EUP7981 150mA Low-Noise LDO in SC-70 DESCRIPTION FEATURES 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. z z z z z z z z z z z z APPLICATIONS z z z z Block Diagram Figure 1. DS7981 Ver1.0 Jan. 2008 Space-Saving 5-pin SC-70 Package 2.5V to 5.5V Input Voltage Range 50µV(rms) Output Noise 140mV Dropout @ 150mA 75dB PSRR at 1kHz Low 70µA Ground Current 150mA Output Current Stability with 1µF 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 1 Cellular Phones Bluetooth Portable Radios and Accessories PDA and Palmtop Computers Consumer/Personal Electronics EUP7981 Typical Application Circuit Figure 2. Pin Configurations Package Type Pin Configurations SC-70 Pin Description PIN PIN VIN 1 Input voltage of the LDO GND 2 Common ground VEN 3 Enable input logic, enable high BYPASS ADJ VOUT DS7981 Ver1.0 4 DESCRIPTION Optional bypass capacitor for noise reduction Adjustable regulator feedback input. Connect to resistor divider. 5 Output voltage of the LDO Jan. 2008 2 EUP7981 Ordering Information Order Number Package Type Marking Operating Temperature range EUP7981-15NIR1 SC-70 MC □ □ -40 °C to 125°C EUP7981-18NIR1 SC-70 MD □ □ -40 °C to 125°C EUP7981-185NIR1 SC-70 MU □ □ -40 °C to 125°C EUP7981-25NIR1 SC-70 MB □ □ -40 °C to 125°C EUP7981-28NIR1 SC-70 ME □ □ -40 °C to 125°C EUP7981-285NIR1 SC-70 MF □ □ -40 °C to 125°C EUP7981-30NIR1 SC-70 MG □ □ -40 °C to 125°C EUP7981-33NIR1 SC-70 MH □ □ -40 °C to 125°C EUP7981NIR1 SC-70 MA □ □ -40 °C to 125°C EUP7981- □□□ □ □ □ □ Lead Free Code 1: Lead Free 0: Lead Packing R: Tape & Reel 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) ≦ 6V Junction Temperature --------------------------------------------------------------------- 150°C Storage Temperature Range ---------------------------------------------------- -65°C to +150°C Lead Temperature -------------------------------------------------------------------------- 260°C Maximum Power Dissipation SC-70 ---------------------------------------------------0.3W Thermal Resistance θJA(SC-70) --------------------------------------------------------- 320°C/W ESD Rating Human Body Model --------------------------------------------------------------------- 2kV Operating Ratings DS7981 Ver1.0 VIN -------------------------------------------------------------------------------------- 2.5 to 5.5V VEN ------------------------------------------------------------------------- 0 to (VIN+0.3) ≦ 5.5V Operating Temperature Range ------------------------------------------------- -40°C to +125°C Jan. 2008 3 EUP7981 Electrical Characteristics Conditions: VIN=VOUT+0.5V or 2.5V whichever is greater,VEN=VIN,CIN=1uF,COUT=1uF,TA=-40~85℃ ,Unless otherwise specified. Symbol Parameter Conditions Input Voltage ∆VOUT Output Voltage Accuracy IOUTMAX Maximum Output Current IOUT=1mA,TA=25℃ 5.5 2 V % IOUT=1mA,TA=-40℃ to 85℃ -3 3 % TA>0℃ 150 150 Current Limit VOUT=VOUT(nom) × 90%, TA>0℃ VDROP Dropout Voltage (Note1) Quiescent Current VLNR Line Regulation VLDR Load Regulation ISHDN Shutdown Supply Current PSRR Power Supply Ripple Rejection Unit 2.5 -2 ILIMIT IQ EUP7981 Min Typ Max. mA 220 400 mA IOUT=150mA 140 240 mV IOUT=1mA VIN=(VOUT+0.5V) to 5.5V, IOUT=1mA 1mA ≤ IOUT ≤ 150mA 70 160 µA 0.02 0.25 %/V 