176333

LT1763 Series 500mA, Low Noise, LDO Micropower Regulators FEATURES n n n n n n n n n n n n n n n DESCRIPTION The LT®1763 series are micropower, low noise, low dropout regulators. The devices are capable of supplying 500mA of output current with a dropout voltage of 300mV. 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 LT1763 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 LT1763 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 LT1763 regulators are available in 8-lead SO and 12-lead, low profile (4mm × 3mm × 0.75mm) DFN packages. , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 6144250, 6118263. Low Noise: 20μVRMS (10Hz to 100kHz) Output Current: 500mA Low Quiescent Current: 30μA Wide Input Voltage Range: 1.8V to 20V Low Dropout Voltage: 300mV 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 SO and 12-Lead (4mm × 3mm) DFN Packages APPLICATIONS n n n Cellular Phones Battery-Powered Systems Noise-Sensitive Instrumentation Systems TYPICAL APPLICATION 3.3V Low Noise Regulator DROPOUT VOLTAGE (mV) 3.3V AT 500mA 20μVRMS NOISE 10μF 0.01μF 400 350 VIN 3.7V TO 20V IN 1μF OUT SENSE LT1763-3.3 SHDN BYP GND 1763 TA01 Dropout Voltage + 300 250 200 150 100 50 0 0 100 300 400 200 OUTPUT CURRENT (mA) 500 1763 TA02 1763fe 1 LT1763 Series ABSOLUTE MAXIMUM RATINGS (Note 1) IN Pin Voltage ........................................................ ±20V OUT Pin Voltage ..................................................... ±20V Input to Output Differential Voltage ........................ ±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 2) C, I Grade...........................................–40°C to 125°C MP Grade...........................................–55°C to 125°C Storage Temperature Range S8 Package ........................................–65°C to 150°C DFN Package......................................–65°C to 150°C Lead Temperature (Soldering, 10 sec) S8 Package ....................................................... 300°C PIN CONFIGURATION TOP VIEW NC OUT OUT NC SENSE/ADJ* BYP 1 2 3 4 5 6 13 12 NC 11 IN 10 IN 9 8 7 NC SHDN GND S8 PACKAGE 8-LEAD PLASTIC SO TJMAX = 150°C, θJA = 70°C/W, θJC = 35°C/W *PIN 2: SENSE FOR LT1763-1.5/LT1763-1.8/LT1763-2.5/LT1763-3/LT1763-3.3/LT1763-5 ADJ FOR LT1763 SEE THE APPLICATIONS INFORMATION SECTION. OUT 1 SENSE/ADJ* 2 GND 3 BYP 4 TOP VIEW 8 7 6 5 IN GND GND SHDN DE PACKAGE 12-LEAD (4mm 3mm) PLASTIC DFN TJMAX = 125°C, θJA = 40°C/W, θJC = 5°C/W EXPOSED PAD (PIN 13) IS GND, MUST BE SOLDERED TO PCB *PIN 5: SENSE FOR LT1763-1.5/LT1763-1.8/LT1763-2.5/LT1763-3/LT1763-3.3/LT1763-5 ADJ FOR LT1763 SEE THE APPLICATIONS INFORMATION SECTION. ORDER INFORMATION LEAD FREE FINISH