LT1962 Series 300mA, Low Noise, Micropower LDO Regulators U FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ DESCRIPTIO Low Noise: 20µVRMS (10Hz to 100kHz) Output Current: 300mA Low Quiescent Current: 30µA Wide Input Voltage Range: 1.8V to 20V Low Dropout Voltage: 270mV Very Low Shutdown Current: < 1µA No Protection Diodes Needed Fixed Output Voltages: 1.5V, 1.8V, 2.5V, 3V, 3.3V, 5V Adjustable Output from 1.22V to 20V Stable with 3.3µF Output Capacitor Stable with Aluminum, Tantalum or Ceramic Capacitors Reverse Battery Protection No Reverse Current Overcurrent and Overtemperature Protected 8-Lead MSOP Package U APPLICATIO S ■ ■ ■ Cellular Phones Battery-Powered Systems Noise-Sensitive Instrumentation Systems The LT ®1962 series are micropower, low noise, low dropout regulators. The devices are capable of supplying 300mA of output current with a dropout voltage of 270mV. Designed for use in battery-powered systems, the low 30µA quiescent current makes them an ideal choice. Quiescent current is well controlled; it does not rise in dropout as it does with many other regulators. A key feature of the LT1962 regulators is low output noise. With the addition of an external 0.01µF bypass capacitor, output noise drops to 20µVRMS over a 10Hz to 100kHz bandwidth. The LT1962 regulators are stable with output capacitors as low as 3.3µF. Small ceramic capacitors can be used without the series resistance required by other regulators. Internal protection circuitry includes reverse battery protection, current limiting, thermal limiting and reverse current protection. The parts come in fixed output voltages of 1.5V, 1.8V, 2.5V, 3V, 3.3V and 5V, and as an adjustable device with a 1.22V reference voltage. The LT1962 regulators are available in the 8-lead MSOP package. , LTC and LT are registered trademarks of Linear Technology Corporation. U TYPICAL APPLICATIO Dropout Voltage 400 3.3V Low Noise Regulator IN OUT 1µF + SENSE LT1962-3.3 SHDN GND 3.3V AT 300mA 20µVRMS NOISE 10µF 0.01µF BYP 1962 TA01 DROPOUT VOLTAGE (mV) VIN 3.7V TO 20V 350 300 250 200 150 100 50 0 0 50 100 150 200 LOAD CURRENT (mA) 250 300 1962 TA02 1 LT1962 Series W W W AXI U U ABSOLUTE RATI GS U U W PACKAGE/ORDER I FOR ATIO (Note 1) IN Pin Voltage ........................................................ ±20V OUT Pin Voltage .................................................... ±20V Input to Output Differential Voltage (Note 2) ......... ±20V SENSE Pin Voltage ............................................... ±20V ADJ Pin Voltage ...................................................... ±7V BYP Pin Voltage.................................................... ±0.6V SHDN Pin Voltage ................................................. ±20V Output Short-Circuit Duration ......................... Indefinite Operating Junction Temperature Range (Note 3) ............................................ – 40°C to 125°C Storage Temperature Range ................. – 65°C to 150°C Lead Temperature (Soldering, 10 sec).................. 300°C ORDER PART NUMBER TOP VIEW OUT SENSE/ADJ* BYP GND 1 2 3 4 8 7 6 5 IN NC NC SHDN MS8 PACKAGE 8-LEAD PLASTIC MSOP *PIN 2: SENSE FOR LT1962-1.5/LT1962-1.8/ LT1962-2.5/LT1962-3/LT1962-3.3/LT1962-5. ADJ FOR LT1962 TJMAX = 150°C, θJA = 125°C/ W LT1962EMS8 LT1962EMS8-1.5 LT1962EMS8-1.8 LT1962EMS8-2.5 LT1962EMS8-3 LT1962EMS8-3.3 LT1962EMS8-5 MS8 PART MARKING SEE THE APPLICATIONS INFORMATION SECTION FOR ADDITIONAL INFORMATION ON THERMAL RESISTANCE LTPQ LTPS LTPR LTML LTSZ LTTA LTPT Consult factory for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25°C. (Note 3) PARAMETER CONDITIONS Minimum Operating Voltage (LT1962) ILOAD = 300mA (Notes 4, 12) ● Regulated Output Voltage (Notes 4, 5) LT1962-1.5 VIN = 2V, ILOAD = 1mA 2.5V < VIN < 20V, 1mA < ILOAD < 300mA ● VIN = 2.3V, ILOAD = 1mA 2.8V < VIN < 20V, 1mA < ILOAD < 300mA LT1962-1.8 LT1962-2.5 LT1962-3 LT1962-3.3 LT1962-5 MIN TYP MAX UNITS 1.8 2.3 V 1.485 1.462 1.500 1.500 1.515 1.538 V V ● 1.782 1.755 1.800 1.800 1.818 1.845 V V VIN = 3V, ILOAD = 1mA 3.5V < VIN < 20V, 1mA < ILOAD < 300mA ● 2.475 2.435 2.500 2.500 2.525 2.565 V V VIN = 3.5V, ILOAD = 1mA 4V < VIN < 20V, 1mA < ILOAD < 300mA ● 2.970 2.925 3.000 3.000 3.030 3.075 V V VIN = 3.8V, ILOAD = 1mA 4.3V < VIN < 20V, 1mA < ILOAD < 300mA ● 3.267 3.220 3.300 3.300 3.333 3.380 V V VIN = 5.5V, ILOAD = 1mA 6V < VIN < 20V, 1mA < ILOAD < 300mA ● 4.950 4.875 5.000 5.000 5.050 5.125 V V VIN = 2V, ILOAD = 1mA 2.3V < VIN < 20V, 1mA < ILOAD < 300mA ● 1.208 1.190 1.220 1.220 1.232 1.250 V V 1 1 1 1 1 1 1 5 5 5 5 5 5 5 mV mV mV mV mV mV mV 3 8 15 mV mV 4 9 18 mV mV ADJ Pin Voltage (Notes 4, 5) LT1962 Line Regulation LT1962-1.5 LT1962-1.8 LT1962-2.5 LT1962-3 LT1962-3.3 LT1962-5 LT1962 (Note 4) ∆VIN = 2V to 20V, ILOAD = 1mA ∆VIN = 2.3V to 20V, ILOAD = 1mA ∆VIN = 3V to 20V, ILOAD = 1mA ∆VIN = 3.5V to 20V, ILOAD = 1mA ∆VIN = 3.8V to 20V, ILOAD = 1mA ∆VIN = 5.5V to 20V, ILOAD = 1mA ∆VIN = 2V to 20V, ILOAD = 1mA ● ● ● ● ● ● ● Load Regulation LT1962-1.5 VIN = 2.5V, ∆ILOAD = 1mA to 300mA VIN = 2.5V, ∆ILOAD = 1mA to 300mA ● VIN = 2.8V, ∆ILOAD = 1mA to 300mA VIN = 2.8V, ∆ILOAD = 1mA to 300mA ● LT1962-1.8 2 LT1962 Series ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25°C. (Note 3) PARAMETER CONDITIONS Load Regulation LT1962-2.5 LT1962-3 LT1962-3.3 LT1962-5 LT1962 (Note 4) MIN VIN = 3.5V, ∆ILOAD = 1mA to 300mA VIN = 3.5V, ∆ILOAD = 1mA to 300mA ● VIN = 4V, ∆ILOAD = 1mA to 300mA VIN = 4V, ∆ILOAD = 1mA to 300mA ● VIN = 4.3V, ∆ILOAD = 1mA to 300mA VIN = 4.3V, ∆ILOAD = 1mA to 300mA ● VIN = 6V, ∆ILOAD = 1mA to 300mA VIN = 6V, ∆ILOAD = 1mA to 300mA ● VIN = 2.3V, ∆ILOAD = 1mA to 300mA VIN = 2.3V, ∆ILOAD = 1mA to 300mA ● Dropout Voltage VIN = VOUT(NOMINAL) ILOAD = 10mA ILOAD = 10mA ● (Notes 6, 7, 12) ILOAD = 50mA ILOAD = 50mA ● ILOAD = 100mA ILOAD = 100mA ● ILOAD = 300mA ILOAD = 300mA ● GND Pin Current VIN = VOUT(NOMINAL) (Notes 6, 8) ILOAD = 0mA ILOAD = 1mA ILOAD = 50mA ILOAD = 100mA ILOAD = 300mA ● ● ● ● ● Output Voltage Noise COUT = 10µF, CBYP = 0.01µF, ILOAD = 300mA, BW = 10Hz to 100kHz ADJ Pin Bias Current (Notes 4, 9) Shutdown Threshold VOUT = Off to On VOUT = On to Off TYP MAX 5 12 25 mV mV 7 15 30 mV mV 7 17 33 mV mV 12 25 50 mV mV 2 6 12 mV mV 0.10 0.15 0.21 V V 0.15 0.20 0.28 V V 0.18 0.24 0.33 V V 0.27 0.33 0.43 V V 30 65 1.1 2 8 75 120 1.6 3 12 µA µA mA mA mA µVRMS 20 ● ● 0.25 UNITS 30 100 nA 0.8 0.65 2 V V SHDN Pin Current (Note 10) VSHDN = 0V VSHDN = 20V 0.01 1 0.5 5 µA µA Quiescent Current in Shutdown VIN = 6V, VSHDN = 0V 0.1 1 µA Ripple Rejection VIN – VOUT = 1.5V (Avg), VRIPPLE = 0.5VP-P, fRIPPLE = 120Hz, ILOAD = 300mA Current Limit VIN = 7V, VOUT = 0V VIN = VOUT(NOMINAL) + 1V, ∆VOUT = – 0.1V ● Input Reverse Leakage Current VIN = – 20V, VOUT = 0V ● Reverse Output Current (Note 11) LT1962-1.5 LT1962-1.8 LT1962-2.5 LT1962-3 LT1962-3.3 LT1962-5 LT1962 (Note 4) VOUT = 1.5V, VIN < 1.5V VOUT = 1.8V, VIN < 1.8V VOUT = 2.5V, VIN < 2.5V VOUT = 3V, VIN < 3V VOUT = 3.3V, VIN < 3.3V VOUT = 5V, VIN < 5V VOUT = 1.22V, VIN < 1.22V Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: Absolute maximum input to output differential voltage cannot be achieved with all combinations of rated IN pin and OUT pin voltages. With the IN pin at 20V, the OUT pin may not be pulled below 0V. The total measured voltage from in to out can not exceed ±20V. 55 65 dB 700 mA mA 320 10 10 10 10 10 10 5 1 mA 20 20 20 20 20 20 10 µA µA µA µA µA µA µA Note 3: The LT1962 regulators are tested and specified under pulse load conditions such that TJ ≈ TA. The LT1962 is 100% tested at TA = 25°C. Performance at – 40°C and 125°C is assured by design, characterization and correlation with statistical process controls. Note 4: The LT1962 (adjustable version) is tested and specified for these conditions with the ADJ pin connected to the OUT pin. 3 LT1962 Series ELECTRICAL CHARACTERISTICS Note 5: 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 6: To satisfy requirements for minimum input voltage, the LT1962 (adjustable version) is tested and specified for these conditions with an external resistor divider (two 250k resistors) for an output voltage of 2.44V. The external resistor divider will add a 5µA DC load on the output. Note 7: 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. Note 8: GND pin current is tested with VIN = VOUT(NOMINAL) or VIN = 2.3V (whichever is greater) 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 9: ADJ pin bias current flows into the ADJ pin. Note 10: SHDN pin current flows into the SHDN pin. This current is included in the specification for