MIC5238 Micrel MIC5238 Ultra-Low Quiescent Current, 150mA Cap LDO Regulator Final General Description Features The MIC5238 is an ultra-low voltage output, 150mA LDO regulator. Designed to operate in a single supply or dual supply mode, the MIC5238 consumes only 23A of bias current, improving efficiency. When operating in the dual supply mode, the efficiency greatly improves as the higher voltage supply is only required to supply the 23A bias current while the output and base drive comes off of the much lower input supply voltage. As a Cap regulator, the MIC5238 operates with a 2.2F ceramic capacitor on the output, offering a smaller overall solution. It also incorporates a logic-level enable pin that allows the MIC5238 to be put into a zero off-current mode when disabled. * * * * * * * * * * Ultra-low input voltage range: 1.5V to 6V Ultra-low output voltage: 0.9V minimum output voltage Low dropout voltage: 310mV at 150mA High output accuracy: 2.0% over temperature Cap: stable with ceramic or tantalum capacitors Excellent line and load regulation specifications Zero shutdown current Reverse leakage protection Thermal shutdown and current limit protection IttyBittyTM SOT-23-5 package Applications * * * * The MIC5238 is fully protected with current limit and thermal shutdown. It is offered in the IttyBittyTM SOT-23-5 package with an operating junction temperature range of -40C to +125C. PDAs and pocket PCs Cellular phones Battery powered systems Low power microprocessor power supplies Ordering Information Part Number Marking Voltage* Junction Temp. Range Package* MIC5238-0.9BM5 L409 0.9V -40C to +125C SOT-23-5 MIC5238-1.0BM5 L410 1.0V -40C to +125C SOT-23-5 MIC5238-1.1BM5 L411 1.1V -40C to +125C SOT-23-5 MIC5238-1.2BM5 L412 1.2V -40C to +125C SOT-23-5 MIC5238-1.3BM5 L413 1.3V -40C to +125C SOT-23-5 MIC5238-1.1BD5 N411 1.1V -40C to +125C TSOT-23-5 MIC5238-1.3BD5 N413 1.3V -40C to +125C TSOT-23-5 * For other voltages and package option contact the factory. Typical Application MIC5238-1.0BM5 VIN=1.5V EN OFF ON 1 CIN 5 2 3 4 1.0V COUT=2.2F ceramic VBIAS=2.5V CBIAS Ultra-Low Voltage Application IttyBitty is a trademark of Micrel, Inc. Micrel, Inc. * 1849 Fortune Drive * San Jose, CA 95131 * USA * tel + 1 (408) 944-0800 * fax + 1 (408) 944-0970 * http://www.micrel.com April 2003 1 MIC5238 MIC5238 Micrel Pin Configuration EN GND IN 3 2 EN GND IN 1 3 L4xx 4 BIAS 2 1 N4xx 5 4 BIAS OUT SOT-23-5 (M5) 5 OUT TSOT-23-5 (D5) Pin Description SOT-23-5 Pin Name Pin Function 1 IN Supply Input 2 GND 3 EN 4 BIAS Bias Supply Input 5 OUT Regulator Output MIC5238 Ground Enable (Input): Logic low = shutdown; logic high = enable. Do no leave open. 2 April 2003 MIC5238 Micrel Absolute Maximum Ratings (Note 1) Operating Ratings (Note 2) Input Supply Voltage ........................................ -0.3V to 7V Bias Supply Voltage ......................................... -0.3V to 7V Enable Input Voltage ........................................ -0.3V to 7V Power Dissipation .................................... Internally Limited Junction Temperature .............................. -40C to +125C Storage Temperature ............................... -65C to +150C ESD Rating, >1.5A HBM, Note 3 Input Supply Voltage .......................................... 1.5V to 6V BIAS Supply Voltage .......................................... 2.3V to 6V Enable Input Voltage ............................................. 0V to 6V Junction Temperature (TJ) ....................... -40C to +125C Package Thermal Resistance SOT-23-5 (JA) .................................................. 