LX8821 ® TM DUAL CHANNEL 2.5A LOW DROPOUT REGULATOR P RODUCTION S HEET KEY FEATURES DESCRIPTION Two Independent Regulated Outputs Wide DC Supply Voltage of 3.0V to 10.0V Accurate Output Voltages Low Tolerance Line (0.5%) and Load (0.5%) Regulation Max. Dropout of 0.6V at Rated Current Independent Thermal and Current Limit Protection Loop Stability Independent of Output Capacitor Type SMT Power Package bs ol et e Power sequencing logic ensures proper startup regardless of the The level of VCTRL or VPWR. LX8821 outputs remain off while VPWR < 2.2V. Thermal and Short Circuit Current Protection are integrated on-chip and operate independently for each regulator output. The LX8821 regulator is stable with a wide range of output capacitance and ESR; typically 10μF tantalum or ceramic on the outputs is sufficient. Microsemi uses a low profile power package with low thermal resistance and ease of assembly using surface mount technology. WWW . Microsemi .C OM The LX8821 is a positive-voltage linear regulator with one fixed and one adjustable output featuring lowdropout and high accuracy. To maximize efficiency, the LX8821 accepts two supply voltage inputs for the VCONTROL and VPOWER sections. This configuration reduces power dissipation by operating the regulator near dropout (VPWR-VOUT = VDO = 0.4V @ 2A) while providing sufficient operating headroom for the control logic. Each channel can supply up to 2.5A independently with a regulator design optimized for system efficiency by consuming minimal ground current and directing quiescent current to the load The internal voltage reference is trimmed at wafer level, enabling precise output voltages, typically ±1% of its specified value. DATA APPLICATIONS/BENEFITS ASIC, Memory, I/O Low Voltage Logic Supplies Active SCSI Terminators Battery Charging Circuits PC Peripherals Instrumentation IMPORTANT: For the most current data, consult Microsemi’s website: http://www.microsemi.com PRODUCT HIGHLIGHT VOUT1 VPWR VPOWER Part 10µF VOUT2 1µF ⎡ R1 ⎤ VOUT2 = 1.25 • ⎢1 + ⎥ + I ADJ • R1 ⎣ R2 ⎦ ADJ 33µF R2 GROUND LX8821 O GND LX8821 VOUT2 R1 VCONTROL VCONTROL VOUT1 33µF PACKAGE ORDER INFO TA (°C) Output V1 Output V2 0 to 100 1.5V Adjustable DF Plastic S-Pak 7-Pin RoHS Compliant LX8821CDF Note: Available in Tape & Reel. Append the letters “TR” to the part number. (i.e. LX8821CDF-TR) Copyright © 2005 Rev. 1.1, 2005-03-09 Microsemi Microsemi Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 1 LX8821 ® TM DUAL CHANNEL 2.5A LOW DROPOUT REGULATOR P RODUCTION ABSOLUTE MAXIMUM RATINGS DATA PACKAGE PIN OUT TAB is GND NC 6 ADJ V2 5 V OUT2 4 G ND 3 V PW R 2 V OUT1 1 V CTRL bs ol et e Note: Exceeding these ratings could cause damage to the device. All voltages are with respect to Ground. Currents are positive into, negative out of specified terminal. 7 DF P ACKAGE (Top View) THERMAL DATA WWW . Microsemi .C OM Input Voltage (VCTRL, VPWR).........................................................................13.5V Load Current (Internally Limited) ..................................................................3.0A Power Dissipation ......................................................................Internally Limited Short-Circuit Protection .......................................................................... Indefinite Operating Junction Temperature.................................................................. 150°C Storage Temperature Range...........................................................