MIC5255 Micrel MIC5255 150mA Low Noise µCap CMOS LDO General Description Features The MIC5255 is an efficient, precise CMOS voltage regulator optimized for ultra-low-noise applications. It offers 1% initial accuracy, extremely-low dropout voltage (135mV at 150mA) and low ground current (typically 90µA). The MIC5255 provides a very-low-noise output, ideal for RF applications where a clean voltage source is required. A noise bypass pin is also available for further reduction of output noise. • • • • • • Designed specifically for handheld and battery-powered devices, the MIC5255 provides a TTL-logic-compatible enable pin. When disabled, power consumption drops nearly to zero. • • • • • The MIC5255 also works with low-ESR ceramic capacitors, reducing the amount of board space necessary for power applications, critical in handheld wireless devices. Key features include current limit, thermal shutdown, faster transient response, and an active clamp to speed up device turn-off. Available in the 6-pin 2mm × 2mm MLF™ package, the IttyBitty® SOT-23-5 package and the new Thin SOT-235, which offers the same footprint as the standard IttyBitty® SOT-23-5, but only 1mm tall. The MIC5255 offers a range of output voltages. Input voltage range: 2.7V to 6.0V Thin SOT package: 1mm height SOT-23-5 Ultra-low output noise: 30µV(rms) Stability with ceramic output capacitors Ultra-low dropout: 135mV @ 150mA High output accuracy: 1.0% initial accuracy 2.0% over temperature Low quiescent current: 90µA Tight load and line regulation TTL-Logic-controlled enable input “Zero” off-mode current Thermal shutdown and current limit protection Applications • • • • • Cellular phones and pagers Cellular accessories Battery-powered equipment Laptop, notebook, and palmtop computers Consumer/personal electronics All support documentation can be found on Micrel’s web site at www.micrel.com. Typical Application CIN = 1.0µF Ceramic Enable Shutdown VIN MIC5255-x.xBM5 1 5 2 3 4 VIN VOUT COUT = 1.0µF Ceramic ENABLE SHUTDOWN EN EN EN (pin 3) may be connected directly to IN (pin 1). VOUT MIC5255-x.xBML 1 6 2 5 3 4 CBYP COUT (optional) CBYP = 0.01µF Ultra-Low-Noise Regulator Application IttyBitty is a registered trademark of Micrel, Inc. MicroLeadFrame and MLF are trademarks of Amkor Technology. Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000• http://www.micrel.com August, 2004 1 M0385-080204 MIC5255 Micrel Ordering Information Standard Part Number Pb-Free MIC5255-2.5BM5 MIC5255-2.5YM5 Marking Voltage Standard Pb-Free LW25 LW25 2.5V Temperature Range Package –40°C to +125°C SOT-23-5 MIC5255-2.6BM5 MIC5255-2.6YM5 LW26 LW26 2.6V –40°C to +125°C SOT-23-5 MIC5255-2.7BM5 MIC5255-2.7YM5 LW27 LW27 2.7V –40°C to +125°C SOT-23-5 MIC5255-2.8BM5 MIC5255-2.8YM5 LW28 LW28 2.8V –40°C to +125°C MIC5255-2.8BML MIC5255-2.8YML W28 W28 2.8V –40°C to +125°C SOT-23-5 6-Pin 2×2 MLF™ MIC5255-2.85BM5 MIC5255-2.85YM5 LW2J LW2J 2.85V –40°C to +125°C SOT-23-5 MIC5255-2.9BM5 MIC5255-2.9YM5 LW29 LW29 2.9V –40°C to +125°C SOT-23-5 MIC5255-3.0BM5 MIC5255-3.0YM5 LW30 LW30 3.0V –40°C to +125°C SOT-23-5 MIC5255-3.0BML MIC5255-3.0YML W30 W30 3.0V –40°C to +125°C 6-Pin 2×2 MLF™ MIC5255-3.1BM5 MIC5255-3.1YM5 LW31 LW31 3.1V –40°C to +125°C SOT-23-5 MIC5255-3.2BM5 MIC5255-3.2YM5 LW32 LW32 3.2V –40°C to +125°C SOT-23-5 MIC5255-3.3BM5 