MIC39500/39501 Micrel MIC39500/39501 5A Low-Voltage Low-Dropout Regulator Advance Information General Description Features The MIC39500 and MIC39501 is a 5A low-dropout linear voltage regulator that provides a low-voltage, high-current output with a minimum of external components. Utilizing Micrel’s proprietary Super βeta PNP™ pass element, the MIC39500 offers extremely low dropout (typically 400mV at 5A) and low ground current (typically 70mA at 5A). The MIC39500 is ideal for PC Add-In cards that need to convert from standard 5V or 3.3V, down to new, lower core voltages. A guaranteed maximum dropout voltage of 500mV over all operating conditions allows the MIC39500 to provide 2.5V from a supply as low as 3V. The MIC39500 also has fast transient response, for heavy switching applications. The device requires only 47µF of output capacitance to maintain stability and achieve fast transient response The MIC39500 is fully protected with overcurrent limiting, thermal shutdown, reversed-battery and reversed-lead insertion protection. The MIC39501 offers a TTL-logic-compatible enable pin and an error flag that indicates undervoltage and overcurrent conditions. The MIC39500 comes in the TO220 and TO-263 packages and is an ideal upgrade to older, NPN-based linear voltage regulators. • • • • • • • • • • For applications requiring input voltage greater than 16V, see the MIC29500/1/2/3 family. 5A minimum guaranteed output current 500mV maximum dropout voltage over temperature 1% initial accuracy Low ground current Current limiting and thermal shutdown Reversed-battery and reversed-lead insertion protection Fast transient response TO-263 and TO-220 packages TTL/CMOS compatible enable pin (MIC39501 only) Error flag output (MIC39501 only) Applications • • • • • • • LDO linear regulator for PC add-in cards PowerPC™ power supplies High-efficiency linear power supplies SMPS post regulator Multimedia and PC processor supplies Low-voltage microcontrollers StrongARM™ processor supply Ordering Information Part Number Voltage Junction Temp. Range Package MIC39500-2.5BT 2.5V –40°C to +125°C 3-lead TO-220 MIC39500-2.5BU 2.5V –40°C to +125°C 3-lead TO-263 MIC39501-2.5BT 2.5V –40°C to +125°C 5-lead TO-220 MIC39501-2.5BU 2.5V –40°C to +125°C 5-lead TO-263 100KΩ Typical Application MIC39501-2.5 MIC39500-2.5 VIN 3.3V 1.0µF IN VOUT 2.5V OUT GND 47µF Enable Shutdown EN VIN 3.3V IN FLG VOUT 2.5V OUT GND 1.0µF MIC39500 ERROR FLAG OUTPUT 47µF MIC39501 StrongARM is a trademark of Advanced RISC Machines, Ltd. Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com June 1999 1 MIC39500/39501 MIC39500/39501 Micrel 3 OUT 2 GND 1 IN TAB TAB Pin Configuration MIC39500-x.xBT TO-220 (T) OUT 2 GND 1 IN MIC39500-x.xBU TO-263 (U) FLG OUT GND IN EN 5 4 3 2 1 TAB 5 4 3 2 1 TAB 3 FLG OUT GND IN EN MIC39501-x.xBU TO-263-5 (U) MIC39501-x.xBT TO-220-5 (T) Pin Description Pin Number MIC39500 Pin Number MIC39501 Pin Name 1 EN Enable (Input): TTL/CMOS compatible input. Logic high = enable; logic low or open = shutdown 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 FLG Error Flag (Ouput): Open collector output. Active low indicates an output fault condition. MIC39500/39501 Pin Function 2 June 1999 MIC39500/39501 Micrel Absolute Maximum Ratings (Note 1) Operating Ratings (Note 2) Supply Voltage (VIN) ..................................... –20V to +20V Enable Voltage (VEN) .................................................. +20V Storage Temperature (TS) ....................... –65°C to +150°C Lead Temperature (soldering, 5 sec.) ....................... 260°C ESD, Note 3 Supply Voltage (VIN) .................................. +2.25V to +16V Enable Voltage (VEN) .................................................. +16V Maximum Power Dissipation (PD(max))..................... Note 4 Junction Temperature (TJ) ....................... –40°C to +125°C Package Thermal Resistance TO-263 (θJC) ......................................................... 2°C/W TO-220 (θJC) ......................................................... 