MIC5238 Micrel MIC5238 Ultra-Low Quiescent Current, 150mA µCap LDO Regulator 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 23µA 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 23µA bias current while the output and base drive comes off of the much lower input supply voltage. As a µCap regulator, the MIC5238 operates with a 2.2µF 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. The MIC5238 is fully protected with current limit and thermal shutdown. It is offered in the IttyBitty™ SOT-23-5 package with an operating junction temperature range of –40°C to +125°C. • • • • • • • • • • Ultra-low input voltage range: 1.5V to 6V Ultra-low output voltage: 1.1V minimum output voltage Low dropout voltage: 310mV at 150mA High output accuracy: ±2.0% over temperature µCap: stable with ceramic or tantalum capacitors Excellent line and load regulation specifications Zero shutdown current Reverse leakage protection Thermal shutdown and current limit protection IttyBitty™ SOT-23-5 package Applications • • • • PDAs and pocket PCs Cellular phones Battery powered systems Low power microprocessor power supplies Ordering Information Part Number Marking Voltage* Junction Temp. Range Package* L411 1.1V –40°C to +125°C SOT-23-5 MIC5238-1.3BM5 L413 1.3V –40°C to +125°C SOT-23-5 MIC5238-1.1BD5 N411 1.1V –40°C to +125°C TSOT-23-5 MIC5238-1.3BD5 N413 1.3V –40°C to +125°C TSOT-23-5 MIC5238-1.1BM5 * 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=2.2µF 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 August 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 BiasSupply Input 5 OUT Regulator Output MIC5238 Ground Enable (Input): Logic low = shutdown; logic high = enable. Do no leave open. 2 August 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 .............................. –40°C to +125°C Storage Temperature ............................... –65°C to +150°C ESD Rating, >1.5µA 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) ....................... –40°C to +125°C Package Thermal Resistance SOT-23-5 (θJA) .................................................. 235°C/W Electrical Characteristics (Note 4) TA = 25°C with VIN = VOUT + 1V; VBIAS = 3.3V; IOUT = 100µA; VEN = 2V, Bold values indicate –40°C < TJ < +125°C; 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 = 100µA to 150mA 0.7 Dropout Voltage IOUT = 100µA IOUT = 50mA 50 230 IOUT = 100mA 270 IOUT = 150mA 310 BIAS Current, Note 6 IOUT = 100µA 23 Input Current, Pin 1 IOUT = 100µA IOUT = 50mA, Note 7 IOUT = 100mA IOUT = 150mA 7 0.35 1 2 2.5 µA mA mA mA VEN ≤ 0.2V; VIN = 6V; VBIAS = 6V 1.5 5 µA 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 µA 20 µA 500 mA µA 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 at rated load current. August 2003 3 V V 0.01 0.1 1.0 1.0 µA µA MIC5238 MIC5238 Micrel Typical Characteristics 1.2 OUTPUT VOLTAGE (V) 50 40 30 COUT = 2.2µF ceramic VIN = 2.1V 10 V = 1.1V OUT 20 0 10 250 200 150 100 50 GROUND CURRENT (µA) 0.6 0.5 1600 1200 1000 800 600 400 200 0 0 Ground Current (VBIAS) vs. Output Current 25 50 75 100 125 150 OUTPUT CURRENT (mA) 1 0.9 0.85 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) 20 15 10 5 25 50 75 100 125 150 OUTPUT CURRENT (mA) 30 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0 0 7 ILOAD = 150mA 20 15 10 5 0 0.5 1 1.5 2 2.5 4 3 2 1 0 IN 12 10 8 6 4 2 0 0 MIC5238 10 0.5 1 1.5 ENABLE (V) 2 VIN GROUNF CURRENT (µA) GROUND CURRENT (mA) GROUND CURRENT (mA) 14 No Load 25 20 15 10 5 0 0 0.5 1 1.5 ENABLE (V) 4 0.5 1 1.5 2 ENABLE (V) 30 18 No Load 16 Shutdown Current of VIN 5 0 3 Shutdown Current VBIAS + V Tied 20 2.0 6 INPUT VOLTAGE (V) Shutdown Current of VBIAS 0.5 1.0 1.5 VIN SUPPLY (V) No Load 25 0 Ground Current (VIN) vs. VIN Supply 1.1V 1.8 150mA 1.6 Ground Current (VBIAS) vs. Input Voltage VIN = VOUT + 1 150mA 0.95 2.0 VIN = VOUT + 1 100µA 1.05 Ground Current (VIN) vs. Output Current 1400 25 50 75 100 125 150 OUTPUT CURRENT (A) 25 0 0 0.7 1800 VIN = VOUT + 1 300 30 0.8 Dropout Voltage vs. Load 350 0 0 0.9 Output Voltage vs. VIN 1.1 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 FREQUENCY (Hz) GROUND CURRENT (µA) DROPOUT VOLTAGE (mV) 400 150mA 1 VBIAS GROUND CURRENT (µA) PSRR (dB) 60 100µA 1.1 VIN GROUND CURRENT (mA) 70 1.15 GROUND CURRENT (µA) 80 Output Voltage vs. VBIAS OUTPUT VOLTAGE (V) PSRR 150mA Load 2 9 8 Ground Current (VIN) vs Temperature 1.1V 100µA 7 6 5 4 3 2 1 0 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) August 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) August 2003 1.1V 35 100µA 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 100µA 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 (µA) 1.1V 75mA 40 VBIAS Ground Current vs. Temperature DROPOUT VOLTAGE (mV) VIN GROUND CURRENT (µA) 35 Ground Current vs. Temperature BIAS 1.1V 2.2 150mA 2 VBIAS Ground Current vs. Temperature 40 V VIN GROUND CURRENT (µA) 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 (200 s/div.) 1mA OUTPUT CURRENT OUTPUT VOLTAGE (100mA/div.) (200mV/div.) Load Transient Response ENABLE (2V/div.) OUTPUT VOLTAGE (500mA/div.) 150mA TIME (400 s/div.) EN Turn-On Characteristic TIME (40 s/div.) MIC5238 1.1V output COUT = 4.7µF ceramic OUTPUT CURRENT (50mA/div.) 1.1V Output COUT = 4.7 F ceramic OUTPUT VOLTAGE (10mV/div.) INPUT VOLTAGE (1V/div.) 3.1V 150mA 0mA VIN = 4V VOUT = 3V COUT = 4.7µF ceramic TIME (400µs/div.) 6 August 2003 MIC5238 Micrel Functional Diagram OUT IN BIAS EN ENABLE VREF GND Block Diagram – Fixed Output Voltage August 2003 7 MIC5238 MIC5238 Micrel Applications Information θJA Recommended Minimum Footprint SOT-23-5 235°C/W Table 1. SOT-23-5 Thermal Resistance 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. 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. Output Capacitor The MIC5238 requires an output capacitor for stability. The design requires 2.2µF 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 3Ω. The output capacitor can be increased without limit. Larger valued capacitors help to improve transient response. 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 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 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: 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 50°C with a minimum footprint layout, the maximum input voltage for a set output current can be determined as follows: 125°C − 50°C PD(MAX) = 235°C/W PD(MAX) = 319mW The junction-to-ambient (θJA) thermal resistance for the minimum footprint is 235°C/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 Since the bias supply draws only 18µA, 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 50°C 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) VIN = 3.07V For higher current outputs only a lower input voltage will work for higher ambient temperatures. 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 Maximum input voltage for a 20mA load current at 50°C ambient temperature is 16.8V. Since the device has a 6V rating, it will operate over the whole input range. Dual Suppy Mode Efficiency 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 µA’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 TJ(MAX) − TA PD(MAX) = θ JA TJ(MAX) is the maximum junction temperature of the die, 125°C, and TA is the ambient operating temperature. θJA is layout dependent; Table 1 shows the junction-to-ambient thermal resistance for the MIC5238. MIC5238 8 August 2003 MIC5238 Micrel Input power = VIN × output current + VIN × VIN ground current + VBIAS x VBIAS ground current Input power = 1.5 × 150mA + 1.5 × 0.002 + 2.5 × 0.0002 = 225mW Output power = 1V × 150mA = 150mW Efficiency = 150/225 × 100 = 66.6 % Therefore, by using the dual supply MIC5238 LDO the efficiency is nearly doubled over the single supply version. 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. current of 150mA. The input ground current under these conditions is 2mA, while the bias current is only 20µA. If we calculate the conversion efficiency using the single supply approach, it is as follows: Input power = VIN × output current + VIN × (VBIAS ground current + VIN ground current) Input power = 2.5V × 150mA + 2.5 × (0.0002+0.002) = 380.5mW Output power = 1V × 0.15 = 150mW Efficiency = 150/380.5 × 100 = 39.4% 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: August 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 + 1 (408) 944-0800 FAX + 1 (408) 944-0970 WEB USA 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. © 2003 Micrel, Incorporated. MIC5238 10 August 2003