REG104 REG 104 REG 104 SBVS025C – SEPTEMBER 2001 DMOS 1A Low-Dropout Regulator FEATURES DESCRIPTION ● NEW DMOS TOPOLOGY: Ultra Low Dropout Voltage: 230mV typ at 1A and 3.3V Output Output Capacitor NOT Required for Stability ● FAST TRANSIENT RESPONSE ● VERY LOW NOISE: 33µVrms ● HIGH ACCURACY: ±2% max ● HIGH EFFICIENCY: IGND = 1.7mA at IOUT = 1A Not Enabled: IGND = 0.5µA ● 2.5V, 2.7V, 3.0V, 3.3V, 5.0V AND ADJUSTABLE OUTPUT VERSIONS ● THERMAL PROTECTION ● SMALL SURFACE-MOUNT PACKAGES: SOT223-5, DDPAK-5 The REG104 is a family of low-noise, low-dropout linear regulators with low ground pin current. Its new DMOS topology provides significant improvement over previous designs, including low dropout voltage (only 230mV typ at full load), and better transient performance. In addition, no output capacitor is required for stability, unlike conventional low dropout regulators that are difficult to compensate and require expensive low ESR capacitors greater than 1µF. Typical ground pin current is only 1.7mA (at IOUT = 1A) and drops to 0.5µA in “not enabled” mode. Unlike regulators with PNP pass devices, quiescent current remains relatively constant over load variations and under dropout conditions. The REG104 has very low output noise (typically 33µVrms for VOUT = 3.3V with CNR = 0.01µF), making it ideal for use in portable communications equipment. On-chip trimming results in high output voltage accuracy. Accuracy is maintained over temperature, line, and load variations. Key parameters are tested over the specified temperature range (–40°C to +85°C). The REG104 is well protected—internal circuitry provides a current limit which protects the load from damage. Thermal protection circuitry keeps the chip from being damaged by excessive temperature. The REG104 is available in the DDPAK-5 and the SOT223-5. APPLICATIONS ● ● ● ● ● PORTABLE COMMUNICATION DEVICES BATTERY-POWERED EQUIPMENT MODEMS BAR-CODE SCANNERS BACKUP POWER SUPPLIES Enable Enable VOUT VIN + 0.1µF NR REG104 (Fixed Voltage Versions) + COUT(1) VIN VOUT + 0.1µF REG104-A R1 + COUT(1) Adj Gnd Gnd R2 NR = Noise Reduction NOTE: (1) Optional. Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. Copyright © 2000, Texas Instruments Incorporated PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. www.ti.com ABSOLUTE MAXIMUM RATINGS(1) ELECTROSTATIC DISCHARGE SENSITIVITY Supply Input Voltage, VIN ....................................................... –0.3V to 16V Enable Input ............................................................................ –0.3V to VIN Output Short-Circuit Duration ...................................................... Indefinite Operating Temperature Range ....................................... –55°C to +125°C Storage Temperature Range .......................................... –65°C to +150°C Junction Temperature ..................................................... –55°C to +150°C Lead Temperature (soldering, 3s, SOT, and DDPAK) ........................ +240°C This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. NOTE: (1) Stresses above these ratings may cause permanent damage. Exposure to absolute maximum conditions for extended periods may degrade device reliability. ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications. PACKAGE/ORDERING INFORMATION PACKAGE-LEAD PACKAGE DESIGNATOR SPECIFIED TEMPERATURE RANGE PACKAGE MARKING ORDERING NUMBER TRANSPORT MEDIA, QUANTITY 5V Output REG104FA-5 DDPAK-5 KTT –40°C to +85°C REG104FA-5.0 " " " " " REG104GA-5 SOT223-5 DCQ –40°C to +85°C R104G50 " " " " " REG104FA-5 REG104FA-5 REG104GA-5 REG104GA-5 Rails, 49 Tape and Reel, 500 Rails, 78 Tape and Reel, 2500 DDPAK-5 KTT –40°C to +85°C REG104FA-3.3 " " " " SOT223-5 DCQ –40°C to +85°C R104G33 " " " " REG104FA-3.3 REG104FA-3.3 REG104GA-3.3 REG104GA-3.3 Rails, 49 Tape and Reel, 500 Rails, 78 Tape and Reel, 2500 REG104FA-3 DDPAK-5 KTT –40°C to +85°C REG104FA-3.0 " " " " " REG104GA-3 SOT223-5 DCQ –40°C to +85°C R104G30 " " " " " REG104FA-3 REG104FA-3 REG104GA-3 REG104GA-3 Rails, 49 Tape and Reel, 500 Rails, 78 Tape and Reel, 2500 DDPAK-5 KTT –40°C to +85°C REG104FA-2.7 " " " " SOT223-5 DCQ –40°C to +85°C R104G27 " " " " REG104FA-2.7 REG104FA-2.7 REG104GA-2.7 REG104GA-2.7 Rails, 49 Tape and Reel, 500 Rails, 78 Tape and Reel, 2500 DDPAK-5 KTT –40°C to +85°C REG104FA-2.5 " " " " SOT223-5 DCQ –40°C to +85°C R104G25 " " " " REG104FA-2.5 REG104FA-2.5 REG104GA-2.5 REG104GA-2.5 Rails, 49 Tape and Reel, 500 Rails, 78 Tape and Reel, 2500 REG104FA-A REG104FA-A REG104GA-A REG104GA-A Rails, 49 Tape and Reel, 500 Rails, 78 Tape and Reel, 2500 PRODUCT 3.3V Output REG104FA-3.3 " REG104GA-3.3 " 3.0V Output 2.7V Output REG104FA-2.7 " REG104GA-2.7 " 2.5V Output REG104FA-2.5 " REG104GA-2.5 " Adjustable Output REG104FA-A DDPAK-5 KTT –40°C to +85°C REG104FA-A " " " " " REG104GA-A SOT223-5 DCQ –40°C to +85°C R104GA " " " " " PIN CONFIGURATIONS Top View SOT223-5 DDPAK-5 Tab is Gnd Tab is Gnd 1 2 3 4 5 1 VO Gnd NR/Adjust(1) VIN Enable (KTT Package) 2 VIN VOUT 3 4 5 Gnd Enable NR/Adjust(1) (DCQ Package) NOTE: (1) For REG104A-A: voltage setting resistor pin. All other models: noise reduction capacitor pin. 2 REG104 SBVS025C ELECTRICAL CHARACTERISTICS: VS = +2.7V to +5.5V Boldface limits apply over the specified temperature range, TJ = –40°C to +85°C At TJ = +25°C, VIN = VOUT + 1V (VOUT = 3.0V for REG104-A), VENABLE = 2V, IOUT = 10mA, CNR = 0.01µF, and COUT = 0.1µF(1), unless otherwise noted. REG104GA REG104FA PARAMETER OUTPUT VOLTAGE Output Voltage Range REG104-2.5 REG104-2.7 REG104-3.0 REG104-3.3 REG104-5 REG104-A Reference Voltage Adjust Pin Current Accuracy TJ = –40°C to +85°C vs Temperature vs Line and Load TJ = –40°C to +85°C DC DROPOUT VOLTAGE(2, 3) For all models except 5V For 5V model For all models except 5V TJ = –40°C to +85°C For 5V models TJ = –40°C to +85°C VOLTAGE NOISE f = 10Hz to 100kHz Without CNR (all models) With CNR (all fixed voltage models) OUTPUT CURRENT Current Limit(4) TJ = –40°C to +85°C CONDITION MIN 2.5 2.7 3.0 3.3 5 dVOUT/dT VDROP 1.295 0.2 ±0.5 TJ = –40°C to +85°C IOUT = 10mA to 1A, VIN = (VOUT + 0.7V) to 15V VIN = (VOUT + 0.9V) to 15V 70 ±0.5 IOUT = 10mA IOUT = 1A IOUT = 1A IOUT = 1A 3 230 320 IOUT = 1A TEMPERATURE RANGE Specified Range Operating Range Storage Range Thermal Resistance DDPAK-5 Surface Mount SOT223-5 Surface Mount ±3.5 25 400 500 480 mV mV mV mV 580 mV 1 ±2 ±3.0 ±2.5 Vn CNR = 0, COUT = 0 CNR = 0.01µF, COUT = 10µF ICL µVrms µVrms 35µVrms/V • VOUT 10µVrms/V • VOUT 1.2 1.0 1.7 2.1 2.2 65 