GND pin current. Note 11: 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 12: For the LT1962, LT1962-1.5 and LT1962-1.8 dropout voltage will be limited by the minimum input voltage specification under some output voltage/load conditions. See the curve of Minimum Input Voltage in the Typical Performance Characteristics. For other fixed voltage versions of the LT1962, the minimum input voltage is limited by the dropout voltage. U W TYPICAL PERFOR A CE CHARACTERISTICS Guaranteed Dropout Voltage 500 GUARANTEED DROPOUT VOLTAGE (mV) DROPOUT VOLTAGE (mV) 350 TJ = 125°C 300 250 200 TJ = 25°C 150 100 50 0 = TEST POINTS 450 350 TJ ≤ 125°C 400 350 TJ ≤ 25°C 300 250 200 150 100 0 0 50 100 200 250 150 OUTPUT CURRENT (mA) 0 300 IL = 300mA 300 250 IL = 100mA 200 IL = 50mA 150 IL = 10mA 100 50 50 50 250 150 200 100 OUTPUT CURRENT (mA) IL = 1mA 0 – 50 – 25 300 75 50 25 TEMPERATURE (°C) 0 1962 G02 1962 G01 Quiescent Current 1.532 45 100 125 1962 G03 LT1962-1.8 Output Voltage LT1962-1.5 Output Voltage 50 1.836 IL = 1mA 1.524 1.827 1.516 1.818 IL = 1mA 35 30 25 20 15 10 5 VIN = 6V VSHDN = VIN RL = ∞, IL = 0 (LT1962-1.5/-1.8 /2.5/-3/-3.3/-5) RL = 250k, IL = 5µA (LT1962) 0 –50 –25 50 25 0 75 TEMPERATURE (°C) 1.508 1.500 1.492 1.484 1.476 100 125 1962 G04 4 OUTPUT VOLTAGE (V) 40 OUTPUT VOLTAGE (V) QUIESCENT CURRENT (µA) Dropout Voltage 400 DROPOUT VOTLAGE (mV) Typical Dropout Voltage 400 1.468 –50 1.809 1.800 1.791 1.782 1.773 –25 50 75 0 25 TEMPERATURE (°C) 100 125 1962 G05 1.764 –50 –25 50 75 0 25 TEMPERATURE (°C) 100 125 1962 G06 LT1962 Series U W TYPICAL PERFOR A CE CHARACTERISTICS LT1962-2.5 Output Voltage 3.060 IL = 1mA 3.360 IL = 1mA 3.045 3.345 2.52 3.030 3.330 2.51 2.50 2.49 2.48 OUTPUT VOTLAGE (V) 2.53 OUTPUT VOTLAGE (V) OUTPUT VOTLAGE (V) 2.54 LT1962-3.3 Output Voltage LT1962-3 Output Voltage 3.015 3.000 2.985 2.970 2.955 2.47 2.46 – 50 – 25 75 50 25 TEMPERATURE (°C) 100 0 75 50 25 TEMPERATURE (°C) 0 100 LT1962-5 Output Voltage 3.270 125 3.240 – 50 – 25 5.050 1.230 5.025 5.000 4.975 4.950 75 50 25 TEMPERATURE (°C) 100 0 125 800 IL = 1mA 1.225 1.220 1.215 1.210 100 400 300 200 VSHDN = 0V 500 400 300 200 VSHDN = 0V 8 9 10 1962 G13 2 3 4 5 6 7 INPUT VOLTAGE (V) 8 9 10 1962 G12 800 TJ = 25°C RL = ∞ 700 600 500 400 300 200 VSHDN = 0V 100 VSHDN = VIN 0 0 1 LT1962-3 Quiescent Current 600 100 VSHDN = VIN VSHDN = 0V VSHDN = VIN 0 QUIESCENT CURRENT (µA) 500 3 4 5 6 7 INPUT VOLTAGE (V) 200 125 TJ = 25°C RL = ∞ 700 QUIESCENT CURRENT (µA) 600 2 300 LT1962-2.5 Quiescent Current TJ = 25°C RL = ∞ 1 400 0 75 50 25 TEMPERATURE (°C) 0 800 100 500 1962 G11 LT1962-1.8 Quiescent Current 700 600 100 1.200 – 50 – 25 125 TJ = 25°C RL = ∞ 700 1962 G10 800 100 LT1962-1.5 Quiescent Current 1.205 4.900 – 50 – 25 75 50 25 TEMPERATURE (°C) 0 1962 G09 QUIESCENT CURRENT (µA) 1.235 ADJ PIN VOTLAGE (V) OUTPUT VOTLAGE (V) 1.240 IL = 1mA 4.925 QUIESCENT CURRENT (µA) 3.285 LT1962 ADJ Pin Voltage 5.075 0 3.300 1962 G08 1962 G07 5.100 3.315 3.255 2.940 – 50 – 25 125 IL = 1mA VSHDN = VIN 0 0 1 2 3 4 5 6 7 INPUT VOLTAGE (V) 8 9 10 1962 G14 0 1 2 3 4 5 6 7 INPUT VOLTAGE (V) 8 9 10 1962 G15 5 LT1962 Series U W TYPICAL PERFOR A CE CHARACTERISTICS TJ = 25°C RL = ∞ 600 500 400 300 200 VSHDN = 0V 100 600 500 400 300 200 VSHDN = 0V 100 VSHDN = VIN 0 2 3 4 5 6 7 INPUT VOLTAGE (V) 8 9 10 1 2 3 4 5 6 7 INPUT VOLTAGE (V) 8 750 500 RL = 150Ω IL = 10mA* 250 9 RL = 1.5k IL = 1mA* 3 4 5 6 7 INPUT VOLTAGE (V) 8 9 750 500 RL = 180Ω IL = 10mA* RL = 1.8k IL = 1mA* 10 1 2 3 4 5 6 7 INPUT VOLTAGE (V) 1250 750 RL = 300Ω IL = 10mA* 500 250 RL = 3k IL = 1mA* 8 9 2 3 4 5 6 7 INPUT VOLTAGE (V) 8 9 10 1962 G22 RL = 2.5k IL = 1mA* 0 1 2 3 4 5 6 7 INPUT VOLTAGE (V) 8 750 10 LT1962-5 GND Pin Current TJ = 25°C VIN = VSHDN *FOR VOUT = 5V 1250 RL = 330Ω IL = 10mA* 500 9 1962 G21 1500 RL = 3.3k IL = 1mA* RL = 100Ω IL = 50mA* 1000 750 RL = 500Ω IL = 10mA* 500 RL = 5k IL = 1mA* 250 0 1 RL = 250Ω IL = 10mA* 500 10 RL = 66Ω IL = 50mA* 1000 250 0 0 750 250 TJ = 25°C VIN = VSHDN *FOR VOUT = 3.3V 1250 GND PIN CURRENT (µA) RL = 60Ω IL = 50mA* RL = 50Ω IL = 50mA* 1000 LT1962-3.3 GND Pin Current 1500 TJ = 25°C VIN = VSHDN *FOR VOUT = 3V 1000 TJ = 25°C VIN = VSHDN *FOR VOUT = 2.5V 1962 G20 LT1962-3 GND Pin Current 1250 6 8 10 12 14 16 18 20 INPUT VOLTAGE (V) 0 0 1962 G19 1500 4 1500 