LT3010/LT3010-5 50mA, 3V to 80V Low Dropout Micropower Linear Regulator U FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ DESCRIPTIO Wide Input Voltage Range: 3V to 80V Low Quiescent Current: 30µA Low Dropout Voltage: 300mV Output Current: 50mA Thermally Enhanced 8-Lead MSOP Package No Protection Diodes Needed Fixed Output Voltage: 5V (LT3010-5) Adjustable Output from 1.275V to 60V (LT3010) 1µA Quiescent Current in Shutdown Stable with 1µF Output Capacitor Stable with Aluminum, Tantalum or Ceramic Capacitors Reverse-Battery Protection No Reverse Current Flow from Output Thermal Limiting U APPLICATIO S ■ ■ ■ ■ The LT®3010 is a high voltage, micropower low dropout linear regulator. The device is capable of supplying 50mA output current with a dropout voltage of 300mV. Designed for use in battery-powered or high voltage systems, the low quiescent current (30µA operating and 1µA in shutdown) makes the LT3010 an ideal choice. Quiescent current is also well controlled in dropout. Other features of the LT3010 include the ability to operate with very small output capacitors. The regulators are stable with only 1µF 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. The device is available in a fixed output voltage of 5V and as an adjustable device with a 1.275V reference voltage. The LT3010 regulator is available in the 8-lead MSOP package with an exposed pad for enhanced thermal handling capability. Low Current High Voltage Regulators Regulator for Battery-Powered Systems Telecom Applications Automotive Applications , LTC and LT are registered trademarks of Linear Technology Corporation. U TYPICAL APPLICATIO Dropout Voltage 350 5V Supply with Shutdown VIN 5.4V TO 80V OUT LT3010-5 1µF 1µF SHDN SENSE GND 3010 TA01 VSHDN (PIN 5) OUTPUT <0.3V OFF >2.0V ON NC ON VOUT 5V 50mA DROPOUT VOLTAGE (mV) IN 300 250 200 150 100 50 0 0 10 20 30 40 50 OUTPUT CURRENT (mA) 3010 TA02 3010f 1 LT3010/LT3010-5 W W W AXI U U ABSOLUTE RATI GS U U W PACKAGE/ORDER I FOR ATIO (Note 1) IN Pin Voltage ................................................... ±80V 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 ............ –65°C to 150°C Operating Junction Temperature Range (Notes 3, 10, 11) ......................... –40°C to 125°C Lead Temperature (Soldering, 10 sec)............ 300°C ORDER PART NUMBER TOP VIEW OUT SENSE/ADJ* NC GND 1 2 3 4 8 7 6 5 IN NC NC SHDN LT3010EMS8E LT3010EMS8E-5 MS8E PACKAGE 8-LEAD PLASTIC MSOP *SENSE FOR LT3010-5, ADJ FOR LT3010 TJMAX = 125°C, θJA = 40°C/ W, θJC = 16°C/ W† SEE APPLICATIONS INFORMATION SECTION. EXPOSED PAD IS GND (MUST BE SOLDERED TO PCB) †MEASURED AT BOTTOM PAD MS8 PART MARKING LTZF LTAEF 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 LT3010 ILOAD = 50mA ● Regulated Output Voltage (Note 3) LT3010-5 VIN = 5.5V, ILOAD = 1mA 6V < VIN < 80V, 1mA < ILOAD < 50mA ● VIN = 3V, ILOAD = 1mA 4V < VIN < 80V, 1mA < ILOAD < 50mA ● ADJ Pin Voltage (Notes 2,3) LT3010 Line Regulation LT3010-5 LT3010 (Note 2) ∆VIN = 5.5V to 80V, ILOAD = 1mA ∆VIN = 3V to 80V, ILOAD = 1mA ● ● Load Regulation LT3010-5 VIN = 6V, ∆ILOAD = 1mA to 50mA VIN = 6V, ∆ILOAD = 1mA to 50mA ● VIN = 4V, ∆ILOAD = 1mA to 50mA VIN = 4V, ∆ILOAD = 1mA to 50mA ● LT3010 (Note 2) Dropout Voltage VIN = VOUT(NOMINAL) ILOAD = 1mA ILOAD = 1mA ● (Notes 4, 5) ILOAD = 10mA ILOAD = 10mA ● ILOAD = 50mA ILOAD = 50mA ● GND Pin Current VIN = VOUT(NOMINAL) (Notes 4, 6) ILOAD = 0mA ILOAD = 1mA ILOAD = 10mA ILOAD = 50mA ● ● ● ● Output Voltage Noise COUT = 10µF, ILOAD = 50mA, BW = 10Hz to 100kHz TYP MAX UNITS 3 4 V 4.925 4.850 5.000 5.000 5.075 5.150 V V 1.258 1.237 1.275 1.275 1.292 1.313 V V 3 3 15 13 mV mV 25 50 90 mV mV 10 20 32 mV mV 100 150 190 mV mV 200 260 350 mV mV 300 370 550 mV mV 30 100 400 1.8 60 180 700 3.3 µA µA µA mA µVRMS 100 ADJ Pin Bias Current (Note 7) 50 100 nA Shutdown Threshold VOUT = Off to On VOUT = On to Off 1.3 0.8 2 V V 0.5 0.1 2 0.5 µA µA 1 5 µA SHDN Pin Current (Note 8) VSHDN = 0V VSHDN = 6V Quiescent Current in Shutdown VIN = 6V, VSHDN = 0V 0.3 3010f 2 LT3010/LT3010-5 ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at TJ = 25°C. PARAMETER CONDITIONS Ripple Rejection LT3010 LT3010-5 MIN TYP Current Limit VIN = 7V, VOUT = 0V LT3010-5 VIN = 6V, ∆VOUT = –0.1V LT3010 (Note 2) VIN = 4V, ∆VOUT = –0.1V ● ● Input Reverse Leakage Current VIN = –80V, VOUT = 0V ● Reverse Output Current (Note 9) LT3010-5 LT3010 (Note 2) VIN = 7V(Avg), VRIPPLE = 0.5VP-P, fRIPPLE = 120Hz, ILOAD = 50mA VIN = 7V(Avg), VRIPPLE = 0.5VP-P, fRIPPLE = 120Hz, ILOAD = 50mA 65 60 UNITS 75 68 dB dB 140 mA mA mA 60 60 VOUT = 5V, VIN < 5V VOUT = 1.275V, VIN < 1.275V Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: The LT3010 (adjustable version) 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 LT3010 (adjustable version) 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 will add 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 will be equal to (VIN – VDROPOUT). MAX 10 8 6 mA 20 15 µA 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 will decrease 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 the GND pin. Note 10: The LT3010E 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. U W TYPICAL PERFOR A CE CHARACTERISTICS Typical Dropout Voltage Guaranteed Dropout Voltage 600 500 = TEST POINTS 450 450 350 TJ = 125°C 300 250 200 TJ = 25°C 150 100 400 DROPOUT VOLTAGE (mV) 500 400 DROPOUT VOLTAGE (mV) DROPOUT VOLTAGE (mV) Dropout Voltage 500 TJ ≤ 125°C 300 TJ ≤ 25°C 200 350 IL = 50mA 300 250 IL = 10mA 200 150 IL = 1mA 100 100 50 50 0 400 0 0 5 10 15 20 25 30 35 40 45 50 OUTPUT CURRENT (mA) 3010 G01 0 5 10 15 20 25 30 35 40 45 50 OUTPUT CURRENT (mA) 3010 G02 0 –50 –25 50 25 0 75 TEMPERATURE (°C) 100 125 3010 G03 3010f 3 LT3010/LT3010-5 U W TYPICAL PERFOR A CE CHARACTERISTICS LT3010 ADJ Pin Voltage LT3010-5 Output Voltage 1.295 35 1.290 5.06 1.285 5.04 25 VIN > 6V RL = ∞, IL = 0 (LT3010-5) RL = 250k, IL = 5µA (LT3010) 15 10 5 1.280 1.275 1.270 1.265 1.260 VSHDN = 0V 0 – 50 – 25 IL = 1mA 75 50 25 TEMPERATURE (°C) 0 100 125 1.255 – 50 – 25 75 50 25 TEMPERATURE (°C) 0 100 3010 G04 QUIESCENT CURRENT (µA) QUIESCENT CURRENT (µA) 30 25 20 15 10 5 0 1 2 3 4 5 6 7 INPUT VOLTAGE (V) 8 9 1.6 140 120 100 80 60 VSHDN = VIN 40 1 2 3 4 5 6 7 INPUT VOLTAGE (V) LT3010-5 GND Pin Current 1.6 1.6 0.8 RL = 500Ω IL = 10mA* 0 0 1 2 3 4 5 6 7 INPUT VOLTAGE (V) 8 9 3010 G09 RL = 1.27k IL = 1mA* 0 1 2 3 4 5 6 7 INPUT VOLTAGE (V) 8 10 