VENABLE IENABLE 2 –0.2 VENABLE = 2V to VIN, VIN = 2.1V to 6.5(5) VENABLE = 0V to 0.5V 1 2 50 1.5 IGND IOUT = 10mA IOUT = 1A VENABLE ≤ 0.5V 0.5 1.7 0.5 A A dB VIN 0.5 100 100 V V nA nA µs ms °C °C 150 130 Enable Pin Low INPUT VOLTAGE Operating Input Voltage Range(6) Specified Input Voltage Range TJ = –40°C to +85°C UNITS V V V V V V V µA % % ppm/°C % % 5.5 VREF VREF IADJ THERMAL SHUTDOWN Junction Temperature Shutdown Reset from Shutdown GROUND PIN CURRENT Ground Pin Current MAX VOUT RIPPLE REJECTION f = 120Hz ENABLE CONTROL VENABLE High (output enabled) VENABLE Low (output disabled) IENABLE High (output enabled) IENABLE Low (output disabled) Output Disable Time Output Enable Softstart Time TYP 0.7 1.8 mA mA µA 2.1 VOUT + 0.7 VOUT + 0.9 15 15 15 V V V –40 –55 –65 +85 +125 +150 °C °C °C VIN VIN > 2.7V VIN > 2.9V TJ θJC θJC Junction-to-Case Junction-to-Case 4 15 °C/W °C/W NOTES: (1) The REG104 does not require a minimum output capacitor for stability. However, transient response can be improved with proper capacitor selection. (2) Dropout voltage is defined as the input voltage minus the output voltage that produces a 2% change in the output voltage from the value at VIN = VOUT + 1V at fixed load. (3) Not applicable for VOUT less than 2.7V. (4) Current limit is the output current that produces a 15% change in output voltage from VIN = VOUT + 1V and IOUT = 10mA. (5) For VIN > 6.5V, see typical characteristic “VENABLE vs IENABLE.” (6) The REG104 no longer regulates when VIN < VOUT + VDROP (MAX). In drop-out or when the input voltage is between 2.7V and 2.1V, the impedance from VIN to VOUT is typically less than 1Ω at TJ = +25°C. See typical characteristic “Output Voltage Change vs VIN”. REG104 SBVS025C 3 TYPICAL CHARACTERISTICS For all models, at TJ = +25°C and VENABLE = 2V, unless otherwise noted. OUTPUT VOLTAGE CHANGE vs IOUT (VIN = VOUT + 1V, Output Voltage % Change Referred to IOUT = 10mA at +25°C) DC DROPOUT VOLTAGE vs IOUT 350 0.8 300 +125°C 0.4 DC Dropout Voltage (mV) Output Voltage Change (%) 0.6 0.2 0 +25°C –0.2 –0.4 –0.6 –0.8 –55°C +125°C 250 +25°C 200 –55°C 150 100 50 –1 0 –1.2 0 100 200 300 400 500 600 700 0 800 900 1000 400 600 800 IOUT (mA) OUTPUT VOLTAGE CHANGE vs VIN OUTPUT VOLTAGE CHANGE vs IOUT (Output Voltage % Change Referred to VIN = VOUT + 1V at IOUT = 10mA) (Output Voltage % Change Referred to IOUT = 10mA at +25°C) 1000 0.6 0.5 IOUT = 10mA IOUT = 200mA 0.4 0 IOUT = 10mA 0.2 Output Voltage (%) Output Voltage Change (%) 200 Output Current (mA) IOUT = 1000mA –0.5 –1 IOUT = 200mA 0 –0.2 IOUT = 1000mA –0.4 –0.6 –0.8 –1.5 –1 –2 0 2 4 6 8 10 –1.2 –60 12 20 40 60 80 100 DC DROPOUT VOLTAGE vs TEMPERATURE LINE REGULATION vs TEMPERATURE (VIN = VOUT + 1V to 16V) 120 0.5 Output Voltage Change (%) DC Dropout Voltage (mV) 0 Input Voltage Above VOUT (V) 300 IOUT = 1000mA 250 200 150 100 IOUT = 200mA 50 0.4 0.3 IOUT = 10mA 0.2 0.1 IOUT = 200mA IOUT = 10mA –50 –25 0 25 50 Temperature (°C) 4 –20 Temperature (°C) 350 0 –75 –40 75 100 125 0 –75 –50 –25 0 25 50 75 100 125 Temperature (°C) REG104 SBVS025C TYPICAL CHARACTERISTICS (Cont.) For all models, at TJ = +25°C and VENABLE = 2V, unless otherwise noted. LOAD TRANSIENT RESPONSE LINE TRANSIENT RESPONSE 50mV/div 500mV/div REG104-3.3 COUT = 0 