GND PIN CURRENT (µA) 2 2 1962 G18 0 1 VSHDN = 0V 0 LT1962-2.5 GND Pin Current RL = 36Ω IL = 50mA* 1000 250 0 0 10 10 TJ = 25°C VIN = VSHDN *FOR VOUT = 1.8V 1250 GND PIN CURRENT (µA) GND PIN CURRENT (µA) RL = 30Ω IL = 50mA* 1000 15 LT1962-1.8 GND Pin Current 1500 TJ = 25°C VIN = VSHDN *FOR VOUT = 1.5V 1250 20 1962 G17 LT1962-1.5 GND Pin Current 1500 25 0 0 GND PIN CURRENT (µA) 1 VSHDN = VIN 30 5 VSHDN = VIN 1962 G16 GND PIN CURRENT (µA) TJ = 25°C 35 RL = 250k 0 0 6 LT1962 Quiescent Current 40 TJ = 25°C RL = ∞ 700 QUIESCENT CURRENT (µA) 700 QUIESCENT CURRENT (µA) LT1962-5 Quiescent Current 800 QUIESCENT CURRENT (µA) LT1962-3.3 Quiescent Current 800 0 0 1 2 3 4 5 6 7 INPUT VOLTAGE (V) 8 9 10 1962 G23 0 1 2 3 4 5 6 7 INPUT VOLTAGE (V) 8 9 10 1962 G24 LT1962 Series U W TYPICAL PERFOR A CE CHARACTERISTICS 1500 8 TJ = 25°C VIN = VSHDN *FOR VOUT = 1.22V 1250 RL = 24.4Ω IL = 50mA* 1000 750 500 RL = 1.22k IL = 1mA* RL = 122Ω IL = 10mA* 250 0 6 7 RL = 5Ω IL = 300mA* 5 RL = 7.5Ω IL = 200mA* 4 3 RL = 15Ω IL = 100mA* 2 1 2 3 4 5 6 7 INPUT VOLTAGE (V) 9 8 0 10 1 2 3 4 5 6 7 INPUT VOLTAGE (V) 8 3 RL = 25Ω IL = 100mA* 2 1 0 0 2 3 4 5 6 7 INPUT VOLTAGE (V) 8 9 RL = 10Ω IL = 300mA* 6 5 RL = 15Ω IL = 200mA* 4 3 RL = 30Ω IL = 100mA* 2 10 2 3 4 5 6 7 INPUT VOLTAGE (V) 8 9 1 RL = 4.07Ω IL = 300mA* 5 4 RL = 6.1Ω IL = 200mA* 3 2 RL = 12.2Ω IL = 100mA* 1 2 3 4 5 6 7 INPUT VOLTAGE (V) 8 9 10 1962 G31 RL = 33Ω IL = 100mA* 2 1 2 3 4 5 6 7 INPUT VOLTAGE (V) 8 0 1 2 3 4 5 6 7 INPUT VOLTAGE (V) 9 10 1962 G30 8 VIN = VOUT(NOMINAL) + 1V 7 6 5 4 3 2 1 0 0 3 GND Pin Current vs ILOAD 6 1 0 RL = 16.5Ω IL = 200mA* 4 0 GND PIN CURRENT (mA) GND PIN CURRENT (mA) RL = 50Ω IL = 100mA* RL = 11Ω IL = 300mA* 5 10 TJ = 25°C VIN = VSHDN *FOR VOUT = 1.22V 7 3 2 6 LT1962 GND Pin Current RL = 25Ω IL = 200mA* 4 10 0 1 8 TJ = 25°C 7 VIN = VSHDN *FOR VOUT = 5V 9 TJ = 25°C VIN = VSHDN *FOR VOUT = 3.3V 7 1962 G29 LT1962-5 GND Pin Current 5 8 1 0 8 RL = 16.7Ω IL = 300mA* 3 4 5 6 7 INPUT VOLTAGE (V) LT1962-3.3 GND Pin Current 1962 G28 6 2 8 0 1 1 1962 G27 1 0 RL = 18Ω IL = 100mA* 2 10 GND PIN CURRENT (mA) GND PIN CURRENT (mA) RL = 12.5Ω IL = 200mA* 4 9 TJ = 25°C VIN = VSHDN *FOR VOUT = 3V 7 RL = 8.33Ω IL = 300mA* 5 3 LT1962-3 GND Pin Current 8 6 RL = 9Ω IL = 200mA* 4 1962 G26 TJ = 25°C VIN = VSHDN *FOR VOUT = 2.5V 7 5 0 0 LT1962-2.5 GND Pin Current 8 RL = 6Ω IL = 300mA* 6 TJ = 25°C VIN = VSHDN *FOR VOUT = 1.8V 1 1962 G25 GND PIN CURRENT (mA) 8 1 0 GND PIN CURRENT (mA) LT1962-1.8 GND Pin Current TJ = 25°C VIN = VSHDN *FOR VOUT = 1.5V 7 GND PIN CURRENT (mA) GND PIN CURRENT (µA) LT1962-1.5 GND Pin Current GND PIN CURRENT (mA) LT1962 GND Pin Current 8 9 10 1962 G32 0 0 50 100 200 250 150 OUTPUT CURRENT (mA) 300 1962 G33 7 LT1962 Series U W TYPICAL PERFOR A CE CHARACTERISTICS SHDN Pin Threshold (On-to-Off) IL = 1mA SHDN Pin Input Current 1.4 0.9 0.8 SHDN PIN THRESHOLD (V) SHDN PIN THRESHOLD (V) 0.9 SHDN Pin Threshold (Off-to-On) 1.0 0.7 0.6 0.5 0.4 0.3 0.2 0.1 SHDN PIN INPUT CURRENT (µA) 1.0 0.8 0.7 IL = 300mA 0.6 IL = 1mA 0.5 0.4 0.3 0.2 0.1 0 –50 –25 50 25 0 75 TEMPERATURE (°C) 100 50 25 0 75 TEMPERATURE (°C) 100 1962 G34 1.0 0.8 0.6 0.4 75 50 25 TEMPERATURE (°C) 100 20 15 10 0.6 0.5 0.4 0.3 0.1 0 50 25 75 0 TEMPERATURE (°C) 100 125 0 Reverse Output Current 0.4 0.2 TJ = 25°C 90 VIN = 0V CURRENT FLOWS 80 INTO OUTPUT PIN 70 VOUT = VADJ (LT1962) Reverse Output Current 50 40 LT1962-3 30 LT1962-3.3 20 10 100 125 1962 G40 LT1962 LT1962-1.5 LT1962-1.8 LT1962-2.5 60 0 VIN = 0V VOUT = 1.22V (LT1962) 25 VOUT = 1.5V (LT1962-1.5) VOUT = 1.8V (LT1962-1.8) VOUT = 2.5V (LT1962-2.5) 20 V OUT = 3V (LT1962-3) VOUT = 3.3V (LT1962-3.3) V = 5V (LT1962-5) 15 OUT LT1962-1.5/-1.8/-2.5/-3/-3.3/-5 10 5 LT1962-5 0 1 2 7 6 30 REVERSE OUTPUT CURRENT (µA) REVERSE OUTPUT CURRENT (µA) 0.6 4 3 2 5 INPUT VOLTAGE (V) 1962 G39 100 0.8 1 1962 G38 Current Limit 50 25 75 0 TEMPERATURE (°C) 0.7 0.2 1962 G37 1.0 10 0.8 25 0 –50 –25 125 VIN = 7V VOUT = 0V 9 VOUT = 0V 0.9 5 0 7 8 3 4 5 6 SHDN PIN VOLTAGE (V) Current Limit 1.0 CURRENT LIMIT (A) ADJ PIN BIAS CURRENT (nA) SHDN PIN INPUT CURRENT (µA) 1.2 2 1 1962 G36 30 0.2 CURRENT LIMIT (A) 0.2 0 VSHDN = 20V 1.4 8 0.4 125 35 0 –50 –25 0.6 ADJ Pin Bias Current SHDN Pin Input Current 1.2 0.8 1962 G35 1.6 0 – 50 – 25 1.0 0 0 –50 –25 125 1.2 3 4 5 6 7 8 