MIC5255-3.3YM5 LW33 LW33 3.3V –40°C to +125°C SOT-23-5 MIC5255-2.6BD5 MIC5255-2.6YD5 NW26 NW26 2.6V –40°C to +125°C TSOT-23-5 MIC5255-2.7BD5 MIC5255-2.7YD5 NW27 NW27 2.7V –40°C to +125°C TSOT-23-5 MIC5255-2.8BD5 MIC5255-2.8YD5 NW28 NW28 2.8V –40°C to +125°C TSOT-23-5 NW2J NW2J 2.85V –40°C to +125°C TSOT-23-5 MIC5255-2.85BD5 MIC5255-2.85YD5 MIC5255-2.9BD5 MIC5255-2.9YD5 NW29 NW2J 2.9V –40°C to +125°C TSOT-23-5 MIC5255-3.0BD5 MIC5255-3.0YD5 NW30 NW2J 3.0V –40°C to +125°C TSOT-23-5 MIC5255-3.3BD5 MIC5255-3.3YD5 NW33 NW2J 3.3V –40°C to +125°C TSOT-23-5 August, 2004 2 M0385-080204 MIC5255 Micrel Pin Configuration EN GND IN EN GND IN 3 2 3 1 2 EN GND IN 1 3 KWxx LWxx 2 1 NWxx 4 5 4 5 4 5 BYP OUT BYP OUT BYP OUT MIC5255-x.xBM5 (SOT-23-5) MIC5255-x.xYM5 (SOT-23-5) MIC5255-x.xBD5 (TSOT-23-5) 6 BYP EN 1 5 NC GND 2 4 OUT IN 3 MIC5255-x.xBML 6-Pin 2mm × 2mm MLF™ (ML) (Top View) Pin Description Pin Number SOT-23-5 TSOT-23-5 Pin Number 6-MLF™ Pin Name Pin Function 1 3 IN Supply Input. 2 2 GND 3 1 EN Enable/Shutdown (Input): CMOS compatible input. Logic high = enable; logic low = shutdown. Do not leave open. 4 6 BYP Reference Bypass: Connect external 0.01µF ≤ CBYP ≤ 1.0µF capacitor to GND to reduce output noise. May be left open. 5 4 OUT Regulator Output – 5 NC – EP GND August, 2004 Ground. No internal connection. Ground: Internally connected to the exposed pad. Connect externally to GND pin. 3 M0385-080204 MIC5255 Micrel Absolute Maximum Ratings(1) Operating Ratings(2) Supply Input Voltage (VIN) .................................. 0V to +7V Enable Input Voltage (VEN) ................................. 0V to +7V Power Dissipation (PD) ........................ Internally Limited(3) Junction Temperature (TJ) ....................... –40°C to +125°C Storage Temperature (TS) ....................... –65°C to +150°C Lead Temperature (soldering, 5 sec.) ....................... 260°C ESD(4) .............................................................................................. 2kV Electrical Characteristics(5) Input Voltage (VIN) ......................................... +2.7V to +6V Enable Input Voltage (VEN) .................................. 0V to VIN Junction Temperature (TJ) ....................... –40°C to +125°C Thermal Resistance SOT-23 (θJA) .....................................................235°C/W 2×2 MLF™ (θJA) ..................................................90°C/W VIN = VOUT + 1V, VEN = VIN; IOUT = 100µA; TJ = 25°C, bold values indicate –40°C ≤ TJ ≤ +125°C; unless noted. Symbol Parameter Conditions VO Output Voltage Accuracy IOUT = 100µA ∆VLNR Line Regulation VIN = VOUT + 1V to 6V ∆VLDR VIN – VOUT IQ IGND PSRR Load Regulation Dropout Voltage(7) Quiescent Current Ground Pin Current(8) Ripple Rejection Min Max Units 1 2 % % 0.02 0.05 %/V 1.5 2.5 % IOUT = 100µA 0.1 5 mV IOUT = 100mA 90 150 mV IOUT = 150mA 135 200 250 mV mV VEN ≤ 0.4V (shutdown) 0.2 1 µA IOUT = 0mA 90 150 µA IOUT = 150mA 117 µA f = 10Hz, COUT = 1.0µF, CBYP = 0.01µF 60 dB f = 100Hz, VIN = VOUT +1 60 dB f = 10kHz, VIN = VOUT +1 50 dB 425 mA 30 µV(rms) IOUT = 0.1mA to Typical –1 –2 150mA(6) ILIM Current Limit VOUT = 0V 160 en Output Voltage Noise COUT = 1.0µF, CBYP = 0.01µF, f = 10Hz to 100kHz 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 VIL ≤ 0.4V, regulator shutdown 0.01 µA VIH ≥ 1.6V, regulator enabled 0.01 µA 500 Ω Thermal Shutdown Temperature 150 °C Thermal Shutdown Hysteresis 10 °C Enable Input Shutdown Resistance Discharge 0.4 1.6 V 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 1V differential. 