LX8816

LX8816 TM ® Dual Channel 1A Low Dropout Regulator P RODUCTION D ATA S HEET DESCRIPTION KEY FEATURES W WW . Microsemi . C OM The LX8816 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 LX8816 provides designers with a flexible power management solution, minimal printed circuit board area and shorter design cycles. Each channel can supply up to one amp independently with a regulator design optimized for system efficiency by consuming minimal ground current and directing quiescent current to the load. The LX8816 features on-chip trimming of the internal voltage enabling precise output voltages, typically ±1% of it’s specified value, while the BiPolar output transistor has a low dropout voltage even at full output current (VDO < 1.2V typ. @ 1A). Thermal and Short Circuit Current Protection are integrated on-chip and operate independently for each regulator output. The LX8816 regulator is stable with a low-value output capacitor, typically 2.2µF on the outputs, allowing designers flexibility in external component selection. Microsemi’s S-PAK package enables maximum power dissipation and ease of assembly using surface mount technology. Two Independent Regulated Outputs Accurate Output Voltages Typical Dropout of 1.2V at 1A and 1.1V at 500mA Independent Thermal and Current Limit Protection Low Profile 5 Lead SMT Power Package Low Tolerance Load Regulation Wide DC Supply Voltage of 4.3V to 10V Loop Stability Independent of Output Capacitor Type APPLICATIONS/BENEFITS 5V to 3.3V / ADJ Regulators Hard Disk Drives, CD-ROMs ADSL and Cable Modems Battery Charging Circuits Instrumentation PC Peripherals IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com APPLICATION CIRCUITS VIN = 5V VIN 22µF V2 10 µF LX8816-04 GND ADJ V1 3.3V @ 1.0A R1 499 R2 499 2.5V* @ 1.0A 10µF ⎛ R1 ⎞ *V1 = VREF ⎜1 + ⎜ R 2 ⎟ + I ADJ R1 ⎠ ⎝ LX8816 LX8816 PACKAGE ORDER INFO TJ (°C) 0 to 125 Copyright © 2000 Rev. 1.2c, 2005-05-18 OUTPUT V1 (PIN 4) Adj. OUTPUT V2 (PIN 5) 3.3V DF Plastic S-PAK 5-PIN RoHS Compliant Transition DC: 0515 LX8816-04CDF Page 1 Note: Available in Tape & Reel. Append the letters “TR” to the part number. (i.e. LX8816-04CDF-TR) Microsemi Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 LX8816 TM ® Dual Channel 1A Low Dropout Regulator P RODUCTION D ATA S HEET ABSOLUTE MAXIMUM RATINGS Input Voltage (VBAT).................................................................................................. 13.5V Load Current (Internally Limited)................................................................................... 1A 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 seconds maximum exposure)..................................................................260°C (+0, -5) 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. PACKAGE PIN OUT Tab is GND 5 4 3 2 1 W WW . Microsemi . C OM V2 V1 GND ADJ VIN THERMAL DATA DF PACKAGE (Top View) DF Plastic S-Pak 5-Pin 4.5°C/W 24.5°C/W RoHS 100% Matte Tin Lead Finish THERMAL RESISTANCE-JUNCTION TO TAB, θJT THERMAL RESISTANCE-JUNCTION TO AMBIENT, θJA 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 25°C/W to > 40°C/W depending on mounting technique. (See Application Notes Section: Thermal considerations) FUNCTIONAL PIN DESCRIPTION PIN NAME VIN DESCRIPTION Positive unregulated supply input for the regulator. Bypass to GND with at least 2.2µF capacitance having low ESR for good transient response. Adjustable Input. The output voltage can be set by two external resistors with the following