3010 G10 SHDN Pin Threshold 1.4 1.4 1.2 1.0 0.8 0.6 0 9 1.6 OFF-TO-ON 1.2 1.0 0.8 ON-TO-OFF 0.6 0.4 0.2 0.2 10 RL = 127Ω IL = 10mA* 0.6 0 10 0.4 RL = 5k, IL = 1mA* 0.2 9 SHDN PIN THRESHOLD (V) RL = 200Ω IL = 25mA* 0.4 0.8 0.2 VIN = VOUT(NOMINAL) + 1V 1.8 TJ = 25°C GND PIN CURRENT (mA) GND PIN CURRENT (mA) TJ = 25°C 1.8 *FOR VOUT = 5V 1.2 RL = 51Ω IL = 25mA* 1.0 GND Pin Current vs ILOAD 2.0 0.6 1.2 3010 G07 2.0 1.0 8 RL = 25.5Ω IL = 50mA* 1.4 0.4 VSHDN = 0V 0 125 TJ = 25°C *FOR VOUT = 1.275V 1.8 3010 G08 1.4 100 LT3010 GND Pin Current 160 0 10 RL = 100Ω IL = 50mA* 75 50 25 TEMPERATURE (°C) 0 2.0 20 VSHDN = 0V 0 4.96 LT3010-5 Quiescent Current VSHDN = VIN 35 4.98 3010 G05 TJ = 25°C 180 RL = ∞ 40 5.00 4.92 – 50 – 25 125 200 TJ = 25°C RL = ∞ 45 5.02 3010 G06 LT3010 Quiescent Current 50 IL = 1mA 4.94 GND PIN CURRENT (mA) 20 5.08 OUTPUT VOLTAGE (V) VSHDN = VIN 30 ADJ PIN VOLTAGE (V) QUIESCENT CURRENT (µA) Quiescent Current 40 0 5 10 15 20 25 30 35 40 45 50 OUTPUT CURRENT (mA) 3010 G11 0 – 50 – 25 75 50 25 TEMPERATURE (°C) 0 100 125 3010 G12 3010f 4 LT3010/LT3010-5 U W TYPICAL PERFOR A CE CHARACTERISTICS SHDN Pin Current SHDN Pin Current 0.6 TJ = 25°C CURRENT FLOWS 0.5 OUT OF SHDN PIN 80 VSHDN = 0V 0.7 CURRENT FLOWS OUT OF SHDN PIN 0.4 0.3 0.2 0.1 70 ADJ PIN BIAS CURRENT (nA) SHDN PIN CURRENT (µA) SHDN PIN CURRENT (µA) ADJ Pin Bias Current 0.8 0.6 0.5 0.4 0.3 0.2 0.1 0 0 0.5 1 1.5 2 2.5 3 3.5 4 SHDN PIN VOLTAGE (V) 4.5 75 50 25 TEMPERATURE (°C) 0 100 3010 G13 180 160 160 CURRENT LIMIT (mA) CURRENT LIMIT (mA) VOUT = 0V 180 TJ = 25°C 140 120 100 80 60 60 50 25 0 75 TEMPERATURE (°C) 100 Reverse Output Current 18 15 12 LT3010-5 9 LT3010 75 50 25 TEMPERATURE (°C) 40 100 125 3010 G19 ADJ PIN CLAMP (SEE APPLICATIONS INFORMATION) LT3010 30 20 LT3010-5 0 1 2 3 4 5 6 7 8 OUTPUT VOLTAGE (V) 9 Input Ripple Rejection 78 90 76 80 74 72 70 68 66 50 25 0 75 TEMPERATURE (°C) VIN = 7V + 50mVRMS RIPPLE IL = 50mA 70 COUT = 10µF 60 50 40 COUT = 1µF 30 20 VIN = 7V + 0.5VP-P RIPPLE AT f = 120Hz IL = 50mA VOUT = 1.275V 60 –50 –25 10 3010 G18 100 62 0 50 80 64 3 0 – 50 – 25 60 0 125 RIPPLE REJECTION (dB) VIN = 0V VOUT = VADJ = 1.275V (LT3010) VOUT = VSENSE = 5V (LT3010-5) 6 70 Input Ripple Rejection RIPPLE REJECTION (dB) REVERSE OUTPUT CURRENT (µA) 21 80 3010 G17 3010 G16 24 TJ = 25°C VIN = 0V CURRENT FLOWS INTO OUTPUT PIN VOUT = VADJ (LT3010) VOUT = VSENSE (LT3010-5) 10 0 –50 –25 10 125 3010 G15 90 80 20 9 VIN = 7V VOUT = 0V 100 20 8 100 Reverse Output Current 120 40 3 4 5 6 7 INPUT VOLTAGE (V) 75 50 25 TEMPERATURE (°C) 0 100 140 40 2 20 Current Limit 200 1 30 0 – 50 – 25 125 REVERSE OUTPUT CURRENT (µA) Current Limit 0 40 3010 G14 200 0 50 10 0 – 50 – 25 5 60 10 0 100 125 3010 G20 10 100 1k 10k FREQUENCY (Hz) 100k 1M 3010 G21 3010f 5 LT3010/LT3010-5 U W TYPICAL PERFOR A CE CHARACTERISTICS ILOAD = 50mA 3.5 –5 3.0 –10 Output Noise Spectral Density ∆IL = 1mA TO 50mA LT3010 LOAD REGULATION (mV) MINIMUM INPUT VOLTAGE (V) Load Regulation 0 OUTPUT NOISE SPECTRAL DENSITY (µV/√Hz) LT3010 Minimum Input Voltage 4.0 2.5 2.0 1.5 1.0 0.5 0 – 50 – 25 –15 LT3010-5 –20 –25 –30 –35 75 50 25 TEMPERATURE (°C) 0 100 125 –40 – 50 – 25 75 50 25 TEMPERATURE (°C) 0 100 3010 G22 1 0.1 0.01 10 