LT3014 20mA, 3V to 80V Low Dropout Micropower Linear Regulator U FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ DESCRIPTIO The LT®3014 is a high voltage, micropower low dropout linear regulator. The device is capable of supplying 20mA of output current with a dropout voltage of 350mV. Designed for use in battery-powered or high voltage systems, the low quiescent current (7µA operating and 1µA in shutdown) makes the LT3014 an ideal choice. Quiescent current is also well controlled in dropout. Wide Input Voltage Range: 3V to 80V Low Quiescent Current: 7µA Low Dropout Voltage: 350mV Output Current: 20mA LT3014HV Survives 100V Transients (2ms) No Protection Diodes Needed Adjustable Output from 1.22V to 60V 1µA Quiescent Current in Shutdown Stable with 0.47µF Output Capacitor Stable with Aluminum, Tantalum or Ceramic Capacitors Reverse-Battery Protection No Reverse Current Flow from Output Thermal Limiting Available in 5-Lead ThinSOTTM and 8-Lead DFN Packages Other features of the LT3014 include the ability to operate with very small output capacitors. The regulators are stable with only 0.47µF on the output while most older devices require between 10µF and 100µF for stability. Small ceramic capacitors can be used without the necessary addition of ESR as is common with other regulators. Internal protection circuitry includes reverse-battery protection, current limiting, thermal limiting and reverse current protection. U APPLICATIO S ■ ■ ■ Low Current High Voltage Regulators Regulator for Battery-Powered Systems Telecom Applications Automotive Applications , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents including 6118263, 6144250. U ■ The device is available as an adjustable device with a 1.22V reference voltage. The LT3014 regulator is available in the 5-lead ThinSOT and 8-lead DFN packages. TYPICAL APPLICATIO Dropout Voltage 400 5V Supply with Shutdown VIN 5.4V TO 80V OUT LT3014 3.92M VOUT 5V 20mA 0.47µF 1µF SHDN GND ADJ 1.27M 3014 TA01 VSHDN OUTPUT <0.3V OFF >2.0V ON DROPOUT VOLTAGE (mV) IN 350 300 250 200 150 100 50 0 0 2 4 6 8 10 12 14 16 18 20 OUTPUT CURRENT (mA) 3014 TA02 3014fb 1 LT3014 W W W AXI U U ABSOLUTE RATI GS (Note 1) IN Pin Voltage, Operating ................................. ±80V Transient (2ms Survival, LT3014HV) .............. +100V OUT Pin Voltage ............................................... ±60V IN to OUT Differential Voltage ........................... ±80V ADJ Pin Voltage .................................................. ±7V SHDN Pin Input Voltage ................................... ±80V Output Short-Circuit Duration ..................... Indefinite Storage Temperature Range ThinSOT Package......................... –65°C to 150°C DFN Package ............................... –65°C to 125°C Operating Junction Temperature Range (Notes 3, 10, 11) ......................... –40°C to 125°C Lead Temperature, SOT-23 (Soldering, 10 sec) ..................................... 300°C U U W PACKAGE/ORDER I FOR ATIO TOP VIEW TOP VIEW IN 1 5 OUT GND 2 SHDN 3 4 ADJ S5 PACKAGE 5-LEAD PLASTIC SOT-23 TJMAX = 125°C, θJA = 150°C/ W θJC = 25°C/ W MEASURED AT PIN 2. SEE APPLICATIONS INFORMATION SECTION. ORDER PART NUMBER LT3014ES5 LT3014HVES5 S5 PART MARKING LTBMF LTBRS OUT 1 8 IN ADJ 2 7 NC NC 3 6 NC GND 4 5 SHDN 9 DD PACKAGE 8-LEAD (3mm × 3mm) PLASTIC DFN EXPOSED PAD IS GND (PIN 9) MUST BE SOLDERED TO PCB TJMAX = 125°C, θJA = 40°C/ W θJC = 10°C/ W MEASURED AT PIN 9. ORDER PART NUMBER LT3014EDD LT3014HVEDD DD PART MARKING LBMG LBRT Order Options Tape and Reel: Add #TR Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF Lead Free Part Marking: http://www.linear.com/leadfree/ Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at TJ = 25°C. PARAMETER CONDITIONS MIN Minimum Input Voltage ILOAD = 20mA ● ADJ Pin Voltage (Notes 2, 3) VIN = 3.3V, ILOAD = 100µA 3.3V < VIN < 80V, 100µA < ILOAD < 20mA ● Line