LX8240ILD

LX8240 800mA Very High PSRR Low-Dropout Linear Regulator Features Description  High PSRR, higher than 48 dB over all frequency up to 100kHz  High PSRR, higher than 32 dB over all frequency up to 1MHz  +/-2% Accuracy over Temp, Supply and Load  Adjustable Output (0.5V reference)  Over Current Limit  Thermal Protection LX8240 is a low-dropout regulator offering the highest Power Supply Rejection Ratio (PSRR), higher than 48 dB over all frequency up to 100kHz, and higher than 32 dB over all frequency up to 1MHz for LDO devices supplying 800mA of output current. LX8240 also requires very low quiescent current. It has separate Bias and Input supply rails to improve efficiency and minimize power dissipation. The VBIAS input includes a voltage compliance range from 2.7V to 5.5V, and the VIN supply range is 1.2V to 4.2V. The output voltage is programmed by an external resistor divider utilizing the 0.5V reference feedback (FB) pin allowing output voltages as low as 1V. Applications  Low Power Mobile Devices  Portable Devices  Post Processing for a Switching Regulator LX8240 is an ideal selection for battery-powered systems where the low quiescent current cannot be compromised. It is also guaranteed to be the stable even with only a 1µF ceramic capacitor. To protect the device the LX8240 aso includes internal thermal shutdown, and overcurrent limit features. 2 5V BIAS OUT 8 C1 1µF 1 1.8V IN LX8240 FB 7 1.5V @500mA C4 10nF C2 10µF C3 1µF 5 EN GND 4 Figure 1 · Typical Application of LX8240 June 2013 Rev. 1.0 www.microsemi.com © 2013 Microsemi Corporation 1 800mA Very High PSRR Low-Dropout Linear Regulator Pin Configuration and Pinout IN 1 8 OUT BIAS 2 7 FB N/C 3 6 N/C GND 4 5 EN Figure 2 · Pinout WDFN 3mm x 2mm 8L Top View Marking: Line 1 8240 Line 2 Date / Lot Code Line 3 * MSC ( *Pin 1 identifier ) Ordering Information Ambient Temperature Type Package -40°C to 85°C RoHS Compliant, Pb-free WDFN 3mm x 2mm 8L Part Number Packaging Type LX8240ILD Bulk / Tube LX8240ILD-TR Tape and Reel Pin Description Pin Pin Number Designator 2 Description Power Source Input. Bypass IN to GND with a 1μF or greater capacitor. 1 IN 2 BIAS 3, 6 NC 4 GND 5 EN Enable Input. Drive EN high to turn on, drive EN low to turn it off. For automatic startup, connect EN to Bias. 7 FB Feedback Input. Connect a resistive voltage divider from OUT to FB to set the output voltage. OUT feedback threshold is 0.5V. 8 OUT Bias Voltage. Bypass to GND with a 1μF capacitor or greater. No Connect. Ground. Regulator Output. OUT is the output of the linear regulator. Bypass OUT to GND with a 1μF or greater capacitor. Block Diagram Block Diagram BIAS 2 IN 1 OUT EN 5 8 REF FB 7 4 GND Figure 3 · Simplified Block Diagram of LX8240 Absolute Maximum Ratings Min Max Units IN to GND -0.3 7 V BIAS to GND -0.3 < VEN EN, FB to GND -0.3 7 V OUT to GND -0.3 7 V Junction Temperature -40 150 °C Storage Temperature -65 150 °C 260 (+0,-5) °C HBM 5000 V CDM 2000 V Parameter Peak Solder Reflow Temperature (40 seconds) ESD Rating Note: Performance is not necessarily guaranteed over this entire range. These are maximum stress ratings only. Exceeding these ratings, even momentarily, can cause immediate damage, or negatively impact