-65°C to 150°C Peak Package Solder Reflow Temperature (40 second maximum exposure) ..................................................... 260°C (+0, -5) DF S HEET Pin 4 and Tab are common RoHS 100% Matte Tin Lead Finish Plastic S-Pak 7-Pin THERMAL RESISTANCE-JUNCTION TO TAB, θJT THERMAL RESISTANCE-JUNCTION TO AMBIENT, θJA 4.5°C/W 20 - 50°C/W Junction Temperature Calculation: TJ = TA + (PD x θJA). The θJA numbers are guidelines for the thermal performance of the device/pc-board system. All of the above assume no ambient airflow. θJA can vary from 10°C/W to > 50°C/W depending on mounting technique. (See Application Notes Section: Thermal considerations) FUNCTIONAL PIN DESCRIPTION PIN 1 2 3 4 5 6 DESCRIPTION VCTRL Unregulated input voltage supply, provides bias for control circuitry, (VCTRL – VOUT) > 1V. VOUT1 Regulator #1 fixed output voltage, 1.5V nominal. VPWR Unregulated input voltage supply for power section. For proper operation: (VPWR – VOUT) > VDROPOUT. GND Common terminal for ground reference, Tab of package is internally connected to this pin. VOUT2 Regulator #2 output ADJ V2 Regulator #2 feedback voltage, servos to 1.25V. Using external resistors to program VOUT2. --- Not used, no internal connection, may be left floating or connected to any other pin or voltage. Copyright © 2005 Rev. 1.1, 2005-03-09 PACKAGE DATA O 7 NAME Microsemi Microsemi Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 2 LX8821 ® TM DUAL CHANNEL 2.5A LOW DROPOUT REGULATOR P RODUCTION DATA S HEET ELECTRICAL CHARACTERISTICS Parameter ` V1 Min LX8821 Typ Max ΔV1(VIN) Load Regulation ΔV1(I1) Current Limit I1 (MAX) 5mA < I1 < 2.5A, 3.75V < VCTRL < 8V 3.3V < VPWR < 5.5V 1.455 1.500 1.545 V 1 5 mV 1 5 mV 3.3V<VCTRL<10V, 3.3V<VPWR<5.5V, I1 = 5mA bs ol et e Line Regulation Minimum Load Current Units I1 5mA < I1 < 2.5A, VCTRL=5V, VPWR=3.3V 2.55 Note 1 3.0 A 0 5 mA 1.225 1.25 1.275 1.225 1.25 1.288 0.5 5 mV mV ADJUSTABLEOUTPUT: VOUT 2 Output Voltage V2 Line Regulation ΔV2(VIN) Load Regulation ΔV2(I2) VPWR-V2 Dropout Voltage, VOUT 2 VCNTR-V2 Adjust Pin Current Current Limit 5mA < I2 < 2.5A, 3.75V < VCTRL < 8V 2.97V < VPWR < 3.63V 5mA < I2 < 2.5A, 3.75V < VCTRL < 8V, 3.3V < VPWR < 5.5V 3.3V<VCTRL<10V, 3.3V<VPWR<5.5V, I2 = 5mA 5mA < I2 < 2.5A, VCTRL=5V, VPWR=3.3V I2 V 8 20 IOUT = 2.5A, ∆VO = -2% 0.500 0.750 IOUT = 2.0A, ∆VO = -2% 0.413 0.600 IOUT = 1.0A, ∆VO = -2% 0.167 0.400 IOUT = 2.5A, ∆VO = -2% 0.95 1.10 IOUT = 1.0A, ∆VO = -2% 0.80 1.00 I1 = I2 = 5mA, TJ = 25°C 0.2 1 µA 5 mA 2.6 V 3.3 V 2.2 V 3 5 mA 5 10 mA I2 (MAX) Minimum Load Current ` Test Conditions FIXED OUTPUT: VOUT 1 Total Output Voltage Variation ` Symbol WWW . Microsemi .C OM Unless otherwise specified, the following specifications apply over the operating ambient temperature 0°C ≤ TA ≤ 100°C except where otherwise noted and the following test conditions: VCTRL = 5V, VPWR = 3.3V IOUT = 5mA, C1, 2, 3, 4 = 10μF (Tantalum), and TJ = TA using low duty cycling methods. Typical values represent performance @ 23°C 2.55 Note 1 3.0 1 V V A ENTIRE REGULATOR Minimum Operating Voltage VPWR VCONTROL VPWR Rising, 3.0V<VCTRL < 10V, Both Outputs Guaranteed Off Quiescent Current Ripple Rejection IQ PSRR RMS Output Noise Thermal Shutdown I1=I2=5mA I1 = I2 = 2.5A f=120Hz, TJ = 25°C 60 10Hz < f < 10kHz TJSD 75 dB 0.003 %VOUT 160 °C Note 1: Minimum load current is defined as the amount of output current required to maintain regulation Copyright © 