1.5A Ultra Low Dropout Linear Regulator FEATURES TJ3965 MSOP8 / SOP8 / SOP8-PP PKG Ultra Low Dropout Voltage Low Ground Pin Current Excellent Line and Load Regulation Guaranteed Output Current of 1.5A Available in MSOP8, SOP8, SOP8-PP, SOT-223, TO-252, TO-263, TO-220, and SOT-89 Packages z Fixed Output Voltages : 1.2V, 1.8V, 2.5V, 3.3V, and 5.0V z SENSE Option Improves Load Regulation z Over-Temperature/Over-Current Protection z z z z z SOT-223 3L PKG TO252 3L / 5L PKG z -40℃ to 125℃ Junction Temperature Range TO-263 3L / 5L PKG z Moisture Sensitivity Level 3 APPLICATION z z z z z z Battery Powered Equipments Motherboards and Graphic Cards Microprocessor Power Supplies Peripheral Cards High Efficiency Linear Regulators Battery Chargers TO-220 3L / 5L PKG SOT-89 5L PKG DESCRIPSION The TJ3965 series of high performance ultra low-dropout linear regulators operates from 2.5V to 6V input supply and provides ultra low-dropout voltage, high output current with low ground current. Wide range of preset output voltage options are available. These ultra low dropout linear regulators respond fast to step changes in load which makes them suitable for low voltage microprocessor applications. The TJ3965 is developed on a CMOS process technology which allows low quiescent current operation independent of output load current. This CMOS process also allows the TJ3965 to operate under extremely low dropout conditions. ORDERING INFORMATION Device TJ3965MD-ADJ TJ3965MD-X.X TJ3965D-ADJ TJ3965D-X.X TJ3965DP-ADJ TJ3965DP-X.X 3965S-X.X TJ3965GRS-ADJ TJ3965GRS-X.X TJ3965GR-ADJ TJ3965GR-X.X TJ3965T-ADJ TJ3965T-X.X 3965F-ADJ 3965F-X.X Package MSOP8 SOP8 SOP8-PP SOT-223 3L TO-252 3L/5L TO-263 3L/5L TO-220 3L/5L SOT-89 5L X.X = Output Voltage = 1.2, 1.8, 2.5, 3.3, and 5.0 Absolute Maximum Ratings CHARACTERISTIC SYMBOL MIN. MAX. UNIT Input Supply Voltage (Survival) VIN -0.3 6.5 V Enable Input Voltage (Survival) VEN (1) -0.3 6.5 V Maximum Output Current IMAX - 1.5 A Lead Temperature (Soldering, 5 sec) TSOL 260 ℃ Storage Temperature Range TSTG -65 150 ℃ Operating Junction Temperature Range TJOPR -40 125 ℃ (1) It is recommended for VEN voltage not to exceed VIN voltage. Jul. 2010 – Rev. 1.12 -1- HTC 1.5A Ultra Low Dropout Linear Regulator TJ3965 Ordering Information VOUT ADJ 1.2V 1.8V Package MSOP8 SOP8 SOP8-PP TO-252 5L TO-252 5L TO-263 5L TO-263 5L TO-220 5L SOT-89 5L MSOP8 SOP8 SOP8-PP SOT-223 3L TO-252 3L TO-252 3L TO-252 5L TO-252 5L TO-263 3L TO-263 3L TO-263 5L TO-263 5L TO-220 3L TO-220 5L SOT-89 5L MSOP8 SOP8 SOP8-PP SOT-223 3L TO -252 3L TO -252 3L TO -252 5L TO -252 5L TO -263 3L TO -263 3L TO -263 5L TO -263 5L TO-220 3L TO-220 5L SOT-89 5L Jul. 2010 – Rev. 1.12 Order No. TJ3965MD-ADJ-8L TJ3965D-ADJ-8L TJ3965DP-ADJ-8L TJ3965RS-ADJ-5L TJ3965GRS-ADJ-5L TJ3965R-ADJ-5L TJ3965GR-ADJ-5L TJ3965T-ADJ-5L TJ3965F-ADJ-5L TJ3965MD-1.2V-8L TJ3965D-1.2V-8L TJ3965DP-1.2-8L TJ3965S-1.2V-3L TJ3965RS-1.2V-3L TJ3965GRS-1.2V-3L TJ3965RS-1.2V-5L TJ3965GRS-1.2V-5L TJ3965R-1.2V-3L TJ3965GR-1.2V-3L TJ3965R-1.2V-5L TJ3965GR-1.2V-5L TJ3965T-1.2V-3L TJ3965T-1.2V-5L TJ3965F-1.2V-5L TJ3965MD-1.8V-8L TJ3965D-1.8V-8L TJ3965DP-1.8V-8L TJ3965S-1.8V-3L TJ3965RS-1.8V-3L TJ3965GRS-1.8V-3L TJ3965RS-1.8V-5L TJ3965GRS-1.8V-5L TJ3965R-1.8V-3L TJ3965GR-1.8V-3L TJ3965R-1.8V-5L TJ3965GR-1.8V-5L TJ3965T-1.8V-3L TJ3965T-1.8V-5L TJ3965F-1.8V-5L Description 1.5A, Adjustable, Enable 1.5A, Adjustable, Enable 1.5A, Adjustable, Enable 