MIC35152

MIC35152 MICREL | Alldatasheet

Document overview

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Technical content

Features

• 1.5A minimum guaranteed output current
• 600mV maximum dropout voltage over temperature – Ideal for 3.0V to 2.5V conversion – Ideal for 2.5V to 1.8V, 1.65V, or 1.5V conversion
• Stable with ceramic or tantalum capacitor
• Wide input voltage range – V IN: 2.25V to 6.0V
• ±1.0% initial output tolerance
• Excellent line and load regulation speci fications
• Logic controlled shutdown
• Thermal shutdown and current limit protection
• Reverse-leakage protection
• –40 °C to +125°C junction temperature
• Power D-Pak package (TO-252)

Applications

• LDO linear regulator for low-voltage digital IC
• PC add-in cards
• High efficiency linear power supplies
• SMPS post regulator
• Battery charger Typical Application** Adjustable Regulator Application (*See Minimum Load Curren Section)

Micrel, Inc. MIC35152 October 2009 2 M9999-102309-A

Ordering Information

Part Number Output Current Voltage Junction Temp. Range(1) Package MIC35152WD* 1.5A Adjustable –40° to +125°C 5-Pin TO-252 Note: *RoHS compliant with ‘high-melting solder’ exemption. Pin Configuration 5-Pin TO-252 D-Pak (D) Pin Description Pin Number Pin Name Pin Function 1 EN Enable (Input): CMOS compatible input. Logic high = enable, logic low = shutdown.

2 IN Input Voltage: Supplies the curr ent to the output power device

3 GND, TAB Ground: TAB is also connected internally to the IC’s ground on D-PAK.

4 OUT Regulator Output: The output voltage is set by the resistor divider

connected from OUT to GND (with the divided connection tied to ADJ). A minimum value capacitor must be used to maintain stability. See Applications Information.

5 ADJ Adjustable Regulator Feedback Input: Connect to the resistor voltage

divider that is placed from OUT to GND in order to set the output voltage.

Micrel, Inc. MIC35152 October 2009 3 M9999-102309-A Absolute Maximum Ratings(1) Operating Ratings(2) Package Thermal Resistance Electrical Characteristics(5) TJ = 25°C with VIN = VEN = VOUT + 1V; IOUT = 10mA; bold values indicate –40°C < TJ < +125°C, unless otherwise noted. Parameter Condition Min Typ Max Units Output Voltage Line Regulation V IN = VOUT +1.0V to 6.0V 0.06 0.5 % Output Voltage Load Regulation I OUT = 10mA to 1.5A 0.2 1 % IOUT = 750mA 225 350 mV Dropout Voltage, VIN – VOUT Note 6 IOUT = 1.5A 365 600 mV Ground Pin Current, Note 7 IOUT = 1.5A 11 30 mA Ground Pin Current in Shutdown V IL ≤ 0.5V, VIN = VOUT + 1V 1.0 µA Current Limit V OUT = 0 2.7 4.0 A Start-up Time V EN = VIN, IOUT = 10mA, COUT = 47µF 45 150 µs Enable Input Regulator enable 2.25 V Enable Input Threshold Regulator shutdown 0.8 V VIL ≤ 0.8V (regulator shutdown) 2 µA µA Enable Pin Input Current VIH ≥ 2.25V (regulator enabled) 1 15 30 µA µA Adjust Pin 1.228 1.240 1.252 V Reference Voltage 1.215 1.265 V Reference Voltage Temp. Coefficient Note 8 20 ppm/°C Adjust Pin Bias Current 40 80 120 nA nA Adjust Pin Bias Current Temp. Coefficient 0.1 nA/°C Notes: 1. Exceeding the absolute maximum rating may damage the device. 2. The device is not guaranteed to function outside its operating rating. 3. Devices are ESD sensitive. Handling precautions recommended. 4. P D(MAX) = (TJ(MAX) – TA) / θJA, where θJA, depends upon the printed circuit layout. See “Applications Information.” 5. Specification for packaged product only. 6. V DO = VIN – VOUT when VOUT decreased to 98% of its nominal output voltage with VIN = VOUT +1V. For output voltages below 1.75V, dropout voltage specification does not apply due to a minimum input operating voltage of 2.25V. 7. I GND is the quiescent current. IIN = IGND + IOUT. 8. Thermal regulation is de fined 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 200mA load pulse at VIN = 6V for t = 10ms.

