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| EUP7981 150mA Low-Noise LDO in SC-70 DESCRIPTION The EUP7981 is an efficient, CMOS voltage regulator optimized for ultra-low-noise applications. It offers high output accuracy, extremely low dropout voltage low ground current and fast start-up time. The EUP7981 provides a very low noise output, ideal for RF applications where a clean voltage source is required. A noise bypass pin is also available for further reduction of output noise. Designed specifically for handheld and batterypowered devices, the EUP7981 provides a TTL-logic-compatible enable pin. When disabled, power consumption drops nearly to zero. The EUP7981 also works with low-ESR ceramic capacitors, reducing the amount of board space necessary for power applications, critical in handheld wireless devices. Available in the SC-70 package, the EUP7981 offers a wide range of output voltages. Key features include current limit, thermal shutdown and faster transient response. FEATURES Space-Saving 5-pin SC-70 Package 2.5V to 5.5V Input Voltage Range 50V(rms) Output Noise 140mV Dropout @ 150mA 75dB PSRR at 1kHz Low 70A Ground Current 150mA Output Current Stability with 1F Ceramic Output Capacitors Excellent Load/Line Transient Thermal Shutdown and Current Limit Protection Available in 1.5V,1.8V,1.85V,2.5V,2.8V,2.85V, 3.0V ,3.3V and Adjustable Voltages RoHS Compliant and 100% Lead (Pb)-Free APPLICATIONS Cellular Phones Bluetooth Portable Radios and Accessories PDA and Palmtop Computers Consumer/Personal Electronics Block Diagram Figure 1. DS7981 Ver1.0 Jan. 2008 1 EUP7981 Typical Application Circuit Figure 2. Pin Configurations Package Type Pin Configurations SC-70 Pin Description PIN VIN GND VEN BYPASS ADJ VOUT PIN 1 2 3 4 5 Input voltage of the LDO Common ground Enable input logic, enable high Optional bypass capacitor for noise reduction Adjustable regulator feedback input. Connect to resistor divider. Output voltage of the LDO DESCRIPTION DS7981 Ver1.0 Jan. 2008 2 EUP7981 Ordering Information Order Number EUP7981-15NIR1 EUP7981-18NIR1 EUP7981-185NIR1 EUP7981-25NIR1 EUP7981-28NIR1 EUP7981-285NIR1 EUP7981-30NIR1 EUP7981-33NIR1 EUP7981NIR1 Package Type SC-70 SC-70 SC-70 SC-70 SC-70 SC-70 SC-70 SC-70 SC-70 1/4 1/4 1/4 1/4 Marking Operating Temperature range -40 C to 125C MC 1/4 MD 1/4 MU 1/4 MB 1/4 ME 1/4 MF 1/4 MG 1/4 MH 1/4 MA 1/4 Lead Free Code 1: Lead Free 0: Lead Packing R: Tape & Reel 1/4 1/4 1/4 1/4 1/4 1/4 1/4 1/4 -40 C to 125C -40 C to 125C -40 C to 125C -40 C to 125C -40 C to 125C 1/4 -40 C to 125C -40 C to 125C -40 C to 125C EUP7981- 1/4 Operating temperature range I: Industry Standard Package Type N: SC-70 Output Voltage 15: 1.5V 18: 1.8V 185:1.85V 25: 2.5V 28: 2.8V 285: 2.85V 30: 3.0V 33: 3.3V Blank: Adjustable Absolute Maximum Ratings VIN,VEN ------------------------------------------------------------------------------- -0.3 to 6V VOUT ----------------------------------------------------------------- -0.3 to (VIN+0.3) O 6V Junction Temperature --------------------------------------------------------------------- 150C Storage Temperature Range ---------------------------------------------------- -65C to +150C Lead Temperature -------------------------------------------------------------------------- 260C Maximum Power Dissipation SC-70 ---------------------------------------------------0.3W Thermal Resistance JA(SC-70) --------------------------------------------------------- 320C/W ESD Rating Human Body Model --------------------------------------------------------------------- 2kV Operating Ratings VIN -------------------------------------------------------------------------------------- 2.5 to 5.5V VEN ------------------------------------------------------------------------- 0 to (VIN+0.3) O 5.5V Operating Temperature Range ------------------------------------------------- -40C to +125C DS7981 