relationship: V1 = VREF * (1 + R1 / R2) + IADJ * R1 where R1 is the resistor connected between V1 and ADJ, and R2 is the resistor connected between ADJ and GND. ADJ GND V1 Common terminal for ground reference. The input and output bypass capacitors should be connected to this pin. In addition the tab on the S-Pak package and pin 3 are also used for heat sinking the device. Adjustable regulator output (Regulator #1) It is recommended to bypass to GND with at least 2.2uF. Size your output capacitor to meet the transient loading requirement. If you have a very dynamic load, a lower ESR capacitor will improve the response to these load steps. P D PACKAGE DATA V2 Fixed regulator output (Regulator #2). It is recommended to bypass to GND with at least 2.2µF. Size your output capacitor to meet the transient loading requirement. For dynamic loads, a lower ESR capacitor will improve the response to these load steps. Copyright © 2000 Rev. 1.2c, 2005-05-18 Microsemi Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 2 LX8816 TM ® Dual Channel 1A Low Dropout Regulator P RODUCTION D ATA S HEET RECOMMENDED OPERATING CONDITIONS Parameter Input Voltage Output Voltage (adjustable) Load Current each output (with adequate heat sinking) Input Capacitor (VIN to GND) Output Capacitor (VOUT to GND) improve the response to these load steps. W WW . Microsemi . C OM Symbol VIN VOUT Min 4.5 0 2.2 1.0 LX8816-04 Typ Max 10 5.5 1000 Units V V mA µF µF 20 10* * Size your output capacitor to meet the transient loading requirement. If you have a very dynamic load, a lower ESR and larger value capacitor will 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: VIN = 5V, IOUT = 10mA, C1= 10µF (Tantalum), C2= C3= 4.7µF (Tant.), & TJ = TA using low duty cycling methods. LX8816-04 Parameter Symbol Test Conditions Units Min Typ Max Adjustable Output (Output 1) Reference Voltage Line Regulation Line Regulation Load Regulation Dropout Voltage Current Limit Minimum Load Current Adjust Pin Bias Current Fixed Output (Output 2) Output Voltage Line Regulation Line Regulation Load Regulation Dropout Voltage Current Limit Minimum Load Current Entire Regulator Quiescent Current Quiescent Current Ripple Rejection RMS Output Noise (% of VOUT) Thermal Shutdown IQ IQ PSRR VOUT (RMS) TJSD VIN < 10V, I1 = 5mA, I2 = 5mA VIN < 10V, I1 = 1A, I2 = 1A f=120Hz, VIN = 5V 10Hz < f < 10kHz 135 60 2.6 3.5 75 0.003 140 3.8 6 mA mA dB %V °C V2 ∆V2(VIN) ∆V2(VIN) ∆V2(I2) ∆V IOUT (MAX) IL Note 1 5mA < I2 < 1A, 4.75V < VIN < 10V 4.75V < VIN < 5.5V, IOUT = 5mA 4.50V < VIN < 10V, IOUT = 5mA 5mA < I2 < 1A, VIN = 4.75V ILOAD = 1A, ∆V2 = -2% 1.0 3.234 3.30 6 0.17 2.6 1.2 1.4 0 3.3825 8 0.22 6 1.3 V mV %V mV V A mA VREF ∆V1(VIN) ∆V1(VIN) ∆VREF(I1) ∆V IOUT (MAX) IL IADJ Note 1, The external resistor divider current can be included in this requirement. Bias current flows into part. 5mA < I1 < 1A, 4.75V < VIN < 10V 4.75V < VIN < 5.5V, IOUT = 5mA 4.50V < VIN < 10V, IOUT = 5mA 5mA < I1 < 1A, VIN = 4.75V ILOAD = 1A, ∆V1 = -2% 1.0 1.225 1.25 1.5 0.17 0.04 1.2 1.4 2 0.12 3 1 1.273 2.5 0.22 0.15 1.3 V mV %V %V V A mA µA ELECTRICALS ELECTRICALS Note 1: Minimum load current is defined as the amount of output current required to maintain regulation. Copyright © 2000 Rev. 1.2c, 2005-05-18 Microsemi Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 3 LX8816 TM ® Dual Channel 1A Low Dropout Regulator P RODUCTION D ATA S HEET BLOCK DIAGRAM W WW . Microsemi . C OM VIN C1 10µF 1 5 VOUT2 (Fixed) BIAS + - C2 10µF 1.25V VREF VIN 4 VOUT1 (Adjustable) R1 + - 2 C3 10µF R2 GND 3 Note: Application circuit above using ceramic capacitors. R1 and R2 used with adjustable version only. ⎛ VOUT1 = 1.25 × ⎜1 + ⎜ ⎝ R1 R2 ⎞ ⎟+ I ×R ⎟ ADJ 1 ⎠ Figure 1 – Simplified Block Diagram BLOCK DIAGRAM BLOCK DIAGRAM Copyright © 2000 Rev. 1.2c, 2005-05-18 Microsemi Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 4 LX8816 TM ® Dual Channel 1A Low Dropout Regulator P RODUCTION D ATA S HEET CHARACTERISTIC CURVES LOAD TRANSIENT RESPONSE VIN = 20µF Ceramic, ESR= 45mΩ; V1,V2 = 10µF Ceramic, ESR= 75mΩ 50mV / DIV 50mV / DIV W WW . Microsemi . C OM LOAD TRANSIENT RESPONSE VIN = 22µF Tantalum, ESR=232mΩ; V1,V2 = 10µF Tantalum, ESR=198mΩ VIN = 5V 50mV / DIV 50mV / DIV V1 = 1.5V 180Ω Load V1 = 1.5V V2 = 3.3V 1A Step Load 50mV / DIV V2 = 3.3V 1A Step Load 1A 1A 1mA 2µs / DIV 0mA 2µs / DIV TURN ON CHARACTERISTICS 500mV / DIV CURRENT LIMIT RESPONSE 20mV(A C) / DIV 500mV / DIV V2 = 3.3V V1 = 1.5V 1.2A V2 = 3.3V 1V / DIV VIN = 5V 500m V / DIV V1 = 1.5V Rising Load On V2 200mA / DIV 100µs / DIV 100µs / DIV RIPPLE REJECTION VS. FREQUENCY VIN = 5V, CIN = 22µF, COUT1,2 = 10µF, V2=3.3V, IOUT2=1A 45 40 VOUT AND ICHIP VS. VIN RAMP 5 4.5 4 3.5 Ichip, ma 6 5 V2,(Rext=13K ohms) V1, adj(Rext=909 ohms) RIPPLE REJECTION (DB) 35 30 25 20 15 4 VOUT (Volts) Ichip (mA) 3 2.5 2 1.5 1 2 3 CHARTS CHARTS 10 0.5 1 5 0 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 0 100 1000 10000 100000 VIN (Volts) FREQUENCY (HZ) Copyright © 2000 Rev. 1.2c, 2005-05-18 Microsemi Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 5 LX8816 TM ® Dual Channel 1A Low Dropout Regulator P RODUCTION D ATA S HEET APPLICATION INFORMATION W WW . Microsemi . C OM Description The LX8816 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 one amp independently with a regulator design optimized for system efficiency by consuming minimal ground current and directing quiescent current to the load. Temperature Protection The thermal protection shuts the LX8816 down when the junction temperature exceeds 1400C. Each output has independent thermal shutdown capability. Exposure to absolute maximum rated conditions for extended periods may affect device reliability, see Thermal Considerations below. Current Limit Protection The LX8816 includes over current protection, when the output load current exceeds typically 1.4A the circuit forces the regulator decrease in output. Input Capacitor To improve load transient response and noise rejection a input bypass capacitor is of at least 2.2uF is required. Generally we recommend a 20uF ceramic or tantalum or 22uF electrolytic capacitor. 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: Output Capacitor The regulator requires output capacitors connected between V1, V2 and 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 LX8816 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. PD = (VIN(MAX)-V1) * I1 + (VIN(MAX)-V2 ) * I2 (Note: power dissipation resulting from quiescent (ground) current is negligible) For the S-PAK package, thermal resistance, θTAB-AMB is 25-450C/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 = PD MAX * θJT ; VIN V2 TTAB-AMB = (PD REG1 + PD REG2) * θPCB LX8816-04 ADJ IADJ 1µA V1 R1 An example: Given conditions: TA = 50°C, VIN= 5.0V, V1= 2.5V, I1= 210mA, V2= 3.3V I2= 1A. Calculated values: TJ-TAB REG1 = (5V-2.5V) * (210mA) * 4.5°C/W = (0.525) * 4.5°C/W = 2.4°C VREF APPLICATION APPLICATION ⎛ R1 ⎞ V1 = VREF ⎜1 + ⎜ R 2 ⎟ + I ADJ R1 ⎠ ⎝ TJ-TAB REG2 R2 = (5V-3.3V) * (1.0A) * 4.5°C/W = (1.7) * 4.5°C/W = 7.7°C FIGURE 2 - BASIC ADJUSTABLE REGULATOR TTAB-AMB RISE = ( 0.525W + 1.7W ) * 30°C/W = 66.8°C TJUNCTION = 10.1°C + 66.8°C + 50°C = 126.9°C It is important to note that although each output of the regulator will produce up to 1A 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. Minimum Load Requirement The LX8816 has a minimum load is requirement for proper output regulation. This minimum current is specified at 0mA for the fixed output and 2ma for the adjustable output regulators. Copyright © 2000 Rev. 1.2c, 2005-05-18 Microsemi Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 6 LX8816 TM ® Dual Channel 1A Low Dropout Regulator P RODUCTION D ATA S HEET APPLICATION INFORMATION W WW . Microsemi . C OM Layout Consideration The layout must be done with low impedance paths for VIN, V1, V2 and Ground by using sufficiently wide traces to avoid voltage drops and noise pick up. The output capacitors must be placed as close as possible to the voltage regulator output pins. To allow the same voltage reference for all circuits, use a star configuration from the output capacitors to the different loads. The input capacitor should be connected between VIN and ground with short leads. Although it may not be immediately obvious, best load regulation for the adjustable output is obtained when the top of the resistor divider, (R1), is connected as close as possible to the case of the regulator, not to the load. Heatsink Consideration The PCB copper can be used as a heatsink for the surface mounted S-Pak. Using the minimum size as shown in the recommended pad layout limits the usable power to about 1W for ambient temperature of 50°C. Since most applications require greater than 2W there is the need to provide additional heat sinking. This can be accomplished by using additional copper area both on the PCB surface as shown in the possible heat sink layout below, or to an embedded ground plane. Since the die pad (copper tab) is in electrical contact with ground, the designer can use thermal vias on the surface of the PCB taking advantage of the heat-spreading (Cu) layer of an internal ground plane. HEAT SINK LAYOUT B o a rd L e ve l Com ponent T ra ce G ro u n d P la n e B A Component B VIAS Component Trace Ground Plane Inner Power Plane Backside Trace A Figure 3 - Heatsink RECOMMENDED MINIMUM PCB FOOTPRINT 9.75mm 11.56mm 9.98mm APPLICATION APPLICATION 8.84mm 7.92mm 8.89mm 1.37mm 0mm .86mm 4.39mm 5.36mm 1.83mm 3.28mm Copyright © 2000 Rev. 1.2c, 2005-05-18 Microsemi Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 7 LX8816 TM ® Dual Channel 1A Low Dropout Regulator P RODUCTION D ATA S HEET PACKAGE DIMENSIONS W WW . Microsemi . C OM DF 5-Pin Plastic S-Pak M A C L B K H J F G I E D Dim A B C D E F G H I J K L M Note: MILLIMETERS MIN MAX 9.27 9.52 7.87 8.13 1.78 2.03 8.03 BSC 0.25 BSC 0.63 0.79 1.70 BSC 0.79 1.04 6.50 BSC 0.03 0.13 10.41 10.67 0.25 BSC 0.76 1.27 INCHES MIN MAX 0.365 0.375 0.310 0.320 0.070 0.080 0.316 BSC 0.010 BSC 0.025 0.031 0.067 BSC 0.031 0.041 0.256 BSC 0.001 0.005 0.410 0.420 0.01 BSC 0.03 0.05 MECHANICALS MECHANICALS 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. 1.2c, 2005-05-18 Microsemi Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 8 LX8816 TM ® Dual Channel 1A Low Dropout Regulator P RODUCTION D ATA S HEET NOTES W WW . Microsemi . C OM N 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. 1.2c, 2005-05-18 Microsemi Integrated Products 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 9