500mV/div VOUT 1A VOUT 50mV/div COUT = 10µF ILOAD 6V VOUT COUT = 10µF VOUT VIN 5V 10µs/div 50µs/div LOAD TRANSIENT RESPONSE LOAD TRANSIENT RESPONSE REG104–A REG104–A CFB = 0.01µF, VOUT = 3.3V Load = 200mA, CFB = 0.01µF, VOUT = 3.3V 50mV/div 50mV/div 500mV/div 500mV/div 10mA REG104-3.3 IOUT = 200mA COUT = 0 COUT = 0 COUT = 10µF 1A COUT = 0 COUT = 10µF 6V ILOAD VIN 5V 10mA 10µs/div 50µs/div LOAD REGULATION vs TEMPERATURE (VIN = VOUT + 1V and 10mA < IOUT < 1000mA) OUTPUT NOISE DENSITY 10 0.5 Noise Density (µV/√Hz) Output Voltage Change (%) 5 0.4 0.3 0.2 0.1 2 1 0.5 0.2 CNR = 0 COUT = 0 0.1 0.05 CNR = 0.01µF COUT = 10µF 0.02 0 –60 0.01 –40 –20 0 20 40 60 Temperature (°C) REG104 SBVS025C 80 100 120 10 100 1000 10000 100,000 Frequency (Hz) 5 TYPICAL CHARACTERISTICS (Cont.) For all models, at TJ = +25°C and VENABLE = 2V, unless otherwise noted. GROUND PIN CURRENT, NOT ENABLED vs TEMPERATURE GROUND PIN CURRENT vs TEMPERATURE 3 1.8 VENABLE = 0V IOUT = 1000mA 1.6 2.5 2 IGND (µA) IGND (mA) 1.4 1.2 1 IOUT = 200mA 0.8 1.5 1 0.5 0.6 IOUT = 10mA 0.4 –60 –40 –20 0 20 40 60 80 100 0 –75 120 –50 –25 0 25 50 75 100 125 Temperature (°C) Temperature (°C) IADJUST vs TEMPERATURE GROUND PIN CURRENT vs IOUT 1.6 0.28 1.4 0.26 Adjust Pin Current (µA) REG104-A IGND (mA) 1.2 1 0.8 0.6 0.24 0.22 0.20 0.18 0.16 0.4 1 10 100 1000 0.14 –60 –40 –20 0 20 40 60 80 100 120 140 Temperature (°C) IOUT (mA) RIPPLE REJECTION vs FREQUENCY CURRENT LIMIT vs TEMPERATURE 70 1850 VOUT = VOUT-NOMINAL • 0.90 60 Ripple Rejection (dB) Current Limit (mA) 1800 1750 VOUT = 1V 1700 1650 COUT = 0 20 –40 –20 0 20 40 60 Temperature (°C) 6 COUT = 10µF 40 30 1600 1550 –60 50 80 100 120 10 100 1k 10k 100k Frequency (Hz) REG104 SBVS025C TYPICAL CHARACTERISTICS (Cont.) For all models, at TJ = +25°C and VENABLE = 2V, unless otherwise noted. RIPPLE REJECTION vs IOUT SOFT START 75 VRIPPLE = 3Vp-p, f = 120Hz 1V/div Ripple Rejection (dB) 70 65 VOUT 60 55 50 45 2V VENABLE 0 40 0 200 400 600 800 1000 250µs/div IOUT (mA) OUTPUT DISABLE TIME OUTPUT VOLTAGE DRIFT HISTOGRAM 45 1V/div COUT = 0 40 35 Percent of Units (%) VOUT 2V VENABLE 30 25 20 15 10 5 0 0 10µs/div 40 45 50 55 60 65 70 75 80 85 90 VOUT Drift (ppm/°C) OUTPUT VOLTAGE ACCURACY HISTOGRAM 60 Percent of Units (%) 50 40 30 20 10 0 –1 –0.8 –0.6 –0.4 –0.2 0 0.2 0.4 0.6 0.8 1 Error (%) REG104 SBVS025C 7 BASIC OPERATION The REG104 series is a family of LDO (Low DropOut) linear regulators. The family includes five fixed output versions (2.5V to 5.0V) and an adjustable output version. An internal DMOS power device provides low dropout regulation with near constant ground pin current (largely independent of load and dropout conditions) and very fast line and load transient response. All versions include internal current limit and thermal shutdown circuitry. Figure 1 shows the basic circuit connections for the fixed voltage models. Figure 2 gives the connections for the adjustable output version (REG104A) and example resistor values for some commonly used output voltages. Values for other voltages can be calculated from the equation shown in Figure 2. None of the versions require an output capacitor for regulator stability. The REG104 will accept any output capacitor type less than 1µF. For capacitance values