Ver1.0 Jan. 2008 3 EUP7981 Electrical Characteristics Conditions: VIN=VOUT+0.5V or 2.5V whichever is greater,VEN=VIN,CIN=1uF,COUT=1uF,TA=-40~85J ,Unless otherwise specified. Symbol Parameter Input Voltage Conditions IOUT=1mA,TA=25J IOUT=1mA,TA=-40J to 85J TA>0J VOUT=VOUT(nom) x 90%, TA>0J IOUT=150mA IOUT=1mA VIN=(VOUT+0.5V) to 5.5V, IOUT=1mA 1mA IOUT 150mA VEN=0,TA=25J VIN=(VOUT+1V)DC+0.5VP-P f=1kHz, ILOAD=10mA f=10Hz~100kHz, ILOAD=10mA f=10Hz~100kHz, ILOAD=10mA RLOAD=50,TA=25J VIN=2.5V to 5.5V VIN=2.5V to 5.5V VIN=5.5V, VEN=0 or 5.5V VIN=5.5V, VFB=1.3V TA=25J EUP7981 Min Typ Max. 2.5 -2 -3 150 150 220 140 70 0.02 0.002 400 240 160 0.25 0.013 1 75 50 239 200 0.4 1.5 1 1 1.176 1.2 155 15 1.224 5.5 2 3 Unit V % % mA mA mV A %/V %/mA A dB V V s V V nA nA V J J VOUT Output Voltage Accuracy IOUTMAX Maximum Output Current ILIMIT VDROP IQ VLNR VLDR ISHDN PSRR Current Limit Dropout Voltage (Note1) Quiescent Current Line Regulation Load Regulation Shutdown Supply Current Power Supply Ripple Rejection Output Noise Voltage (Bypass) Output Noise Voltage (ADJ) Turn-on Time (Note2) VENL VENH VENL (Maximum Low Level Input Voltage at EN) VENH (Minimum high Level Input Voltage at EN) VEN Input Bias Current FB Input Bias Current (ADJ Version) FB Pin Voltage (ADJ Version) Thermal Shutdown Temperature Thermal Shutdown Hysteresis VFB TSD TSD Note 1: Dropout is defined as VIN-VOUT when VOUT is 100mV below the value of VOUT for VIN=VOUT+0.6V Note 2: Test time needed for VOUT to reach 90% of final value. DS7981 Ver1.0 Jan. 2008 4 EUP7981 Typical Operating Characteristics OUTPUT VOLTAGE vs. INPUT VOLTAGE 3.0 OUTPUT VOLTAGE (V) 2.5 2.0 1.5 1.0 IOUT=120mA OUTPUT VOLTAGE ACCURACY vs. LOAD CURRENT 0.4 DEVIATION (%) IOUT=0mA 0.2 0.0 -0.2 0.5 0.0 0 1 2 3 4 INPUT VOLTAGE (V) 5 6 -0.4 0 20 40 60 80 LOAD CURRENT (mA) 100 120 OUTPUT VOLTAGE ACCURACY vs. TEMPERATURE 0.8 IOUT=1mA DROPOUT VOLTAGE vs. LOAD CURRENT 120 o DEVIATION (%) 0.4 DROPOUT VOLTAGE (mV) Temp=85 C 80 Temp=25 C o 0.0 40 -0.4 Temp=-40 C o -0.8 -40 0 -15 10 35 o 60 85 0 20 40 60 80 100 120 Temperature ( C) LOAD CURRENT (mA) GROUND CURRENT vs. INPUT VOLTAGE 200 GROUND CURRENT vs. LOAD CURRENT 200 GROUND CURRENT (uA) 160 GROUND CURRENT (uA) IOUT=120mA 160 Vin=5.5V 120 Vin=3.3V 80 120 80 40 IOUT=0mA 40 0 0 1 2 3 4 5 6 0 0 20 INPUT VOLTAGE (V) LOAD CURRENT (mA) 40 60 80 100 120 DS7981 Ver1.0 Jan. 2008 5 EUP7981 GROUND CURRENT vs. TEMPERATURE 120 GROUND CURRENT (uA) 100 80 60 40 20 0 -40 -20 0 20 TEMPERATURE ( C) 40 60 o 80 100 120 140 DS7981 Ver1.0 Jan. 2008 6 EUP7981 DS7981 Ver1.0 Jan. 2008 7 EUP7981 Application Note External Capacitors Like any low-dropout regulator, the EUP7981 requires external capacitors for regulator stability. The EUP7981 is specifically designed for portable applications requiring minimum board space and smallest components. These capacitors must be correctly selected for good performance. Input Capacitor An input capacitance of 1F is required between the EUP7981 input pin and ground (the amount of the capacitance may be increased without limit). This capacitor must be located a distance of not more than 1cm from the input pin and returned to a clean analog ground. Any good quality ceramic, tantalum, or film capacitor may be used at the input. If a tantalum capacitor is used at the input, it must be guaranteed by the manufacturer to have a surge current rating sufficient for the application. There are no requirements for the ESR on the input capacitor, but tolerance and temperature coefficient must be considered when selecting the capacitor to ensure the capacitance will be 1F over the entire operating temperature range. Output Capacitor The EUP7981 is designed specifically to work with very small ceramic output capacitors. A ceramic capacitor (temperature characteristics X7R, X5R, Z5U, or Y5V) in 1 to 22F range with 5m to 500m ESR range is suitable in the EUP7981 