100 1k 10k FREQUENCY (Hz) 100k 3010 G24 3010 G25 LOAD CURRENT (mA) OUTPUT VOLTAGE DEVIATION (V) LT3010-5 Transient Response VOUT 100µV/DIV 1ms/DIV COUT = 1µF IL = 50mA 3010 G23 LT3010-5 10Hz to 100kHz Output Noise COUT = 1µF IL = 50mA 125 10 0.2 0.1 0 –0.1 VIN = 6V CIN = 1µF CERAMIC COUT = 1µF CERAMIC ∆ILOAD = 1mA TO 50mA –0.2 50 25 0 0 200 600 400 TIME (µs) 800 1000 3010 G26 3010f 6 LT3010/LT3010-5 U U U PI FU CTIO S OUT (Pin 1): Output. The output supplies power to the load. A minimum output capacitor of 1µF 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. SENSE (Pin 2): Sense. For the LT3010-5, the SENSE pin is the input to the error amplifier. Optimum regulation will be obtained at the point where the SENSE pin is connected to the OUT pin of the regulator. In critical applications, small voltage drops are caused by the resistance (RP) of PC traces between the regulator and the load. These may be eliminated by connecting the SENSE pin to the output at the load as shown in Figure 1 (Kelvin Sense Connection). Note that the voltage drop across the external PC traces will add to the dropout voltage of the regulator. The SENSE pin bias current is 10µA at the nominal rated output voltage. ADJ (Pin 2): Adjust. For the adjustable LT3010, this is the input to the error amplifier. This pin is internally clamped to ±7V. It has a bias current of 50nA which flows into the pin (see curve of ADJ Pin Bias Current vs Temperature in 8 VIN + 5 IN OUT LT3010 SHDN SENSE 1 2 RP + LOAD GND 4, TAB 3010 F01 Figure 1. Kelvin Sense Connection the Typical Performance Characteristics). The ADJ pin voltage is 1.275V referenced to ground, and the output voltage range is 1.275V to 60V. GND (Pin 4, Tab): Ground. The exposed backside of the package is an electrical connection for GND. As such, to ensure optimum device operation, the exposed pad must be connected directly to pin 4 on the PC board. SHDN (Pin 5): Shutdown. The SHDN pin is used to put the LT3010 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 open-collector logic with a pull-up resistor. The pull-up resistor is only required to supply the pull-up current of the open-collector gate, normally several microamperes. If unused, the SHDN pin can be left open circuit. The device will be active, output on, if the SHDN pin is not connected. IN (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 1µF to 10µF is sufficient. The LT3010 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 LT3010 will act as if there is a diode in series with its input. There will be no reverse current flow into the LT3010 and no reverse voltage will appear at the load. The device will protect both itself and the load. 3010f 7 LT3010/LT3010-5 U W U U APPLICATIO S I FOR ATIO The LT3010 is a 50mA high voltage low dropout regulator with micropower quiescent current and shutdown. The device is capable of supplying 50mA at a dropout voltage of 300mV. The low operating quiescent current (30µA) drops to 1µA in shutdown. In addition to the low quiescent current, the LT3010 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 LT3010 acts like it has a diode in series with its output and prevents reverse current flow. A small