OUTPUT VOLTAGE (V) LT1962 9 10 1962 F07 0 –50 –25 50 25 75 0 TEMPERATURE (°C) 100 125 1962 G42 LT1962 Series U W TYPICAL PERFOR A CE CHARACTERISTICS Input Ripple Rejection Input Ripple Rejection 50 COUT = 10µF 40 30 COUT = 3.3µF 20 CBYP = 0.01µF 70 10 0 100 100k 1k 10k FREQUENCY (Hz) 1M 60 50 CBYP = 100pF 40 30 20 IL = 300mA VIN = VOUT(NOMINAL) + 1V 10 + 50mVRMS RIPPLE COUT = 10µF 0 100 10 1k 10k FREQUENCY (Hz) 100k LOAD REGULATION (mV) MINIMUM INPUT VOLTAGE (V) LT1962 0 1.50 IL = 1mA 1.25 1.00 0.75 0.50 LT1962-1.8 LT1962-1.5 –5 LT1962-3.3 LT1962-3 LT1962-2.5 –10 –15 LT1962-5 –20 VIN = VOUT(NOMINAL) + 1V ∆IL = 1mA TO 300mA –25 50 25 75 –50 –25 0 TEMPERATURE (°C) 0.25 0 –50 –25 50 25 0 75 TEMPERATURE (°C) 125 100 100 1962 G46 140 CBYP = 1000pF 1 CBYP = 100pF LT1962 CBYP = 0.01µF 0.1 OUTPUT NOISE (µVRMS) OUTPUT NOISE SPECTRAL DENSITY (µV/√Hz) 160 10 IL = 300mA COUT = 10µF CBYP = 0 LT1962-5 LT1962-3.3 LT1962-3 1 LT1962 0.1 LT1962-2.5 LT1962-1.8 LT1962-1.5 0.01 125 10 100 1k 10k FREQUENCY (Hz) RMS Output Noise vs Load Current (10Hz to 100kHz) 160 140 120 LT1962-5 LT1962-3 LT1962-3.3 80 LT1962-2.5 LT1962-1.8 LT1962-1.5 60 40 100k 1962 G48 IL = 300mA COUT = 10µF f = 10Hz to 100kHz 100 125 1962 G45 RMS Output Noise vs Bypass Capacitor IL = 300mA COUT = 10µF LT1962-5 100 1962 G47 Output Noise Spectral Density 10 56 IL = 300mA 54 VIN = VOUT(NOMINAL) + 1V + 0.5VP-P RIPPLE AT f = 120Hz 52 75 0 50 25 – 50 – 25 Output Noise Spectral Density 5 IL = 300mA 1.75 58 Load Regulation VOUT = 1.22V 2.00 60 1962 G44 LT1962 Minimum Input Voltage 2.25 62 TEMPERATURE (°C) 1962 G43 2.50 64 1M OUTPUT NOISE SPECTRIAL DENSITY (µV/√Hz) 10 66 CBYP = 1000pF OUTPUT NOISE (µVRMS) RIPPLE REJECTION (dB) 60 68 RIPPLE REJECTION (dB) IL = 300mA VIN = VOUT(NOMINAL) + 1V + 50mVRMS RIPPLE CBYP = 0 70 Ripple Rejection 80 RIPPLE REJECTION (dB) 80 LT1962 20 COUT = 10µF CBYP = 0µF CBYP = 0.01µF 120 LT1962-5 100 80 60 LT1962 40 LT1962-5 20 LT1962 0 0.01 10 100 1k 10k FREQUENCY (Hz) 100k 10 100 1k 10k CBYP (pF) 1962 G49 1962 G50 0 0.01 0.1 1 10 100 LOAD CURRENT (mA) 1000 1962 G51 9 LT1962 Series U W TYPICAL PERFOR A CE CHARACTERISTICS LT1962-5 10Hz to 100kHz Output Noise (CBYP = 100pF) LT1962-5 10Hz to 100kHz Output Noise (CBYP = 0) VOUT 100µV/DIV LT1962-5 10Hz to 100kHz Output Noise (CBYP = 1000pF) VOUT 100µV/DIV VOUT 100µV/DIV COUT = 10µF IL = 300mA 1ms/DIV COUT = 10µF IL = 300mA 1962 G52 1ms/DIV COUT = 10µF IL = 300mA 1962 G53 LT1962-5 Transient Response COUT = 10µF IL = 300mA 1ms/DIV 1962 G55 OUTPUT VOLTAGE DEVIATION (mV) VIN = 6V 0.4 CIN = 10µF COUT = 10µF 0.2 C BYP = 0 0 –0.2 –0.4 300 200 100 0 0 1962 G54 LT1962-5 Transient Response 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 TIME (ms) 1962 G56 LOAD CURRENT (mA) VOUT 100µV/DIV LOAD CURRENT (mA) OUTPUT VOLTAGE DEVIATION (V) LT1962-5 10Hz to 100kHz Output Noise (CBYP = 0.01µF) 1ms/DIV VIN = 6V CIN = 10µF COUT = 10µF CBYP = 0.01µF 0.10 0.05 0 –0.05 –0.10 300 200 100 0 0 50 100 150 200 250 300 350 400 450 500 TIME (µs) 1962 G57 U U U PI FU CTIO S OUT (Pin 1): Output. The output supplies power to the load. A minimum output capacitor of 3.3µF 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 fixed voltage versions of the LT1962 (LT1962-1.5/LT1962-1.8/LT1962-2.5/LT1962-3/ LT1962-3.3/LT1962-5), 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 10 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. The SENSE pin can be pulled below ground (as in a dual supply system where the regulator load is returned to a negative supply) and still allow the device to start and operate. ADJ (Pin 2): Adjust. For the adjustable LT1962, this is the input to the error amplifier. This pin is internally clamped to ±7V. It has a bias current of 30nA which flows into the LT1962 Series U U U PI FU CTIO S 8 IN OUT 1 RP LT1962 + 5 SHDN VIN SENSE + 2 LOAD GND 4 RP 1962 F01 Figure 1. Kelvin Sense Connection pin. The ADJ pin voltage is 1.22V referenced to ground and the output voltage range is 1.22V to 20V. BYP (Pin 3): Bypass. The BYP pin is used to bypass the reference of the LT1962 to achieve low noise performance from the regulator. The BYP pin is clamped internally to ±0.6V (one VBE). A small capacitor from the output to this pin will bypass the reference to lower the output voltage noise. A maximum