application circuit. The output capacitor must meet the requirement for minimum amount of capacitance and also have an ESR (Equivalent Series Resistance) value which is within a stable range (5m to 500m) No-Load Stability The EUP7981 will remain stable and in regulation with no external load. This is specially important in CMOS RAM keep-alive applications. Capacitor Characteristics The EUP7981 is designed to work with ceramic capacitors on the output to take advantage of the benefits they offer: for capacitance values in the range of 1F to 4.7F range, ceramic capacitors are the smallest, least expensive and have the lowest ESR values (which makes them best for eliminating high frequency noise). The ESR of a typical 1F ceramic capacitor is in the range of 20m to 40m, which easily meets the ESR requirement for stability by the EUP7981. The ceramic capacitor's capacitance can vary with temperature. The capacitor type X7R, which operates over a temperature range of -55C to +125C, will only vary the capacitance to within 15%. Most large value ceramic capacitors ( 2.2F) are manufactured with Z5U or Y5V temperature characteristics. Their DS7981 Ver1.0 Jan. 2008 capacitance can drop by more than 50% as the temperature goes from 25C to 85C. Therefore, X7R is recommended over Z5U and Y5V in applications where the ambient temperature will change significantly above or below 25C. Noise Bypass Capacitor Connecting a 0.01F capacitor between the CBYPASS pin and ground significantly reduces noise on the regulator output. This cap is connected directly to a high impedance node in the bandgap reference circuit. Any significant loading on this node will cause a change on the regulated output voltage. For this reason, DC leakage current through this pin must be kept as low as possible for best output voltage accuracy. The types of capacitors best suited for the noise bypass capacitor are ceramic and film. Unlike many other LDO's, addition of a noise reduction capacitor does not effect the load transient response of the device. Adjustable Operation The adjustable version of the EUP7981 has an output voltage range of 1.2V to 4.5V. The output voltage of the EUP7981 adjustable regulator is programmed using an external resistor divider as shown in Figure3. The output voltage is calculated using: V =V O ref x (1 + R R 1) 2 Where: Vref= 1.2V typ. (the internal reference voltage) Utilize the following equation for adjusting the output to a particular voltage: V PI = R 2 O - 1 1.2V Choose R2=50k to optimize accuracy, power supply rejection, noise and power consumption. Figure3. Adjustable Regulator with Resistors 8 EUP7981 On/Off Input Operation The EUP7981 is turned off by pulling the VEN pin low, and turned on by pulling it high. If this feature is not used, the VEN pin should be tied to VIN to keep the regulator output on at all time. To assure proper operation, the signal source used to drive the VEN input must be able to swing above and below the specified turn-on/off voltage thresholds listed in the Electrical Characteristics section under VIL and VIH. Fast Start up The EUP7981 output starts up after Vref voltage reaches its final value (1.2V nomial). The start-up time is determined by the time constant of the bypass capacitor. The smaller the capacitor value., the shorter the start-up time, but less noise gets reduced. As a result, start-up time and noise reduction need to be taken into design consideration when choosing the value of the bypass capacitor. DS7981 Ver1.0 Jan. 2008 9 EUP7981 Packaging Information SC-70 SYMBOLS A A1 b D E E1 e L MILLIMETERS MIN. MAX. 0.80 1.10 0.025 0.10 0.15 0.40 2.00 1.25 1.90 2.30 0.65 0.21 0.46 INCHES MIN. 0.031 0.001 0.006 0.079 0.049 0.075 0.026 0.008 0.018 0.091 MAX. 0.044 0.004 0.016 DS7981 Ver1.0 Jan. 2008 10 |
Price & Availability of EUP7981-18NIR1
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