1.5A, Adjustable, Enable 1.5A, Adjustable, Enable 1.5A, Adjustable, Enable 1.5A, Adjustable, Enable 1.5A, Adjustable, Enable 1.5A, Adjustable, Enable 1.5A, Enable, SENSE 1.5A, Enable, SENSE 1.5A, Enable, SENSE 1.5A 1.5A 1.5A 1.5A, Enable, SENSE 1.5A, Enable, SENSE 1.5A 1.5A 1.5A, Enable, SENSE 1.5A, Enable, SENSE 1.5A 1.5A, Enable, SENSE 1.5A, Enable, SENSE 1.5A, Enable, SENSE 1.5A, Enable, SENSE 1.5A, Enable, SENSE 1.5A 1.5A 1.5A 1.5A, Enable, SENSE 1.5A, Enable, SENSE 1.5A 1.5A 1.5A, Enable, SENSE 1.5A, Enable, SENSE 1.5A 1.5A, Enable, SENSE 1.5A, Enable, SENSE -2- Supplied As Reel Reel Reel Reel Reel Reel Reel Tube Reel Reel Reel Reel Reel Reel Reel Reel Reel Reel Reel Reel Reel Tube Tube Reel Reel Reel Reel Reel Reel Reel Reel Reel Reel Reel Reel Reel Tube Tube Reel Status Contact us Active Active Obsolete Active Obsolete Active Active Active Contact us Active Active Active Obsolete Active Obsolete Active Obsolete Active Obsolete Active Active Active Active Contact us Active Active Active Obsolete Active Obsolete Active Obsolete Active Obsolete Active Active Active Active HTC 1.5A Ultra Low Dropout Linear Regulator TJ3965 Ordering Information VOUT 2.5V 3.3V 5.0V Package MSOP8 SOP8 SOP8-PP SOT-223 3L TO -252 3L TO -252 3L TO -252 5L TO -252 5L TO -263 3L TO -263 3L TO -263 5L TO -263 5L TO-220 3L TO-220 5L SOT-89 5L MSOP8 SOP8 SOP8-PP SOT-223 3L TO -252 3L TO -252 3L TO -252 5L TO -252 5L TO -263 3L TO -263 3L TO -263 5L TO -263 5L TO-220 3L TO-220 5L SOT-89 5L MSOP8 SOP8 SOP8-PP SOT-223 3L TO -252 3L TO -252 3L TO -252 5L TO -252 5L TO -263 3L TO -263 3L TO -263 5L TO -263 5L TO-220 3L TO-220 5L SOT-89 5L Jul. 2010 – Rev. 1.12 (Continued) Order No. TJ3965MD-2.5V-8L TJ3965D-2.5V-8L TJ3965DP-2.5V-8L TJ3965S-2.5V-3L TJ3965RS-2.5V-3L TJ3965GRS-2.5V-3L TJ3965RS-2.5V-5L TJ3965GRS-2.5V-5L TJ3965R-2.5V-3L TJ3965GR-2.5V-3L TJ3965R-2.5V-5L TJ3965GR-2.5V-5L TJ3965T-2.5V-3L TJ3965T-2.5V-5L TJ3965F-2.5V-5L TJ3965MD-3.3V-8L TJ3965D-3.3V-8L TJ3965DP-3.3V-8L TJ3965S-3.3V-3L TJ3965RS-3.3V-3L TJ3965GRS-3.3V-3L TJ3965RS-3.3V-5L TJ3965GRS-3.3V-5L TJ3965R-3.3V-3L TJ3965GR-3.3V-3L TJ3965R-3.3V-5L TJ3965GR-3.3V-5L TJ3965T-3.3V-3L TJ3965T-3.3V-5L TJ3965F-3.3V-5L TJ3965MD-5.0V-8L TJ3965D-5.0V-8L TJ3965DP-5.0V-8L TJ3965S-5.0V-3L TJ3965RS-5.0V-3L TJ3965GRS-5.0V-3L TJ3965RS-5.0V-5L TJ3965GRS-5.0V-5L TJ3965R-5.0V-3L TJ3965GR-5.0V-3L TJ3965R-5.0V-5L TJ3965GR-5.0V-5L TJ3965T-5.0V-3L TJ3965T-5.0V-5L TJ3965F-5.0V-5L Description 1.5A, Enable, SENSE 1.5A, Enable, SENSE 1.5A, Enable, SENSE 1.5A 1.5A 1.5A 1.5A, Enable, SENSE 1.5A, Enable, SENSE 1.5A 1.5A 1.5A, Enable, SENSE 1.5A, Enable, SENSE 1.5A 1.5A, Enable, SENSE 1.5A, Enable, SENSE 1.5A, Enable, SENSE 1.5A, Enable, SENSE 1.5A, Enable, SENSE 1.5A 1.5A 1.5A 1.5A, Enable, SENSE 1.5A, Enable, SENSE 1.5A 1.5A 1.5A, Enable, SENSE 1.5A, Enable, SENSE 1.5A 1.5A, Enable, SENSE 1.5A, Enable, SENSE 1.5A, Enable, SENSE 1.5A, Enable, SENSE 1.5A, Enable, SENSE 1.5A 1.5A 1.5A 1.5A, Enable, SENSE 1.5A, Enable, SENSE 1.5A 1.5A 1.5A, Enable, SENSE 1.5A, Enable, SENSE 1.5A 1.5A, Enable, SENSE 1.5A, Enable, SENSE -3- Supplied As Reel Reel Reel Reel Reel Reel Reel Reel Reel Reel Reel Reel Tube Tube Reel Reel Reel Reel Reel Reel Reel Reel Reel Reel Reel Reel Reel Tube Tube Reel Reel Reel Reel Reel Reel Reel Reel Reel Reel Reel Reel Reel Tube Tube Reel Status Contact us Active Active Active Obsolete Active Obsolete Active Obsolete Active