Regulation ∆VIN = 3.3V to 80V, ILOAD = 100µA (Note 2) ● Load Regulation VIN = 3.3V, ∆ILOAD = 100µA to 20mA (Note 2) VIN = 3.3V, ∆ILOAD = 100µA to 20mA ● 1.200 1.180 TYP MAX UNITS 3 3.3 V 1.220 1.220 1.240 1.260 V V 1 10 mV 13 25 40 mV mV 3014fb 2 LT3014 ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at TJ = 25°C. PARAMETER CONDITIONS Dropout Voltage VIN = VOUT(NOMINAL) (Notes 4, 5) ILOAD = 100µA ILOAD = 100µA ● ILOAD = 1mA ILOAD = 1mA ● ILOAD = 10mA ILOAD = 10mA ● ILOAD = 20mA ILOAD = 20mA ● ILOAD = 0mA ILOAD = 100µA ILOAD = 1mA ILOAD = 10mA ILOAD = 20mA ● ● ● ● ● GND Pin Current VIN = VOUT(NOMINAL) (Notes 4, 6) MIN Output Voltage Noise COUT = 0.47µF, ILOAD = 20mA, BW = 10Hz to 100kHz ADJ Pin Bias Current (Note 7) Shutdown Threshold VOUT = Off to On VOUT = On to Off ● ● SHDN Pin Current (Note 8) VSHDN = 0V VSHDN = 6V Quiescent Current in Shutdown VIN = 6V, VSHDN = 0V MAX UNITS 120 180 250 mV mV 200 270 360 mV mV 300 350 450 mV mV 350 410 570 mV mV 7 12 40 250 650 20 30 100 450 1000 µA µA µA µA µA µVRMS 115 4 10 nA 1.3 1.3 2 V V ● ● 1 0 4 1 µA µA ● 1 4 µA Ripple Rejection VIN = 7V(Avg), VRIPPLE = 0.5VP-P, fRIPPLE = 120Hz, ILOAD = 20mA Current Limit VIN = 7V, VOUT = 0V VIN = 3.3V, ∆VOUT = –0.1V (Note 2) ● Input Reverse Leakage Current VIN = –80V, VOUT = 0V ● Reverse Output Current (Note 9) VOUT = 1.22V, VIN < 1.22V (Note 2) Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: The LT3014 is tested and specified for these conditions with the ADJ pin connected to the OUT pin. Note 3: Operating conditions are limited by maximum junction temperature. The regulated output voltage specification will not apply for all possible combinations of input voltage and output current. When operating at maximum input voltage, the output current range must be limited. When operating at maximum output current, the input voltage range must be limited. Note 4: To satisfy requirements for minimum input voltage, the LT3014 is tested and specified for these conditions with an external resistor divider (249k bottom, 392k top) for an output voltage of 3.3V. The external resistor divider adds a 5µA DC load on the output. Note 5: Dropout voltage is the minimum input to output voltage differential needed to maintain regulation at a specified output current. In dropout, the output voltage is equal to (VIN – VDROPOUT). TYP 0.25 60 70 dB 70 mA mA 25 2 6 mA 4 µA Note 6: GND pin current is tested with VIN = VOUT (nominal) and a current source load. This means the device is tested while operating in its dropout region. This is the worst-case GND pin current. The GND pin current decreases slightly at higher input voltages. Note 7: ADJ pin bias current flows into the ADJ pin. Note 8: SHDN pin current flows out of the SHDN pin. Note 9: Reverse output current is tested with the IN pin grounded and the OUT pin forced to the rated output voltage. This current flows into the OUT pin and out of the GND pin. Note 10: The LT3014E is guaranteed to meet performance specifications from 0°C to 125°C operating junction temperature. Specifications over the –40°C to 125°C operating junction temperature range are assured by design, characterization and correlation with statistical process controls. Note 11: This IC includes overtemperature protection that is intended to protect the device during momentary overload conditions. Junction temperature will exceed 125°C when overtemperature protection is active. Continuous operation above the specified maximum operating junction temperature may impair device reliability. 