capacitor (C1) placed in parallel with the top resistor (R2) of the output divider is necessary for stability and transient performance of the adjustable LT3010. The impedance of C1 at 10kHz should be less than the value of R1. The adjustable 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 1.275V. Specifications for output voltages greater than 1.275V will be proportional to the ratio of the desired output voltage to 1.275V; (VOUT/1.275V). For example, load regulation for an output current change of 1mA to 50mA is –10mV typical at VOUT = 1.275V. At VOUT = 12V, load regulation is: Adjustable Operation (12V/1.275V) • (–10mV) = –94mV The adjustable version of the LT3010 has an output voltage range of 1.275V 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 1.275V referenced to ground. The current in R1 is then equal to 1.275V/R1 and the current in R2 is the current in R1 plus the ADJ pin bias current. The ADJ pin bias current, 50nA at 25°C, flows through R2 into the ADJ pin. The output voltage can be calculated using the formula in Figure 2. The value of R1 should be less than 250k 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. IN VIN Output Capacitance and Transient Response The LT3010 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 1µF with an ESR of 3Ω or less is recommended to prevent oscillations. The LT3010 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 LT3010, will increase the effective output capacitor value. OUT R2 LT3010 C1 + VOUT ADJ GND R1 3010 F02 ( ) VOUT = 1.275V 1 + R2 + (IADJ)(R2) R1 VADJ = 1.275V IADJ = 50nA AT 25°C OUTPUT RANGE = 1.275V TO 60V Figure 2. Adjustable Operation 3010f 8 LT3010/LT3010-5 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 3 and 4. 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, 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 20 BOTH CAPACITORS ARE 16V, 1210 CASE SIZE, 10µF 20 CHANGE IN VALUE (%) CHANGE IN VALUE (%) 0 X5R –20 –40 –60 Y5V X5R –20 –40 Y5V –60 –80 –80 –100 0 0 2 4 8 6 10 12 DC BIAS VOLTAGE (V) 14 16 3010 F03 Figure 3. Ceramic Capacitor DC Bias Characterics BOTH CAPACITORS ARE 16V, 1210 CASE SIZE, 10µF –100 50 25 75 –50 –25 0 TEMPERATURE (°C) 100 125 3010 F04 Figure 4. Ceramic Capacitor Temperature Characterics 3010f 9 LT3010/LT3010-5 U W U U APPLICATIO S I FOR ATIO The LT3010 series regulators have 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. Measured Thermal Resistance COPPER AREA 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 50mA, 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: 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 VIN(MAX) = 30V 225 sq mm 2500 sq mm 2500 sq mm 50°C/W IGND at (IOUT = 50mA, VIN = 30V) = 1mA 100 sq mm 2500 sq mm 2500 sq mm 62°C/W The thermal resistance junction-to-case (θJC), measured at the exposed pad on the back of the die, is 16°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 IOUT(MAX) = 50mA So: P = 50mA • (30V – 5V) + (1mA • 30V) = 1.28W The thermal resistance 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: 1.31W • 50°C/W = 65.5°C 3010f 10 LT3010/LT3010-5 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 + 65.5°C = 115.5°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 