MIC5235 Ultra-Low Quiescent Current, 150mA µCap LDO Regulator General Description Features The MIC5235 is a 150mA highly accurate, low dropout regulator with high input voltage and ultra-low ground current. This combination of high voltage and low ground current makes the MIC5235 ideal for USB and portable electronics applications, using 1-cell, 2-cell or 3-cell Li-Ion battery inputs. A µCap LDO design, the MIC5235 is stable with either ceramic or tantalum output capacitor. It only requires a 2.2µF capacitor for stability. Features of the MIC5235 includes enable input, thermal shutdown, current limit, reverse battery protection, and reverse leakage protection. Available in fixed and adjustable output voltage versions, ® the MIC5235 is offered in the IttyBitty SOT-23-5 package with a junction temperature range of –40°C to +125°C. • • • • • • • • • • • • Wide input voltage range: 2.3V to 24V Ultra low ground current: 18µA 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 battery protection Reverse leakage protection Thermal shutdown and current limit protection IttyBitty® SOT-23-5 package Adjustable output from 1.24V-20V Applications • • • • • • USB power supply Cellular phones Keep-alive supply in notebook and portable computers Logic supply for high-voltage batteries Automotive electronics Battery powered systems Typical Application MIC5235BM5 VIN 1 5 R1 2 CIN=1.0µF 3 EN VOUT=1.8V 4 R2 COUT=2.2µF ceramic IGND=18µA GROUND CURRENT (µA) 40 35 30 IOUT = 1mA 25 20 15 10 49 Ultra-Low Current Adjustable Regulator Application IOUT = 100µA IOUT = 10µA 14 19 INPUT VOLTAGE (V) 24 Ground Current vs. Input Voltage IttyBitty is a registered trademark of Micrel, Inc Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com May 2008 M9999-051508 Micrel, Inc. MIC5235 Ordering Information Part Number Marking Codes Junction Temp. Range Package Standard Pb-Free Standard Pb-Free* Voltage** MIC5235-1.5BM5 MIC5235-1.5YM5 L215 L215 1.5V –40° to +125°C 5-Pin SOT-23 MIC5235-1.8BM5 MIC5235-1.8YM5 L218 L218 1.8V –40° to +125°C 5-Pin SOT-23 MIC5235-2.5BM5 MIC5235-2.5YM5 L225 L225 2.5V –40° to +125°C 5-Pin SOT-23 MIC5235-2.7BM5 MIC5235-2.7YM5 L227 L227 2.7V –40° to +125°C 5-Pin SOT-23 MIC5235-3.0BM5 MIC5235-3.0YM5 L230 L230 3.0V –40° to +125°C 5-Pin SOT-23 MIC5235-3.3BM5 MIC5235-3.3YM5 L233 L233 3.3V –40° to +125°C 5-Pin SOT-23 MIC5235-5.0BM5 MIC5235-5.0YM5 L250 L250 5.0V –40° to +125°C 5-Pin SOT-23 MIC5235BM5 MIC5235YM5 L2AA L2AA Adj. –40° to +125°C 5-Pin SOT-23 * Under bar symbol (_) may not be to scale. ** Contact factory regarding availability for voltages not listed. Pin Configuration EN GND IN 3 2 EN GND IN 1 3 L2xx L2xx 2 1 L2xx L2xx 4 5 4 5 NC OUT ADJ OUT SOT-23-5 (Fixed) SOT-23-5 (Adjustable) Pin Description Pin Number Pin Name Pin Function 1 IN Supply Input. 2 GND 3 EN 4 NC (fixed) No Connect. ADJ (adj.) Adjust (Input): Feedback input. Connect to resistive voltage-divider network. 5 May 2008 Ground. OUT Enable (Input): Logic low = shutdown; logic high = enable. Regulator Output. 2 M9999-051508 Micrel, Inc. MIC5235 Absolute Maximum Ratings(1) Operating Ratings(2) Input Supply Voltage ........................................ –20V to 38V Enable Input Voltage....................................... –0.3V to 38V Power Dissipation .....................................Internally Limited Junction Temperature ...............................–40°C to +125°C Storage Temperature ................................