LX8817 L I N F I N I T Y Dual Channel 2.5A Low Dropout Regulator D I V I S I O N P RODUCTION D ATA S HEET KEY FEATURES DESCRIPTION and directing quiescent current to the load. The LX8817 features on-chip trimming of the internal voltage reference, enabling precise output voltages, typically ±1% of it’s specified value. Power sequencing logic ensures proper startup regardless of the level of VCTRL or VPWR. The LX8817 outputs remain off while VPWR < 2.4V. Thermal and Short Circuit Current Protection are integrated on-chip and operate independently for each regulator output. The LX8817 regulator is stable with a low-value output capacitor, typically 10µF tantalum or ceramic on the outputs, allowing designers flexibility in external component selection. Linfinity’s S-PAK power package offers maximum power dissipation and ease of assembly using surface mount technology. ! Two Independent Regulated Outputs ! Accurate Output Voltages ! Max. Dropout of 0.6V at Rated Current ! Independent Thermal and Current Limit Protection ! Low Profile 7 Lead SMT Power Package ! Low Tolerance Line (0.2%) and Load (0.4%) Regulation ! Wide DC Supply Voltage of 3.0V to 10.0V ! Loop Stability Independent of Output Capacitor Type W W W. Microsemi .COM The LX8817 is a dual channel positive-voltage linear regulator. This dual regulator has one fixed output coupled with an adjustable output. Each channel features low-dropout and high accuracy. The LX8817 utilizes dual inputs that can be used as separate sources for the control and power sections. This configuration reduces power dissipation by operating the regulator near dropout (VPWR-VOUT = VDO = 0.6V @ 2.5A) while providing sufficient operating headroom for the control logic. The LX8817 provides designers with an efficient flexible power management solution, minimal printed circuit board area, and shorter design cycles. Each channel can supply up to 2.5A independently with a regulator design optimized for system efficiency by consuming minimal ground current APPLICATIONS/BENEFITS APPLICATIONS/BENEFITS ! 3.3V to 2.5V/ADJ Linear Regulator ! Low Voltage Logic Supplies ! Active SCSI Terminators ! Battery Charging Circuits ! Instrumentation ! PC Peripherals IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com PRODUCT HIGHLIGHT VPWR VPWR VOUT1 3 V1 2 LX8817 VOUT2 V2 5 VCTRL VCTRL 1 ADJV2 6 GND 4 LX8817 PACKAGE ORDER INFO TA (°C) OUTPUT V1 OUTPUT V2 0 to 125 2.5V Adj Plastic S-PAK 7-PIN LX8817-25CDF DF Note: Available in Tape & Reel. Append the letter “T” to the part number. (i.e. LX8817-25CDFT) Copyright 2000 Rev. 0.3D, 2002-01-08 Microsemi Linfinity Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 1 LX8817 L I N F I N I T Y Dual Channel 2.5A Low Dropout Regulator D I V I S I O N P RODUCTION D ATA S HEET ABSOLUTE MAXIMUM RATINGS PACKAGE PIN OUT W W W. Microsemi .COM 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 Lead Temperature (Soldering 180 seconds) .................................................235°C TAB is GND 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 NC 6 ADJ V2 5 V O UT2 4 GND 3 VPW R 2 V O UT1 1 V CTRL DF P ACKAGE (Top View) THERMAL DATA DF Plastic S-PAK 7-PIN THERMAL RESISTANCE-JUNCTION TO T AB, θJT THERMAL RESISTANCE-JUNCTION TO AMBIENT, θJA 4.5°°C/W 30°°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 significantly depending on mounting technique. (See Application Notes Section: Thermal considerations) FUNCTIONAL PIN DESCRIPTION PIN NAME DESCRIPTION 1 VCTRL Unregulated input voltage supply, provides bias for control circuitry, (VCTRL – VOUT) > 1V. 2 VOUT1 Regulator #1 fixed output voltage. 3 VPWR Unregulated input voltage supply for power section. For proper operation: (VPWR – VOUT) > VDROPOUT. 4 GND Common terminal for ground reference, Tab of package is internally connected to this pin. 5 VOUT2 Regulator #2 adjustable output. 