500mA LDO Regulator. Product Description. Applications. Typical Application Circuit. Block Diagram GS2905

Transcription

1 500mA LDO Regulator Product Description The is a 500mA fixed output voltage, low dropout linear regulator with high ripple rejection ratio and fast turn-on time. It includes a reference voltage source, an error amplifier, driver transistors and an internal current limiter. The current limiter s holdback circuit operates as a short protection. The works well with low ESR ceramic capacitors, suitable for wireless battery-powered applications with stringent space requirements and demanding performance. It also offers low quiescent current. Features Wide 2.5V to 7V Operating Range Quick Start-Up Current Limiting Protection Thermal Shutdown Protection Low Dropout : 300mA; V OUT = 5V High Ripple Rejection 55dB@10Hz Standby Current Less Than 0.1μA Applications Battery-Powered Equipment Portable Instruments Slim DVDs Digital Camera WLAN Communication Hand-Held Instruments Typical Application Circuit Figure1. Fixed Operation Figure2. Adjustable Operation Block Diagram 1

2 Packages & Pin Assignments SOT-23-5L(ADJ) SOT-89(Fixed) SOT-223(Fixed) Pin Define Pin No. Pin No. Pin No. Symbol Description 1 2,4, TAB 2,4, TAB V IN Input GND Ground EN ADJ Chip Enable Pin Feedback Pin (Adjustable Version Only) V OUT Output Pin Ordering Information SOT-23-5L(ADJ) SOT-89(Fixed) SOT-223(Fixed) Output Voltage LF - - Adjustable - Y15F X15F 1.5V - Y18F X18F 1.8V - Y25F X25F 2.5V - Y33F X33F 3.3V - Y36F X36F 3.6V - Y50F X50F 5.0V Marking Information SOT-23-5L SOT-23-5L(ADJ) Marking Output Voltage LF CHA YWG Adjustable SOT-89/SOT-223 2

3 Absolute Maximum Ratings Absolute Maximum Ratings (Note 1) Supply Voltage V IN 8V Power Dissipation, P T A =25ºC SOT-23-5L 400mW SOT mW SOT mW Thermal Resistance, θja SOT-23-5L 250ºC/W SOT ºC/W SOT ºC/W Lead Temperature 260ºC Storage Temperature -65ºC to 150ºC Recommended Operating Conditions Input Voltage VIN 2.5V to 7V EN Input Voltage 0V to 7V Junction Temperature -40ºC to 125ºC Ambient Operating Temperature -40ºC to 85ºC 3

4 Electrical Characteristics T A = 25 ºC, Unless otherwise noted. V OUT (T) =2.0 (Note 1) Symbol Parameter Conditions Min Typ Max Unit VIN Operating Voltage Range V ISBY Shutdown Supply Current V EN = GND,Shutdown μa ILIMIT Supply Current Limit R LOAD = 1Ω 800 ma IQ Quiescent Current V EN 1.2V, I OUT = 0mA μa VDROP Dropout Voltage (Note 3) I OUT =600mA Vout = 1.5V mv Vout = 1.8V mv Vout = 2.5V mv Vout = 2.8V mv Vout = 3.3V mv Vout = 5.0V mv I OUT =300mA Vout = 5.0V mv IIBSD EN input Bias Current V EN = GND or V IN na VLINE Line regulation V IN = (V OUT +1V) to 6V, I OUT = 1mA 6 mv/v VLOAD Load Regulation 1mA < I OUT < 600mA 55 mv eno TSD TSD Output Noise Voltage Thermal Shutdown Temperature Thermal Shutdown Temperature Hysteresis 10Hz to 100KHz,I OUT =200mA, C OUT = 1µF 100 µvrms 165 ºC 30 ºC VOUT Output Voltage Accuracy I OUT =1mA % V IL Logic-Low V V IN = 2.5V to 6V,Shutdown 0.4 V EN Threshold Logic-High V V IN = 2.5V to 6V,Start-Up 1.6 V V IH PSRR Power Supply Rejection Rate f = 10Hz C OUT = 1µF, I OUT = 10mA 55 db Note 1: Stresses listed as the above Absolute Maximum Ratings may cause permanent damage to the device. These are for stress ratings. Functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may remain possibility to affect device reliability. Note 2: V IN(MIN) =V OUT +V DROPOUT Note 3: The dropout voltage is defined as (V IN -V OUT ) when V OUT is 100mV below the target value of V OUT. 4