2°C/W Electrical Characteristics TJ = 25°C, bold values indicate –40°C ≤ TJ ≤ +125°C; unless noted Symbol Parameter Condition VOUT Output Voltage 10mA ≤ IOUT ≤ 5A, VOUT + 1V ≤ VIN ≤ 16V Line Regulation IOUT = 10mA, VOUT + 1V ≤ VIN ≤ 16V Load Regulation VIN = VOUT + 1V, 10mA ≤ IOUT ≤ 5A ∆VOUT/∆T Output Voltage Temp. Coefficient, Note 5 VDO Dropout Voltage, Note 6 IGND Ground Current, Note 7 Min Typ Max Units 1 2 % % 0.06 0.5 % 0.2 1 % 20 100 ppm/°C IOUT = 250mA, ∆VOUT = –2% 125 250 mV IOUT = 2.5A, ∆VOUT = –2% 320 IOUT = 5A, ∆VOUT = –2% 400 500 mV IOUT = 2.5A, VIN = VOUT + 1V 15 50 mA IOUT = 5A, VIN = VOUT + 1V 70 mA –1 –2 mV IGND(do) Dropout Ground Pin Current VIN ≤ VOUT(nominal) – 0.5V, IOUT = 10mA 2.1 mA IOUT(lim) Current Limit VOUT = 0V, VIN = VOUT + 1V 7.5 A en Output Noise Voltage COUT = 47µF, IOUT = 100mA, 10Hz to 100kHz 260 µV(rms) Enable Input (MIC39501) VEN Enable Input Voltage logic low (off) logic high (on) Enable Input Current IIN 0.8 2.4 VEN = VIN V 35 75 µA µA 2 4 µA µA 10 20 µA 30 VEN = 0.8V IOUT(shdn) Shutdown Output Current Note 8 V Flag Output (MIC39501) IFLG(leak) Output Leakage Current VOH = 16V 0.01 1 2 µA µA VFLG(do) Output Low Voltage VIN = 2.250V, IOL, = 250µA, Note 9 125 150 200 mV mV Note 1. Exceeding the absolute maximum ratings 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. PD(max) = (TJ(max) – TA) ÷ θJA, where θJA depends upon the printed circuit layout. See “Applications Information.” Note 5. Output voltage temperature coefficient is ∆VOUT(worst case) ÷ (TJ(max) – TJ(min)) where TJ(max) is +125°C and TJ(min) is 0°C. Note 6. VDO = VIN – VOUT when VOUT decreases to 98% of its nominal output voltage with VIN = VOUT + 1V. Note 7. IGND is the quiescent current. IIN = IGND + IOUT. Note 8. VEN ≤ 0.8V, VIN ≤ 8V, and VOUT = 0V Note 9. For a 2.5V device, VIN = 2.250V (device is in dropout). June 1999 3 MIC39500/39501 MIC39500/39501 Micrel Functional Diagram OUT IN O.V. ILIMIT 1.180V FLAG* Ref. 18V 1.240V EN* Thermal Shutdown GND * MIC39501 only MIC39500/39501 4 June 1999 MIC39500/39501 Micrel 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 βeta 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 1µF 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 specification. Output capacitor The MIC39500/1 requires an output capacitor to maintain stability and improve transient response. Proper capacitor selection is important to ensure proper operation. The MIC39500/1 output capacitor selection is dependent upon the ESR (equivalent series resistance) of the output capacitor to maintain stability. When the output capacitor is 47µF or greater, the output capacitor should have less than 1Ω of ESR. This will improve transient response as well as promote stability. Ultra-low-ESR capacitors, such as ceramic chip capacitors may promote instability. These very low ESR levels may cause an oscillation and/or underdamped transient response. A low-ESR solid tantalum capacitor works extremely well and provides good transient response and stability over temperature. Aluminum electrolytics can also be used, as long as the ESR of the capacitor is < 1Ω. The value of the output capacitor can be increased without limit. Higher capacitance values help to improve transient response and ripple rejection and reduce output noise. Input capacitor An input capacitor of 1µF or greater is recommended when the device is more than 4 inches away from the bulk ac supply capacitance, or when the supply is a battery. Small surfacemount ceramic chip capacitors can be used for bypassing. Larger values will help to improve ripple rejection by bypassing the input to the regulator, further improving the integrity of the output voltage. Transient Response The MIC39500/1 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 47µF output capacitor, preferably tantalum, is all that is required. Larger values improve performance even further. 