50mA 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) + (200µA • 48V) = 0.23W P2(48V in, 50mA load) = 50mA • (48V – 5V) + (1mA • 48V) = 2.20W P3(72V in, 5mA load) = 5mA • (72V – 5V) + (200µA • 72V) = 0.35W P4(72V in, 50mA load) = 50mA • (72V – 5V) + (1mA • 72V) = 3.42W 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%(0.23W) + 19%(2.20W) + 4%(0.35W) + 1%(3.42W) = 0.64W 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 26°C to 38°C. Protection Features The LT3010 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 of the adjustable device 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 try and force the current limit current out of the output. This will cause the output to go to a unregulated high voltage. Pulling the ADJ pin above the reference voltage will turn off all output current. 3010f 11 LT3010/LT3010-5 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 5. 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 LT3010 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 LT3010 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) 100 TA = 25°C 90 VIN = 0V CURRENT FLOWS 80 INTO OUTPUT PIN 70 VOUT = VADJ (LT3010) VOUT = VSENSE 60 (LT3010-5) ADJ PIN CLAMP (SEE ABOVE) 50 40 LT3010 30 20 LT3010-5 10 0 0 1 2 3 4 5 6 7 8 OUTPUT VOLTAGE (V) 9 10 3010 F05 Figure 5. Reverse Output Current 3010f 12 LT3010/LT3010-5 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 SW VIN 2 14 SHDN VOUT 5V 1A/50mA D1 10MQ060N LT1766 15 L1† 15µH BIAS SYNC FB GND 10 R1 15.4k 12 R2 4.99k VC + C1 100µF 10V SOLID TANTALUM 1, 8, 9, 16 11 CC 1nF 8 IN OUT 1 3010 TA03 * 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 LT3010-5 OPERATING CURRENT 5 SHDN LOW HIGH SENSE 2 GND 4 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 3010 TA04 3010f 13 LT3010/LT3010-5 U TYPICAL APPLICATIO LT3010 Automotive Application VIN 12V (LATER 42V) IN + 1µF NO PROTECTION DIODE NEEDED! OUT LT3010-5 1µF SENSE SHDN GND LOAD: CLOCK, SECURITY SYSTEM ETC OFF ON LT3010 Telecom Application VIN 48V (72V TRANSIENT) IN OUT LT3010-5 1µF SHDN NO PROTECTION DIODE NEEDED! SENSE + 1µF GND OFF ON LOAD: SYSTEM MONITOR ETC – BACKUP BATTERY 3010 TA05 Constant Brightness for Indicator LED over Wide Input Voltage Range RETURN IN 1µF OFF ON OUT LT3010 SHDN 1µF ADJ GND –48V ILED = 1.275V/RSET –48V CAN VARY FROM –4V TO –80V RSET 3010 TA06 3010f 14 LT3010/LT3010-5 U PACKAGE DESCRIPTIO MS8E Package 8-Lead Plastic MSOP (Reference LTC DWG # 05-08-1662) BOTTOM VIEW OF EXPOSED PAD OPTION 2.06 ± 0.102 (.080 ± .004) 1 5.23 (.206) MIN 1.83 ± 0.102 (.072 ± .004) 0.889 ± 0.127 (.035 ± .005) 2.794 ± 0.102 (.110 ± .004) 2.083 ± 0.102 3.2 – 3.45 (.082 ± .004) (.126 – .136) 8 0.42 ± 0.04 (.0165 ± .0015) TYP 3.00 ± 0.102 (.118 ± .004) (NOTE 3) 0.65 (.0256) BSC 8 7 6 5 0.52 (.206) REF RECOMMENDED SOLDER PAD LAYOUT 0.254 (.010) 3.00 ± 0.102 (.118 ± .004) NOTE 4 4.90 ± 0.15 (1.93 ± .006) DETAIL “A” 0° – 6° TYP GAUGE PLANE 0.53 ± 0.015 (.021 ± .006) DETAIL “A” 1 2 3 4 1.10 (.043) MAX 0.86 (.034) REF 0.18 (.077) SEATING PLANE 0.22 – 0.38 (.009 – .015) TYP 0.65 (.0256) BSC 0.13 ± 0.076 (.005 ± .003) MSOP (MS8E) 0802 NOTE: 1. DIMENSIONS IN MILLIMETER/(INCH) 2. DRAWING NOT TO SCALE 