6 ADJV2 Regulator #2 voltage feedback. Sets the output voltage for regulator #2 via an external resistor divider. 7 NC Not used. PACKAGE DATA Copyright 2000 Rev. 0.3D, 2002-01-08 Microsemi Linfinity Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 2 LX8817 L I N F I N I T Y Dual Channel 2.5A Low Dropout Regulator D I V I S I O N P RODUCTION D ATA S HEET Parameter Symbol Min LX8817-25 Typ Units Max VCTRL 10 VPWR 7.5 V Load Current (Internally Limited) I1, I2 3.0 A Operating Junction Temperature TJ 125 °C Input Voltage V ELECTRICAL CHARACTERISTICS Unless otherwise specified, the following specifications apply over the operating ambient temperature 0°C ≤ TA ≤ 125°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. Parameter ! ! FIXED OUTPUT Output Voltage • LX8817-2500 Line Regulation Load Regulation ∆V1(VIN) ∆V1(I1) Dropout Voltage (PWR) VPWR-V1 Current Limit Minimum Load Current ADJUSTABLE OUTPUT I1 (MAX) I1 V1 Reference Voltage ! Symbol V2 Line Regulation Load Regulation ∆V2(VIN) ∆V2(I2) Dropout Voltage VPWR-V2 Current Limit Minimum Load Current Adjust Pin Bias Current ENTIRE REGULATOR Minimum Operating Voltage I2 (MAX) I2 IADJ Test Conditions 5mA < I1 < 2.5A, 3.75V < VCTRL < 10V 3.3V < VPWR < 5.5V 3.3V<VCTRL<10V, 3.3V<VPWR<5.5V, I1 = 5mA 5mA < I1 < 2.5A, VCTRL=5V, VPWR=3.3V I1 = 2.5A, ∆V1 = -2% I1 = 2.0A, ∆V1 = -2% I1 = 1.0A, ∆V1 = -2% Min 2.438 2.55 Note 1 5mA < I2 < 2.5A, 3.75V < VCTRL < 10V 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 = 2.5A, ∆V2 = -2% I2 = 2.0A, ∆V2 = -2% I2 = 1.0A, ∆V2 = -2% 1.231 2.55 Note 1 LX8817-25 Typ Max 2.538 V 1 1 0.500 0.375 0.225 3.0 0 5 5 0.730 0.580 0.390 mV mV 1.250 1.288 V 0.05 10 0.500 0.375 0.225 3.0 1 1 3 19 0.730 0.580 0.390 mV mV VPWR VCONTROL Under Voltage Lockout IQ Ripple Rejection RMS Output Noise Thermal Shutdown PSRR VPWR Rising, 3.0V<VCTRL < 10V, Both Outputs Off I1=I2=5mA I1=I2=2.5A f=120Hz, TJ = 25°C 10Hz < f < 10kHz 60 TJSD 3 6 75 0.003 160 5 2 2.6 3.3 2.2 5 10 V A mA V A mA µA V V V mA mA dB %VOUT °C Note 1: Minimum load current is defined as the amount of output current required to maintain regulation. Typically this current provides the bias to the external resistor divider network used to set the output voltage. Copyright 2000 Rev. 0.3D, 2002-01-08 Microsemi Linfinity Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 3 ELECTRICALS Quiescent Current Units 2.500 5 W W W. Microsemi .COM RECOMMENDED MAX OPERATING CONDITION LX8817 L I N F I N I T Y Dual Channel 2.5A Low Dropout Regulator D I V I S I O N P RODUCTION D ATA S HEET Dropout Voltage 2.51 1.255 2.5 1.25 2.49 1.245 2.48 1.24 2.47 1.235 2.46 1.23 2.45 1.225 2.44 1.22 Vo1: 2.5V Fixed Vo2: Adjustable 2.43 VDD (V) Output Voltage (V) VOUT vs Temperature W W W. Microsemi .COM CHARACTERISTIC CURVES 1.215 2.42 1.21 2.41 1.205 Iout=2.5A Iout=1A Iout=0.5A 150 Temperature (°C) 125 100 75 Temperature (°C) 50 25 0 -25 -50 175 170 165 145 125 100 70 50 23 0 -20 -40 -60 -70 -80 -85 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 Supply Ramp (Vcntrl+Vpwr) Quiescent Current 8 IL1&IL2=2.5A IL1&IL2=5mA 7 IGROUND (mA) 6 1 5 4 2 3 3 2 1 0 4 150 125 100 75 50 25 0 -25 -50 CH1 CH3 Temperature (°C) 2.00V 1.00V BW CH2 CH4 2.00V 2.00V BW CH1 = VP = VC CH2 = VO1 Step Load Response With Ceramic Cap (10µF) M 1.00ms A CH1 800mV CH3 = VO2 CH4 = IP 2A/DIV Step Load Response With Tantalum Cap (10µF) 1 1 2 2 CHARTS 4 4 CH1 200mV BW CH2 CH4 CH1 = VO1 CH2 = VP Copyright 2000 Rev. 0.3D, 2002-01-08 200mV 1.00A Ω BW M 10.0µs A CH4 360mA CH4 = IO1 (10mA to 2.5A Step) CH1 100mV BW CH2 CH4 CH1 = VO1 CH2 = VP 200mV 10mV BW M 4.00µs A CH4 13.2mV BW CH4 = IO1 (10mA to 2.5A Step) Microsemi Linfinity Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 4 LX8817 L I N F I N I T Y D I V I S I O N Dual Channel 2.5A Low Dropout Regulator P RODUCTION D ATA S HEET VPWR W W W. Microsemi .COM APPLICATION CIRCUIT/BLOCK DIAGRAM 