MIC5234 Low-Quiescent Current 150mA LDO Regulator General Description Features The MIC5234 is a low-quiescent current, μCap lowdropout regulator. With a maximum operating input voltage of 30V and quiescent current of 20μA, it is ideal for supplying keep-alive power in systems with high-voltage batteries. Capable of 150mA output, the MIC5234 has a dropout voltage of only 320mV. It can also survive an input transient of –20V to +32V. The MIC5234 requires only a 2.2μF output capacitor for stable operation. The MIC5234 includes a logic compatible enable input. Other features of the MIC5234 include thermal shutdown, current limit, overvoltage shutdown, load dump protection, reverse-leakage and reverse battery protection. The MIC5234 is available in an 8-pin ePad SOIC package with a junction operating range from –40°C to +125°C. Data sheets and support documentation can be found on Micrel’s web site at: www.micrel.com. • Ultra-low quiescent current (IQ = 20μA @ IO = 100μA) • Wide input voltage range: 2.3V to 30V • Low dropout: − 230mV @50mA − 320mV @150mA • Adjustable output voltage • Typical ±1.0% initial output accuracy • Logic compatible enable input • Overcurrent protection • Thermal-shutdown protection • Reverse-leakage and reverse-battery protection • Thermally enhanced 8-pin ePad SOIC package Applications • “Keep-alive” supply in notebook and portable personal computers • Logic supply from high-voltage batteries • Automotive electronics • Battery-powered systems _________________________________________________________________________________________________________________________ Typical Application Regulator with Adjustable Output Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com September 2011 M9999-092711-B [email protected] or (408) 955-1690 Micrel, Inc. MIC5234 Ordering Information Part Number Voltage Junction Temperature Range Package(1) Lead Finish MIC5234YME Adjustable –40°C to +125°C 8-Pin ePad SOIC NiPdAu Note: 1. ePad SOIC is a Green RoHS-compliant package. Mold compound is halogen free. Pin Configuration 8-Pin ePad SOIC Pin Description Pin Number Pin Name 1 VOUT Pin Function Regulated Output. 2, 3, 6 NC No Connect. 4 ADJ Adjustable Feedback Input. Connect to voltage divider network. 5 EN Enable (Input). Logic low = shutdown; logic high = enabled. Do not leave floating. 7 GND Ground. 8 VIN Power Supply Input. EP ePad September 2011 Exposed Thermal Pad. Connect to the ground plane to maximize thermal performance. 2 M9999-092711-B Micrel, Inc. MIC5234 Absolute Maximum Ratings(1) Operating Ratings(2) Supply Voltage (VIN) ....................................... −20V to +32V Power Dissipation(3)...................................Internally Limited Junction Temperature (TJ) ....................................... +150°C Storage Temperature (TS)......................... −65°C to +150°C Lead Temperature (soldering, 10s)............................ 260°C ESD Rating(4) ................................................ ESD Sensitive Supply Voltage (VIN)...................................... +2.3V to +30V Enable Voltage (VEN).......................................... 0V to +30V Junction Temperature (TJ) ........................ –40°C to +125°C Package Thermal Resistance ePad SOIC (θJA) ................................................41°C/W Electrical Characteristics(5) VIN = VOUT + 1V; VEN = 2.0V; COUT = 4.7µF, IOUT = 100µA; TJ = 25°C, bold values indicate –40°C ≤ TJ ≤ +125°C, unless noted. Symbol Parameter VADJ Feedback Voltage ΔVOUT/ΔT ΔVOUT/VOUT Condition Min. Typ. Max. Units 1.2054 1.23 1.2546 V Output Voltage Temperature Coefficient 50 (6) Line Regulation VIN = VOUT + 1V to 30V IOUT = 100µA to 50mA(7) ΔVOUT/VOUT IGND Ground Pin Current 0.5 0.15 0.3 0.3 IOUT = 100µA to 150mA Dropout Voltage(8) 0.2 0.5 Load Regulation (7) ΔV ppm/°C 0.6 % % 1.0 IOUT = 100µA 50 120 IOUT = 50mA 230 400 IOUT = 100mA 270 IOUT = 150mA 320 550 VEN = 2.0V, IOUT = 100µA 20 30 VEN = 2.0V, IOUT = 50mA 0.5 0.9 VEN = 2.0V, IOUT = 100mA 1.5 VEN = 2.0V, IOUT = 150mA 2.8 5.0 0.1 1 µA 260 400 mA IGND(SHDN) Ground Pin in Shutdown VEN = 0V, VIN = 30V ISC Short-Circuit Current VOUT = 0V eN Output Noise 10Hz to 100kHz, VOUT = 3.0V, COUT = 2.2µF 150 mV µA mA 160 µVRMS 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. 4. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5kΩ in series with 100pF. 5. Specification for packaged parts only. 6. Output voltage temperature coefficient is defined as the worst-case voltage change divided by the total temperature range. 7. Regulation is measured at constant junction temperature using pulse testing with a low duty cycle. Changes in output voltage due to heating effects are covered by the speculation for thermal regulation. 