1k 1% ADJ 49.9k 1% GND 4 × 330µF AVX TPSE337M006R0100 tantalum +20mV 3.525V –20mV 1ms/division LOAD CURRENT VOUT load (not shown): Intel® Power Validator MIC29512 Load Transient Response Test Circuit 5A 200mA 0mA INPUT VOLTAGE 4.525V 4.525V 200µs/division IOUT = 5A COUT = 10µF IOUT = 5A COUT = 100µF OUTPUT VOLTAGE +20mV 6.525V 200µs/division 3.525V –20mV MIC2951x Dropout Voltage vs. Output Current +20mV 3.525V –20mV MIC2951x Dropout Voltage vs. Temperature MIC29510-3.3 Dropout Characteristics 1.0 0.8 0.6 0.4 0.2 0 0 1 2 3 4 OUTPUT CURRENT (A) 5 5.0 0.8 0.6 ILOAD = 5A 0.4 0.2 0 -60 -30 0 30 60 90 120 150 TEMPERATURE (°C) 3-100 OUTPUT VOLTAGE (V) 1.0 DROPOUT VOLTAGE (V) OUTPUT VOLTAGE MIC29512 Line Transient Response with 5A Load, 100µF Output Capacitance 6.525V DROPOUT VOLTAGE (V) INPUT VOLTAGE MIC29512 Line Transient Response with 5A Load, 10µF Output Capacitance VIN = 4.3V 4.0 ILOAD = 10mA 3.0 ILOAD = 5A 2.0 1.0 0.0 0 2 4 INPUT VOLTAGE (V) 6 1997 MIC29510/29512 Micrel MIC2951x-3.3 Ground Current vs. Supply Voltage 100 0 8 8 0.0 -60 -30 0 30 60 90 120 150 TEMPERATURE (°C) 2 50 0 1 2 3 4 OUTPUT CURRENT (A) 5 40 30 VEN = 5V 20 10 VEN = 2V 0 -60 -30 0 30 60 90 120 150 TEMPERATURE (°C) 3 100 VIN = 4.3V ILOAD = 5A 50 10 3.34 3.32 3.30 3.28 3.26 3.24 3 DEVICES 3.22 3.20 -60 -30 0 30 60 90 120 150 TEMPERATURE (°C) MIC29512 Enable Current vs. Temperaure 150 9 8 7 VOUT = 0V 6 5 4 3 2 1 0 -60 -30 0 30 60 90 120 150 TEMPERATURE (°C) MIC29512 Adjust Pin Current vs. Temperature MIC2951x Output Impedance vs. Frequency 80 10 60 40 20 ILOAD = 10mA 0 -60 -30 0 30 60 90 120 150 TEMPERATURE (°C) 1 0.1 0.01 0.001 10x100 25 0 ENABLE CURRENT (µA) OUTPUT VOLTAGE (V) 50 200 MIC2951x Short Circuit Current vs. Temperature 125 75 MIC2951x-3.3 Ground Current vs. Temperature MIC29510-3.3 Output Voltage vs. Temperature 3.38 3.36 VIN = 4.3V FREQUENCY (Hz) 1997 20 0 -60 -30 0 30 60 90 120 150 TEMPERATURE (°C) 3.40 100 -10 0 10 INPUT VOLTAGE (V) 0 -60 -30 0 30 60 90 120 150 TEMPERATURE (°C) 150 ADJUST PIN CURRENT (nA) GROUND CURRENT (mA) MIC2951x-3.3 Ground Current vs. Output Current MIC2951x Ground Current vs. Temperature IOUT = 500mA RLOAD = 100Ω 3-101 1x106 IOUT = 10mA 0.2 4 0.0 -0.5 -20 8 6 0.5 100x103 0.4 2 4 6 SUPPLY VOLTAGE (V) 1.0 10x103 0.6 0 1.5 1x103 MIC2951x Ground Current vs. Temperature GROUND CURRENT (mA) GROUND CURRENT (mA) 0.8 2 4 6 SUPPLY VOLTAGE (V) ILOAD = 5A 50 0 0 GROUND CURRENT (mA) 2 150 VOUT = 3.3V 2.0 CURRENT (A) 4 200 OUTPUT IMPEDANCE (Ω) 6 2.5 GROUND CURRENT (mA) GROUND CURRENT (mA) GROUND CURRENT (mA) RLOAD = 10mA 8 MIC2951x Ground Current vs. Input Voltage 250 100x100 MIC2951x-3.3 Ground Current vs. Supply Voltage 10 MIC29510/29512 Micrel Applications Information The MIC29510 and MIC29512 are high performance lowdropout voltage regulators suitable for all moderate to highcurrent 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. MIC29510/512 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 MIC29512 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 highcurrent Super ßeta PNP™ regulators have identical pinouts. VIN VOUT Figure 3. The MIC29510 LDO 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. 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: 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. MIC29510/2 regulators are stable with a minimum capacitor value of 47µF 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 MIC29510/2 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. 3-102 1997 MIC29510/29512 Micrel Adjustable Regulator Design the 16V maximum operating rating of the family. Two resistors are used. Resistors can be quite large, up to 100kΩ, because of the very high input impedance and low bias current of the sense comparator. The resistor values are calculated by: VOUT R1 = R2 × ( –—— – 1 ) 1.240 MIC29512BT VIN 4.75 to 5.25 VOUT R1 100k 10µF 3.45V 47µF R2 56.2k VOUT = 1.240V × [1 + (R1 / R2)] Figure 4. Adjustable Regulator with Resistors The adjustable regulator version, MIC29512, allows programming the output voltage anywhere between 1.25V and Where VO is the desired output voltage. Figure 4 shows component definition. Enable Input The MIC29512 versions 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. 3 Resistor Value Table for the MIC29512 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 1997 Standard (Ω) R1 100k 100k 100k 100k 100k 100k 100k 100k 100k 100k 100k 3-103 R2 76.8k 75.0k 69.8k 66.5k 64.9k 60.4k 56.2k 52.3k 48.7k 45.3k 43.2k