MIC5255 150mA Low Noise µCap CMOS LDO General Description Features The MIC5255 is an efficient, precise CMOS voltage • Input voltage range: 2.7V to 6.0V regulator optimized for ultra-low-noise applications. It • Thin SOT package: 1mm height SOT-23-5 offers 1% initial accuracy, extremely-low dropout voltage • Ultra-low output noise: 30µV(rms) (135mV at 150mA) and low ground current (typically • Stability with ceramic output capacitors 90µA). The MIC5255 provides a very-low-noise output, • Ultra-low dropout: 135mV @ 150mA ideal for RF applications where a clean voltage source is required. A noise bypass pin is also available for further • High output accuracy: reduction of output noise. – 1.0% initial accuracy Designed specifically for handheld and battery-powered – 2.0% over temperature devices, the MIC5255 provides a TTL-logic-compatible en• Low quiescent current: 90µA able pin. When disabled, power consumption drops nearly • Tight load and line regulation to zero. • TTL-Logic-controlled enable input The MIC5255 also works with low-ESR ceramic • “Zero” off-mode current capacitors, reducing the amount of board space necessary for power applications, critical in handheld wireless • Thermal shutdown and current limit protection devices. Key features include current limit, thermal shutdown, faster Applications transient response, and an active clamp to speed up ® device turn-off. Available in the 6-pin 2mm × 2mm MLF • Cellular phones and pagers package, the IttyBitty® SOT-23-5 package and the new • Cellular accessories Thin SOT-23-5, which offers the same footprint as the • Battery-powered equipment standard IttyBitty® SOT-23-5, but only 1mm tall. The • Laptop, notebook, and palmtop computers MIC5255 offers a range of output voltages. • Consumer/personal electronics Data sheets and 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.x_M5 1 5 2 3 EN EN (pin 3) may be connected directly to IN (pin 1). 4 VOUT COUT = 1.0µF Ceramic CBYP = 0.01µF Ultra-Low-Noise Regulator Application IttyBitty is a registered trademark of Micrel, Inc MLF and MicroLeadFrame are registered trademarks of Amkor Technology, 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 November 2006 1 M9999-110906 Micrel, Inc. MIC5255 Ordering Information Part Number Marking Voltage* Junction Temp. Range Package Standard Pb-Free Standard Pb-Free** MIC5255-2.5BD5 MIC5255-2.5YD5 NW25 NW25 2.5V –40° to +125°C 5-Pin TSOT-23 MIC5255-2.5BM5 MIC5255-2.5YM5 LW25 KW25 2.5V –40° to +125°C 5-Pin SOT-23 MIC5255-2.6BD5 MIC5255-2.6YD5 NW26 NW26 2.6V –40° to +125°C 5-Pin TSOT-23 MIC5255-2.6BM5 MIC5255-2.6YM5 LW26 KW26 2.6V –40° to +125°C 5-Pin SOT-23 MIC5255-2.7BD5 MIC5255-2.7YD5 NW27 NW27 2.7V –40° to +125°C 5-Pin TSOT-23 MIC5255-2.7BM5 MIC5255-2.7YM5 LW27 KW27 2.7V –40° to +125°C 5-Pin SOT-23 MIC5255-2.75BM5 MIC5255-2.75YM5 LW2H KW2H 2.75V –40° to +125°C 5-Pin SOT-23 MIC5255-2.8BD5 MIC5255-2.8YD5 NW28 NW28 2.8V –40° to +125°C 5-Pin TSOT-23 MIC5255-2.8BM5 MIC5255-2.8YM5 LW28 KW28 2.8V –40° to +125°C 5-Pin SOT-23 MIC5255-2.8BML MIC5255-2.8YML W28 W28*** 2.8V –40° to +125°C 6-Pin 2x2 MLF ® MIC5255-2.85BD5 MIC5255-2.85YD5 NW2J NW2J 2.85V –40° to +125°C 5-Pin TSOT-23 MIC5255-2.85BM5 MIC5255-2.85YM5 LW2J KW2J 2.85V –40° to +125°C 5-Pin SOT-23 MIC5255-2.85BML MIC5255-2.85YML W2J W2J*** 2.85V –40° to +125°C 6-Pin 2x2 MLF ® MIC5255-2.9BD5 MIC5255-2.9YD5 NW29 NW29 2.9V –40° to +125°C 5-Pin TSOT-23 MIC5255-2.9BM5 MIC5255-2.9YM5 LW29 KW29 2.9V –40° to +125°C 5-Pin SOT-23 MIC5255-3.0BD5 MIC5255-3.0YD5 NW30 NW30 3.0V –40° to +125°C 5-Pin TSOT-23 MIC5255-3.0BM5 MIC5255-3.0YM5 LW30 KW30 3.0V –40° to +125°C 5-Pin SOT-23 MIC5255-3.0BML MIC5255-3.0YML W30 W30*** 3.0V –40° to +125°C 6-Pin 2x2 MLF MIC5255-3.1BM5 MIC5255-3.1YM5 LW31 KW31 3.1V –40° to +125°C 5-Pin SOT-23 MIC5255-3.2BM5 MIC5255-3.2YM5 LW32 KW32 3.2V –40° to +125°C 5-Pin SOT-23 ® MIC5255-3.3BD5 MIC5255-3.3YD5 NW33 NW33 3.3V –40° to +125°C 5-Pin TSOT-23 MIC5255-3.3BM5 MIC5255-3.3YM5 LW33 KW33 3.3V –40° to +125°C 5-Pin SOT-23 MIC5255-3.3BML MIC5255-3.3YML W33 W33*** 3.3V –40° to +125°C 6-Pin 2x2 MLF MIC5255-3.5BM5 MIC5255-3.5YM5 LW35 KW35 3.5V –40° to +125°C 5-Pin SOT-23 ® Notes: * Other Voltage available. Contact Micrel for details. ** Under bar / Over bar symbol may not be to scale. *** Over bar symbol located after Pin 1 identifier. November 2006 2 M9999-110906 Micrel, Inc. MIC5255 Pin Configuration E N GND IN 3 2 E N GND IN 1 3 LW xx 2 1 Wxx N W xx 4 5 4 5 OUT BYP OUT MIC5255-x.xBM5 5-Pin SOT23 (M5) MIC5255-x.xBD5 5-Pin Thin SOT23 (D5) E N GND IN E N GND IN 2 1 3 KW xx 2 1 4 OUT IN 3 MIC5255-x.xBML ® 6-Pin 2x2 MLF (ML) 6 BYP EN 1 Wxx N W xx GND 2 4 5 4 5 BYP OUT BYP OUT MIC5255-x.xYM5 5-Pin SOT23 (M5) 5 NC GND 2 BYP 3 6 BYP EN 1 MIC5255-x.xYD5 5-Pin Thin SOT23 (D5) IN 3 5 NC 4 OUT MIC5255-x.xYML ® 6-Pin 2x2 MLF (ML) Pin Description Pin Number SOT23-5 TSOT23-5 1 Pin Number Pin Name 3 IN 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. 6-MLF – 5 NC – EP GND November 2006 Pin Name Supply Input. Ground. No internal connection. Ground: Internally connected to the exposed pad. Connect externally to GND pin. 3 M9999-110906 Micrel, Inc. MIC5255 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 2x2 MLF-6 (θJA) .................................................90°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 Condition VO Output Voltage Accuracy IOUT = 100µA ∆VLNR Line Regulation VIN = VOUT + 1V to 6V ∆VLDR VIN – VOUT IQ IGND PSRR (7) Dropout Voltage Quiescent Current (8) Ripple Rejection Typ Max Units 1 2 % % 0.02 0.05 %/V 1.5 2.5 % –1 –2 IOUT = 0.1mA to 150mA Load Regulation Ground Pin Current Min (6) 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 ILIM Current Limit VOUT = 0V en Output Voltage Noise COUT = 1.0µF, CBYP = 0.01µF, f = 10Hz to 100kHz 160 425 mV 30 µV(rms) 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 V V 1.6 Thermal Protection November 2006 4 M9999-110906 Micrel, Inc. MIC5255 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. Human body model, 1.5k in series with 100pF. 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 1.0mA 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. November 2006 5 M9999-110906 Micrel, Inc. MIC5255 Typical Characteristics November 2006 6 M9999-110906 Micrel, Inc. MIC5255 Typical Characteristics November 2006 7 M9999-110906 Micrel, Inc. MIC5255 Functional Characteristics November 2006 8 M9999-110906 Micrel, Inc. MIC5255 Functional Diagram November 2006 9 M9999-110906 Micrel, Inc. MIC5255 large capacitor on the bypass pin without significantly slowing turn-on time. Refer to the “Typical Characteristics” section for performance with different bypass capacitors. Application 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-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. 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. 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. 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. 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: 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. 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. ⎛ 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 examples of junction-to-ambient thermal resistance for the MIC5255. 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 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: 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 November 2006 ⎞ ⎟ ⎟ ⎠ ⎛ 125°C − 50°C ⎞ PD(max) = ⎜ ⎟ ⎝ 235°C/W ⎠ PD(max) = 315mW 10 M9999-110906 Micrel, Inc. MIC5255 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 November 2006 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 LowDropout Voltage Regulators handbook. 11 M9999-110906 Micrel, Inc. MIC5255 Package Information 5-Pin SOT (M5) 5-Pin Thin SOT (D5) November 2006 12 M9999-110906 Micrel, Inc. MIC5255 ® 6-Pin MLF (ML) 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. © 2004 Micrel, Incorporated. November 2006 13 M9999-110906