–65°C to +150°C ESD Rating(3) Input Supply Voltage ......................................... 2.3V to 24V Enable Input Voltage............................................ 0V to 24V Junction Thermal....................................... –40°C to +125°C Package Thermal Resistance SOT-23-5 (θJA).................................................235°C/W Electrical Characteristics(4) TA = 25°C with VIN = VOUT + 1V; IOUT = 100µA, Bold values indicate –40°C<TJ<+125°C; unless otherwise specified. Parameter Condition Min Output Voltage Accuracy Variation from nominal VOUT –1.0 –2.0 Line Regulation VIN = VOUT + 1V to 24V 0.04 Load Regulation Load = 100µA to 150mA 0.25 Dropout Voltage IOUT = 100µA IOUT = 50mA 50 230 IOUT = 100mA 270 IOUT = 150mA 310 Max Units +1.0 +2.0 % % % 1 % 300 400 400 450 450 500 mV mV mV mV mV mV mV 1.24 1.25 V IOUT = 100µA 18 IOUT = 50mA IOUT = 100mA IOUT = 150mA 0.35 1 2 30 35 0.7 2 4 µA µA mA mA mA Reference Voltage Ground Current Typ 1.22 Ground Current in Shutdown VEN ≤ 0.6V; VIN = 24V 0.1 1 µA Short Circuit Current VOUT = 0V 350 500 mA Output Leakage, Reverse Polarity Input Load = 500Ω; VIN = –15V –0.1 µA Enable Input 0.6 Input Low Voltage Regulator OFF Input High Voltage Regulator ON 2.0 Enable Input Current VEN = 0.6V; Regulator OFF VEN = 2.0V; Regulator ON VEN = 24V; Regulator ON –1.0 V V 0.01 0.1 0.5 1.0 1.0 2.5 µA µA µA Notes: 1. Exceeding the absolute maximum rating may damage the device. 2. The device is not guaranteed to function outside its operating rating. 3. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF. 4. Specification for packaged product only. May 2008 3 M9999-051508 Micrel, Inc. MIC5235 Typical Characteristics 70 350 60 DROPOUT VOLTAGE (mV) ILOAD = 150mA 40 30 20 10 100 50 ILOAD = 150mA 1 0.5 2000 1500 1000 500 0 02 GROUND CURRENT (µA) ILOAD = 10mA 70 65 60 55 50 45 -40 -20 02 04 06 08 0 100 120 700 680 580 560 540 520 500 -40 -20 02 GROUND CURRENT (µA) GROUND CURRENT (µA) 80 70 60 IOUT = 100µA 30 May 2008 04 06 08 0 100 120 TEMPERATURE (°C) IOUT = 10mA IOUT = 10µA 2 2.5 3 3.5 INPUT VOLTAGE (V) ILOAD = 75mA 4 2.4 2.2 2 1.8 26 24 IOUT =150mA IOUT = 75mA 0.6 2 2.5 3 3.5 INPUT VOLTAGE (V) 4 4 VIN = 24V VIN = 12V 22 20 18 VIN = 4V 16 14 12 100 200 300 400 500 OUTPUT CURRENT (µA) Ground Pin Current vs. Temperature 2.5 2.4 ILOAD = 150mA 2.3 2.2 2.1 2 1.9 1.8 1.7 1.6 1.5 -40 -20 02 04 06 08 0 100 120 TEMPERATURE (°C) Ground Pin Current vs. Input Voltage 40 1.4 1.2 0.4 1.5 30 28 Ground Pin Current vs. Input Voltage 1.6 1 0.8 Ground Pin Current vs. Output Current 10 0 Ground Pin Current vs. Temperature 620 600 Ground Pin Current vs. Input Voltage 0 1.5 100 50 0 -40 -20 02 04 06 08 0 100 120 TEMPERATURE (°C) 04 06 08 0 100 120 140 160 OUTPUT CURRENT (mA) 660 640 TEMPERATURE (°C) 50 IOUT = 1mA 40 VIN = 4V 2500 Ground Pin Current vs. Temperature 75 20 10 250 200 150 3000 ILOAD = 100µA 1.5 100 90 04 06 08 0 100 120 140 160 OUTPUT CURRENT (mA) 350 300 Ground Pin Current vs. Output Current 0 0 0.5 1 1.5 2 2.5 3 3.5 4 INPUT VOLTAGE (V) GROUND CURRENT (µA) 150 Dropout Characteristics 2 40 200 0 02 1000 2.5 ILOAD = 75mA 80 250 500 450 IOUT = 150mA 400 GROUND CURRENT (µA) 3 300 GROUND CURRENT (mA) OUTPUT VOLTAGE (V) 3.5 0.1 11 0 100 FREQUENCY (kHz) GROUND CURRENT (µA) 0 0.01 Dropout Voltage vs. Temperature GROUND CURRENT (µA) PSRR (dB) 50 Dropout Voltage vs. Output Current DROPOUT VOLTAGE (mV) Power Supply Rejection Ratio 35 30 IOUT = 1mA 25 IOUT = 100µA 20 15 10 49 IOUT = 10µA 14 19 INPUT VOLTAGE (V) 24 M9999-051508 Micrel, Inc. MIC5235 