8. Dropout voltage is defined as the input-to-output differential at which the output voltage drops 2% below its nominal value measured at VIN=VOUT+1V. September 2011 3 M9999-092711-B Micrel, Inc. MIC5234 Electrical Characteristics(4) (Continued) VIN = VOUT + 1V; VEN = 2.0V; COUT = 4.7µF, IOUT = 100µA; TJ = 25°C, bold values indicate –40°C ≤ TJ ≤ +125°C, unless noted. Symbol Parameter Condition VIL Input Low Voltage Regulator off VIH Input High Voltage Regulator on Min. Typ. Max. Units 0.6 V Enable Input 2.0 VEN = 0.6V, regulator off IEN Enable Input Current VEN = 2.0V, regulator on VEN = 30V, regulator on September 2011 4 V 0.01 1.0 2.0 0.15 1.0 2.0 0.5 µA 2.5 5.0 M9999-092711-B Micrel, Inc. MIC5234 Typical Characteristics September 2011 5 M9999-092711-B Micrel, Inc. MIC5234 Typical Characteristics (Continued) September 2011 6 M9999-092711-B Micrel, Inc. MIC5234 Functional Characteristics September 2011 7 M9999-092711-B Micrel, Inc. MIC5234 Functional Diagram September 2011 8 M9999-092711-B Micrel, Inc. MIC5234 Application Information The MIC5234 is a µcap low dropout linear regulator which provides wide input voltage range, reversedbattery protection, reduced quiescent current and small package. When disabled, the quiescent current is reduced to 0.1μA. Enable A low on the enable pin disables the part, forcing the quiescent current to less than 0.1μA. Thermal shutdown is not functional while the device is disabled. The maximum enable bias current is 2μA for a 2.0V input. An open collector pull-up resistor tied to the input voltage should be set low enough to maintain 2V on the enable input. Figure 1 shows an open collector output driving the enable pin through a 200k pull-up resistor tied to the input voltage. In order to avoid output oscillations, slow transitions from low to high should be avoided. Figure 2. Output Capacitor ESR Reverse Current Protection The MIC5234 is designed to limit the reverse current flow from output to input in the event that the MIC5234 output has been tied to the output of another power supply. Refer to the Typical Characteristics to see the graphs detailing the reverse current flow with the input grounded and open. Thermal Shutdown The MIC5234 has integrated thermal protection. This feature is only for protection purposes. The device should never be intentionally operated near this temperature as this may have detrimental effects on the life of the device. The thermal shutdown may become inactive while the enable input is transitioning a high to a low. When disabling the device via the enable pin, transition from a high to low quickly. This will insure that the output remains disabled in the event of a thermal shutdown. Figure 1. Remote Enable Input Capacitor An input capacitor may be required when the device is not near the source power supply or when supplied by a battery. Small, surface mount, ceramic capacitors can be used for bypassing. Larger values may be required if the source supply has high ripple. Output Capacitor The MIC5234 has been designed to minimize the effect of the output capacitor ESR on the closed loop stability. As a result, ceramic or film capacitors can be used at the output. Figure 2 displays a range of ESR values for a 10μF capacitor. A 10μF capacitor with an ESR less than 3.4Ω is sufficient for stability over the entire input voltage range. Stability can also be maintained throughout the specified load and line conditions with 2.2μF film or ceramic capacitors. September 2011 ePad SOIC-8 Thermal Characteristics The MIC5234 is a high input voltage device intended to provide 150mA of continuous output current in one a small profile package. The ePad SOIC-8 allows the device to dissipate approximately 50% more power than the SOIC-8 package. The benefit of the MIC5234 ePad SOIC-8 package is an improvement to less than half the thermal resistance over the standard SO-8 packing. Lower thermal resistance means more output current or higher input voltage for a given package size. Lower thermal resistance is achieved by joining the die with the die attach paddle to create a single piece electrical and thermal conductor. This concept has been used by MOSFET manufacturers for years, proving very reliable and cost effective for the user. Thermal resistance consists of two main elements, θJC (junction-to-case thermal resistance) and θCA (case-to-ambient thermal resistance). See Figure 3. θJC is the resistance from the die to the case (ePad) of the package. θCA is the 9 M9999-092711-B Micrel, Inc. MIC5234 resistance from the case (ePad) to the ambient air and it includes θCS case (ePad)-to-sink thermal resistance and θSA