2005 Rev. 1.1, 2005-03-09 Microsemi Microsemi Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 3 ELECTRICALS O Under Voltage Lockout LX8821 ® TM DUAL CHANNEL 2.5A LOW DROPOUT REGULATOR P RODUCTION DATA S HEET CHARACTERISTIC CURVERS VOUT Error vs. Temperature 0.125% 0.100% Vo1 VDD (V) Vo2 0.075% 0.050% 0.025% 0.000% Iout=1A Iout=0.5A IGROUND (mA) 7 6 5 4 150 Power On Ramp: Supply Ramp Quiescent Current 8 125 Tem perature (°C) 125 100 100 75 75 50 50 25 25 0 0 -25 -50 -0.025% Temp, °C Iout=2.5A bs ol et e Error Voltage 0.175% 0.150% 0.70 0.65 0.60 0.55 0.50 0.45 0.40 0.35 0.30 0.25 0.20 0.15 0.10 0.05 WWW . Microsemi .C OM Dropout Voltage 0.200% IL1&IL2=5mA IL1&IL2=2.5A 1 2 3 2 1 0 3 150 125 100 75 50 25 0 -25 -50 Tem perature (°C) 4 CH1 CH3 2.00V 1.00V BW CH2 CH4 2.00V 2.00V BW CH1 = VP = VC CH2 = VO1 1.00ms A CH1 800mV CH3 = VO2 CH4 = IP 2A/DIV Step Load Response With Tantalum Cap (10µF) O Step Load Response With Ceramic Cap (10µF) M GRAPHS CH1 = VO1 , CH2 = V02 , CH4 = IO1 (50mA to 0.55A Step) Copyright © 2005 Rev. 1.1, 2005-03-09 CH1 = VO1 , CH2 = V02 , CH4 = IO1 (50mA to 0.55A Step) Microsemi Microsemi Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 4 LX8821 ® TM DUAL CHANNEL 2.5A LOW DROPOUT REGULATOR P RODUCTION DATA S HEET APPLICATION INFORMATION CURRENT LIMIT PROTECTION The LX8821 includes over current protection; when the output load current exceeds typically 3A the circuit forces the regulator decrease in output. bs ol et e INPUT CAPACITOR To improve load transient response and noise rejection an input bypass capacitor is of at least 10µF is required. Generally we recommend a 10µF ceramic or tantalum or 22µF electrolytic capacitor. TEMPERATURE PROTECTION The thermal protection shuts the LX8821 down when the junction temperature exceeds 160°C. Each output has independent thermal shutdown capability. Exposure to absolute maximum rated conditions for extended periods may affect device reliability: see Thermal Considerations below. OUTPUT CAPACITOR The regulator requires output capacitors connected between each output (V1, V2) to GND to stabilize the internal control loop. Many types of capacitors are available, with different capacitance values tolerances, temperature coefficients and equivalent series resistance. We recommend a minimum of 10µF. To ensure good transient response from the power supply system under rapidly changing current load conditions, designers generally use additional output capacitors connected in parallel. Such an arrangement serves to minimize the effects of the parasitic resistance (ESR) and inductance (ESL) that are present in all capacitors. The regulator has been tested stable with capacitor ESR’s in the range of 0.05 to 2 ohms. We have found it best to use the same type of capacitor for both input and output bypass. ADJUSTABLE OUTPUT VOLTAGE The LX8821 develops a 1.25V reference voltage between the adjust terminal and GND (See Figure 2). By placing a resistor, R2, between these two terminals, a constant current is caused to flow through R1 and down through R2 to set the overall output voltage. Because IADJ is very small and constant when compared with the current through R2, it represents a small error and can usually be ignored. V1 VIN VREF TTAB− AMB = (0.735W + 1.7W) × 30°C/W = 73.1°C R2 TJUNCTION-MAX = 7.7°C + 73.1°C + 50°C = 130.8°C MINIMUM LOAD REQUIREMENT The LX8821 has a minimum load requirement for proper output regulation. This typical current