3014fb 3 LT3014 U W TYPICAL PERFOR A CE CHARACTERISTICS Typical Dropout Voltage Guaranteed Dropout Voltage 600 500 = TEST POINTS 450 450 400 TJ = 125°C 350 300 TJ = 25°C 250 200 150 100 400 DROPOUT VOLTAGE (mV) TJ ≤ 125°C 500 DROPOUT VOLTAGE (mV) DROPOUT VOLTAGE (mV) Dropout Voltage 500 TJ ≤ 25°C 300 200 2 4 0 6 8 10 12 14 16 18 20 OUTPUT CURRENT (mA) 2 4 VSHDN = VIN 8 6 4 VSHDN = 0V 0 – 50 – 25 0 50 75 25 TEMPERATURE (°C) 100 125 1.230 1.225 1.220 1.215 1.210 75 50 25 TEMPERATURE (°C) 0 1 2 3 4 5 6 7 INPUT VOLTAGE (V) 4 125 GND PIN CURRENT (µA) 8 9 10 VSHDN = 0V 0 1 2 3 4 5 6 7 INPUT VOLTAGE (V) 3014 G05 500 400 300 3014 G06 1.6 1.4 1.2 1.0 0.8 0.6 200 0.4 100 0.2 2 4 10 1.8 600 0 9 SHDN Pin Threshold 700 0 8 2.0 VIN = 3.3V 900 TJ = 25°C = 1.22V V 800 OUT RL = 1.22k IL = 1mA* 100 VSHDN = VIN 6 GND Pin Current vs ILOAD RL = 122Ω IL = 10mA* 200 100 1000 500 300 8 0 800 400 10 1.200 – 50 – 25 TJ = 25°C 900 *FOR VOUT = 1.22V 600 12 2 GND Pin Current 125 TJ = 25°C 14 RL = ∞ VOUT = 1.22V 1.205 1000 RL = 61Ω IL = 20mA* 100 16 IL = 100µA 3014 G04 700 50 25 0 75 TEMPERATURE (°C) Quiescent Current QUIESCENT CURRENT (µA) 10 ADJ PIN VOLTAGE (V) QUIESCENT CURRENT (µA) IL = 100µA 3014 G03 1.235 2 GND PIN CURRENT (µA) 150 ADJ Pin Voltage VIN = 6V RL = ∞ IL = 0 0 IL = 1mA 200 3014 G02 1.240 12 0 250 0 –50 –25 6 8 10 12 14 16 18 20 OUTPUT CURRENT (mA) SHDN PIN THRESHOLD (V) 0 Quiescent Current 14 IL = 10mA 300 50 0 3014 G01 16 IL = 20mA 100 100 50 0 400 350 6 8 10 12 14 16 18 20 OUTPUT CURRENT (mA) 0 –50 –25 0 25 50 75 TEMPERATURE (°C) 100 125 3014 G09 3014 G07 3014 G08 3014fb 4 LT3014 U W TYPICAL PERFOR A CE CHARACTERISTICS SHDN Pin Current SHDN Pin Current 1.6 1.2 VSHDN = 0V 1.4 CURRENT FLOWS OUT OF SHDN PIN 0.8 0.6 0.4 0.2 1.2 1.0 0.8 0.6 0.4 0 2.5 3 1 1.5 2 SHDN PIN VOLTAGE (V) 0.5 3.5 0 – 50 – 25 4 0 50 75 25 TEMPERATURE (°C) 3014 G10 50 40 30 20 0 70 60 50 40 30 100 25 20 10 100 125 3014 G16 0 1 2 3 4 5 6 7 8 OUTPUT VOLTAGE (V) VIN = 7V + 50mVRMS RIPPLE IL = 20mA 70 66 64 62 60 60 50 40 COUT = 4.7µF 30 20 COUT = 0.47µF 10 0 50 75 25 TEMPERATURE (°C) 10 Input Ripple Rejection VIN = 7V + 0.5VP-P 70 RIPPLE AT f = 120Hz IL = 20mA 68 56 – 50 – 25 9 3014 G15 80 58 1 CURRENT FLOWS INTO OUTPUT PIN 15 125 RIPPLE REJECTION (dB) RIPPLE REJECTION (dB) 2 50 75 25 TEMPERATURE (°C) 30 Input Ripple Rejection 3 ADJ PIN ESD CLAMP 35 0 50 25 0 75 TEMPERATURE (°C) 72 VIN = 0V VOUT = VADJ = 1.22V 0 TJ = 25°C 45 VIN = 0V = VADJ V 40 OUT 3014 G14 Reverse Output Current 125 5 3014 G13 4 100 Reverse Output Current VIN = 7V VOUT = 0V 0 –50 –25 6 8 10 12 14 16 18 20 INPUT VOLTAGE (V) 5 50 75 25 TEMPERATURE (°C) 3014 G12 10 6 0 50 20 10 0 – 50 – 25 4 0 – 50 – 25 125 80 CURRENT LIMIT (mA) CURRENT LIMIT (mA) 90 60 4 6 Current Limit 100 VOUT = 0V 70 TJ = 25°C REVERSE OUTPUT CURRENT (µA) 100 REVERSE OUTPUT CURRENT (µA) Current Limit 2 8 3014 G11 80 0 10 2 0.2 0 7 12 ADJ PIN BIAS CURRENT (nA) SHDN PIN CURRENT (µA) SHDN PIN CURRENT (µA) TJ = 25°C CURRENT FLOWS 1.0 OUT OF SHDN PIN 8 ADJ Pin Bias Current 14 100 125 3014 G17 0 10 100 1k 10k FREQUENCY (Hz) 100k 1M 3014 G18 3014fb 5 LT3014 U W TYPICAL PERFOR A CE CHARACTERISTICS ILOAD = 20mA –5 3.0 LOAD REGULATION (mV) MINIMUM INPUT VOLTAGE (V) Load Regulation 0 2.5 2.0 1.5 1.0 0.5 Output Noise Spectral Density ∆IL = 100µA TO 20mA VOUT = 1.22V OUTPUT NOISE SPECTRAL DENSITY (µV/√Hz) Minimum Input Voltage 3.5 –10 –15 –20 –25 –30 –35 0 –50 –25 25 75 0 50 TEMPERATURE (°C) 100 125 –40 – 50 – 25 0 25 50 75 100 COUT = 0.47µF IL = 20mA VOUT = 1.22V 1 0.1 0.01 10 100 TEMPERATURE (°C) 3014 G19 100k 3014 G21 3014 G22 LOAD CURRENT (mA) OUTPUT VOLTAGE DEVIATION (V) Transient Response VOUT 200µV/DIV 1ms/DIV 1k 10k FREQUENCY (Hz) 3014 G20 10Hz to 100kHz Output Noise COUT = 0.47µF IL = 20mA VOUT = 1.22V 125 10 0.04 0.02 0 VIN = 7V VOUT = 5V CIN = COUT = 0.47µF CERAMIC ∆ILOAD = 1mA TO 5mA –0.02 –0.04 6 4 2 0 0 200 600 400 TIME (µs) 800 1000 3014 G23 U U U PI FU CTIO S (SOT-23 Package/DD Package) IN (Pin 1/Pin 8): Input. Power is supplied to the device through the IN pin. A bypass capacitor is required on this pin if the device is more than six inches away from the main input filter capacitor. In general, the output impedance of a battery rises with frequency, so it is advisable