MIC5270 Micrel, Inc. MIC5270 µCap Negative Low-Dropout Regulator General Description Features The MIC5270 is a µCap 100mA negative regulator in a SOT-23-5 package. With better than 2% initial accuracy, this regulator provides a very accurate supply voltage for applications that require a negative rail. The MIC5270 sinks 100mA of output current at very low dropout voltage (600mV maximum at 100mA of output current). The µCap regulator design is optimized to work with lowvalue, low-cost ceramic capacitors. The output typically requires only a 1µF capacitance for stability. Designed for applications where small packaging and efficiency are critical, the MIC5270 combines LDO design expertise with IttyBitty® packaging to improve performance and reduce power dissipation. Ground current is optimized to help improve battery life in portable applications. The MIC5270 is available in the SOT-23-5 package for space saving applications and it is available with fixed –3.0V, –4.1V, –5.0V, and adjustable outputs. Data sheets and support documentation can be found on Micrel’s web site at www.micrel.com. • • • • • • • • Stable with ceramic or tantalum capacitor Low dropout voltage: 500mV @ 100mA Low ground current: 35µA @ load = 100µA Tight initial accuracy: ±2% Tight load and line regulation Thermal shutdown Current limiting IttyBitty® SOT-23-5 packaging Applications • • • • GaAsFET bias Portable cameras and video recorders PDAs Battery-powered equipment Ordering Information Part Number Marking Code PbFree Standard Marking Code Junction Temp. Range Voltage Package MIC5270BM5 LLAA MIC5270YM5 LLAA Adj. –40°C to +125°C SOT-23-5 MIC5270-3.0BM5 LL30 MIC5270-3.0YM5 LL30 –3.0V –40°C to +125°C SOT-23-5 MIC5270-4.1BM5 LL41 MIC5270-4.1YM5 LL41 –4.1V –40°C to +125°C SOT-23-5 MIC5270-5.0BM5 LL50 MIC5270-5.0YM5 LL50 –5.0V –40°C to +125°C SOT-23-5 Typical Application MIC5270-5.0BM5 2 VIN –6.0V 5 –IN –OUT 1µF MIC5270BM5 2 GND 4 VOUT –5.0V VIN –6.0V 5 GND ADJ –IN 1µF 10µF Regulator With Fixed Output –OUT R1 3 4 R2 V OUT –5.0V 10µF Regulator With Adjustable Output 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 2005 1 M9999-052705 MIC5270 Micrel, Inc. Pin Configuration ADJ GND NC 3 2 NC GND NC 1 3 LLAA 2 1 LLxx 4 5 4 5 –OUT –IN –OUT –IN MIC5270-x.xBM5 Fixed Output Voltage MIC5270BM5 Adjustable Voltage Pin Description Pin Number (Adj.) Pin Number (Fixed) Pin Name 1 1 NC 2 2 GND 3 NC Not internally connected. ADJ Adjustable (Input): Adjustable feedback output connects to resistor voltage divider. 3 4 4 –OUT 5 5 –IN M9999-052705 Pin Function Not internally connected. Ground. Negative Regulator Output. Negative Supply Input. 2 May 2005 MIC5270 Micrel, Inc. Absolute Maximum Ratings (Note 1) Operating Ratings (Note 2) Input Voltage (VIN) ....................................... –20V to +0.3V Power Dissipation (PD) ............................ Internally Limited Junction Temperature (TJ) ....................... –40°C to +125°C Lead Temperature (soldering, 5 sec.) ....................... 260°C Storage Temperature (TS) ....................... –65°C to +150°C ESD Rating, Note 3 Input Voltage (VIN) ....................................... –16V to –3.3V Junction Temperature (TJ) ....................... –40°C to +125°C Thermal Resistance (θJA) ........................................ Note 4 Electrical Characteristics (Note 5) VIN = VOUT – 1.0V; COUT = 4.7µF, IOUT = 100µA; TJ = 25°C, bold values indicate –40°C ≤ TJ ≤ +125°C; unless noted. Symbol Parameter Condition VOUT Output Voltage Accuracy Variation from nominal VOUT ∆VOUT/∆T Output Voltage Temperature Coefficient Note 6 100 ∆VOUT/VOUT Line Regulation VIN = VOUT – 1V to –16V 0.05 0.15 0.2 %/V ∆VOUT/VOUT Load Regulation IOUT = 100µA to 100mA, Note 7 1.5 1.8 2.0 % % VIN – VOUT Dropout Voltage, Note 8 IOUT = 100µA 40 IOUT = 50mA 360 500 mV IOUT = 100mA 500 700 900 mV IOUT = 100µA 35 100 µA IOUT = 50mA 0.7 IOUT = 100mA 2.1 IGND Ground Current, Note 9 Min Typ –2 –3 PSRR Ripple Rejection f = 120Hz 50 ILIMIT Current Limit VOUT = 0V 160 ∆VOUT/∆PD Thermal Regulation Note 10 0.05 Max Units 2 3 % % ppm/°C mV mA 3.0 mA dB 300 mA %/W 