MIC5256 150mA µCap LDO with Error Flag General Description Features The MIC5256 is an efficient, precise CMOS voltage regulator. It offers better than 1% initial accuracy, extremely low-dropout voltage (typically 135mV at 150mA) and low ground current (typically 90µA) over load. The MIC5256 features an error flag that indicates an output fault condition such as overcurrent, thermal shutdown and dropout. Designed specifically for handheld and battery-powered devices, the MIC5256 provides a TTL-logic-compatible enable pin. When disabled, power consumption drops nearly to zero. The MIC5256 also works with low-ESR ceramic capacitors, reducing the amount of board space necessary for power applications, critical in hand-held wireless devices. Key features include current limit, thermal shutdown, faster transient response, and an active clamp to speed up ® device turnoff. Available in the IttyBitty SOT-23-5 package and the new Thin SOT-23-5, which offers the same footprint as the standard IttyBitty® SOT-23-5, but only 1mm tall. The MIC5256 offers a range of output voltages. Data sheets and support documentation can be found on Micrel’s web site at www.micrel.com. • • • • • • • • • • • Input voltage range: 2.7V to 6.0V Thin SOT package: 1mm height Error flag indicates fault condition Stable with ceramic output capacitor Ultralow dropout: 135mV @ 150mA High output accuracy: – 1.0% initial accuracy – 2.0% over temperature Low quiescent current:90µA Tight load and line regulation Thermal-shutdown and current-limit protection “Zero” off-mode current TTL logic-controlled enable input Applications • • • • • Cellular phones and pagers Cellular accessories Battery-powered equipment Laptop, notebook, and palmtop computers Consumer/personal electronics ___________________________________________________________________________________________________________ Typical Application Low-Noise Regulator Application 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 August 2010 1 M9999-080510 Micrel, Inc. MIC5256 Ordering Information Part Number Marking Voltage** Junction Temperature Range Package LX15 1.5V –40° to +125°C 5-Pin SOT23 LX18 LX18 1.8V –40° to +125°C 5-Pin SOT23 LX25 LX25 2.5V –40° to +125°C 5-Pin SOT23 MIC5256-2.6YM5 LX26 LX26 2.6V –40° to +125°C 5-Pin SOT23 MIC5256-2.7YM5 LX27 LX27 2.7V –40° to +125°C 5-Pin SOT23 Standard Pb-Free Standard Pb-Free* MIC5256-1.5BM5 MIC5256-1.5YM5 LX15 MIC5256-1.8BM5 MIC5256-1.8YM5 MIC5256-2.5BM5 MIC5256-2.5YM5 MIC5256-2.6BM5 MIC5256-2.7BM5 MIC5256-2.8BM5 MIC5256-2.8YM5 LX28 LX28 2.8V –40° to +125°C 5-Pin SOT23 MIC5256-2.85BM5 MIC5256-2.85YM5 LX2J LX2J 2.85V –40° to +125°C 5-Pin SOT23 MIC5256-2.9BM5 MIC5256-2.9YM5 LX29 LX29 2.9V –40° to +125°C 5-Pin SOT23 MIC5256-3.0BM5 MIC5256-3.0YM5 LX30 LX30 3.0V –40° to +125°C 5-Pin SOT23 MIC5256-3.1BM5 MIC5256-3.1YM5 LX31 LX31 3.1V –40° to +125°C 5-Pin SOT23 MIC5256-3.3BM5 MIC5256-3.3YM5 LX33 LX33 3.3V –40° to +125°C 5-Pin SOT23 MIC5256-2.85BD5 MIC5256-2.85YD5 NX2J NX2J 2.85V –40° to +125°C 5-Pin TSOT23 Notes: * Under bar symbol ( _ ) may not be to scale. ** Other Voltage available. Contact Micrel for details. Pin Configuration August 2010 MIC5256-x.xBM5 5-Pin SOT23 MIC5256-x.xBD5 5-Pin Thin SOT23 MIC5256-x.xYM5 5-Pin SOT23 MIC5256-x.xYD5 5-Pin Thin SOT23 2 M9999-080510 Micrel, Inc. MIC5256 Pin Description Pin Number Pin Name 1 IN 2 GND 3 EN Enable/Shutdown (Input): CMOS compatible input. Logic high = enable; logic low = shutdown. Do not leave open. 4 FLG Error Flag (Output): Open-drain output. Active low indicates an output undervoltage condition. 5 OUT Regulator Output. August 2010 Pin Name Supply Input. Ground. 3 M9999-080510 Micrel, Inc. MIC5256 Absolute Maximum Ratings(1) Operating Ratings(2) Supply Voltage (VIN) ............................................. 0V to +7V Enable Voltage (VEN)............................................ 0V to +7V Power Dissipation (PD) ........................... Internally Limited(3) Junction Temperature (TJ) ........................–40°C to +125°C Storage Temperature (Ts) .........................–60°C to +150°C Lead Temperature (soldering, 5 sec.)........................ 260°C EDS Rating(4) .................................................................. 2kV Supply Voltage (VIN)........................................ +2.7V to +6V Enable Voltage (VEN).............................................. 0V to VIN Junction Temperature (TJ) ........................ –40°C to +125°C Thermal Resistance SOT23-5 (θJA) ..................................................235°C/W Electrical Characteristics(5) VIN = VOUT + 1V, VEN = VIN; IOUT = 100µA; TJ = 25°C, bold values indicate –40°C ≤ TJ ≤ +125°C; unless noted. Symbol Parameter VO Output Voltage Accuracy ΔVLNR Line Regulation ΔVLDR Load Regulation Condition Min. Typ. Max. Units 1 2 % % 0.02 0.05 %/V IOUT = 0.1mA to 150mA 1.5 2.5 % IOUT = 100µA 0.1 5 mV –1 –2 IOUT = 100µA VIN = VOUT + 1V to 6V (6) VIN – VOUT Dropout Voltage(7) IOUT = 100mA 90 150 mV IOUT = 150mA 135 200 250 mV mV IQ Quiescent Current VEN ≤ 0.4V (shutdown) 0.2 1 µA IGND Ground Pin Current(8) IOUT = 0mA 90 150 µA IOUT = 150mA 117 µA f = 10Hz, VIN = VOUT + 1V; COUT = 1.0µF 60 dB f = 100Hz, VIN = VOUT + 0.5V; COUT = 1.0µF 60 dB f = 10kHz, VIN = VOUT + 0.5V 45 dB 425 mV TBD µV(rms) PSRR Ripple Rejection ILIM Current Limit en Output Voltage Noise VOUT = 0V 160 Enable Input VIL Enable Input Logic-Low Voltage VIN = 2.7V to 5.5V, regulator shutdown VIH Enable Input Logic-High Voltage VIN = 2.7V to 5.5V, regulator enabled IEN Enable Input Current V V 1.6 VIL ≤ 0.4V, regulator shutdown 0.01 µA VIH ≥ 1.6V, regulator enabled 0.01 µA 500 Ω Shutdown Resistance Discharge August 2010 0.4 4 M9999-080510 Micrel, Inc. MIC5256 Electrical Characteristics(5) (Continued) VIN = VOUT + 1V, VEN = VIN; IOUT = 100µA; TJ = 25°C, bold values indicate –40°C ≤ TJ ≤ +125°C; unless noted. Symbol Parameter Condition Min. Typ. Max. Units VFLG Low Threshold High Threshold % of VOUT (Flag ON) % of VOUT (Flag OFF) 96 % % VOL Output Logic-Low Voltage IL = 100µA, fault condition 0.02 IFL Flag Leakage Current flag off, VFLG = 6V 0.01 µA Thermal-Shutdown Temperature 150 °C Thermal-Shutdown Hysteresis 10 °C Error Flag 90 0.1 V Thermal Protection Notes: 1. Exceeding the absolute maximum rating may damage the device. 2. The device is not guaranteed to function outside its operating rating. 3. The maximum allowable power dissipation of any TA (ambient temperature) is PD(max) = TJ(max)–TA / θJA. Exceeding the maximum allowable power dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown. The θJA of the MIC5255-x.xBM5 (all versions) is 235°C/W on a PC board (see “Thermal Considerations” section for further details). 4. Devices are ESD sensitive. Handling precautions recommended. 5. Specification for packaged product only. 6. Regulation is measured at constant junction temperature using low duty cycle pulse testing. Parts are tested for load regulation in the load range from 0.1mA to 150mA. Changes in output voltage due to heating effects are covered by the thermal regulation specification. 7. Dropout Voltage is defined as the input to output differential at which the output voltage drops 2% below its nominal value measured at 1Vdifferential. For outputs below 2.7V, dropout voltage is the input-to-output voltage differential with the minimum input voltage 2.7V. Minimum input operating voltage is 2.7V. 8. Ground pin current is the regulator quiescent current. The total current drawn from the supply is the sum of the load current plus the ground pin current. Test Circuit August 2010 5 M9999-080510 Micrel, Inc. MIC5256 Typical Characteristics Ground Pin Current 125 120 115 110 105 VIN = VOUT + 1V 1 10 100 1000 OUTPUT CURRENT (mA) GROUND CURRENT (µA) 140 120 100 80 60 40 20 DROPOUT VOLTAGE (mV) 3.5 ILOAD = 150mA 0 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 INPUT VOLTAGE (V) 180 August 2010 Ground Pin Current OUTPUT VOLTAGE (V) 100 0.1 Dropout Voltage 160 140 120 100 80 60 40 20 I = 150mA LOAD 0 -40 -20 0 20 40 60 80 100120140 TEMPERATURE (°C) 6 Dropout Characteristics 3 ILOAD = 100µA 2.5 ILOAD = 150mA 2 1.5 1 0.5 0 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 INPUT VOLTAGE (V) 180 DROPOUT VOLTAGE (mV) GROUND CURRENT (µA) 130 Dropout Voltage T = –40C 160 140 120 100 80 60 T = 25C T = 125C 40 20 0 0 20 40 60 80 100 120 140 160 OUTPUT CURRENT (mA) M9999-080510 Micrel, Inc. MIC5256 SHORT CIRCUIT CURRENT (mA) Typical Characteristics (Continued) 600 Short Circuit Current 500 400 300 200 100 0 3 3.5 4 4.5 5 5.5 INPUT VOLTAGE (V) August 2010 6 7 M9999-080510 Micrel, Inc. MIC5256 Functional Characteristics August 2010 8 M9999-080510 Micrel, Inc. MIC5256 Functional Diagram August 2010 9 M9999-080510 Micrel, Inc. MIC5256 drain transistor to indicate a fault. This prevents chattering or inadvertent triggering of the error flag. The error flag must be pulled-up using a resistor from the flag pin to either the input or the output. The error flag circuit was designed essentially to work with a capacitor to ground to act as a power-on reset generator, signaling a power-good situation once the regulated voltage was up and/or out of a fault condition. This capacitor delays the error signal from pulling high, allowing the down stream circuits time to stabilize. When the error flag is pulled-up to the input without using a pull-down capacitor, then there can be a glitch on the error flag upon start up of the device. This is due to the response time of the error flag circuit as the device starts up. When the device comes