value of 0.01µF can be used for reducing output voltage noise to a typical 20µVRMS over a 10Hz to 100kHz bandwidth. If not used, this pin must be left unconnected. GND (Pin 4): Ground. SHDN (Pin 5): Shutdown. The SHDN pin is used to put the LT1962 regulators 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 required to supply the pull-up current of the opencollector gate, normally several microamperes, and the SHDN pin current, typically 1µA. If unused, the SHDN pin must be connected to VIN. The device will not function if the SHDN pin is not connected. NC (Pins 6, 7): No Connect. These pins are not internally connected. For improved power handling capabilities, these pins can be connected to the PC board. 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 LT1962 regulators are designed to withstand reverse voltages on the IN pin with respect to ground and the OUT pin. In the case of a reverse input, which can happen if a battery is plugged in backwards, the device will act as if there is a diode in series with its input. There will be no reverse current flow into the regulator and no reverse voltage will appear at the load. The device will protect both itself and the load. U W U U APPLICATIO S I FOR ATIO The LT1962 series are 300mA low dropout regulators with micropower quiescent current and shutdown. The devices are capable of supplying 300mA at a dropout voltage of 300mV. Output voltage noise can be lowered to 20µVRMS over a 10Hz to 100kHz bandwidth with the addition of a 0.01µF reference bypass capacitor. Additionally, the reference bypass capacitor will improve transient response of the regulator, lowering the settling time for transient load conditions. The low operating quiescent current (30µA) drops to less than 1µA in shutdown. In addition to the low quiescent current, the LT1962 regulators incorporate several protection features which make them ideal for use in battery-powered systems. The devices are 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 LT1962-X acts like it has a diode in series with its output and prevents reverse current flow. Additionally, in dual supply applications where the regulator load is returned to a negative supply, the output can be pulled below ground by as much as 20V and still allow the device to start and operate. Adjustable Operation The adjustable version of the LT1962 has an output voltage range of 1.22V to 20V. 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 ADJ pin voltage 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 11 LT1962 Series U W U U APPLICATIO S I FOR ATIO OUT LT1962 VOUT R2 + ADJ GND R1 1962 F02 R2 VOUT = 1.22V 1 + + (IADJ )(R2) R1 VADJ = 1.22V IADJ = 30nA AT 25°C OUTPUT RANGE = 1.22V TO 20V Figure 2. Adjustable Operation plus the ADJ pin bias current. The ADJ pin bias current, 30nA 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 no greater 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. The adjustable device is tested and specified with the ADJ pin tied to the OUT pin 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 300mA is – 2mV typical at VOUT = 1.22V. At VOUT = 12V, load regulation is: (12V/1.22V)(–2mV) = – 19.7mV Bypass Capacitance and Low Noise Performance The LT1962 regulators may be used with the addition of a bypass capacitor from VOUT to the BYP pin to lower output voltage noise. A good quality low leakage capacitor is recommended. This capacitor will bypass the reference of the regulator, providing a low frequency noise pole. The noise pole provided by this bypass capacitor will lower the output voltage noise to as low as 20µVRMS with the addition of a 0.01µF bypass capacitor. Using a bypass capacitor has the added benefit of improving transient response. With no bypass capacitor and a 10µF output capacitor, a 10mA to 300mA load step will settle to within 1% of its final value in less than 100µs. With the addition of a 0.01µF bypass capacitor, the output will settle to within 1% for a 10mA to 300mA load step in less than 10µs, with total output voltage deviation of less than 2% 12 (see LT1962-5 Transient Response in the Typical Performance Characteristics). However, regulator start-up time is inversely proportional to the size of the bypass capacitor, slowing to 15ms with a 0.01µF