sink-to-ambient thermal resistance. Power dissipation in a linear regulator is calculated as follows: PD = (VIN – VOUT) × IOUT + (VIN × IGND) If we use a 3V output device and a 8V input with an output current of 150mA, then our power dissipation is as follows: PD = (8V – 3V) × 150mA + (8V × 2.6mA) PD = 750mW + 20.8mW PD = 770.8mW A copper plane should be provided to dissipate the heat to keep junction temperature 125°C. Adjustable Regulator Application The MIC5234 can be adjusted from 1.24V to 20V by using two external resistors (see Figure 4). The resistors set the output voltage based on Equation 1: Figure 3. Thermal Resistance Using the ePad SOIC-8 reduces the θJC dramatically and allows the user to reduce θCA. The total thermal resistance, θJA (junction-to-ambient thermal resistance) is the limiting factor in calculating the maximum power dissipation capability of the device. Typically, the ePad SOIC-8 has a θJC of 14.7°C/W, this is significantly lower than the standard SOIC-8 which is typically 48.8°C/W. θCA is reduced because ePad can now be soldered directly to a ground plane which significantly reduces the case-to-sink thermal resistance and sink-to-ambient thermal resistance. Low-dropout linear regulators from Micrel are rated to a maximum junction temperature of 125°C. It is important not to exceed this maximum junction temperature during operation of the device. To prevent this maximum junction temperature from being exceeded, the appropriate ground plane heat sink must be used. The maximum allowable temperature rise must be calculated to determine the required heat sink: ⎛ R1 ⎞ VOUT = VREF × ⎜1 + ⎟ ⎝ R2 ⎠ Eq. 1 Where VREF = 1.23V. Figure 4. Adjustable Voltage Application ΔT = TJ(MAX) – TA(MAX) TJ(MAX) = 125°C TA(MAX) = maximum ambient operating temperature Example: If output voltage to be set is 3.3V and R2 is selected as 1.2kΩ. ⎛V ⎞ Then R1 = R2 × ⎜ OUT − 1⎟ ⎜V ⎟ ⎝ REF ⎠ For example, the maximum ambient temperature is 50°C, the ΔT is determined as follows: ⎛ 3.3V ⎞ R1 = 1.2kΩ × ⎜ − 1⎟ = 2.019 kΩ 1.23V ⎝ ⎠ ΔT = 125°C – 50°C ΔT = 75°C September 2011 10 M9999-092711-B Micrel, Inc. MIC5234 Evaluation Board Schematic Bill of Materials Item C1, C5 Part Number EKY-500ELL101MHB5D 12065C475KAT2A C2, C3 C4 GRM31CR71H475KA12L Manufacturer United Chemi-con Capacitor, Aluminum, 100µF, 50V, 20%, Radial 2 Capacitor, 4.7µF, 50V, X5R, size 1206 2 Capacitor, 2.2µF, 16V, X7R, size 0805 1 AVX Murata(3) (4) TDK 0805YD225KAT2A AVX(2) C2012X7R1C225K Qty. (2) C3216X5R1H475K GRM219R61C225KA88D DESCRIPTION (1) Murata(3) TDK (4) CRCW060310K0FKEA Vishay (5) Resistor, 10KΩ, 1%, size 0603 1 R2 CRCW06031200FKEA Vishay (5) Resistor, 120Ω, 1%, size 0603 1 R3 CRCW06033830FKEA Vishay (5) Resistor, 383Ω, 1%, size 0603 1 CRCW06032000FKEA Vishay (5) Resistor, 200Ω, 1%, size 0603 1 (5) Resistor, 127Ω, 1%, size 0603 1 Resistor, 56Ω, 1%, size 0603 1 Low-Quiescent Current µCap LDO Regulator 1 R1 R4 R5 CRCW06031270FKEA Vishay R6 CRCW060356R0FKEA Vishay (5) U1 MIC5234YME Micrel (6) Notes: 1. United Chemi-Con: www.chemi-con.com. 2. AVX: www.avx.com. 3. Murata: www.murata.com. 4. TDK: www.tdk.com. 5. Vishay: www.vishay.com. 6. Micrel, Inc.: www.micrel.com. September 2011 11 M9999-092711-B Micrel, Inc. MIC5234 PCB Layout Recommendations MIC5234 Evaluation Board Top Layer MIC5234 Evaluation Board Bottom Layer September 2011 12 M9999-092711-B Micrel, Inc. MIC5234 PCB Layout Recommendations (Continued) MIC5234 Evaluation Board Top Silk MIC5234 Evaluation Board Bottom Silk September 2011 13 M9999-092711-B Micrel, Inc. MIC5234 Package Information 8-Pin ePad SOIC (NE) September 2011 14 M9999-092711-B Micrel, Inc. MIC5234 Recommended Land Pattern 8-Pin ePad SOIC (NE) September 2011 15 M9999-092711-B Micrel, Inc. MIC5234 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 Micrel makes no representations or warranties with respect to the accuracy or completeness of the information furnished in this data sheet. This information is not intended as a warranty and Micrel does not assume responsibility for its use. Micrel reserves the right to change circuitry, specifications and descriptions at any time without notice. No license, whether express, implied, arising by estoppel or otherwise, to any intellectual property rights is granted by this document. Except as provided in Micrel’s terms and conditions of sale for such products, Micrel assumes no liability whatsoever, and Micrel disclaims any express or implied warranty relating to the sale and/or use of Micrel products including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right. 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. © 2011 Micrel, Incorporated. September 2011 16 M9999-092711-B