235C/W Electrical Characteristics (Note 4) TA = 25C with VIN = VOUT + 1V; VBIAS = 3.3V; IOUT = 100A; VEN = 2V, Bold values indicate -40C < TJ < +125C; unless otherwise specified. Parameter Condition Min. Output Voltage Accuracy Variation from nominal VOUT -1.5 -2 Line Regulation VBIAS = 2.3V to 6V, Note 5 0.25 Input Line Regulation VIN = (VOUT + 1V) to 6V 0.04 Load Regulation Load = 100A to 150mA 0.7 Dropout Voltage IOUT = 100A IOUT = 50mA 50 230 IOUT = 100mA 270 IOUT = 150mA 310 Bias Current, Note 6 IOUT = 100A 23 Input Current, Pin 1 IOUT = 100A IOUT = 50mA, Note 7 IOUT = 100mA IOUT = 150mA 7 0.35 1 2 2.5 A mA mA mA VEN 0.2V; VIN = 6V; VBIAS = 6V 1.5 5 A VEN = 0V; VIN = 6V; VBIAS = 6V 0.5 Short Circuit Current VOUT = 0V 350 Reverse Leakage VIN = 0V; VEN = 0V; VOUT = nom VOUT Ground Current in Shutdown Typ. Max. Units +1.5 +2 % % 0.5 % % 1 300 400 450 500 % mV mV mV mV mV mV mV A 20 A 500 mA A 5 Enable Input Input Low Voltage Regulator OFF 0.2 Input High Voltage Regulator ON 2.0 Enable Input Current VEN = 0.2V; Regulator OFF VEN = 2.0V; Regulator ON -1.0 Note 1. 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. Human body model, 1.5k in series with 100pF. Note 4. Specification for packaged product only. Note 5. Line regulation measures a change in output voltage due to a change in the bias voltage. Note 6. Current measured from bias input to ground. Note 7. Current differential between output current and main input current. April 2003 3 V V 0.01 0.1 1.0 1.0 A A MIC5238 MIC5238 Micrel Typical Characteristics 80 1.2 OUTPUT VOLTAGE (V) 70 60 PSRR (dB) Output Voltage vs. VBIAS 50 40 30 COUT = 2.2F ceramic VIN = 2.1V 10 V = 1.1V 20 1.15 100A 1.1 OUTPUT VOLTAGE (V) PSRR 150mA Load 150mA 1 0.9 0.8 0.7 0.6 0.5 1 0.95 0.9 0.85 GROUND CURRENT (A) 300 250 200 150 100 50 1400 1200 1000 800 600 400 200 0 0 25 50 75 100 125 150 OUTPUT CURRENT (A) Ground Current (VBIAS) vs. Output Current VIN = VOUT + 1 20 15 10 5 25 50 75 100 125 150 OUTPUT CURRENT (mA) 30 0.6 0.4 0.2 0 0 15 10 5 0 0.5 1 1.5 14 12 10 8 6 4 2 0.5 1 1.5 ENABLE (V) 2 2.0 Shutdown Current of VIN 2 2.5 6 5 4 3 2 1 0 3 0 0.5 1 1.5 2 INPUT VOLTAGE (V) ENABLE (V) Shutdown Current VBIAS + VIN Tied Ground Current (VIN) vs Temperature No Load 25 20 15 10 5 0 0 0.5 1.0 1.5 VIN SUPPLY (V) No Load 30 18 No Load 16 GROUND CURRENT (mA) GROUND CURRENT (mA) 1.0 0.8 7 20 0 20 MIC5238 1.4 1.2 ILOAD = 150mA 25 Shutdown Current of VBIAS 0 0 25 50 75 100 125 150 OUTPUT CURRENT (mA) Ground Current (VIN) vs. VIN Supply 1.1V 1.8 150mA 1.6 Ground Current (VBIAS) vs. Input Voltage 25 0 0 2.0 VIN = VOUT + 1 GROUND CURRENT (A) GROUND CURRENT (A) 30 1600 Ground Current (VIN) vs. Output Current VIN GROUND CURRENT (A) 0 0 0.8 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 2.1 INPUT VIN (V) VIN GROUND CURRENT (mA) 1800 VIN = VOUT + 1 350 VBIAS GROUND CURRENT (A) DROPOUT VOLTAGE (mV) 400 Dropout Voltage vs. Load 150mA 1.05 0.4 1.2 1.7 2.2 2.7 3.2 3.7 4.2 4.7 5.2 INPUT BIAS (V) 100 1k 10k 100k 1M 10M TEMPERATURE (C) 100A 1.1 OUT 0 10 Output Voltage vs. VIN 0.5 1 1.5 ENABLE (V) 4 2 10 9 8 1.1V 100A 7 6 5 4 3 2 1 0 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (C) April 2003 MIC5238 Micrel 1 0.8 0.6 0.4 0.2 0 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (C) 1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (C) 30 25 20 15 10 5 1.1V 150mA 35 30 25 20 15 10 5 0 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (C) Short Circuit Current vs. Temperature Dropout Voltage vs. Temperature 450 400 350 300 250 200 150 100 50 0 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (C) April 2003 1.1V 35 100A 30 25 20 15 10 5 0 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (C) 500 450 1.1025 Output Voltage vs. Temperature 1.1V 1.1020 100A 1.1015 1.1010 1.1005 1.1000 1.0995 1.0990 1.0985 1.0980 0 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (C) 500 LOAD CURRENT (mA) 40 VIN GROUND CURRENT (A) 1.1V 75mA 40 VBIAS Ground Current vs. Temperature DROPOUT VOLTAGE (mV) VIN GROUND CURRENT (A) 35 Ground Current vs. Temperature BIAS 1.1V 2.2 150mA 2 VBIAS Ground Current vs. Temperature 40 V VIN GROUND CURRENT (A) 