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. Note 4. The maximum allowable power dissipation is a function of the maximum junction temperature, TJ(max), the junction-to-ambient thermal resistance, θJA, and the ambient temperature, TA. The maximum allowable power dissipation at any ambient temperature is calculated using: PD(max) = (TJ(max) – TA) ÷ θJA, where θJA is 235°C/W. Exceeding the maximum allowable power dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown. See the “Thermal Considerations” section for details. Note 5. Specification for packaged product only. Note 6. Output voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range. Note 7. Regulation is measured at constant junction temperature using low duty cycle pulse testing. Parts are tested for load regulation in the load range from 100µA to 100mA. Changes in output voltage due to heating effects are covered by the thermal regulation specification. Note 8. 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. Note 9. Ground pin current is the regulator quiescent current plus pass transistor base current. The total current drawn from the supply is the sum of the load current plus the ground pin current. Note 10. Thermal regulation is defined as the change in output voltage at a time “t” after a change in power dissipation is applied, excluding load or line regulation effects. Specifications are for a 100mA load pulse at VIN = –16V for t = 10ms. May 2005 3 M9999-052705 MIC5270 Micrel, Inc. Typical Characteristics Dropout Characteristics -3.305 -1 -100mA Load 0 0 -1 -2 -3 -4 SUPPLY VOLTAGE (V) -3.265 -5 -3.26 0 -2 -1.5 -1 -0.5 5VIN 0 0 -90 GROUND CURRENT (µA) GROUND CURRENT (mA) -3.27 Ground Current vs. Output Current -2.5 Ground Current vs. Temperature -1mA Load -25 -20 0A Load -15 -10 -5 -300 -200 -100 0 0 M9999-052705 -20 -40 -60 -80 -100 OUTPUT CURRENT (mA) -1mA Load -30 -20 0µA Load -10 -1 -2 -3 -4 SUPPLY VOLTAGE (V) -1.5 -50mA Load -1 -2.5 -100mA Load -1.5 -1 -50A Load 0 0 -10mA Load -250 -200 -150 0A Load -100 -50 0 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) 4 -1 -2 -3 -4 SUPPLY VOLTAGE (V) -5 Negative Enable Threshold vs. Supply Voltage -1.6 -1.4 Enable On -1.2 -1 Enable Off -0.8 -0.6 -0.4 -0.2 0 -4 Dropout vs. Temperature -300 -10mA Load -0.5 -5 -3 -350 -2 -100mA Load Ground Current vs. Temperature -2 Ground Current Characteristics -2.5 -50 -100µA Load -40 -400 DROPOUT VOLTAGE (mV) -400 Ground Current Characteristics -60 -0.5 -3.26 -3.24 -3.22 -3.2 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) 0 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) Dropout vs. Output Current -500 -20 -40 -60 -80 -100 OUTPUT CURRENT (mA) -70 -3.5 0 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) -600 -80 0 0 -20 -40 -60 -80 -100 OUTPUT CURRENT (mA) -30 GROUND CURRENT (µA) -3.28 -3.275 -3.34 -3.32 -3.3 -3.28 GROUND CURRENT (mA) -0.5 OUTPUT VOLTAGE (V) -1.5 -3.29 -3.285 ENABLE THRESHOLD (V) -2 -3.295 Output Voltage vs. Temperature -3.4 -3.38 -3.36 -700 DROPOUT VOLTAGE (mV) OUTPUT VOLTAGE (V) 0 Load -2.5 DROPOUT VOLTAGE (mV) Output Voltage vs. Output Current -3.3 -3 GROUND CURRENT (µA) OUTPUT VOLTAGE (V) -3.5 -600 -7 -10 -13 SUPPLY VOLTAGE (V) -16 Dropout vs. Temperature -100mA Load -500 -400 -300 -50mA Load -200 -100 0 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) May 2005 MIC5270 Micrel, Inc. Functional Characteristics Load Transient VOUT (10mV/div.) -10mA -100mA COUT = 1µF Ceramic VIN = 5V VOUT = 3V Output Current (50mA/div.) Output Current (50mA/div.) VOUT (10mV/div.) Load Transient TIME (2ms/div.) -10mA -100mA COUT = 1µF Ceramic VIN = 5V VOUT = 3V TIME (2ms/div.) m May 2005 5 M9999-052705 MIC5270 Micrel, Inc. Functional Diagram GND VIN VOUT MIC5270-x.x M9999-052705 6 May 2005 MIC5270 Micrel, Inc. minimum footprint board layout, is 235°C/W. The maximum power dissipation at an ambient temperature of 25°C can be determined with the following equation: Applications Information The MIC5270 is a general-purpose negative regulator that can be used in any system that requires a clean negative voltage from a negative output. This includes post regulating