to include a bypass capacitor in battery-powered circuits. A bypass capacitor in the range of 0.1µF to 10µF is sufficient. The LT3014 is designed to withstand reverse voltages on the IN pin with respect to ground and the OUT pin. In the case of a reversed input, which can happen if a battery is plugged in backwards, the LT3014 will act as if there is a diode in series with its input. There will be no reverse current flow into the LT3014 and no reverse voltage will appear at the load. The device will protect both itself and the load. GND (Pin 2/Pins 4, 9): Ground. SHDN (Pin 3/Pin 5): Shutdown. The SHDN pin is used to put the LT3014 into a low power shutdown state. The output will be off when the SHDN pin is pulled low. The SHDN pin can be driven either by 5V logic or opencollector logic with a pull-up resistor. The pull-up resistor is only required to supply the pull-up current of the opencollector gate, normally several microamperes. If unused, the SHDN pin must be tied to IN or to a logic high. 3014fb 6 LT3014 U U U PI FU CTIO S (SOT-23 Package/DD Package) ADJ (Pin 4/Pin 2): Adjust. This is the input to the error amplifier. This pin is internally clamped to ±7V. It has a bias current of 4nA which flows into the pin (see curve of ADJ Pin Bias Current vs Temperature in the Typical Performance Characteristics). The ADJ pin voltage is 1.22V referenced to ground, and the output voltage range is 1.22V to 60V. OUT (Pin 5/Pin 1): Output. The output supplies power to the load. A minimum output capacitor of 0.47µF is required to prevent oscillations. Larger output capacitors will be required for applications with large transient loads to limit peak voltage transients. See the Applications Information section for more information on output capacitance and reverse output characteristics. U W U U APPLICATIO S I FOR ATIO The LT3014 is a 20mA high voltage low dropout regulator with micropower quiescent current and shutdown. The device is capable of supplying 20mA at a dropout voltage of 350mV. The low operating quiescent current (7µA) drops to 1µA in shutdown. In addition to the low quiescent current, the LT3014 incorporates several protection features which make it ideal for use in battery-powered systems. The device is protected against both reverse input and reverse output voltages. In battery backup applications where the output can be held up by a backup battery when the input is pulled to ground, the LT3014 acts like it has a diode in series with its output and prevents reverse current flow. Adjustable Operation The LT3014 has an output voltage range of 1.22V to 60V. The output voltage is set by the ratio of two external resistors as shown in Figure 2. The device servos the output to maintain the voltage at the adjust pin at 1.22V referenced to ground. The current in R1 is then equal to 1.22V/R1 and the current in R2 is the current in R1 plus the ADJ pin bias current. The ADJ pin bias current, 4nA at 25°C, flows through R2 into the ADJ pin. The output voltage can be calculated using the formula in Figure 1. The value of R1 should be less than 1.62M to minimize errors in the output voltage caused by the ADJ pin bias current. Note that in shutdown the output is turned off and the divider current will be zero. The device is tested and specified with the ADJ pin tied to the OUT pin and a 5µA DC load (unless otherwise specified) for an output voltage of 1.22V. Specifications for output voltages greater than 1.22V will be proportional to the ratio of the desired output voltage to 1.22V (VOUT/1.22V). For example, load regulation for an output current change of 1mA to 20mA is –13mV typical at VOUT = 1.22V. At VOUT = 12V, load regulation is: (12V/1.22V) • (–13mV) = –128mV IN VIN VOUT OUT R2 LT3014 + ADJ GND R1 ( ) 3014 F01 VOUT = 1.22V • 1 + R2 + (IADJ)(R2) R1 VADJ = 1.22V IADJ = 4nA AT 25°C OUTPUT RANGE = 1.22V TO 60V Figure 1. Adjustable