Obsolete Active Active Active Active Contact us Active Active Active Obsolete Active Obsolete Active Obsolete Active Obsolete Active Active Active Active Contact us Active Active Active Obsolete Active Obsolete Active Obsolete Active Obsolete Active Active Active Active HTC 1.5A Ultra Low Dropout Linear Regulator TJ3965 (Continued) TJ 3965 Lead Count : 3L(Fixed Output Only) / 5L / 8L Output Voltage : ADJ / 1.2V / 1.8V / 2.5V / 3.3V / 5.0V Package Type Root Name MD D DP S RS R T F : MSOP8 : SOP8 : SOP8-PP : SOT223 : TO252 : TO263 : TO220 : SOT89 G : Halogen Free Blank : Pb Free Root Name Product Code Jul. 2010 – Rev. 1.12 -4- HTC 1.5A Ultra Low Dropout Linear Regulator TJ3965 PIN CONFIGURATION EN 1 VIN 2 8 GND Exposed 7 GND PAD 6 GND VOUT 3 SENSE/ADJ MSOP8 / SOP8 5 GND 4 SOT223-3L SOP8-PP(Exposed PAD) TO252-3L TO252-5L TO263-3L TO263-5L 4 VIN 5 VOUT TO220-3L TO220-5L 3 EN 2 GND 1 SENSE/ADJ SOT89-5L PIN DESCRIPTION Pin No. SOT223 / TO252 / TO263 / TO220 3LEAD SOT-223 5LEAD SOT-89 5LEAD Name Function Name Function Name Function 1 VIN Input Supply EN Chip Enable SENSE/ADJ Remote Sense or Output Adjust 2 GND Ground VIN Input Supply GND Ground 3 VOUT Output Voltage VOUT Output Voltage EN Chip Enable 4 - - SENSE/ADJ Remote Sense or Output Adjust VIN Input Supply 5 - - GND Ground VOUT Output Voltage TO252 / TO263 / TO220 5LEAD MSOP8 / SOP8 / SOP8-PP 8LEAD Pin No. Name Function Name Function 1 EN Chip Enable EN Chip Enable 2 VIN Input Supply VIN Input Supply 3 GND Ground VOUT Output Voltage 4 VOUT Output Voltage SENSE/ADJ Remote Sense or Output Adjust 5 / 6/ 7 / 8 SENSE/ADJ Remote Sense or Output Adjust GND Ground - - - Exposed Thermal PAD Connect to Ground. (SOP8-PP Only) Jul. 2010 – Rev. 1.12 -5- HTC 1.5A Ultra Low Dropout Linear Regulator TJ3965 TYPICAL APPLICATION Typical 3 Pin Application VIN VIN CIN 68μF VOUT VOUT TJ3965 + + COUT GND - 33μF - Typical 5 / 8 Pin Application VIN VIN CIN VOUT VOUT TJ3965 + EN VEN 68μF - + COUT SENSE GND - 33μF 5 / 8 Pin Remote Load Sense Application VIN VIN TJ3965 + CIN VOUT VOUT EN VEN 68μF - + SENSE GND L O A D COUT - 33μF Typical Adjustable Version Application VIN VIN CIN TJ3965 + 68μF - VOUT VEN EN VOUT R2 ADJ GND R1 + COUT - 33μF * TJ3965 can deliver a continuous current of 1.5A over the full operating temperature. However, the output current is limited by the restriction of power dissipation which differs from packages. A heat sink may be required depending on the maximum power dissipation and maximum ambient temperature of application. With respect to the applied package, the maximum output current of 1.5A may be still undeliverable. * When a Pull-Up resistor is connected between VEN terminal and VEN Signal (or VIN line), the resistance of the Pull-Up resistor should be kept under 10kΩ. * See Application Information Jul. 2010 – Rev. 1.12 -6- HTC 1.5A Ultra Low Dropout Linear Regulator TJ3965 ELECTRICAL CHARACTERISTICS(Note 1) Limits in standard typeface are for TJ=25℃, and limits in boldface type apply over the full operating temperature range. Unless otherwise specified: VIN(Note 2) = VO(NOM) + 1 V, IL = 10 mA, CIN = 68 uF, COUT = 33 uF, VEN = VIN - 0.3 V PARAMETER SYMBOL TEST CONDITION MIN. TYP. MAX. UNIT -2 -3 0 2 3 % 1.117 1.110 1.145 1.174 1.188 V Output Voltage Tolerance VO 10 mA < IL < 1.5 A VOUT+1 V < VIN < 6 V Adjustable Pin Voltage (ADJ version) VADJ 10 mA < IL < 1.5 A VOUT+1.5 V < VIN < 6 V Line Regulation(Note 