of DC-DC converters (transformer based or charge pump based voltage converters). These negative voltages typically require a negative low-dropout voltage regulator to provide a clean output from typically noisy lines. Input Capacitor A 1µF input capacitor should be placed from IN to GND if there is more than 2 inches of wire or trace between the input and the AC filter capacitor, or if a battery is used as the input. Output Capacitor The MIC5270 requires an output capacitor for stable operation. A minimum of 1µF of output capacitance is required. The output capacitor can be increased without limitation to improve transient response. The output does not require ESR to maintain stability, therefore a ceramic capacitor can be used. High-ESR capacitors may cause instability. Capacitors with an ESR of 3Ω or greater at 100kHz may cause a high frequency oscillation. Low-ESR tantalums are recommended due to the tight capacitance tolerance over temperature. Ceramic chip capacitors have a much greater dependence on temperature, depending upon the dielectric. The X7R is recommended for ceramic capacitors because the dielectric will change capacitance value by approximately 15% over temperature. The Z5U dielectric can change capacitance value by as much 50% over temperature, and the Y5V dielectric can change capacitance value by as much as 60% over temperature. To use a ceramic chip capacitor with the Y5V dielectric, the value must be much higher than a tantalum to ensure the same minimum capacitor value over temperature. No-Load Stability The MIC5270 does not require a load for stability. Thermal Considerations Absolute values will be used for thermal calculations to clarify what is meant by power dissipation and voltage drops across the part. Proper thermal design for the MIC5270-5.0BM5 can be accomplished with some basic design criteria and some simple equations. The following information must be known to implement your regulator design: VIN = input voltage VOUT = output voltage IOUT = output current TA = ambient operating temperature IGND = ground current PD(max) = PD(max) = θ JA 125°C − 25°C 235°C/W PD(max) = 425mW The actual power dissipation of the regulator circuit can be determined using one simple equation. ( ) PD = VIN − VOUT IOUT + VIN ⋅ IGND Substituting PD(max), determined above, for PD and solving for the operating conditions that are critical to the application will give the maximum operating conditions for the regulator circuit. The maximum power dissipation number cannot be exceeded for proper operation of the device. The maximum input voltage can be determined using the output voltage of 5.0V and an output current of 100mA. Ground current, of 1mA for 100mA of output current, can be taken from the “Electrical Characteristics ” section of the data sheet. ( ) 425mW = (100mA × VIN + 1mA × VIN ) − 500mW 425mW = VIN − 5.0V 100mA + VIN × 1mA 925mW = 101mA × VIN VIN = 9.16Vmax Therefore, a –5.0V application at 100mA of output current can accept a maximum input voltage of –9.16V in a SOT-23-5 package. For a full discussion of heat sinking and thermal effects on voltage regulators, refer to Regulator Thermals section of Micrel’s “Designing with Low-Dropout Voltage Regulators ” handbook. Adjustable Regulator Application MIC5270BM –VIN 5 2 –IN –OUT GND ADJ 4 3 R2 –VOUT R1 Figure 1. Adjustable Voltage Application The MIC5270BM5 can be adjusted from 1.20V to 14V by using two external resistors (Figure 1). The resistors set the output voltage based on the following equation: Maximum power dissipation can be determined by knowing the ambient temperature, TA, the maximum junction temperature, 125°C, and the thermal resistance, junction to ambient. The thermal resistance for this part, assuming a May 2005 TJ(max) − TA VOUT = VREF (1 + R2 ) R1 Where VREF = 1.20V 7 M9999-052705 MIC5270 Micrel, Inc. 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) MICREL INC. TEL 2180 FORTUNE DRIVE + 1 (408) 944-0800 FAX SAN JOSE, CA 95131 USA + 1 (408) 474-1000 WEB http://www.micrel.com This 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. M9999-052705 8 May 2005