long-term operating reliability 3 800mA Very High PSRR Low-Dropout Linear Regulator Operating Ratings Min Max Units IN 1.2 4.2 V BIAS 2.7 5.5 V Output Voltage 1 4 V Output Current 0 800 mA -40 85 °C Ambient Temperature Note: Performance is generally guaranteed over this range as further detailed below under Electrical Characteristics. Thermal Properties Thermal Resistance Typ Units θJA 55 °C/W θJC 12 °C/W Note: The JX numbers assume no forced airflow. Junction Temperature is calculated using T J = TA + (PD x JA). In particular, θJA is a function of the PCB construction. The stated number above is for a four-layer board in accordance with JESD-51 (JEDEC). Electrical Characteristics Note: The following specifications apply over the operating ambient temperature of -40C ≤ TA ≤ 85C except where otherwise noted with the following test conditions: V IN = 1.8V,VBIAS = 5.0V, VOUT = 1.5V, C1 = C3 = 1µF and C2 = 10µF at TA = 25°C. Symbol Parameters Test Conditions/Comments Min VBIAS Bias Voltage Range VBIAS > VIN + 1.3V VIN VIN < VBIAS - 1.3V, VIN < VOUT + 0.9V @ IOUT = 800mA Input Voltage Range VIN < VBIAS - 1.3V, VIN < VOUT + (0.727 / IOUT)V @ VOUT = 1.5V, (Note 3) Typ Max Units 2.7 5.5 V 1.2 4.2 V 1.2 4.2 V IBIAS Bias Current IOUT = 10µA, VOUT = 1.5V 200 µA IIN Input Current IOUT = 0µA, VOUT = 1.5V 20 µA IFB FB Biasing Current 0.5 µA VREF FB Reference Voltage VDO Dropout Voltage VOUT Output Voltage 4 VFB = 0.5V, TA = 25C -0.5 µA 0 VFB = 0.5V, TA = 85C (Note 1) IOUT = 1mA to 800mA 0.49 0.5 0.51 -40C ≤ TA ≤ 85C 0.49 0.5 0.51 VBIAS = 4.75V, VOUT = 1.5V, IOUT = 800mA, VIN = sweep, (Note 2) 1 V 200 mV 4 V Electrical Characteristics Symbol Parameters VBIAS Line Regulation Test Conditions/Comments IOUT = 100mA, VIN = 1.8V, VOUT = 1.5V, VBIAS = 3.1V to 5.5V ( ) ( VIN Line Regulation PSRR PSRR VBIAS PSRR ( ) ( ) ( ) ( ) Typ Max Units 0.07 0.4 %/V 0.002 0.02 %/V ) IOUT = 1mA, VBIAS = 5V, VOUT = 1.5V, VIN = 1.7V to 4.2V ( Load Regulation Min ( ) ) IOUT = 1mA to 800mA 0.0005 VIN > VOUT + 0.2V, C2 = 10µF, VBIAS(AC) = 100mV, f = 1kHz, ILOAD = 100mA, (Note 1) 55 VIN > VOUT + 0.2V, C2 = 10µF, VBIAS(AC) = 100mV, f = 1MHz, ILOAD = 100mA (Note 1) 33 VBIAS > VOUT + 1.3V, C2 = 10µF, VIN(AC) = 100mV, f = 1kHz, ILOAD = 100mA, (Note 1) 59 dB VIN PSRR dB VBIAS > VOUT + 1.3V, C2 = 10µF, VIN(AC) = 100mV, f = 1MHz, ILOAD =100mA (Note 1) ICL Output Current Limit IQ Quiescent Ground Current 33 850 mA EN = GND 0.1 2 µA 1.3V < EN ≤ VBIAS, ILOAD = 500mA 150 200 µA VOUT Undershoot Over Step Load Transient Load step from 20mA to 450mA with rising time of 100ns (Note 1) 33 mV VOUT Overshoot Over Step Load Transient Load step from 450mA to 20mA with falling time of 600ns (Note 1) 23 mV EN Input High Voltage 1.3 V EN Input Low Voltage EN Input Bias Current TTHERMAL %/mA Thermal Protection Threshold VEN = 1.2V -1 0.4 V 1 µA Rising (Note 1) 155 °C Falling (Note 1) 125 °C Note: 1. Guaranteed by Design Note: 2. Dropout is defined as VIN - VOUT_LDO when VOUT_LDO is 98% of the value of VOUT_LDO for VIN = VOUT(VIN = 1.8V, VBIAS = 5V, IOUT = 800mA) Note: 3. 0.727 is the maximum allowed power before thermal shutdown. 