3.3V to 2.5V Conversion By virtue of its low-dropout voltage, this device does not saturate into dropout as readily as similar NPN-based designs. When converting from 3.3V to 2.5V, the NPN-based regulators are already operating in dropout, with typical dropout requirements of 1.2V or greater. To convert down to 2.5V without operating in dropout, NPN-based regulators require an input voltage of 3.7V at the very least. The MIC39500/1 regulator provides excellent performance with Applications Information The MIC39500/1 is a high-performance low-dropout voltage regulator suitable for moderate to high-current voltage regulator applications. Its 500mV dropout voltage at full load makes it especially valuable in battery-powered systems and as a high-efficiency noise filter in post-regulator applications. Unlike older NPN-pass transistor designs, where the minimum dropout voltage is limited by the base-to-emitter voltage drop and collector-to-emitter 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 βeta PNP™ process reduces this drive requirement to only 2% to 5% of the load current. The MIC39500/1 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. Transient protection allows device (and load) survival even when the input voltage spikes 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. VIN MIC39500-x.x IN CIN VOUT OUT GND COUT Figure 1. Capacitor Requirements Thermal Design Linear regulators are simple to use. The most complicated design parameters to consider are thermal characteristics. Thermal design requires four application-specific parameters: • Maximum ambient temperature (TA) • Output Current (IOUT) • Output Voltage (VOUT) • Input Voltage (VIN) • Ground Current (IGND) Calculate the power dissipation of the regulator from these numbers and the device parameters from this datasheet, where the ground current is taken from data sheet. PD = (VIN – VOUT) × IOUT + VIN × IGND The heat sink thermal resistance is determined by: θSA = TJ(max) − TA PD ( − θ JC + θCS ) where: TJ (max) ≤ 125°C and θCS is between 0° and 2°C/W. June 1999 5 MIC39500/39501 MIC39500/39501 Micrel an input as low as 3.0V. This gives PNP-based regulators a distinct advantage over older, NPN-based linear regulators. A typical NPN regulator does not have the headroom to do this conversion. Minimum Load Current The MIC39500/1 regulator is specified between finite loads. If the output current is too small, leakage currents dominate and the output voltage rises. A 10mA minimum load current is necessary for proper regulation. MIC39500/39501 Error Flag The MIC39501 version features an error flag circuit which monitors the output voltage and signals an error condition when the voltage 5% below the nominal output voltage. The error flag is an open-collector output that can sink 10mA 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 MIC39501 version 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 to up to 20V. 6 June 1999 MIC39500/39501 Micrel Package Information 0.151 D ±0.005 (3.84 D ±0.13) 0.410 ±0.010 (10.41 ±0.25) 0.108 ±0.005 (2.74 ±0.13) 0.176 ±0.005 (4.47 ±0.13) 0.590 ±0.005 (14.99 ±0.13) 0.818 ±0.005 (20.78 ±0.13) 0.050 ±0.005 (1.27 ±0.13) 7° 0.356 ±0.005 (9.04 ±0.13) 7° 3° 1.140 ±0.010 (28.96 ±0.25) 0.050 ±0.003 (1.27 ±.08) 0.030 ±0.003 (0.76 ±0.08) 0.100 ±0.020 (2.54 ±0.51) 0.018 ±0.008 (0.46 ±0.020) 0.100 ±0.005 (2.54 ±0.13) DIMENSIONS: INCH (MM) TO-220 (T) 0.150 D ±0.005 (3.81 D ±0.13) 0.177 ±0.008 (4.50 ±0.20) 0.400 ±0.015 (10.16 ±0.38) 0.050 ±0.005 (1.27 ±0.13) 0.108 ±0.005 (2.74 ±0.13) 0.241 ±0.017 (6.12 ±0.43) 0.578 ±0.018 (14.68 ±0.46) SEATING PLANE 7° Typ. 0.550 ±0.010 (13.97 ±0.25) 0.067 ±0.005 (1.70 ±0.127) 0.032 ±0.005 (0.81 ±0.13) 0.268 REF (6.81 REF) 0.018 ±0.008 (0.46 ±0.20) 0.103 ±0.013 (2.62±0.33) Dimensions: inch (mm) TO-220-5 (T) June 1999 7 MIC39500/39501 MIC39500/39501 Micrel 0.176 ±0.005 0.405±0.005 0.065 ±0.010 20°±2° 0.050 ±0.005 0.050±0.005 0.360±0.005 0.600±0.025 SEATING PLANE 0.004 +0.004 –0.008 0.100 BSC 8° MAX 0.050 0.100 ±0.01 0.015 ±0.002 DIM. = INCH TO-263 (U) 0.176 ±0.005 0.405±0.005 0.065 ±0.010 20°±2° 0.060 ±0.005 0.050±0.005 0.360±0.005 0.600±0.025 SEATING PLANE 0.004 +0.004 –0.008 8° MAX 0.032 ±0.003 0.067±0.005 0.100 ±0.01 0.015 ±0.002 DIM. = INCH TO-263-5 (U) MICREL INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131 TEL + 1 (408) 944-0800 FAX + 1 (408) 944-0970 WEB USA http://www.micrel.com This information is believed to be accurate and reliable, however no responsibility is assumed by Micrel for its use nor for any infringement of patents or other rights of third parties resulting from its use. No license is granted by implication or otherwise under any patent or patent right of Micrel Inc. © 1999 Micrel Incorporated MIC39500/39501 8 June 1999