larger than 1µF the effective ESR should be greater than 0.1Ω. This minimum ESR value includes parasitics such as printed circuit board traces, solder joints, and sockets. A minimum 0.1µF low ESR capacitor connected to the input supply voltage is recommended. ENABLE The Enable pin allows the regulator to be turned on and off. This pin is active HIGH and compatible with standard TTLCMOS levels. Inputs below 0.5V (max) turn the regulator off and all circuitry is disabled. Under this condition groundpin current drops to approximately 0.5µA. When not used, the Enable pin may be connected to VIN. Internal to the part, the Enable pin is connected to an input resistor-zener diode circuit, as shown in Figure 3, creating a nonlinear input impedance. Enable VIN In REG104 Gnd 0.1µF VOUT Out NR Enable COUT 175kΩ CNR 0.01µF VZ = 10V Optional FIGURE 1. Fixed Voltage Nominal Circuit for REG104. FIGURE 3. Enable Pin Equivalent Input Circuit. Enable 5 2 VOUT 1 VIN REG104 4 0.1µF IADJ 3 Gnd R1 CFB 0.01µF EXAMPLE RESISTOR VALUES R1 (Ω)(1) R2 (Ω)(1) 1.295 Short Open 2.5 12.1k 1.21k 13k 1.3k 3 16.9k 1.69k 13k 1.3k 3.3 20k 2.0k 13k 1.3k 5 37.4k 3.74k 13k 1.3k VOUT (V) COUT Load Adj R2 Pin numbers for SOT-223 package. Optional VOUT = (1 + R1/R2) • 1.295V To reduce current through divider, increase resistor values (see table at right). NOTE: (1) Resistors are standard 1% values. As the impedance of the resistor divider increases, IADJ (~200nA) may introduce an error. CFB improves noise and transient response. FIGURE 2. Adjustable Voltage Circuit for REG104A. 8 REG104 SBVS025C The Enable Pin Current versus Applied Voltage relationship is shown in Figure 4. When the Enable pin is connected to VIN greater than 10V, a series resistor may be used to limit the current. VN = 35 µVrms • VOUT V Connecting a capacitor, CNR, from the Noise-Reduction (NR) pin to ground can reduce the output noise voltage. Adding CNR, as shown in Figure 5, forms a low-pass filter for the voltage reference. For CNR = 10nF, the total noise in the 10Hz to 100kHz bandwidth is reduced by approximately a factor of 3.5. This noise reduction effect is shown in Figure 6. 100 10 Enable Current (µA) Since the value of VREF is 1.295V, this relationship reduces to: 1 0.1 45 REG104-3.3 0.001 0 2 4 6 8 10 12 14 16 Enable Voltage FIGURE 4. Enable Pin Current versus Applied Voltage. OUTPUT NOISE A precision band-gap reference is used for the internal reference voltage, VREF, for the REG104. This reference is the dominant noise source within the REG104. It generates approximately 45µVrms in the 10Hz to 100kHz bandwidth at the reference output. The regulator control loop gains up the reference noise, so that the noise voltage of the regulator is approximately given by: VN = 45µVrms V R1 + R 2 = 45µVrms • OUT R2 VREF Output Noise Voltage (µVRMS 10Hz - 100kHz) 0.01 35 COUT = 0 COUT = 10µF 25 0.001 0.01 0.1 1 CNR (µF) FIGURE 6. Output Noise versus Noise Reduction Capacitor. The REG104 adjustable version does not have the noisereduction pin available, however, the adjust pin is the summing junction of the error amplifier. A capacitor, CFB, VIN NR (fixed output versions only) Low Noise Charge Pump CNR (optional) Enable VREF (1.295V) DMOS Output VOUT Over Current