Operation Output Capacitance and Transient Response The LT3014 is designed to be stable with a wide range of output capacitors. The ESR of the output capacitor affects stability, most notably with small capacitors. A minimum output capacitor of 0.47µF with an ESR of 3Ω or less is recommended to prevent oscillations. The LT3014 is a micropower device and output transient response will be a function of output capacitance. Larger values of output capacitance decrease the peak deviations and provide improved transient response for larger load current changes. Bypass capacitors, used to decouple individual components powered by the LT3014, will increase the effective output capacitor value. 3014fb 7 LT3014 U W U U APPLICATIO S I FOR ATIO Extra consideration must be given to the use of ceramic capacitors. Ceramic capacitors are manufactured with a variety of dielectrics, each with different behavior across temperature and applied voltage. The most common dielectrics used are Z5U, Y5V, X5R and X7R. The Z5U and Y5V dielectrics are good for providing high capacitances in a small package, but exhibit strong voltage and temperature coefficients as shown in Figures 2 and 3. When used with a 5V regulator, a 10µF Y5V capacitor can exhibit an effective value as low as 1µF to 2µF over the operating temperature range. The X5R and X7R dielectrics result in more stable characteristics and are more suitable for use as the output capacitor. The X7R type has better stability across temperature, while the X5R is less expensive and is available in higher values. Voltage and temperature coefficients are not the only sources of problems. Some ceramic capacitors have a piezoelectric response. A piezoelectric device generates voltage across its terminals due to mechanical stress, 20 similar to the way a piezoelectric accelerometer or microphone works. For a ceramic capacitor the stress can be induced by vibrations in the system or thermal transients. Thermal Considerations The power handling capability of the device will be limited by the maximum rated junction temperature (125°C). The power dissipated by the device will be made up of two components: 1. Output current multiplied by the input/output voltage differential: IOUT • (VIN – VOUT) and, 2. GND pin current multiplied by the input voltage: IGND • VIN. The GND pin current can be found by examining the GND Pin Current curves in the Typical Performance Characteristics. Power dissipation will be equal to the sum of the two components listed above. 40 BOTH CAPACITORS ARE 16V, 1210 CASE SIZE, 10µF 20 X5R CHANGE IN VALUE (%) CHANGE IN VALUE (%) 0 –20 –40 –60 Y5V –80 –100 0 X5R –20 –40 Y5V –60 –80 0 2 4 8 6 10 12 DC BIAS VOLTAGE (V) 14 16 3014 F02 Figure 2. Ceramic Capacitor DC Bias Characteristics BOTH CAPACITORS ARE 16V, 1210 CASE SIZE, 10µF –100 50 25 75 –50 –25 0 TEMPERATURE (°C) 100 125 3014 F03 Figure 3. Ceramic Capacitor Temperature Characteristics 3014fb 8 LT3014 U W U U APPLICATIO S I FOR ATIO The LT3014 regulator has internal thermal limiting designed to protect the device during overload conditions. For continuous normal conditions the maximum junction temperature rating of 125°C must not be exceeded. It is important to give careful consideration to all sources of thermal resistance from junction to ambient. Additional heat sources mounted nearby must also be considered. For surface mount devices, heat sinking is accomplished by using the heat spreading capabilities of the PC board and its copper traces. Copper board stiffeners and plated through-holes can also be used to spread the heat generated by power devices. The following table lists thermal resistance for several different board sizes and copper areas. All measurements were taken in still air on 3/32" FR-4 board with one ounce copper. Table 1. SOT-23 Measured Thermal Resistance COPPER AREA TOPSIDE BACKSIDE BOARD AREA