3 C1 10µF VCTRL Input Power Sequencing (UVLO) + - V1 2 C3 10µF 1 C2 10µF BIAS 1.25V VREF + - 5 R1 +I V2 = 1.25 × 1 + ADJ × R1 R 2 V2 (Adjustable) R1 C4 10µF 6 GND 4 R2 FIGURE – Block Diagram / Application Circuit APPLICATIONS Copyright 2000 Rev. 0.3D, 2002-01-08 Microsemi Linfinity Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 5 LX8817 L I N F I N I T Y Dual Channel 2.5A Low Dropout Regulator D I V I S I O N P RODUCTION D ATA S HEET The LX8817 is part of a family of Dual LDO (Low Drop-Out) linear regulators in Linfinity’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. INPUT CAPACITOR To improve load transient response and noise rejection a input bypass capacitor is of at least 10uF is required. Generally we recommend a 10uF ceramic or tantalum or 22uF electrolytic capacitor. 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 4.7uF. 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 LX8817x develops a 1.25V reference voltage between the output and the adjust terminal (See Figure 2). By placing a resistor, R1, 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 R1, it represents a small error and can usually be ignored. V1 VIN LX8817-25 V2 PD = (VIN(MAX) − V1 ) × I1 + (VIN(MAX) − V2 ) × I 2 (Note: power dissipation resulting from quiescent (ground) current is negligible) For the S-PAK package, thermal resistance, θTAB-AMB is 25450C/W depending on mounting technique when mounted on a FR4 copper clad PCB. Junction temperature of the integrated circuit can be calculated using: TJUNCTION = TJUNCTION −TAB RISE + TTAB− AMB RISE + TAMB TTAB = PDMAX × θ JT ; TTAB − AMB = (PDREG1 + PDREG 2 ) × θ PCB TJ − TAB REG1 = (5V − 2.5V) × 4.5°C/W = (0.525) × 4.5°C/W = 2.4°C VREF TJ − TAB REG2 = (5V − 3.3V) × (1A) × 4.5°C/W = (1.7) × 4.5°C/W = 7.7°C R2 TTAB − AMBRISE = (0.525W + 1.7W) × 30°C/W = 66.8°C FIGURE 2 - BASIC ADJUSTABLE REGULATOR TJUNCTION = 7.7°C + 66.8°C + 50°C = 124.5°C MINIMUM LOAD REQUIREMENT The LX8817 has a minimum load is requirement for proper output regulation. This typical current is specified at 0mA for the fixed output and 1ma for the adjustable output regulators. Copyright 2000 Rev. 0.3D, 2002-01-08 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. Power dissipation for regulator can be calculated using the following equation: 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 in not exceeded. Microsemi Linfinity Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 6 APPLICATIONS IADJ 1µA R1 V 2 = VREF 1 + + I ADJ R1 R2 CURRENT LIMIT PROTECTION The LX8817 includes over current protection, when the output load current exceeds typically 3A the circuit forces the regulator decrease in output. An example: Given conditions: TA = 50°C, VIN= 5.0V, V1= 2.5V, I1= 210mA, V2= 3.3V I2= 1A. Calculated values: R1 ADJ TEMPERATURE PROTECTION The thermal protection shuts the LX8817 down when the junction temperature exceeds 1600C. Each output has independent thermal shutdown capability. Exposure to absolute maximum rated conditions for extended periods may affect device reliability, see Thermal Considerations below. W W W. Microsemi .COM APPLICATION INFORMATION LX8817 L I N F I N I T Y Dual Channel 2.5A Low Dropout Regulator D I V I S I O N P RODUCTION D ATA S HEET W W W. Microsemi .COM MECHANICAL DIMINESIONS A C D I B K H G F Dim E 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 A B C D E F G H I J K J 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. Copyright 2000 Rev. 0.3D, 2002-01-08 Microsemi Linfinity Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 7 LX8817 L I N F I N I T Y D I V I S I O N Dual Channel 2.5A Low Dropout Regulator P RODUCTION D ATA S HEET W W W. Microsemi .COM NOTES NOTES 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 2000 Rev. 0.3D, 2002-01-08 Microsemi Linfinity Microelectronics Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 8