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. August, 2004 4 M0385-080204 MIC5255 Micrel Typical Characteristics Power Supply Rejection Ratio 70 60 60 60 50 50 PSRR vs. Voltage Drop 70 30 20 40 20 COUT = 1µF CBYP = 0 0 0 200 400 600 800 1000 VOLTAGE DROP (mV) Ground Pin Current 107 105 103 101 99 ILOAD = 100µA 110 105 100 ILOAD = 150mA 60 40 ILOAD = 150mA 0 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 INPUT VOLTAGE (V) 105 1000000 100000 10000 VIN = VOUT + 1V 1 10 100 1000 OUTPUT CURRENT (mA) 120 100 80 60 40 20 ILOAD = 100µA 0 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 INPUT VOLTAGE (V) Dropout Characteristics Dropout Voltage 3.5 OUTPUT VOLTAGE (V) 80 110 Ground Pin Current 95 -40 -20 0 20 40 60 80 100120140 TEMPERATURE (°C) Ground Pin Current 100 115 140 115 140 August, 2004 200 400 600 800 1000 VOLTAGE DROP (mV) 120 95 -40 -20 0 20 40 60 80 100120140 TEMPERATURE (°C) 120 120 Ground Pin Current GROUND CURRENT (µA) 109 125 100 0.1 125 113 111 20 COUT = 1µF CBYP = 0.01µF 10 115 97 ILOAD = 150mA 30 GROUND CURRENT (µA) 0 0 50 0.14 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) 5 DROPOUT VOLTAGE (mV) 10 ILOAD = 100µA 60 ILOAD = 150mA 1000 10 1000000 Ground Pin Current 130 GROUND CURRENT (µA) ILOAD = 100µA PSRR (dB) PSRR (dB) 100000 PSRR vs. Voltage Drop 50 GROUND CURRENT (µA) FRQUENCY (Hz) 80 40 * CBYP ILOAD = 50mA 10 VIN = VOUT + 0.5V = 1µF Ceramic C 0 OUT FRQUENCY (Hz) 70 60 10000 10 1000000 100000 10000 1000 100 10 FRQUENCY (Hz) 30 0µF* 0.01µF* 0.1µF* 1.0µF* 20 * ILOAD 10 COUT = 4.7µF Ceramic 0 40 100 20 *ILOAD 10 COUT = 1µF Ceramic 0 30 1000 30 40 100µA* 50mA* 100mA* 150mA* 100 40 50 PSRR (dB) 100µA* 50mA* 100mA* 150mA* 20 GROUND CURRENT (µA) Power Supply Rejection Ratio 70 PSRR (dB) PSRR (dB) Power Supply Rejection Ratio 70 0.12 0.1 0.08 0.06 0.04 0.02 I = 100µA LOAD 0 -40 -20 0 20 40 60 80 100120140 TEMPERATURE (°C) M0385-080204 Micrel Output Voltage vs. Temperature 490 480 3.05 VIN = VOUT + 1V 470 460 450 440 430 420 410 400 -40 -20 0 20 40 60 80 100120140 TEMPERATURE (°C) OUTPUT VOLTAGE (V) SHORT CIRCUIT CURRENT (mA) Short Circuit Current 500 3.04 3.03 3.02 3.01 3.00 2.99 2.98 2.97 2.96 ILOAD = 100µA 2.95 -40 -20 0 20 40 60 80 100120140 TEMPERATURE (°C) ENABLE THRESHOLD VOLTAGE (V) MIC5255 Enable Threshold vs. Temperature 1.3 1.25 1.2 1.15 1.1 1.05 1 0.95 0.9 0.85 ILOAD = 100µA 0.8 -40 -20 0 20 40 60 80 100120140 TEMPERATURE (°C) Turn-On Time vs. Bypass Capacitance 500 TIME (µs) 450 CIN = 1µF Ceramic 400 COUT = 1µF Ceramic = 100µA I 350 LOAD 300 250 Rise Time 200 150 100 50 Prop Delay 0 100 August, 2004 1000 10000 100000 1000000 BYPASS CAPACITANCE (pF) 6 M0385-080204 MIC5255 Micrel Functional Characteristics Output Voltage (50mV/div) Load Transient Response 5V 4V Output Current (100mA/div) CIN = 1µF Ceramic COUT = 1µF Ceramic CBYP = 0.01µF IOUT = 100µA 150mA 100µA Enable Pin Delay Shutdown Delay Enable Voltage (1V/div) TIME (4µs/div) CIN = 1µF Ceramic COUT = 1µF Ceramic CBYP = 0.01µF VIN = 4V Output Voltage (1V/div) CIN = 1µF Ceramic COUT = 1µF Ceramic CBYP = 0.01µF IOUT = 100µA TIME (10µs/div) August, 2004 CIN = 1µF Ceramic COUT = 1µF Ceramic CBYP = 0.01µF VIN = 4V TIME (400µs/div) Output Voltage (1V/div) Enable Voltage (1V/div) Output Voltage (50mV/div) Input Voltage (1V/div) Line Transient Response TIME (400µs/div) 7 M0385-080204 MIC5255 Micrel Block Diagram IN Reference Voltage Startup/ Shutdown Control Quickstart/ Noise Cancellation EN BYP Thermal Sensor FAULT Error Amplifier Undervoltage Lockout Current Amplifier OUT ACTIVE SHUTDOWN GND August, 2004 8 M0385-080204 MIC5255 Micrel No-Load Stability The MIC5255 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 MIC5255 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: Applications Information Enable/Shutdown The MIC5255 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. 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 MIC5255 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 high frequency 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 MIC5255 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. 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 an X7R ceramic capacitor to ensure the same minimum capacitance over the equivalent operating temperature range. Bypass Capacitor A capacitor can be placed from the noise bypass pin to ground to reduce output voltage noise. The capacitor bypasses the internal reference. A 0.01µF capacitor is recommended for applications that require low-noise outputs. The bypass capacitor can be increased, further reducing noise and improving PSRR. Turn-on time increases slightly with respect to bypass capacitance. A unique quick-start circuit allows the MIC5255 to drive a large capacitor on the bypass pin without significantly slowing turn-on time. Refer to the “Typical Characteristics” section for performance with different bypass capacitors. Active Shutdown The MIC5255 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. August, 2004 T (max) − TA PD (max) = J 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 examples of junction-toambient thermal resistance for the MIC5255. Package SOT-23-5 (M5 or D5) θJA Recommended Minimum Footprint θJA 1" Square Copper Clad θJC 235°C/W 185°C/W 145°C/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 + VIN IGND 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 MIC5255-3.0BM5 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 PD(max) = 315mW 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 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 Therefore, a 3.0V application at 150mA of output current can accept a maximum input voltage of 5.4V in a SOT-23-5 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. 9 M0385-080204 MIC5255 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) 3.02 (0.119) 2.80 (0.110) 0.50 (0.020) 0.35 (0.014) 1.30 (0.051) 0.90 (0.035) 0.20 (0.008) 0.09 (0.004) 10° 0° 0.15 (0.006) 0.00 (0.000) 0.60 (0.024) 0.10 (0.004) SOT-23-5 (M5) Rev 02 TSOT-23-5 (D5) August, 2004 10 M0385-080204 MIC5255 Micrel Package Information (continued) TOP VIEW BOTTOM VIEW DIMENSIONS IN MILLIMETERS SIDE VIEW Rev. 02 6-Pin MLF™ (ML) 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 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 at Purchaser’s own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. © 2004 Micrel, Incorporated. August, 2004 11 M0385-080204