bypass capacitor and 10µF output capacitor. Output Capacitance and Transient Response The LT1962 regulators are 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 3.3µF with an ESR of 3Ω or less is recommended to prevent oscillations. The LT1962-X 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 LT1962, will increase the effective output capacitor value. With larger capacitors used to bypass the reference (for low noise operation), larger values of output capacitance are needed. For 100pF of bypass capacitance, 4.7µF of output capacitor is recommended. With a 1000pF bypass capacitor or larger, a 6.8µF output capacitor is recommended. The shaded region of Figure 3 defines the range over which the LT1962 regulators are stable. The minimum ESR needed is defined by the amount of bypass capacitance used, while the maximum ESR is 3Ω. 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 4.0 3.5 3.0 STABLE REGION 2.5 ESR (Ω) IN VIN 2.0 CBYP = 0 CBYP = 100pF 1.5 CBYP = 330pF CBYP ≥ 1000pF 1.0 0.5 0 1 3 2 4 5 6 7 8 9 10 OUTPUT CAPACITANCE (µF) 1962 F03 Figure 3. Stability LT1962 Series U W U U APPLICATIO S I FOR ATIO 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 capacitance in a small package, but exhibit strong voltage and temperature coefficients as shown in Figures 4 and 5. 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 micro- phone works. For a ceramic capacitor the stress can be induced by vibrations in the system or thermal transients. The resulting voltages produced can cause appreciable amounts of noise, especially when a ceramic capacitor is used for noise bypassing. A ceramic capacitor produced Figure 6’s trace in response to light tapping from a pencil. Similar vibration induced behavior can masquerade as increased output voltage noise. LT1962-5 COUT = 10µF CBYP = 0.01µf ILOAD = 100mA VOUT 500µV/DIV 100ms/DIV 20 1962 F06 BOTH CAPACITORS ARE 16V, 1210 CASE SIZE, 10µF 0 Figure 6. Noise Resulting from Tapping on a Ceramic Capacitor CHANGE IN VALUE (%) X5R –20 Thermal Considerations –40 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: –60 Y5V –80 –100 0 2 4 14 8 6 10 12 DC BIAS VOLTAGE (V) 16 1962 F04 Figure 4. Ceramic Capacitor DC Bias Characteristics 40 CHANGE IN VALUE (%) X5R –20 –40 Y5V –60 –80 BOTH CAPACITORS ARE 16V, 1210 CASE SIZE, 10µF –100 –50 –25 50 25 75 0 TEMPERATURE (°C) 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. 20 0 1. Output current multiplied by the input/output voltage differential: (IOUT)(VIN – VOUT), and 100 125 1962 F05 Figure 5. Ceramic Capacitor Temperature Characteristics The LT1962 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. 13 LT1962 Series U W U U APPLICATIO S I FOR ATIO 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 1/16" FR-4 board with one ounce copper. Table 1. Measured Thermal Resistance COPPER AREA THERMAL RESISTANCE TOPSIDE* BACKSIDE 2 2 2500mm 2 1000mm 2 BOARD AREA 2500mm 2 2500mm 2 (JUNCTION-TO-AMBIENT) 2 110°C/W 2 115°C/W 2 2500mm 2500mm 225mm 2500mm 2500mm 120°C/W 100mm2 2500mm2 2500mm2 130°C/W 2 2 140°C/W 50mm 2 2500mm 2500mm *Device is mounted on topside. Calculating Junction Temperature Example: Given an output voltage of 3.3V, an input voltage range of 4V to 6V, an output current range of 0mA to 100mA 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) = 100mA VIN(MAX) = 6V IGND at (IOUT = 100mA, VIN = 6V) = 2mA So, P = 100mA(6V – 3.3V) + 2mA(6V) = 0.28W The thermal resistance will be in the range of 110°C/W to 140°C/W depending on the copper area. So the junction temperature rise above ambient will be approximately equal to: 0.28W(125°C/W) = 35.3°C The maximum junction temperature will then be equal to the maximum junction temperature rise above ambient plus the maximum ambient temperature or: 14 TJMAX = 50°C + 35.3°C = 85.3°C Protection Features The LT1962 regulators incorporate several protection features which make them 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 devices are protected against reverse input voltages, reverse output 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 20V. Current flow into the device will be limited to less than 1mA (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 output of the LT1962 can be pulled below ground without damaging the device. If the input is left open circuit or grounded, the output can be pulled below ground by 20V. For fixed voltage versions, the output will act like a large resistor, typically 500k or higher, limiting current flow to less than 40µA. For adjustable versions, the output will act like an open circuit; no current will flow out of the pin. If the input is powered by a voltage source, the output will source the short-circuit current of the device and will protect itself by thermal limiting. In this case, grounding the SHDN pin will turn off the device and stop the output from sourcing the short-circuit current. 