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MIC5270 Micrel, Inc. MIC5270 Cap Negative Low-Dropout Regulator General Description The MIC5270 is a Cap 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 Cap regulator design is optimized to work with lowvalue, low-cost ceramic capacitors. The output typically requires only a 1F capacitance for stability. Designed for applications where small packaging and efficiency are critical, the MIC5270 combines LDO design expertise with IttyBitty(R) 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. Features * * * * * * * * Stable with ceramic or tantalum capacitor Low dropout voltage: 500mV @ 100mA Low ground current: 35A @ load = 100A Tight initial accuracy: 2% Tight load and line regulation Thermal shutdown Current limiting IttyBitty(R) SOT-23-5 packaging Applications * * * * GaAsFET bias Portable cameras and video recorders PDAs Battery-powered equipment Ordering Information Standard MIC5270BM5 MIC5270-3.0BM5 MIC5270-4.1BM5 MIC5270-5.0BM5 Part Number Marking Code PbFree LLAA LL30 LL41 LL50 MIC5270YM5 MIC5270-3.0YM5 MIC5270-4.1YM5 MIC5270-5.0YM5 Marking Code LLAA LL30 LL41 LL50 Voltage Adj. -3.0V -4.1V -5.0V Junction Temp. Range -40C to +125C -40C to +125C -40C to +125C -40C to +125C Package SOT-23-5 SOT-23-5 SOT-23-5 SOT-23-5 Typical Application MIC5270-5.0BM5 2 MIC5270BM5 2 R1 R2 V OUT -5.0V VIN -6.0V GND -IN -OUT 4 5 VOUT -5.0V GND ADJ -IN -OUT 3 4 VIN -6.0V 5 1F 10F 1F 10F Regulator With Fixed Output 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 1 NC GND NC 3 2 1 LLAA 4 5 4 LLxx 5 -OUT -IN -OUT -IN MIC5270BM5 Adjustable Voltage MIC5270-x.xBM5 Fixed Output Voltage Pin Description Pin Number (Adj.) 1 2 Pin Number (Fixed) 1 2 3 3 4 5 4 5 Pin Name NC GND NC ADJ -OUT -IN Pin Function Not internally connected. Ground. Not internally connected. Adjustable (Input): Adjustable feedback output connects to resistor voltage divider. Negative Regulator Output. Negative Supply Input. M9999-052705 2 May 2005 MIC5270 Micrel, Inc. Absolute Maximum Ratings (Note 1) Input Voltage (VIN) ....................................... -20V to +0.3V Power Dissipation (PD) ............................ Internally Limited Junction Temperature (TJ) ....................... -40C to +125C Lead Temperature (soldering, 5 sec.) ....................... 260C Storage Temperature (TS) ....................... -65C to +150C ESD Rating, Note 3 Operating Ratings (Note 2) Input Voltage (VIN) ....................................... -16V to -3.3V Junction Temperature (TJ) ....................... -40C to +125C Thermal Resistance (JA) ........................................ Note 4 Electrical Characteristics (Note 5) VIN = VOUT - 1.0V; COUT = 4.7F, IOUT = 100A; TJ = 25C, bold values indicate -40C TJ +125C; unless noted. Symbol VOUT VOUT/T VOUT/VOUT VOUT/VOUT VIN - VOUT Parameter Output Voltage Accuracy Output Voltage Temperature Coefficient Line Regulation Load Regulation Dropout Voltage, Note 8 Condition Variation from nominal VOUT Note 6 VIN = VOUT - 1V to -16V IOUT = 100A to 100mA, Note 7 IOUT = 100A IOUT = 50mA IOUT = 100mA IGND Ground Current, Note 9 IOUT = 100A IOUT = 50mA IOUT = 100mA PSRR ILIMIT VOUT/PD Note 1. Note 2. Note 3. Note 4. Min -2 -3 Typ Max 2 3 Units % % ppm/C 100 0.05 1.5 40 360 500 35 0.7 2.1 50 160 0.05 300 3.0 500 700 900 100 0.15 0.2 1.8 2.0 %/V % % mV mV mV A mA mA dB mA %/W Ripple Rejection Current Limit Thermal Regulation f = 120Hz VOUT = 0V Note 10 Exceeding the absolute maximum rating may damage the device. The device is not guaranteed to function outside its operating rating. Devices are ESD sensitive. Handling precautions recommended. The maximum allowable power dissipation is a function of the maximum junction temperature, TJ(max), the junction-to-ambient thermal resistance, JA, and the ambient temperature, TA. The maximum allowable power dissipation at any ambient temperature is calculated using: PD(max) = (T J(max) - TA) / JA, where JA is 235C/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. Specification for packaged product only. Output voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range. Regulation is measured at constant junction temperature using low duty cycle pulse testing. Parts are tested for load regulation in the load range from 100A to 100mA. Changes in output voltage due to heating effects are covered by the thermal regulation specification. 