Over Temp Protection R1 R2 Adj (Adjustable Versions) REG104 NOTE: R1 and R2 are internal on fixed output versions. FIGURE 5. Block Diagram. REG104 SBVS025C 9 connected from the output to the adjust pin will reduce both the output noise and the peak error from a load transient. Figure 7 shows improved output noise performance for two capacitor combinations. nV/√Hz 10.0 1.0 COUT = 0, CFB = 0 COUT = 0, CFB = 0.01µF COUT = 10µF, CFB = 0.01µF 0.1 10 100 1000 10000 100000 Frequency FIGURE 7. Output Noise Density on Adjustable Versions. The REG104 utilizes an internal charge pump to develop an internal supply voltage sufficient to drive the gate of the DMOS pass element above VIN. The charge-pump switching noise (nominal switching frequency = 2MHz) is not measurable at the output of the regulator. DROP-OUT VOLTAGE The REG104 uses an N-channel DMOS as the “pass” element. When the input voltage is within a few hundred millivolts of the output voltage, the DMOS device behaves like a resistor. Therefore, for low values of VIN to VOUT, the regulator’s input-to-output resistance is the RdsON of the DMOS pass element (typically 230mΩ). For static (DC) loads, the REG104 will typically maintain regulation down to VIN to VOUT voltage drop of 230mV at full rated output current. In Figure 8, the bottom line (DC dropout) shows the minimum VIN to VOUT voltage drop required to prevent dropout under DC load conditions. REG103 –3.3 at 25°C 250 Drop Out Voltage (mV) DC Transient 200 150 100 50 0 0 100 200 300 400 500 For large step changes in load current, the REG104 requires a larger voltage drop across it to avoid degraded transient response. The boundary of this “transient dropout” region is shown as the top line in Figure 8. Values of VIN to VOUT voltage drop above this line insure normal transient response. In the transient dropout region between “DC” and “Transient”, transient response recovery time increases. The time required to recover from a load transient is a function of both the magnitude and rate of the step change in load current and the available “headroom” VIN to VOUT voltage drop. Under worst-case conditions (full-scale load change with VIN to VOUT voltage drop close to DC dropout levels), the REG104 can take several hundred microseconds to re-enter the specified window of regulation. TRANSIENT RESPONSE The REG104 response to transient line and load conditions improves at lower output voltages. The addition of a capacitor (nominal value 10nF) from the output pin to ground may improve the transient response. In the adjustable version, the addition of a capacitor, CFB (nominal value 10nF), from the output to the adjust pin will also improve the transient response. THERMAL PROTECTION Power dissipated within the REG104 will cause the junction temperature to rise. The REG104 has thermal shutdown circuitry that protects the regulator from damage. The thermal protection circuitry disables the output when the junction temperature reaches approximately 150°C, allowing the device to cool. When the junction temperature cools to approximately 130°C, the output circuitry is again enabled. Depending on various conditions, the thermal protection circuit may cycle on and off. This limits the dissipation of the