0.002 0.013 %/mA 1 µA 75 dB Output Noise Voltage (Bypass) VEN=0,TA=25℃ VIN=(VOUT+1V)DC+0.5VP-P f=1kHz, ILOAD=10mA f=10Hz~100kHz, ILOAD=10mA 50 µV Output Noise Voltage (ADJ) f=10Hz~100kHz, ILOAD=10mA 239 µV Turn-on Time (Note2) RLOAD=50Ω,TA=25℃ 200 µs VIN=2.5V to 5.5V 0.4 V VFB 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) TSD Thermal Shutdown Temperature 155 ℃ Thermal Shutdown Hysteresis 15 ℃ VENL VENH ∆TSD VIN=2.5V to 5.5V 1.5 V VIN=5.5V, VEN=0 or 5.5V 1 nA VIN=5.5V, VFB=1.3V 1 nA TA=25℃ 1.176 1.2 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 1.224 V EUP7981 Typical Operating Characteristics OUTPUT VOLTAGE ACCURACY vs. LOAD CURRENT 0.4 OUTPUT VOLTAGE vs. INPUT VOLTAGE 2.5 IOUT=0mA 2.0 DEVIATION (%) OUTPUT VOLTAGE (V) 3.0 1.5 1.0 0.2 0.0 -0.2 IOUT=120mA 0.5 -0.4 0.0 0 1 2 3 4 INPUT VOLTAGE (V) 5 0 6 100 120 120 DROPOUT VOLTAGE (mV) 0.8 IOUT=1mA 0.4 0.0 -0.4 -0.8 -40 o Temp=85 C o Temp=25 C 80 40 o Temp=-40 C 0 -15 10 35 60 0 85 20 40 60 80 100 120 LOAD CURRENT (mA) o Temperature ( C) GROUND CURRENT vs. INPUT VOLTAGE GROUND CURRENT vs. LOAD CURRENT 200 200 IOUT=120mA 160 GROUND CURRENT (uA) GROUND CURRENT (uA) 40 60 80 LOAD CURRENT (mA) DROPOUT VOLTAGE vs. LOAD CURRENT OUTPUT VOLTAGE ACCURACY vs. TEMPERATURE DEVIATION (%) 20 120 80 IOUT=0mA 40 0 0 1 2 3 4 5 Ver1.0 Jan. 2008 Vin=5.5V 120 Vin=3.3V 80 40 0 6 0 INPUT VOLTAGE (V) DS7981 160 5 20 40 60 80 LOAD CURRENT (mA) 100 120 EUP7981 GROUND CURRENT vs. TEMPERATURE GROUND CURRENT (uA) 120 100 80 60 40 20 0 -40 DS7981 -20 Ver1.0 0 20 40 60 80 o TEMPERATURE ( C) Jan. 2008 100 120 140 6 EUP7981 DS7981 Ver1.0 Jan. 2008 7 EUP7981 Application Note capacitance can drop by more than 50% as the temperature goes from 25°C to 85°C. Therefore, X7R is recommended over Z5U and Y5V in applications where the ambient temperature will change significantly above or below 25°C. 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. Noise Bypass Capacitor Connecting a 0.01µF 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. Input Capacitor An input capacitance of 1µF 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 1µF over the entire operating temperature range. 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: 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 22µF range with 5mΩ to 500mΩ 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 (5mΩ to 500mΩ) V =V O Jan. 2008 R R 1) 2 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. 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 1µF to 4.7µF 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 1µF ceramic capacitor is in the range of 20mΩ to 40mΩ, 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 -55°C to +125°C, will only vary the capacitance to within ±15%. Most large value ceramic capacitors ( ≈ 2.2µF) are manufactured with Z5U or Y5V temperature characteristics. Their Ver1.0 × (1 + Where: Vref= 1.2V typ. (the internal reference voltage) 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. DS7981 ref 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 DS7981 Ver1.0 Jan. 2008 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 10 INCHES MIN. 0.031 0.001 0.006 MAX. 0.044 0.004 0.016 0.079 0.049 0.075 0.091 0.026 0.008 0.018