1.4 1.2 2.4 VIN Ground Current vs. Temperature OUTPUT VOLTAGE (V) 1.1V 1.8 75mA 1.6 VIN GROUND CURRENT (mA) VIN GROUND CURRENT (mA) 2 VIN Ground Current vs. Temperature 1.0975 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (C) Load = 150mA 400 350 300 250 200 150 100 50 0 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (C) 5 MIC5238 MIC5238 Micrel Load Transient Response OUTPUT VOLTAGE (200mV/div.) Line Transient Response 2.1V TIME (200s/div.) 150mA 1mA TIME (400s/div.) Load Transient Response OUTPUT VOLTAGE (500mA/div.) ENABLE (2V/div.) OUTPUT CURRENT OUTPUT VOLTAGE (100mA/div.) (200mV/div.) EN Turn-On Characteristic TIME (40s/div.) MIC5238 1.1V output COUT = 4.7F ceramic OUTPUT CURRENT (50mA/div.) 1.1V Output COUT = 4.7F ceramic OUTPUT VOLTAGE (10mV/div.) INPUT VOLTAGE (1V/div.) 3.1V 150mA 0mA VIN = 4V VOUT = 3V COUT = 4.7F ceramic TIME (400s/div.) 6 April 2003 MIC5238 Micrel Functional Diagram OUT IN BIAS EN ENABLE VREF GND Block Diagram - Fixed Output Voltage April 2003 7 MIC5238 MIC5238 Micrel Applications Information Package Enable/Shutdown The MIC5238 comes with an active-high enable pin that allows the regulator to be disabled. Forcing the enable pin low disables the regulator and sends it into a "zero" off-modecurrent state. In this state, current consumed by the regulator goes nearly to zero. Forcing the enable pin high enables the output voltage. SOT-23-5 235C/W Table 1. SOT-23-5 Thermal Resistance The actual power dissipation of the regulator circuit can be determined using the equation: PD = (VIN - VOUT)IOUT + VINIGND Substituting PD(MAX) for PD and solving for the operating conditions that are critical to the application will give the maximum operating conditions for the regulator circuit. For example, when operating the MIC5238-1.0BM5 at 50C with a minimum footprint layout, the maximum input voltage for a set output current can be determined as follows: Input Bias Capacitor The input capacitor must be rated to sustain voltages that may be used on the input. An input capacitor may be required when the device is not near the source power supply or when supplied by a battery. Small, surface mount, ceramic capacitors can be used for bypassing. Larger values may be required if the source supply has high ripple. 125C - 50C PD(MAX) = 235C/W Output Capacitor The MIC5238 requires an output capacitor for stability. The design requires 2.2F or greater on the output to maintain stability. The design is optimized for use with low-ESR ceramic chip capacitors. High ESR capacitors may cause high frequency oscillation. The maximum recommended ESR is 3. The output capacitor can be increased without limit. Larger valued capacitors help to improve transient response. PD(MAX) = 319mW The junction-to-ambient (JA) thermal resistance for the minimum footprint is 235C/W, from Table 1. It is important that the maximum power dissipation not be exceeded to ensure proper operation. With very high input-to-output voltage differentials, the output current is limited by the total power dissipation. Total power dissipation is calculated using the following equation: PD = (VIN - VOUT)IOUT + VIN x IGND + VBIAS x IBIAS X7R/X5R dielectric-type ceramic capacitors are recommended because of their temperature performance. X7Rtype capacitors change capacitance by 15% over their operating temperature range and are the most stable type of ceramic capacitors. Z5U and Y5V dielectric capacitors change value by as much as 50% and 60% respectively over their operating temperature ranges. To use a ceramic chip capacitor with Y5V dielectric, the value must be much higher than a X7R ceramic capacitor to ensure the same minimum capacitance over the equivalent operating temperature range. No-Load Stability Since the bias supply draws only 18A, that contribution can be ignored for this calculation. If we know the maximum load current, we can solve for the maximum input voltage using the maximum power dissipation calculated for a 50C ambient, 319mV. PDMAX = (VIN - VOUT)IOUT + VIN x IGND 319mW = (VIN - 1V)150mA + VIN x 2.8mA Ground pin current is estimated using the typical characteristics of the device. 