regulator, but may have an undesirable effect on the load. Any tendency to activate the thermal protection circuit indicates excessive power dissipation or an inadequate heat sink. For reliable operation, junction temperature should be limited to 125°C, maximum. To estimate the margin of safety in a complete design (including heat sink), increase the ambient temperature until the thermal protection is triggered. Use worst-case loads and signal conditions. For good reliability, thermal protection should trigger more than 35°C above the maximum expected ambient condition of your application. This produces a worst-case junction temperature of 125°C at the highest expected ambient temperature and worst-case load. The internal protection circuitry of the REG104 has been designed to protect against overload conditions. It was not intended to replace proper heat sinking. Continuously running the REG104 into thermal shutdown will degrade reliability. IOUT (mA) FIGURE 8. Transient and DC Dropout. 10 REG104 SBVS025C PD = (VIN – VOUT ) • I OUT ( AVG ) Power dissipation can be minimized by using the lowest possible input voltage necessary to assure the required output voltage. REG104 SBVS025C 5 Power Dissipation (Watts) POWER DISSIPATION The REG104 is available in two different package configurations. The ability to remove heat from the die is different for each package type and, therefore, presents different considerations in the Printed Circuit-Board (PCB) layout. The PCB area around the device that is free of other components moves the heat from the device to the ambient air. While it is difficult-to-impossible to quantify all of the variables in a thermal design of this type, performance data for several configurations are shown in Figure 9. In all cases the PCB copper area is bare copper, free of solder resist mask, and not solder plated. All examples are for 1-ounce copper. Using heavier copper will increase the effectiveness in moving the heat from the device. In those examples where there is copper on both sides of the PCB, no connection has been provided between the two sides. The addition of plated through holes will improve the heat sink effectiveness. Power dissipation depends on input voltage and load conditions. Power dissipation is equal to the product of the average output current times the voltage across the output element, VIN to VOUT voltage drop. CONDITIONS #1 #2 #3 #4 4 3 2 1 0 0 25 50 75 100 125 Ambient Temperature (°C) CONDITION PACKAGE PCB AREA THETA J-A 27°C/W 1 DDPAK 4in2 Top Side Only 2 SOT-223 4in2 Top Side Only 53°C/W 3 DDPAK None 65°C/W 4 SOT-223 0.5in2 Top Side Only 110°C/W FIGURE 9. Maximum Power Dissipation versus Ambient Temperature for the Various Packages and PCB Heat Sink Configurations. 