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. 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 LT1962 Series U W U U APPLICATIO S I FOR ATIO 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. 100 REVERSE OUTPUT CURRENT (µA) from the 1.22V reference when the output is forced to 20V. 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 13V difference between OUT and ADJ pin divided by the 5mA maximum current into the ADJ pin yields a minimum top resistor value of 2.6k. 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 7. 30 LT1962 LT1962-3.3 20 10 When the IN pin of the LT1962 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 device is connected to a discharged (low voltage) battery and the output is held up by either a backup battery U PACKAGE DESCRIPTIO TJ = 25°C 90 VIN = 0V CURRENT FLOWS 80 INTO OUTPUT PIN 70 VOUT = VADJ (LT1962) LT1962-1.5 60 LT1962-1.8 50 LT1962-2.5 40 LT1962-3 0 LT1962-5 0 1 2 3 4 5 6 7 8 OUTPUT VOLTAGE (V) 9 10 1962 F07 Figure 7. Reverse Output Current Dimensions in inches (millimeters) unless otherwise noted. MS8 Package 8-Lead Plastic MSOP (LTC DWG # 05-08-1660) 0.118 ± 0.004* (3.00 ± 0.102) 8 7 6 5 0.118 ± 0.004** (3.00 ± 0.102) 0.193 ± 0.006 (4.90 ± 0.15) 1 2 3 4 0.043 (1.10) MAX 0.007 (0.18) 0.034 (0.86) REF 0° – 6° TYP 0.021 ± 0.006 (0.53 ± 0.015) SEATING PLANE 0.009 – 0.015 (0.22 – 0.38) 0.0256 (0.65) BSC 0.005 ± 0.002 (0.13 ± 0.05) MSOP (MS8) 1100 * DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE ** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE 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 LT1962 Series U TYPICAL APPLICATIO S Adjustable Current Source Paralleling of Regulators for Higher Output Current R1 0.1Ω R5 0.1Ω + VIN >2.7V IN C1 10µF R1* 1k OUT R2 40.2k R3 2k LOAD LT1962-2.5 SHDN LT1004-1.2 + R6 2.2k VIN > 3.7V IN + FB C1 10µF C4 0.01µF LT1962-3.3 FB 3.3V 300mA C2 10µF SHDN BYP GND R7 100k GND OUT R2 0.1Ω R4 2.2k IN – OUT C3 0.33µF C5 0.01µF LT1962 BYP *ADJUST R1 FOR 0mA TO 300mA CONSTANT CURRENT 1/2 LT1490 + 1962 TA04 SHDN SHDN ADJ GND R7 1.21k C2 1µF R3 2.2k R4 2.2k 3 8 + 1/2 LT1490 2 – R6 2k 1 R5 10k 4 1962 TA03 C3 0.01µF RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1120 125mA Low Dropout Regulator with 20µA IQ Includes 2.5V Reference and Comparator LT1121 150mA Micropower Low Dropout Regulator 30µA IQ, SOT-223 Package LT1129 700mA Micropower Low Dropout Regulator 50µA Quiescent Current LT1175 500mA Negative Low Dropout Micropower Regulator 45µA IQ, 0.26V Dropout Voltage, SOT-223 Package LT1521 300mA Low Dropout Micropower Regulator with Shutdown 15µA IQ, Reverse Battery Protection LT1529 3A Low Dropout Regulator with 50µA IQ 500mV Dropout Voltage LTC1627 High Efficiency Synchronous Step-Down Switching Regulator Burst ModeTM Operation, Monolithic, 100% Duty Cycle LT1761 100mA, Low Noise, Low Dropout Micropower Regulator in SOT-23 20µA Quiescent Current, 20µVRMS Noise LT1762 150mA, Low Noise, LDO Micropower Regulator 25µA Quiescent Current, 20µVRMS Noise LT1763 500mA, Low Noise, LDO Micropower Regulator 30µA Quiescent Current, 20µVRMS Noise LT1764 3A, Fast Transient Response Low Dropout Regulator 340mV Dropout Voltage, 40µVRMS Noise LT1772 Constant Frequency Current Mode Step-Down DC/DC Controller Up to 94% Efficiency, SOT-23 Package, 100% Duty Cycle LT1963 1.5A, Fast Transient Response Low Dropout Regulator SO-8, SOT-223 Packages Burst Mode is a trademark of Linear Technology Corporation. 16 Linear Technology Corporation sn1962 1962fas LT/TP 0101 2K REV A • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408)432-1900 ● FAX: (408) 434-0507 ● www.linear-tech.com LINEAR TECHNOLOGY CORPORATION 2000