469mW = VIN (152.8mA) The MIC5238 will remain stable and in regulation with no load unlike many other voltage regulators. This is especially important in CMOS RAM keep-alive applications. Thermal Considerations VIN = 3.07V For higher current outputs only a lower input voltage will work for higher ambient temperatures. The MIC5238 is designed to provide 150mA of continuous current in a very small package. Maximum power dissipation can be calculated based on the output current and the voltage drop across the part. To determine the maximum power dissipation of the package, use the junction-to-ambient thermal resistance of the device and the following basic equation: Assuming a lower output current of 20mA, the maximum input voltage can be recalculated: 319mW = (VIN - 1V)20mA + VIN x 0.2mA 339mW = VIN x 20.2mA VIN = 16.8V TJ(MAX) - TA PD(MAX) = JA Maximum input voltage for a 20mA load current at 50C ambient temperature is 16.8V. Since the device has a 6V rating, it will operate over the whole input range. Dual Supply Mode Efficiency TJ(MAX) is the maximum junction temperature of the die, 125C, and TA is the ambient operating temperature. JA is layout dependent; Table 1 shows the junction-to-ambient thermal resistance for the MIC5238. MIC5238 JA Recommended Minimum Footprint By utilizing a bias supply the conversion efficiency can be greatly enhanced. This can be realized as the higher bias supply will only consume a few A's while the input supply will require a few mA's! This equates to higher efficiency saving valuable power in the system. As an example, consider an output voltage of 1V with an input supply of 2.5V at a load 8 April 2003 MIC5238 Micrel Input power = VIN x output current + VIN x VIN ground current + VBIAS x VBIAS ground current current of 150mA. The input ground current under these conditions is 2mA, while the bias current is only 20A. If we calculate the conversion efficiency using the single supply approach, it is as follows: Input power = 1.5 x 150mA + 1.5 x 0.002 + 2.5 x 0.0002 = 225mW Output power = 1V x 150mA = 150mW Input power = VIN x output current + VIN x (VBIAS ground current + VIN ground current) Input power = 2.5V x 150mA + 2.5 x (0.0002+0.002) = 380.5mW Efficiency = 150/225 x 100 = 66.6 % Therefore, by using the dual supply MIC5238 LDO the efficiency is nearly doubled over the single supply version. Output power = 1V x 0.15 = 150mW Efficiency = 150/380.5 x 100 = 39.4% This is a valuable asset in portable power management applications equating to longer battery life and less heat being generated in the application. This in turn will allow a smaller footprint design and an extended operating life. Now, using a lower input supply of 1.5V, and powering the bias voltage only from the 2.5V input, the efficiency is as follows: April 2003 9 MIC5238 MIC5238 Micrel Package Information 1.90 (0.075) REF 0.95 (0.037) REF 1.75 (0.069) 1.50 (0.059) 3.00 (0.118) 2.60 (0.102) DIMENSIONS: MM (INCH) 1.30 (0.051) 0.90 (0.035) 3.02 (0.119) 2.80 (0.110) 0.20 (0.008) 0.09 (0.004) 10 0 0.15 (0.006) 0.00 (0.000) 0.50 (0.020) 0.35 (0.014) 0.60 (0.024) 0.10 (0.004) SOT-23-5 (M5) 1.90BSC 2.90BSC 0.30 0.45 DIMENSIONS: Millimeter 1.90BSC 0.90 0.80 1.00 0.90 2.9BSC 1.60BSC 0.20 0.12 0.10 0.01 1.60BSC 0.30 0.50 1.90BSC TSOT-23-5 (D5) MICREL, INC. TEL 1849 FORTUNE DRIVE SAN JOSE, CA 95131 USA + 1 (408) 944-0800 FAX + 1 (408) 944-0970 WEB http://www.micrel.com The information furnished by Micrel in this datasheet 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. (c) 2003 Micrel, Incorporated. MIC5238 10 April 2003