5 800mA Very High PSRR Low-Dropout Linear Regulator Typical Performance Curves -- (VOUT = 1.5V) 1.506 1.5054 Load = 100mA Load = 50mA Load = 500mA 1.5058 1.5056 1.5052 1.505 VOUT (V) VOUT (V) 1.5054 1.5052 1.505 1.5048 1.5046 1.5044 1.5048 1.5046 1.5042 1.5044 1.504 1.5042 1.5038 2.7 3.1 3.5 3.9 4.3 VBIAS (V) 4.7 5.1 5.5 1.7 1.5054 90 1.5052 80 3.2 3.7 4.2 70 Dropout (mV) 1.5048 VOUT (V) 2.7 Figure 5 · VIN Line Regulation, VBIAS = 5V 1.505 1.5046 1.5044 1.5042 60 50 40 30 20 1.504 10 1.5038 0 1 10 100 Load Current (mA) 1000 Figure 6 · Load Regulation, VIN = 1.8V, VBIAS = 5V 0 200 400 Load Current (mA) 600 800 Figure 7 · Voltage Dropout, VIN = 1.8V, VBIAS = 4.75V 35 1.498 30 1.496 25 Dropout (mV) 1.494 VOUT (V) 2.2 VIN (V) Figure 4 · VBIAS Line Regulation, VIN = 1.8V 1.492 1.49 20 15 10 1.488 5 0 1.486 -40 -15 10 35 Temperature (°C) 60 Figure 8 · Output Voltage vs. Temperature VIN = 1.8V, VBIAS = 4.75V, ILoad = 300mA 6 Load = 1mA Load = 100mA Load = 500mA 85 -40 -15 10 35 Temperature (°C) 60 Figure 9 · Voltage Dropout vs. Temperature VIN = 1.8V, VBIAS = 4.75V, ILoad = 300mA 85 Typical Performance Curves -- (VOUT = 1.5V) Typical Performance Curves -- (VOUT = 1.5V) 0.5015 60 0.501 50 0.5005 40 Gain (dB) VREF (V) 0.5 0.4995 0.499 0.4985 30 20 0.498 10 0.4975 0.497 0 -40 -15 10 35 Temperature (°C) 60 85 Figure 10 · Reference Voltage vs. Temperature 1 10 Frequency (kHz) 100 1000 Figure 11 · VBIAS to VOUT PSRR VIN = 1.8V, VBIAS = 4.75V, ILoad = 300mA 70 60 Gain (dB) 50 40 30 20 10 0 1 10 Frequency (kHz) 100 1000 Figure 12 · VIN to VOUT PSRR 7 800mA Very High PSRR Low-Dropout Linear Regulator Typical Performance Curves -- Figure 13 · Power Up with 400mA Load Current Figure 14 · Power Down with 400mA Load Current VIN = 1.8V, VBIAS = 5V VIN = 1.8V, VBIAS = 5V CH1: VIN, CH3: VOUT, CH4: Load Current CH1: VIN, CH3: VOUT, CH4: Load Current Figure 15 · Enable Up with 400mA Load Current 8 (Start Up & Shut Down, VOUT = 1.5V) Figure 16 · Enable Down with 400mA Load Current VIN = 1.8V, VBIAS = 5V VIN = 1.8V, VBIAS = 5V CH1: VIN, CH3: VOUT, CH4: Load Current CH1: VIN, CH3: VOUT, CH4: Load Current Typical Performance Curves -- (Step Response & Over Current Limit) Typical Performance Curves -- (Step Response & Over Current Limit) Figure 17 · Dynamic Response, ILoad = 20mA to 450mA Figure 18 · Dynamic Response, ILoad = 20mA to 450mA VIN = 1.2V, VBIAS = 2.7V, VOUT = 1V VIN = 1.8V, VBIAS = 5V, VOUT = 1.5V CH2: VOUT AC, CH3: VOUT DC, CH2: VOUT AC, CH3: VOUT DC, CH4: Load Current CH4: Load Current Figure 19 · Dynamic Response, ILoad = 20mA to 450mA VIN = 4.2V, VBIAS = 5.5V, VOUT = 4V CH2: VOUT AC, CH3: VOUT DC, CH4: Load Current 9 800mA Very High PSRR Low-Dropout Linear Regulator Theory of Operation / Application Information BIAS pin operation The IC uses a BIAS pin to allow low RDSON. VBIAS needs to be higher than VIN by 1.3V to provide circuit headroom since there is no internal charge pump. The VBIAS all insures the high VIN – to - VOUT PSRR, and the low noise performance is achieved with this topology at lower cost. Adaptive PSRR compensation LX8240 has internal adaptive feedforward control. A typical feedforward design depends on the zero from the external feedforward capacitance, C4 in Figure 20. In LX8240, the internal adaptive feedforward control circuit has an automatic pole