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. 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 5. Note 6. Note 7. Note 8. Note 9. 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 OUTPUT VOLTAGE (V) -3.5 OUTPUT VOLTAGE (V) -3.305 -3.3 -3.295 -3.29 -3.285 -3.28 -3.275 -3.27 -3.265 -5 -3.26 0 Output Voltage vs. Output Current OUTPUT VOLTAGE (V) -3 -2.5 -2 -1.5 -1 -0.5 0 0 0 Load -3.4 -3.38 -3.36 -3.34 -3.32 -3.3 -3.28 Output Voltage vs. Temperature -100mA Load -1 -2 -3 -4 SUPPLY VOLTAGE (V) -20 -40 -60 -80 -100 OUTPUT CURRENT (mA) -3.26 -3.24 -3.22 -3.2 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (C) -2.5 Ground Current vs. Output Current GROUND CURRENT (A) -90 -80 -70 -60 Ground Current Characteristics GROUND CURRENT (mA) -1mA Load -2.5 Ground Current Characteristics GROUND CURRENT (mA) -2 -1.5 -1 -0.5 5VIN 0 0 -20 -40 -60 -80 -100 OUTPUT CURRENT (mA) -2 -100mA Load -1.5 -50mA Load -1 -0.5 0 0 -10mA Load -50 -100A Load -40 -30 -20 -10 0 0 0A Load -1 -2 -3 -4 SUPPLY VOLTAGE (V) -5 -1 -2 -3 -4 SUPPLY VOLTAGE (V) -5 -30 GROUND CURRENT (A) Ground Current vs. Temperature GROUND CURRENT (A) -3.5 -3 -2.5 -2 -1.5 -1 -0.5 Ground Current vs. Temperature ENABLE THRESHOLD (V) -1.6 -1.4 -1.2 Negative Enable Threshold vs. Supply Voltage Enable On -1mA Load -25 -20 -15 -10 -5 0 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (C) 0A Load -100mA Load -1 -0.8 -0.6 -0.4 -0.2 0 -4 Enable Off -50A Load 0 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (C) -7 -10 -13 SUPPLY VOLTAGE (V) -16 -600 Dropout vs. Output Current DROPOUT VOLTAGE (mV) -400 -350 -300 -250 -200 -150 -100 -50 Dropout vs. Temperature DROPOUT VOLTAGE (mV) -10mA Load -700 -600 -500 -400 -300 -200 -100 Dropout vs. Temperature -100mA Load DROPOUT VOLTAGE (mV) -500 -400 -300 -200 -100 0 0 -20 -40 -60 -80 -100 OUTPUT CURRENT (mA) -50mA Load 0A Load 0 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (C) 0 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (C) M9999-052705 4 May 2005 MIC5270 Micrel, Inc. Functional Characteristics Load Transient Load Transient VOUT (10mV/div.) Output Current (50mA/div.) -100mA Output Current (50mA/div.) -10mA VOUT (10mV/div.) COUT = 1F Ceramic VIN = 5V VOUT = 3V -10mA COUT = 1F Ceramic VIN = 5V VOUT = 3V -100mA TIME (2ms/div.) TIME (2ms/div.) Negative Enable Transient 0V VOUT (1V/div.) Enable (1V/div.) 0V TIME (20ms/div.) May 2005 5 M9999-052705 MIC5270 Micrel, Inc. Functional Diagram GND VIN MIC5270-x.x VOUT M9999-052705 6 May 2005 MIC5270 Micrel, Inc. minimum footprint board layout, is 235C/W. The maximum power dissipation at an ambient temperature of 25C can be determined with the following equation: PD(max) = TJ(max) - TA JA 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 1F 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 1F 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 3 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 Maximum power dissipation can be determined by knowing the ambient temperature, TA, the maximum junction temperature, 125C, and the thermal resistance, junction to ambient. The thermal resistance for this part, assuming a PD(max) = 125C - 25C 235C/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 x VIN + 1mA x VIN ) - 500mW 425mW = VIN - 5.0V 100mA + VIN x 1mA 925mW = 101mA x 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 4 3 R2 R1 -VOUT GND ADJ 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: VOUT = VREF (1 + Where VREF = 1.20V R2 ) R1 May 2005 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) 3.02 (0.119) 2.80 (0.110) 1.30 (0.051) 0.90 (0.035) 10 0 0.15 (0.006) 0.00 (0.000) 0.20 (0.008) 0.09 (0.004) 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 FAX SAN JOSE, CA 95131 USA WEB + 1 (408) 944-0800 + 1 (408) 474-1000 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. (c) 2003 Micrel, Incorporated. M9999-052705 8 May 2005 |
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