out of the “zero” off mode current state, all the various nodes of the circuit power up before the device begins supplying full current to the output capacitor. The error flag drives low immediately and then releases after a few microseconds. The intelligent circuit that triggers an error detects the output going into current limit AND the output being low while charging the output capacitor. The error output then pulls low for the duration of the turn-on time. A capacitor from the error flag to ground will filter out this glitch. The glitch does not occur if the error flag pulled up to the output. Application Information Enable/Shutdown The MIC5256 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. This part is CMOS and the enable pin cannot be left floating; a floating enable pin may cause an indeterminate state on the output. Input Capacitor The MIC5256 is a high-performance, high-bandwidth device. Therefore, it requires a well-bypassed input supply for optimal performance. A 1µF capacitor is required from the input to ground to provide stability. Low-ESR ceramic capacitors provide optimal performance at a minimum of space. Additional highfrequency capacitors, such as small valued NPO dielectric type capacitors, help filter out high frequency noise and are good practice in any RF based circuit. Output capacitor The MIC5256 requires an output capacitor for stability. The design requires 1µF 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 300mΩ. The output capacitor can be increased, but performance has been optimized for a 1µF ceramic output capacitor and does not improve significantly with larger capacitance. 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 an X7R ceramic capacitor to ensure the same minimum capacitance over the equivalent operating temperature range. Active Shutdown The MIC5256 also features an active shutdown clamp, which is an N-channel MOSFET that turns on when the device is disabled. This allows the output capacitor and load to discharge, de-energizing the load. No Load Stability The MIC5256 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 MIC5256 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: Error Flag The error flag output is an active-low, open-drain output that drives low when a fault condition AND an undervoltage detection occurs. Internal circuitry intelligently monitors overcurrent, overtemperature and dropout conditions and ORs these outputs together to indicate some fault condition. The output of that OR gate is ANDed with an output voltage monitor that detects an undervoltage condition. That output drives the openAugust 2010 ⎛ TJ(max) − TA PD(max) = ⎜⎜ θ JA ⎝ 10 ⎞ ⎟ ⎟ ⎠ M9999-080510 Micrel, Inc. MIC5256 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 junction-to-ambient thermal resistance for the MIC5256. Package θJA Recommended Minimum Footprint θJA 1” Square Copper Clad θJC SOT23-5 (M5 or D5) 235°C/W 185°C/W 145°C/W can be determined. Because this device is CMOS and the ground current is typically 100µA over the load range, the power dissipation contributed by the ground current is < 1% and can be ignored for this calculation. 315mW = (VIN – 3.0V) 150mA 315mW = VIN·•150mA – 450mW 810mW = VIN·•150mA VIN(max) = 5.4V Table 1. SOT-23-5 Thermal Resistance Therefore, a 3.0V application at 150mA of output current can accept a maximum input voltage of 5.4V in a SOT23-5 package. For a full discussion of heat sinking and thermal effects on voltage regulators, refer to the “Regulator Thermals” section of Micrel’s Designing with Low-Dropout Voltage Regulators handbook. The actual power dissipation of the regulator circuit can be determined using the equation: PD = (VIN – VOUT) IOUT + VIN IGND Fixed Regulator Applications 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 MIC5256-3.0BM5 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 ⎠ Figure 1. Low-Noise Fixed Voltage Application PD(max) = 315mW Figure 1 shows a standard low-noise configuration with a 47kΩ pull-up resistor from the error flag to the input voltage and a pull-down capacitor to ground for the purpose of fault indication. EN (Pin 3) is connected to IN (Pin 1) for an application where enable/shutdown is not required. COUT = 1.0µF minimum. The junction-to-ambient thermal resistance for the minimum footprint is 235°C/W, from Table 1. The maximum power dissipation must not be exceeded for proper operation. Using the output voltage of 3.0V and an output current of 150mA, the maximum input voltage August 2010 11 M9999-080510 Micrel, Inc. MIC5256 Package Information 5-Pin SOT (M5) August 2010 12 M9999-080510 Micrel, Inc. MIC5256 Package Information (Continued) 5-Pin Thin SOT (D5) 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. August 2010 13 M9999-080510