Micrel, Inc. MIC35152 October 2009 4 M9999-102309-A Typical Characteristics

Micrel, Inc. MIC35152 October 2009 5 M9999-102309-A Functional Characteristics

Micrel, Inc. MIC35152 October 2009 6 M9999-102309-A

Application Information

The MIC35152 is a high-performance low-dropout voltage regulator suitable for moderate to high-current regulator applications. Its 600mV dropout voltage at full load and over-temperature makes it especially valuable in battery-powered systems and as high-efficiency noise filters in post-regulator applications. Unlike older NPN- pass transistor designs, there the minimum dropout voltage is limited by the based-to-emitter voltage drop and collector-to-emitter saturation voltage, dropout performance of the PNP out put of these devices is limited only by the low V CE saturation voltage. A trade-off for the low dropout voltage is a varying base drive requirement. Micrel’s Super ßeta PNP ® process reduces this drive requirement to only 2% to 5% of the load current. The MIC35152 regulator is fully protected from damage due to fault conditions. Current limiting is provided. This limiting is linear; output current during overload conditions is constant. Thermal shutdown disables the device when the die temperature exceeds the maximum safe operating temperature. Transient protection allows device (and load) survival even when the input voltage spikes above and below nominal. The output structure of these regulators allows voltages in excess of the desired output voltage to be applied without reverse current flow. Thermal Design Linear regulators are simple to use. The most complicated design parameters to consider are thermal characteristics. Thermal design requires the following application-specific parameters:

• Maximum ambient temperature (T
• Output current (I OUT)
• Output voltage (V OUT)
• Input voltage (V IN)
• Ground current (I GND) First, calculate the power dissipation of the regulator from these numbers and the device parameters from this datasheet. P D=(VIN–VOUT)IOUT+VIN IGND Where the ground current is approximated by using numbers from the “Electrical Characteristics” or “Typical Characteristics.” Then, the heat sink thermal resistance is determined with this formula: θSA=((TJ(MAX)–TA)/PD)–(θJC+θCS) Where T J(MAX) ≤ 125°C and θCS is between 0°C and 2°C/W. The heat sink may be signi ficantly reduced in applications where the minimum input voltage is known and is large compared with the dropout voltage. Use a series input resistor to drop excessive voltage and distribute the heat between this resistor and the regulator. The low dropout properties of Micrel Super ßeta PNP ® regulators allow signi ficant reductions in regulator power dissipation and the associated heat sink without compromising performance. When this technique is employed, a capacitor of at least 1.0µF is needed directly between the input and regulator ground. Refer to “Application Note 9” for further details and examples on thermal design and heat sink applications. With no heat sink in the application, calculate the junction temperature to determine the maximum power dissipation that will be a llowed before exceeding the maximum junction temperature of the MIC35152. The maximum power allowed can be calculated using the thermal resistance ( θ JA) of the D-Pak adhering to the following criteria for the PCB design: 2 oz. copper and 100mm2 copper area for the MIC35152. As an example, given an expected maximum ambient temperature (TA) of 75°C with VIN = 2.25V, VOUT = 1.75V, and I OUT = 1.5A, first calculate the expected P D using Equation (1); Next, calcualte the junction temperature for the expected power dissipation. TJ=(θJA×PD)+TA=(56°C/W×0.811W)+75°C=120.4°C Now determine the maximum power dissipation allowed that would not exceed the IC’s maximum junction temperature (125°C) without the use of a heat sink by PD(MAX)=(TJ(MAX)–TA)/θJA=(125°C–75°C)/(56°C/W)=0.893W Output Capacitor The MIC35152 requires an output capacitor for stable operation. As a µCap LDO, the MIC35152 can operate with ceramic output capacitors as long as the amount of capacitance is 47µF or greater. For values of output capacitance lower than 47µF, the recommended ESR range is 200m Ω to 2 Ω. The minimum value of output capacitance recommended for the MIC35152 is 10µF. For 47µF or greater, the ESR range recommended is less than 1 Ω. Ultra-low ESR ceramic capacitors are recommended for output capacitance of 47µF or greater to help improve transient response and noise reduction at high frequency. 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.

standard 10µF tantalum capacito r is all that is required. Larger values help to improve performance even further. Figure 1. Adjustable Regulator with Resistors load current is necessary for proper operation.

Micrel, Inc. MIC35152 October 2009 8 M9999-102309-A

Package Information

5-Pin TO-252 D-PAK (D) 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. © 2009 Micrel, Incorporated.