3) ΔVLINE VOUT+1 V < VIN < 6 V - 0.08 0.18 0.20 %/V Load Regulation(Note 3, 4) ΔVLOAD 10 mA < IL < 1.5 A - 0.25 0.55 1.00 % IL = 150 mA - 40 55 65 (Note 5) Dropout Voltage VDROP Ground Pin Current(Note 6) mV IL = 1.5 A - 380 450 550 IL = 150 mA - 30 55 75 IL = 1.5 A - 30 55 75 VEN < 0.2 V - 30 55 75 uA IGND1 uA Ground Pin Current(Note 7) IGND2 Output Peak Current IPEAK 2.0 1.7 2.2 - A Thermal Shutdown Temperature TSD - 165 - ℃ Thermal Shutdown Hysteresis ΔTSD - 10 - ℃ Logic Low VIL Output = Low - 0 VIN − 0.5 2 V Logic High VIH Output = High VIN + 0.5 2 VIN - V IEN VEN = VIN - 0.05 2 uA Enable threshold Enable Input Current Note 1. Stresses listed as the absolute maximum ratings may cause permanent damage to the device. These are for stress ratings. Functional operating of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may remain possibly to affect device reliability. Note 2. The minimum operating value for input voltage is equal to either (VOUT,NOM + VDROP) or 2.5V, whichever is greater. Note 3. Output voltage line regulation is defined as the change in output voltage from the nominal value due to change in the input line voltage. Output voltage load regulation is defined as the change in output voltage from the nominal value due to change in load current. Note 4. Regulation is measured at constant junction temperature by using a 20ms current pulse. Devices are tested for load regulation in the load range from 10mA to 1.5A Note 5. Dropout voltage is defined as the minimum input to output differential voltage at which the output drops 2% below the nominal value. Dropout voltage specification applies only to output voltages of 2.5V and above. For output voltages below 2.5V, the dropout voltage is nothing but the input to output differential, since the minimum input voltage is 2.5V Note 6. Ground current, or quiescent current, is the difference between input and output currents. It's defined by IGND1 = IIN - IOUT under the given loading condition. The total current drawn from the supply is the sum of the load current plus the ground pin current. Note 7. Ground current, or standby current, is the input current drawn by a regulator when the output voltage is disabled by an enable signal. Jul. 2010 – Rev. 1.12 -7- HTC 1.5A Ultra Low Dropout Linear Regulator TJ3965 TYPICAL OPERATING CHARACTERISTICS Ambient Temperature vs. Output Voltage Change Output Current vs. Dropout Voltage Power Dissipation vs. Case Temperature, MSOP8 Power Dissipation vs. Case Temperature, SOP8 Power Dissipation vs. Case Temperature, SOP8-PP Power Dissipation vs. Case Temperature, TO220 T.B.D. Jul. 2010 – Rev. 1.12 -8- HTC 1.5A Ultra Low Dropout Linear Regulator TJ3965 APPLICATION INFORMATION Output Adjustment (Adjustable Version) An adjustable output device has output voltage range of 1.145V to 5.0V. To obtain a desired output voltage, the following equation can be used with R1 resistor. The sum of R1 and R2 should be in range of 1kΩ to 100kΩ ⎛V ⎞ R 2 = R1⎜ OUT − 1⎟ 1 . 