3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX 3010f 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 LT3010/LT3010-5 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1020 125mA, Micropower Regulator and Comparator VIN: 4.5V to 36V, VOUT = 2.5V, VDO = 0.4V, IQ = 40µA, ISD = 40µA, Comparator and Reference, Class B Outputs, S16, PDIP14 Packages LT1120/LT1120A 125mA, Micropower Regulator and Comparator VIN: 4.5V to 36V, VOUT = 2.5V, VDO = 0.4V, IQ = 40µA, ISD = 10µA, Comparator and Reference,Logic Shutdown, Ref Sources and Sinks 2/4mA, S8, N8 Packages LT1121/ LT1121HV 150mA, Micropower, LDO VIN: 4.2V to 30/36V, VOUT = 3.75V, VDO = 0.42V, IQ = 30µA, ISD = 16µA, Reverse Battery Protection, SOT-223, S8, Z Packages LT1129 700mA, Micropower, LDO VIN: 4.2V to 30V, VOUT = 3.75V, VDO = 0.4V, IQ = 50µA, ISD = 16µA, DD, S0T-223, S8,TO220-5, TSSOP20 Packages LT1616 25V, 500mA (IOUT), 1.4MHz, High Efficiency Step-Down DC/DC Converter VIN: 3.6V to 25V, VOUT = 1.25V, IQ = 1.9mA, ISD = <1µA, ThinSOT Package LT1676 60V, 440mA (IOUT), 100kHz, High Efficiency Step-Down DC/DC Converter VIN: 7.4V to 60V, VOUT = 1.24V, IQ = 3.2mA, ISD = 2.5µA, S8 Package LT1761 100mA, Low Noise Micropower, LDO VIN: 1.8V to 20V, VOUT = 1.22V, VDO = 0.3V, IQ = 20µA, ISD = <1µA, Low Noise < 20µVRMS P-P, Stable with 1µF Ceramic Capacitors, ThinSOT Package LT1762 150mA, Low Noise Micropower, LDO VIN: 1.8V to 20V, VOUT = 1.22V, VDO = 0.3V, IQ = 25µA, ISD = <1µA, Low Noise < 20µVRMS P-P, MS8 Package LT1763 500mA, Low Noise Micropower, LDO VIN: 1.8V to 20V, VOUT = 1.22V, VDO = 0.3V, IQ = 30µA, ISD = <1µA, Low Noise < 20µVRMS P-P, S8 Package LT1764/LT1764A 3A, Low Noise, Fast Transient Response, LDO VIN: 2.7V to 20V, VOUT = 1.21V, VDO = 0.34V, IQ = 1mA, ISD = <1µA, Low Noise < 40µVRMS P-P, “A” Version Stable with Ceramic Capacitors, DD, TO220-5 Packages LT1766 60V, 1.2A (IOUT), 200kHz, High Efficiency Step-Down DC/DC Converter VIN: 5.5V to 60V, VOUT = 1.20V, IQ = 2.5mA, ISD = 25µA, TSSOP16/E Package LT1776 40V, 550mA (IOUT), 200kHz, High Efficiency Step-Down DC/DC Converter VIN: 7.4V to 40V, VOUT = 1.24V, IQ = 3.2mA, ISD = 30µA, N8, S8 Packages LT1934/ LT1934-1 300mA/60mA, (IOUT), Constant Off-Time, High Efficiency Step-Down DC/DC Converter 90% Efficiency, VIN: 3.2V to 34V, VOUT = 1.25V, IQ = 14µA, ISD = <1µA, ThinSOT Package LT1956 60V, 1.2A (IOUT), 500kHz, High Efficiency Step-Down DC/DC Converter VIN: 5.5V to 60V, VOUT = 1.20V, IQ = 2.5mA, ISD = 25µA, TSSOP16/E Package LT1962 300mA, Low Noise Micropower, LDO VIN: 1.8V to 20V, VOUT = 1.22V, VDO = 0.27V, IQ = 30µA, ISD = <1µA, Low Noise < 20µVRMS P-P, MS8 Package LT1963/LT1963A 1.5A, Low Noise, Fast Transient Response, LDO VIN: 2.1V to 20V, VOUT = 1.21V, VDO = 0.34V, IQ = 1mA, ISD = <1µA, Low Noise < 40µVRMS P-P, “A” Version Stable with Ceramic Capacitors, DD, TO220-5, S0T-223, S8 Packages LT1964 VIN: –0.9V to –20V, VOUT = –1.21V, VDO = 0.34V, IQ = 30µA, ISD = 3µA, Low Noise < 30µVRMS P-P, Stable with Ceramic Capacitors, ThinSOT Package 200mA, Low Noise Micropower, Negative LDO 3010f 16 Linear Technology Corporation LT/TP 0403 2K • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com LINEAR TECHNOLOGY CORPORATION 2003