THERMAL RESISTANCE (JUNCTION-TO-AMBIENT) 2500 sq mm 2500 sq mm 2500 sq mm 125°C/W 1000 sq mm 2500 sq mm 2500 sq mm 125°C/W 225 sq mm 2500 sq mm 2500 sq mm 130°C/W 100 sq mm 2500 sq mm 2500 sq mm 135°C/W 50 sq mm 2500 sq mm 2500 sq mm 150°C/W Continuous operation at large input/output voltage differentials and maximum load current is not practical due to thermal limitations. Transient operation at high input/ output differentials is possible. The approximate thermal time constant for a 2500sq mm 3/32" FR-4 board with maximum topside and backside area for one ounce copper is 3 seconds. This time constant will increase as more thermal mass is added (i.e. vias, larger board, and other components). For an application with transient high power peaks, average power dissipation can be used for junction temperature calculations as long as the pulse period is significantly less than the thermal time constant of the device and board. Calculating Junction Temperature Example 1: Given an output voltage of 5V, an input voltage range of 24V to 30V, an output current range of 0mA to 20mA, and a maximum ambient temperature of 50°C, what will the maximum junction temperature be? The power dissipated by the device will be equal to: IOUT(MAX) • (VIN(MAX) – VOUT) + (IGND • VIN(MAX)) where: IOUT(MAX) = 20mA Table 2. DFN Measured Thermal Resistance COPPER AREA TOPSIDE BACKSIDE BOARD AREA THERMAL RESISTANCE (JUNCTION-TO-AMBIENT) 2500 sq mm 2500 sq mm 2500 sq mm 40°C/W 1000 sq mm 2500 sq mm 2500 sq mm 45°C/W 225 sq mm 2500 sq mm 2500 sq mm 50°C/W 100 sq mm 2500 sq mm 2500 sq mm 62°C/W For the DFN package, the thermal resistance junction-tocase (θJC), measured at the exposed pad on the back of the die, is 16°C/W. VIN(MAX) = 30V IGND at (IOUT = 20mA, VIN = 30V) = 0.55mA So: P = 20mA • (30V – 5V) + (0.55mA • 30V) = 0.52W The thermal resistance for the DFN package will be in the range of 40°C/W to 62°C/W depending on the copper area. So the junction temperature rise above ambient will be approximately equal to: 0.52W • 50°C/W = 26°C 3014fb 9 LT3014 U W U U APPLICATIO S I FOR ATIO The maximum junction temperature will then be equal to the maximum junction temperature rise above ambient plus the maximum ambient temperature or: TJMAX = 50°C + 26°C = 76°C Example 2: Given an output voltage of 5V, an input voltage of 48V that rises to 72V for 5ms(max) out of every 100ms, and a 5mA load that steps to 20mA for 50ms out of every 250ms, what is the junction temperature rise above ambient? Using a 500ms period (well under the time constant of the board), power dissipation is as follows: P1(48V in, 5mA load) = 5mA • (48V – 5V) + (100µA • 48V) = 0.22W P2(48V in, 20mA load) = 20mA • (48V – 5V) + (0.55mA • 48V) = 0.89W P3(72V in, 5mA load) = 5mA • (72V – 5V) + (100µA • 72V) = 0.34W P4(72V in, 20mA load) = 20mA • (72V – 5V) + (0.55mA • 72V) = 1.38W Operation at the different power levels is as follows: 76% operation at P1, 19% for P2, 4% for P3, and 1% for P4. PEFF = 76%(0.22W) + 19%(0.89W) + 4%(0.34W) + 1%(1.38W) = 0.36W With a thermal resistance in the range of 40°C/W to 62°C/W, this translates to a junction temperature rise above ambient of 20°C. Protection Features The LT3014 incorporates several protection features which make it ideal for use in battery-powered circuits. In addition to the normal protection features associated with monolithic regulators, such as current limiting and thermal limiting, the device is protected against reverse-input voltages, and reverse voltages from output to input. Current limit protection and thermal overload protection are intended to protect the device against current overload conditions at the output of the device. For normal operation, the junction temperature should not exceed 125°C. The input of the device will withstand reverse voltages of 80V. Current flow into the device will be limited to less than 6mA (typically