11 REGULATOR MOUNTING The tab of both packages is electrically connected to ground. For best thermal performance, the tab of the DDPAK surface-mount version should be soldered directly to a circuitboard copper area. Increasing the copper area improves heat dissipation. Figure 10 shows typical thermal resistance from junction to ambient as a function of the copper area for the DDPAK, Figure 11 shows the same relationship for the SOT-223. Although the tabs of the DDPAK and the SOT-223 are electrically grounded, they are not intended to carry any current. The copper pad that acts as a heat sink should be isolated from the rest of the circuit to prevent current flow through the device from the tab to the ground pin. Solder pad footprint recommendations for the various REG104 devices are presented in the Application Bulletin “Solder Pad Recommendations for Surface-Mount Devices” (SBFA015), available from the Texas Instruments web site (www.ti.com). THERMAL RESISTANCE vs PCB COPPER AREA Thermal Resistance, θJA (°C/W) 50 Circuit Board Copper Area REG104 Surface Mount Package 1 oz. copper 40 30 20 10 REG104 DDPAK Surface Mount Package 0 0 1 2 3 4 5 Copper Area (inches2) FIGURE 10. Thermal Resistance versus PCB Area for the Five Lead DDPAK. THERMAL RESISTANCE vs PCB COPPER AREA Thermal Resistance, θJA (°C/W) 180 Circuit Board Copper Area REG104 Surface Mount Package 1 oz. copper 160 140 120 100 80 60 40 20 REG104 SOT-223 Surface Mount Package 0 0 1 2 3 4 5 Copper Area (inches2) FIGURE 11. Thermal Resistance versus PCB Area for the Five Lead SOT-223. 12 REG104 SBVS025C PACKAGE DRAWINGS MPSF007A – APRIL 2000 – REVISED SEPTEMBER 2000 KTT (R-PSFM-G5) PLASTIC FLANGE-MOUNT 0.405 (10,29) 0.395 (10,03) 0.058 (1,47) 0.052 (1,32) 0.185 (4,70) 0.175 (4,45) 0.050 (1,27) NOM 0.107 (2,72) 0.340 (8,64) 0.330 (8,38) 0.610 (15,49) 0.590 (14,99) 0.103 (2,62) 0.010 (0,25) 0.001 (0,03) 1 0.067 (1,70) 0.268 (6,81) 5 Seating Plane 0.035 (0,89) 0.029 (0,74) 0.004 (0,10) 0.010 (0,25) M 0.010 (0,25) 0.021 (0,53) 0.015 (0,38) 0.110 (2,79) 0.090 (2,29) 0°– 5° 4200577-3/B 09/00 NOTES: A. All linear dimensions are in inches (millimeters). B. This drawing is subject to change without notice. C. Dimensions do not include mold protrusions, not to exceed 0.006 (0,15). REG104 SBVS025C 13 PACKAGE DRAWINGS (Cont.) MPDS098 – MARCH 2001 DCQ (R-PDSO-G6) B PLASTIC SMALL-OUTLINE 0.258 (6,55) 0.254 (6,45) D 0.120 (3,05) 0.116 (2,95) 0.004 (0,10) M C B A Gage Plane H 6X C 0.003 (0,08) 0.004 (0,10) 0.286 (7,26) 0.001 (0,02) 0.270 (6,86) 0.004 (0,10) M C A 0.045 (1,14) 0.036 (0,91) 0.140 (3,55) 0.136 (3,45) D 4X 0.050(1,27) 0.010(0,25) Seating Plane 5X 0.020 (0,51) E F 0.016 (0,41) 0.004 (0,10) M C B 0.200(5,08) 0.013 (0,32) 0.009 (0,24) 0.071 (1,80) MAX F 0.036 (0,91) 0.034 (0,87) 0.065 (1,65) 0.061 (1,55) 0°–8° 4202109/A 03/01 NOTES: A. All linear dimensions are in inches (millimeters). B. This drawing is subject to change without notice. C. Controlling dimension in inches D. Body length and width dimensions are determined at the outermost extremes of the plastic body exclusive of mold flash, tie bar burrs, gate burrs, and interlead flash, but including any mismatch between the top and the bottom of the plastic body. E. Lead width dimension does not include dambar protrusion. F. Lead width and thickness dimensions apply to solder plated leads. G. Interlead flash allow 0.008 inch max. H. Gate burr/protrusion max. 0.006 inch. 14 I. Datums A and B are to be determined at Datum H. J. Package dimensions per JEDEC outline drawing TO–261, issue B, dated Feb. 1999. This variation is not yet included. REG104 SBVS025C IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. 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