compensator to allow different frequency inputs to experience a different zero frequency. This is equivalent to pole-zero pair in the control loop. This method allows LX8240 to maintain high gain over a very wide frequency range. Furthermore, it helps LX8240 sustain PSRR higher than 32dB over the entire frequency range up to 1MHz. Setting the output Voltage A typical LX8240 application circuit is shown in Figure 19. External component selection is driven by the load requirement. The LX8240 develops a 0.5V reference voltage between the feedback pin and the ground. The output voltage is set by a resistive divider according to the following formula: ( 2 5V BIAS OUT ) 8 C1 1uF R1 1 1.8V IN LX8240 FB 7 C3 1uF R2 5 EN Figure 20 · Typical Application 10 1.5V @500mA GND 4 C4 10nF C2 10uF PACKAGE OUTLINE DIMENSIONS PACKAGE OUTLINE DIMENSIONS D D2 Dim L E E2 Pin 1 K e A A1 b A3 MILLIMETERS MIN MAX INCHES MIN MAX A A1 A3 0.70 0.80 0.00 0.05 0.20 REF 0.028 0.032 0.000 0.002 0.008 D D2 b 2.00 BSC 1.50 1.75 0.18 0.30 0.079 BSC 0.059 0.030 0.007 0.012 E E2 3.00 BSC 1.65 1.90 0.118 BSC 0.065 0.075 e L K 0.50 BSC 0.30 0.50 0.20 0.020 BSC 0.012 0.002 0.008 Figure 21 · LD 8-Pin WDFN Package Dimensions Note: 1. Dimensions do not include mold flash or protrusions; these shall not exceed 0.155mm (.006”) on any side. Lead dimension shall not include solder coverage. Note: 2. Dimensions are in mm, inches are for reference only. LAND PATTERN RECOMMENDATION 1.80mm 1.75mm 0.70mm 1.80mm 3.60mm 0.20mm Pin 1 0.50mm 0.30mm Figure 22 · LD 8-Pin WDFN Package Land Pattern Disclaimer: This PCB land pattern recommendation is based on information available to Microsemi by its suppliers. The actual land pattern to be used could be different depending on the materials and processes used in the PCB assembly, end user must account for this in their final layout. Microsemi makes no warranty or representation of performance based on this recommended land pattern. PRODUCTION DATA – Information contained in this document is proprietary to Microsemi and is current as of publication date. This document may not be modified in any way without the express written consent of Microsemi. Product processing does not necessarily include testing of all parameters. Microsemi reserves the right to change the configuration and performance of the product and to discontinue product at any time. 11 Microsemi Corporation (NASDAQ: MSCC) offers a comprehensive portfolio of semiconductor solutions for: aerospace, defense and security; enterprise and communications; and industrial and alternative energy markets. Products include high-performance, high-reliability analog and RF devices, mixed signal and RF integrated circuits, customizable SoCs, FPGAs, and complete subsystems. Microsemi is headquartered in Aliso Viejo, Calif. Learn more at www.microsemi.com. Microsemi Corporate Headquarters One Enterprise, Aliso Viejo CA 92656 USA Within the USA: +1(949) 380-6100 Sales: +1 (949) 380-6136 Fax: +1 (949) 215-4996 © 2013 Microsemi Corporation. All rights reserved. Microsemi and the Microsemi logo are trademarks of Microsemi Corporation. All other trademarks and service marks are the property of their respective owners. LX8240-3/1.0