145 ⎝ ⎠ To enhance output stability, a capacitor of 68pF to 100pF can be placed in series with VOUT and ADJ. EN Pin A CMOS logic level signal at the EN pin will turn-on/off the regulator. If this pin is not used for logic control, it must be tied to Vin for proper operation. When a pull-up resistor is connected between EN pin and VEN signal(or VIN line), the resistance should be kept under 10kΩ. SENSE Pin In applications where the regulator output is not very close to the load, the TJ3965 can provide better remote load regulation characteristics using the SENSE pin. TJ3965 regulates the voltage at the output pin. Hence, the voltage at the remote load will be lower than the voltage at the output pin as a value of the voltage drop across the trace series resistance. If the sense option pin is not required, the sense pin must be connected to the VOUT pin. Connecting the sense pin to the remote load will provide regulation at the remote load because the TJ3965 regulates the voltage at the sense pin when the sense option pin is used. Output Capacitor The TJ3965 requires a proper output capacitance to maintain stability and improve transient response over current. The ESR of the output capacitor within the limits of 0.5Ω to 10Ω is required. A minimum capacitance value of 22µF of tantalum or aluminum electrolytic capacitor is recommended. In a case of ceramic capacitor, a minimum capacitance value of 10µF is required and additional resistance of minimum 1Ω should be added with the output capacitor in series to maintain its minimum ESR. The resistance and capacitance have to be varied upon the load current. Jul. 2010 – Rev. 1.12 -9- HTC 1.5A Ultra Low Dropout Linear Regulator VOUT OUTPUT R2 ADJ GND R1 TJ3965 VOUT OUTPUT R2 + 22µF - Additional Resistance ADJ GND R1 10µF Maximum Output Current Capability The TJ3965 can deliver a continuous current of 1.5A over the full operating junction temperature range. However, the output current is limited by the restriction of power dissipation which differs from packages. A heat sink may be required depending on the maximum power dissipation and maximum ambient temperature of application. With respect to the applied package, the maximum output current of 1.5A may be still undeliverable due to the restriction of the power dissipation of TJ3965. Under all possible conditions, the junction temperature must be within the range specified under operating conditions. The temperatures over the device are given by: TC = TA + PD X θCA / TJ = TC + PD X θJC / TJ = TA + PD X θJA where TJ is the junction temperature, TC is the case temperature, TA is the ambient temperature, PD is the total power dissipation of the device, θCA is the thermal resistance of case-to-ambient, θJC is the thermal resistance of junction-to-case, and θJA is the thermal resistance of junction to ambient. The total power dissipation of the device is given by: PD = PIN – POUT = (VIN X IIN)–(VOUT X IOUT) = (VIN X (IOUT+IGND)) – (VOUT X IOUT) = (VIN - VOUT) X IOUT + VIN X IGND where IGND is the operating ground current of the device which is specified at the Electrical Characteristics. The maximum allowable temperature rise (TRmax) depends on the maximum ambient temperature (TAmax) of the application, and the maximum allowable junction temperature (TJmax): TRmax = TJmax – TAmax The maximum allowable value for junction-to-ambient thermal resistance, θJA, can be calculated using the formula: θJA = TRmax / PD = (TJmax – TAmax) / PD TJ3965 is available in SOT223, MSOP8, SOP8-PP, TO263, TO220, and SOT89 packages. The thermal resistance depends on amount of copper area or heat sink, and on air flow. If the maximum allowable value of θJA calculated above is over 140°C/W for SOT223 package, over 220°C/W for MSOP8 package, over 165°C/W for SOP8 package, over 175°C/W for SOP8-PP