less than 100µA) and no negative voltage will appear at the output. The device will protect both itself and the load. This provides protection against batteries which can be plugged in backward. The ADJ pin can be pulled above or below ground by as much as 7V without damaging the device. If the input is left open circuit or grounded, the ADJ pin will act like an open circuit when pulled below ground, and like a large resistor (typically 100k) in series with a diode when pulled above ground. If the input is powered by a voltage source, pulling the ADJ pin below the reference voltage will cause the device to current limit. This will cause the output to go to an unregulated high voltage. Pulling the ADJ pin above the reference voltage will turn off all output current. 3014fb 10 LT3014 U W U U APPLICATIO S I FOR ATIO In situations where the ADJ pin is connected to a resistor divider that would pull the ADJ pin above its 7V clamp voltage if the output is pulled high, the ADJ pin input current must be limited to less than 5mA. For example, a resistor divider is used to provide a regulated 1.5V output from the 1.22V reference when the output is forced to 60V. The top resistor of the resistor divider must be chosen to limit the current into the ADJ pin to less than 5mA when the ADJ pin is at 7V. The 53V difference between the OUT and ADJ pins divided by the 5mA maximum current into the ADJ pin yields a minimum top resistor value of 10.6k. In circuits where a backup battery is required, several different input/output conditions can occur. The output voltage may be held up while the input is either pulled to ground, pulled to some intermediate voltage, or is left open circuit. Current flow back into the output will follow the curve shown in Figure 4. The rise in reverse output current above 7V occurs from the breakdown of the 7V clamp on the ADJ pin. With a resistor divider on the regulator output, this current will be reduced depending on the size of the resistor divider. When the IN pin of the LT3014 is forced below the OUT pin or the OUT pin is pulled above the IN pin, input current will typically drop to less than 2µA. This can happen if the input of the LT3014 is connected to a discharged (low voltage) battery and the output is held up by either a backup battery or a second regulator circuit. The state of the SHDN pin will have no effect on the reverse output current when the output is pulled above the input. REVERSE OUTPUT CURRENT (µA) 50 TJ = 25°C 45 VIN = 0V = VADJ V 40 OUT ADJ PIN ESD CLAMP 35 30 25 20 CURRENT FLOWS INTO OUTPUT PIN 15 10 5 0 0 1 2 3 4 5 6 7 8 OUTPUT VOLTAGE (V) 9 10 3014 F04 Figure 4. Reverse Output Current 3014fb 11 LT3014 U TYPICAL APPLICATIO S 5V Buck Converter with Low Current Keep Alive Backup D2 D1N914 6 VIN 5.5V* TO 60V C2 0.33µF BOOST 4 C3 4.7µF 100V CERAMIC VIN SW 2 14 BIAS SHDN FB SYNC 10 R1 15.4k 12 R2 4.99k VC GND VOUT 5V 1A/20mA D1 10MQ060N LT1766 15 L1† 15µH + C1 100µF 10V SOLID TANTALUM 1, 8, 9, 16 11 CC 1nF IN OPERATING CURRENT SHDN LOW HIGH 3014 TA03 OUT LT3014 3.92M ADJ GND 1.27M * FOR INPUT VOLTAGES BELOW 7.5V, SOME RESTRICTIONS MAY APPLY † INCREASE L1 TO 30µH FOR LOAD CURRENTS ABOVE 0.6A AND TO 60µH ABOVE 1A Buck Converter Efficiency vs Load Current 100 VOUT = 5V L = 68µH VIN = 10V EFFICIENCY (%) 90 VIN = 42V 80 70 60 50 0 0.25 0.75 1.00 0.50 LOAD CURRENT (A) 1.25 3014 TA04 3014fb 12 LT3014 U TYPICAL APPLICATIO S LT3014 Automotive Application VIN 12V (LATER 42V) IN + 1µF NO PROTECTION DIODE NEEDED! OUT LT3014 R1 1µF ADJ SHDN GND R2 LOAD: CLOCK, SECURITY SYSTEM ETC OFF ON LT3014 Telecom Application VIN 48V (72V TRANSIENT) IN OUT LT3014 1µF ADJ SHDN + R1 NO PROTECTION DIODE NEEDED! GND 1µF R2 OFF ON LOAD: SYSTEM MONITOR ETC – BACKUP BATTERY 3014 TA05 Constant Brightness for Indicator LED over Wide Input Voltage Range RETURN IN 1µF OFF ON OUT LT3014 SHDN 1µF ADJ GND –48V ILED = 1.22V/RSET –48V CAN VARY FROM –3.3V TO –80V RSET 3014 TA06 3014fb 13 LT3014 U PACKAGE DESCRIPTIO S5 Package 5-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1635) 0.62 MAX 0.95 REF 2.90 BSC (NOTE 4) 1.22 REF 1.4 MIN 3.85 MAX 2.62 REF 2.80 BSC 1.50 – 1.75 (NOTE 4) PIN ONE RECOMMENDED SOLDER PAD LAYOUT PER IPC CALCULATOR 0.30 – 0.45 TYP 5 PLCS (NOTE 3) 0.95 BSC 0.80 – 0.90 0.20 BSC 0.01 – 0.10 1.00 MAX DATUM ‘A’ 0.30 – 0.50 REF 0.09 – 0.20 (NOTE 3) NOTE: 1. DIMENSIONS ARE IN MILLIMETERS 2. DRAWING NOT TO SCALE 3. DIMENSIONS ARE INCLUSIVE OF PLATING 4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR 5. MOLD FLASH SHALL NOT EXCEED 0.254mm 6. JEDEC PACKAGE REFERENCE IS MO-193 1.90 BSC S5 TSOT-23 0302 REV B 3014fb 14 LT3014 U PACKAGE DESCRIPTIO DD Package 8-Lead Plastic DFN (3mm × 3mm) (Reference LTC DWG # 05-08-1698) 0.675 ±0.05 3.5 ±0.05 1.65 ±0.05 2.15 ±0.05 (2 SIDES) PACKAGE OUTLINE 0.25 ± 0.05 0.50 BSC 2.38 ±0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS R = 0.115 TYP 5 3.00 ±0.10 (4 SIDES) 0.38 ± 0.10 8 1.65 ± 0.10 (2 SIDES) PIN 1 TOP MARK (NOTE 6) (DD) DFN 1203 0.200 REF 0.75 ±0.05 0.00 – 0.05 4 0.25 ± 0.05 1 0.50 BSC 2.38 ±0.10 (2 SIDES) BOTTOM VIEW—EXPOSED PAD NOTE: 1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-1) 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON TOP AND BOTTOM OF PACKAGE 3014fb Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 15 LT3014 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1129 700mA, Micropower, LDO VIN: 4.2V to 30V, VOUT(MIN) = 3.75V, VDO = 0.4V, IQ = 50µA, ISD = 16µA, DD, SOT-223, S8, TO220, TSSOP-20 Packages LT1175 500mA, Micropower Negative LDO VIN: –20V to –4.3V, VOUT(MIN) = –3.8V, VDO = 0.50V, IQ = 45µA, ISD = 10µA, DD, SOT-223, S8 Packages LT1185 3A, Negative LDO VIN: –35V to –4.2V, VOUT(MIN) = –2.40V, VDO = 0.80V, IQ = 2.5mA, ISD <1µA, TO220-5 Package LT1761 100mA, Low Noise Micropower, LDO VIN: 1.8V to 20V, VOUT(MIN) = 1.22V, VDO = 0.30V, IQ = 20µA, ISD <1µA, ThinSOT Package LT1762 150mA, Low Noise Micropower, LDO VIN: 1.8V to 20V, VOUT(MIN) = 1.22V, VDO = 0.30V, IQ = 25µA, ISD <1µA, MS8 Package LT1763 500mA, Low Noise Micropower, LDO VIN: 1.8V to 20V, VOUT(MIN) = 1.22V, VDO = 0.30V, IQ = 30µA, ISD <1µA, S8 Package LT1764/LT1764A 3A, Low Noise, Fast Transient Response, LDO VIN: 2.7V to 20V, VOUT(MIN) = 1.21V, VDO = 0.34V, IQ = 1mA, ISD <1µA, DD, TO220 Packages LTC1844 150mA, Very Low Dropout LDO VIN: 1.6V to 6.5V, VOUT(MIN) = 1.25V, VDO = 0.08V, IQ = 40µA, ISD <1µA, ThinSOT Package LT1962 300mA, Low Noise Micropower, LDO VIN: 1.8V to 20V, VOUT(MIN) = 1.22V, VDO = 0.27V, IQ = 30µA, ISD <1µA, MS8 Package LT1963/LT1963A 1.5A, Low Noise, Fast Transient Response, LDO VIN: 2.1V to 20V, VOUT(MIN) = 1.21V, VDO = 0.34V, IQ = 1mA, ISD <1µA, DD, TO220, SOT Packages LT1964 200mA, Low Noise Micropower, Negative LDO VIN: –1.9V to –20V, VOUT(MIN) = –1.21V, VDO = 0.34V, IQ = 30µA, ISD = 3µA, ThinSOT Package LT3010 50mA, 80V, Low Noise Micropower, LDO VIN: 3V to 80V, VOUT(MIN) = 1.28V, VDO = 0.3V, IQ = 30µA, ISD <1µA, MS8E Package LT3020 100mA, Low VIN, Low VOUT Micropower, VLDO VIN: 0.9V to 10V, VOUT(MIN) = 0.20V, VDO = 0.15V, IQ = 120µA, ISD <1µA, DFN, MS8 Packages LT3023 Dual 100mA, Low Noise Micropower, LDO VIN: 1.8V to 20V, VOUT(MIN) = 1.22V, VDO = 0.30V, IQ = 40µA, ISD <1µA, DFN, MS10 Packages LT3024 Dual 100mA/500mA, Low Noise Micropower, LDO VIN: 1.8V to 20V, VOUT(MIN) = 1.22V, VDO = 0.30V, IQ = 60µA, ISD <1µA, DFN, TSSOP-16E Packages LT3027 Dual 100mA, Low Noise LDO with Independent Inputs VIN: 1.8V to 20V, VOUT(MIN) = 1.22V, VDO = 0.30V, IQ = 40µA, ISD <1µA, DFN, MS10E Packages LT3028 Dual 100mA/500mA, Low Noise LDO with Independent Inputs VIN: 1.8V to 20V, VOUT(MIN) = 1.22V, VDO = 0.30V, IQ = 60µA, ISD <1µA, DFN, TSSOP-16E Packages 3014fb 16 Linear Technology Corporation LT/LWI 0706 REV B • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2005