is specified at 0mA for the fixed output and 1ma for the adjustable output regulators. It is important to note that although each output of the regulator will produce up to 2.5A in current, the individual or total power dissipation may limit the useful total current draw. The junction temperature should be calculated for each individual output as well as the combined outputs to insure the maximum junction temperature is not exceeded. Microsemi Microsemi Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 5 APPLICATIONS O TJUNCTION = TJUNCTION − TAB + TTAB− AMB + TAMB TJ − TAB REG2 = (5V − 3.3V) × (1A) × 4.5°C/W = (1.7) × 4.5°C/W = 7.7°C Figure 2 – Basic Adjustable Regulator Copyright © 2005 Rev. 1.1, 2005-03-09 (Note: power dissipation resulting from quiescent (ground) current is negligible) Thermal resistance, θTAB-AMB ranges from 25-450C/W depending on mounting technique using a FR4 copper clad PCB. Junction temperature of the integrated circuit can be calculated using: TJ−TAB REG1 = (5V − 1.5V) × (0.21A) × 4.5° C/W = (0.735) × 4.5° C/W = 3.3°C IADJ 1µA ⎛ R1 ⎞ V 2 = VREF ⎜⎜1 + ⎟ + I ADJ R1 ⎝ R2 ⎠ PD = (VIN(MAX) − V1 ) × I1 + (VIN(MAX) − V2 ) × I 2 An example: Given conditions: TA = 50°C, VIN= 5.0V, V1= 1.5V, I1= 210mA, V2= 3.3V I2= 1A. Calculated values: R1 ADJ Power dissipation for regulator can be calculated using the following equation: TTAB = PDMAX × θ JT ; TTAB − AMB = (PDREG1 + PDREG 2 ) × θ PCB V2 Part LX8821 THERMAL CONSIDERATIONS Thermal shutdown protects the integrated circuit from thermal overload caused from a rise in junction temperature during power dissipation. This means of protection is intended for fault protection only and not as a means of current or power limiting during normal application usage. Proper thermal evaluation should be done to ensure that the junction temperature dose not exceed it’s maximum rating. Operating at the maximum TJ of 150°C can impact reliability. Due to variation in individual device electrical characteristics and thermal resistance, the built in thermal overload protection may be activated at power levels slightly above or below the rated dissipation. Also peak output power should be considered for each individual output. WWW . Microsemi .C OM The LX8821 is part of a family of Dual LDO (Low Drop-Out) linear regulators in Microsemi’s S-PAK power package which offer maximum power dissipation in a low profile surface mount technology. The family includes combination fixed and adjustable versions. Each channel can supply up to 2.5A independently with a regulator design optimized for system efficiency by consuming minimal ground current and directing quiescent current to the load. LX8821 ® TM DUAL CHANNEL 2.5A LOW DROPOUT REGULATOR P RODUCTION DATA S HEET MECHANICAL DIMINESIONS WWW . Microsemi .C OM A D C I bs ol et e B K H G F J E Note: 1. Dimensions do not include mold flash or protrusions; these shall not exceed 0.155mm(.006”) on any side. Lead Dim A B C D E F G H I J K MILLIMETERS MIN MAX 9.27 9.52 8.89 9.14 1.77 2.03 7.49 7.74 0.12 0.38 0.58 0.84 1.27 BSC 0.79 1.04 4.31 6.86 0.03 0.13 10.41 10.67 INCHES MIN MAX .365 .375 .350 .360 .070 .080 .295 .305 .005 .015 .023 .033 0.050 BSC .031 .041 .170 .270 .001 .005 .410 .420 MECHANICALS O dimension shall not include solder coverage 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. Copyright © 2005 Rev. 1.1, 2005-03-09 Microsemi Microsemi Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 6