package, over 105 °C/W for TO252 package, over 80 °C/W for TO263 package, over 70 °C/W for TO220 package, no heat sink is needed since the package can dissipate enough heat to satisfy these requirements. If the value for allowable θJA falls near or below these limits, a heat sink or proper area of copper plane is required. In summary, the absolute maximum ratings of thermal resistances are as follow: Absolute Maximum Ratings of Thermal Resistance No heat sink / No air flow / No adjacent heat source / TA = 25° Jul. 2010 – Rev. 1.12 - 10 - HTC 1.5A Ultra Low Dropout Linear Regulator Characteristic TJ3965 Symbol Rating Unit Thermal Resistance Junction-To-Ambient / MSOP8 θJA-MSOP8 220 °C/W Thermal Resistance Junction-To-Ambient / SOP8 θJA-SOP8 165 °C/W Thermal Resistance Junction-To-Ambient / SOP8-PP θJA-SOP8-PP 175 °C/W Thermal Resistance Junction-To-Ambient / SOT223 θJA-SOT223 140 °C/W Thermal Resistance Junction-To-Ambient / TO252 θJA-TO252 105 °C/W Thermal Resistance Junction-To-Ambient / TO263 θJA-TO263 80 °C/W Thermal Resistance Junction-To-Ambient / TO220 θJA-TO220 70 °C/W Thermal Resistance Junction-To-Ambient / SOT89 θJA-SOT89 200 °C/W In case that there is no cooling solution and no heat sink / copper plane area for heat sink, the maximum allowable power dissipation of each package is as follow; Characteristic Symbol Rating Unit Maximum Allowable Power Dissipation at TA=25°C / MSOP8 PDMax-MSOP8 0.455 W Maximum Allowable Power Dissipation at TA=25°C / SOP8 PDMax -SOP8 0.606 W Maximum Allowable Power Dissipation at TA=25°C / SOP8-PP PDMax -SOP8-PP 0.571 W Maximum Allowable Power Dissipation at TA=25°C / SOT223 PDMax -SOT223 0.714 W Maximum Allowable Power Dissipation at TA=25°C / TO252 PDMax -TO252 0.952 W Maximum Allowable Power Dissipation at TA=25°C / TO263 PDMax -TO263 1.250 W Maximum Allowable Power Dissipation at TA=25°C / TO220 PDMax -TO220 1.429 W PDMax –SOT89 0.500 W - Please note that above maximum allowable power dissipation is based on the minimum copper plane area which does not exceed the proper footprint of the package. And the ambient temperature is 25°C. Maximum Allowable Power Dissipation at TA=25°C / SOT89 If proper cooling solution such as heat sink, copper plane area, air flow is applied, the maximum allowable power dissipation could be increased. However, if the ambient temperature is increased, the allowable power dissipation would be decreased. For example, in case of SOT223 and TO263 package, θJA-SOT223 is 140 °C/W and θJA-TO263 is 80 °C/W, however, as shown in below graph, θJA could be decreased with respect to the copper plane area. So, the specification of maximum power dissipation for an application is fixed, the proper copper plane area could be estimated by following graphs. As shown in graph, wider copper plane area leads lower θJA. Jul. 2010 – Rev. 1.12 - 11 - HTC 1.5A Ultra Low Dropout Linear Regulator TJ3965 The maximum allowable power dissipation is also influenced by the ambient temperature. With the above θJA-Copper plane area relationship, the maximum allowable power dissipation could be evaluated with respect to the ambient temperature. As shown in graph, the higher copper plane area leads θJA. And the higher ambient temperature leads lower maximum allowable power dissipation. All this relationship is based on the aforesaid equation ; θJA = TRmax / PD = (TJmax – TAmax) / PD T.B.D Jul. 2010 – Rev. 1.12 - 12 - HTC