5 Application Information Capacitor Selection and Regulator Enable Function Stability The is shut down by pulling the EN pin low, Input Capacitor and turned on by driving the input high. If the An input capacitance of 1μF is required between shutdown feature is not required, the EN pin should the device input pin and ground directly (the be tied to VIN to keep the regulator on at all times amount of the capacitance may be increased (the EN pin MUST NOT be left floating). without limit). The input capacitor MUST be located less than 1 cm from the device to assure input To assure proper operation, the signal source used stability. to drive the EN pin must be able to swing above and below the specified turn-on/off voltage A lower ESR capacitor allows the use of less thresholds listed in the Electrical Characteristics capacitance, while higher ESR type (like aluminum under VIH and VIL. electrolytic) requires more capacitance. Capacitor types (aluminum, ceramic and tantalum) can be The ON/OFF signal may come from either CMOS mixed in parallel, but the total equivalent input output, or an open-collector output with pull-up capacitance/esr must be defined as above for resistor to the device input voltage or another logic stable operation. There are no requirements supply. The highlevel voltage may exceed the for the ESR on the input capacitor, but tolerance device input voltage, but must remain within the and temperature coefficient must be considered absolute maximum ratings for the EN pin. when selecting the capacitor to ensure the capacitance is 1μF over the entire operating range. Thermal Considerations For continuous operation, do not exceed the Output Capacitor maximum operation junction temperature 125 C. The is designed specifically to work with The maximum power dissipation depends on the very small ceramic output capacitors. The thermal resistance of IC package, PCB layout, the minimum capacitance recommended (temperature rate of surroundings airflow and temperature characteristics of X7R, X5R, Z5U or Y5V) is within difference between junctions to ambient. The the 1μF to 10μF range with 5mΩ to 50mΩ ESR maximum power dissipation can be calculated by range ceramic capacitor between LDO output and following formula: GND for transient stability, but it may be increased without limit. Where TJ(MAX) is the maximum operation junction Higher capacitance values help to improve temperature 125 C, TA is the ambient temperature transient response. The output capacitor's ESR is and the θja is the junction to ambient thermal critical because it forms a zero to provide phase resistance. lead which is required for loop stability. 5

6 For recommended operating conditions specification of where TJ(MAX) is the maximum junction temperature of the die (125 C) and TA is the maximum ambient temperature. The junction to ambient thermal resistance θja is layout dependent. For SOP8 packages, the thermal resistance θja is 160 C/W on the standard JEDEC 51-7 four-layers thermal test board. The maximum power dissipation at TA =25 C can be calculated by following formula: PD(MAX) = (125 C 25 C ) / (160 C/W) = 0.625W for SOP8 packages. The maximum power dissipation depends on operating ambient temperature for fixed TJ(MAX) and thermal resistance qja. For packages, the Figure 3 of de-rating curves allows the designer to see the effect of rising ambient temperature on the maximum power allowed. The output voltage can be calculated using: Where: Vref= 1.22V typ. (the internal reference voltage) To enable default output voltage (pre-set), connect ADJ pin to ground. There is no external component needed to decide voltage. Figure3: Maximun Power dissipation Adjustable Operation The adjustable version of the has an output voltage ranging from 1.2V to 5V. The output voltage of the adjustable regulator is programmed using an external resistor divider as shown in Figure4. 6

7 Typical Performance Characteristics (Unless otherwise specified, VIN= VOUT + 1V, TA = 25 C, CIN = COUT = 1μF) Output Voltage vs. Output Current Quiescent Current vs. Temperature Output Voltage vs. Intput Current Dropout Voltage vs. Output Current Enable Threshold vs. Temperature Enable Threshold vs. Input Voltage 7

8 Typical Performance Characteristics(Continue) Start Up Response EN Pin Shutdown Response Line Transient Response Line Transient Response Load Transient Response PSRR 8

9 Package Dimension SOT-23-5L Dimensions SYMBOL Millimeters MIN NOM MAX A A A b C D E e (TYP) - H L Θ1 1º 5º 9º e1-0.95(typ) - 9

10 SOT-89 Dimensions SYMBOL Millimeters Inches MIN NOM MAX MIN NOM MAX A A b b C D D HE E e H S e

11 SOT-223 Dimensions SYMBOL Millimeters Inches MIN NOM MAX MIN NOM MAX A A B B C D E e 2.30 BSC BSC e BSC BSC H L 0.90 MIN MIN L BSC BSC 11

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