Typical Characteristics (continued) 100 80 60 40 20 0 -20 VEN = 5V RLOAD = 30 -10 0 SUPPLY VOLTAGE (V) 10 3.04 3.03 Output Voltage vs. Temperature SHORT CIRCUIT CURRENT (mA) 3.05 OUTPUT VOLTAGE (V) INPUT CURRENT (mA) 120 Input Current vs. Supply Voltage ILOAD = 100 µA 3.02 3.01 3 2.99 2.98 2.97 2.96 2.95 -40 -20 02 04 06 08 0 100 120 TEMPERATURE (°C) 400 Short Circuit Current vs. Temperature 350 300 250 200 150 100 50 VIN = 4V 0 -40 -20 02 04 06 08 0 100 120 TEMPERATURE (°C) 150mA 0mA VIN = 4V VOUT = 3V COUT = 4.7µF ceramic May 2008 5 M9999-051508 Micrel, Inc. MIC5235 Functional Diagram OUT IN EN ENABLE 1.24V VREF GND Block Diagram – Fixed Output Voltage OUT IN EN ENABLE R1 1.24V VREF ADJ R2 GND Block Diagram – Adjustable Output Voltage May 2008 6 M9999-051508 Micrel, Inc. MIC5235 Application Information ⎛ TJ(MAX) − TA PD(MAX) = ⎜⎜ θ JA ⎝ Enable/Shutdown The MIC5235 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-mode-current state. In this state, current consumed by the regulator goes nearly to zero. Forcing the enable pin high enables the output voltage. 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 examples of the junction-to-ambient thermal resistance for the MIC5235. Input Capacitor The MIC5235 has high input voltage capability up to 24V. 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. Package θJA Recommended Minimum Footprint SOT-23-5 235°C 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 MIC5235-3.0BM5 at 50°C with a minimum footprint layout, the maximum input voltage for a set output current can be determined as follows: Output Capacitor The MIC5235 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. X7R-type 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. ⎛ 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. Since the MIC5235 was designed to operate with high input voltages, careful consideration must be given so as not to overheat the device. 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 × IGND Due to the potential for input voltages up to 24V, ground current must be taken into consideration. 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. PD(MAX) = (VIN – VOUT)IOUT + VIN x IGND 319mW = (VIN – 3V)150mA + VIN x 2.8mA Ground pin current is estimated using the typical characteristics of the device. 769mW = VIN (152.8mA) VIN = 5.03V 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: No-Load Stability The MIC5235 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 MIC5235 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: May 2008 ⎞ ⎟ ⎟ ⎠ 7 M9999-051508 Micrel, Inc. MIC5235 Where VREF = 1.24V. Feedback resistor R2 should be no larger than 300kΩ. 319mW = (VIN – 3V)20mA + VIN x 0.2mA 379mW = VIN x 20.2mA VIN = 18.8V Maximum input voltage for a 20mA load current at 50°C ambient temperature is 18.8V, utilizing virtually the entire operating voltage range of the device. VIN VOUT May 2008 IN OUT EN ADJ. VOUT R1 1.0µF Adjustable Regulator Application The MIC5235BM5 can be adjusted from 1.24V to 20V by using two external resistors (Figure 1). The resistors set the output voltage based on the following equation: ⎛ ⎛R = VREF ⎜1 + ⎜⎜ 1 ⎜ ⎝ ⎝ R2 MIC5235BM5 GND 2.2µF R2 Figure 1. Adjustable Voltage Application ⎞⎞ ⎟⎟ ⎟ ⎟ ⎠⎠ 8 M9999-051508 Micrel, Inc. MIC5235 Package Information SOT-23-5 (M5) 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 a Purchaser’s own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. © 2003 Micrel, Incorporated. May 2008 9 M9999-051508