LT1763CDE#PBF LT1763CDE-1.5#PBF LT1763CDE-1.8#PBF LT1763CDE-2.5#PBF LT1763CDE-3#PBF LT1763CDE-3.3#PBF LT1763CDE-5#PBF LT1763CS8#PBF LT1763IS8#PBF LT1763MPS8#PBF TAPE AND REEL LT1763CDE#TRPBF LT1763CDE-1.5#TRPBF LT1763CDE-1.8#TRPBF LT1763CDE-2.5#TRPBF LT1763CDE-3#TRPBF LT1763CDE-3.3#TRPBF LT1763CDE-5#TRPBF LT1763CS8#TRPBF LT1763IS8#TRPBF LT1763MPS8#TRPBF PART MARKING* 1763 76315 76318 76325 17633 76333 17635 1763 1763 1763MP PACKAGE DESCRIPTION 12-Lead (4mm × 3mm) Plastic DFN 12-Lead (4mm × 3mm) Plastic DFN 12-Lead (4mm × 3mm) Plastic DFN 12-Lead (4mm × 3mm) Plastic DFN 12-Lead (4mm × 3mm) Plastic DFN 12-Lead (4mm × 3mm) Plastic DFN 12-Lead (4mm × 3mm) Plastic DFN 8-Lead Plastic SO 8-Lead Plastic SO 8-Lead Plastic SO TEMPERATURE RANGE –40°C to 125°C –40°C to 125°C –40°C to 125°C –40°C to 125°C –40°C to 125°C –40°C to 125°C –40°C to 125°C –40°C to 125°C –40°C to 125°C –55°C to 125°C 1763fe 2 LT1763 Series ORDER INFORMATION LEAD FREE FINISH LT1763CS8-1.5#PBF LT1763IS8-1.5#PBF LT1763CS8-1.8#PBF LT1763IS8-1.8#PBF LT1763CS8-2.5#PBF LT1763IS8-2.5#PBF LT1763CS8-3#PBF LT1763IS8-3#PBF LT1763CS8-3.3#PBF LT1763IS8-3.3#PBF LT1763CS8-5#PBF LT1763IS8-5#PBF LEAD BASED FINISH LT1763CDE LT1763CDE-1.5 LT1763CDE-1.8 LT1763CDE-2.5 LT1763CDE-3 LT1763CDE-3.3 LT1763CDE-5 LT1763CS8 LT1763IS8 LT1763MPS8 LT1763CS8-1.5 LT1763IS8-1.5 LT1763CS8-1.8 LT1763IS8-1.8 LT1763CS8-2.5 LT1763IS8-2.5 LT1763CS8-3 LT1763IS8-3 LT1763CS8-3.3 LT1763IS8-3.3 LT1763CS8-5 LT1763IS8-5 TAPE AND REEL LT1763CS8-1.5#TRPBF LT1763IS8-1.5#TRPBF LT1763CS8-1.8#TRPBF LT1763IS8-1.8#TRPBF LT1763CS8-2.5#TRPBF LT1763IS8-2.5#TRPBF LT1763CS8-3#TRPBF LT1763IS8-3#TRPBF LT1763CS8-3.3#TRPBF LT1763IS8-3.3#TRPBF LT1763CS8-5#TRPBF LT1763IS8-5#TRPBF TAPE AND REEL LT1763CDE#TR LT1763CDE-1.5#TR LT1763CDE-1.8#TR LT1763CDE-2.5#TR LT1763CDE-3#TR LT1763CDE-3.3#TR LT1763CDE-5#TR LT1763CS8#TR LT1763IS8#TR LT1763MPS8#TR LT1763CS8-1.5#TR LT1763IS8-1.5#TR LT1763CS8-1.8#TR LT1763IS8-1.8#TR LT1763CS8-2.5#TR LT1763IS8-2.5#TR LT1763CS8-3#TR LT1763IS8-3#TR LT1763CS8-3.3#TR LT1763IS8-3.3#TR LT1763CS8-5#TR LT1763IS8-5#TR PART MARKING* 176315 176315 176318 176318 176325 176325 17633 17633 176333 176333 17635 17635 PART MARKING* 1763 76315 76318 76325 17633 76333 17635 1763 1763 1763MP 176315 176315 176318 176318 176325 176325 17633 17633 176333 176333 17635 17635 PACKAGE DESCRIPTION 8-Lead Plastic SO 8-Lead Plastic SO 8-Lead Plastic SO 8-Lead Plastic SO 8-Lead Plastic SO 8-Lead Plastic SO 8-Lead Plastic SO 8-Lead Plastic SO 8-Lead Plastic SO 8-Lead Plastic SO 8-Lead Plastic SO 8-Lead Plastic SO PACKAGE DESCRIPTION 12-Lead (4mm × 3mm) Plastic DFN 12-Lead (4mm × 3mm) Plastic DFN 12-Lead (4mm × 3mm) Plastic DFN 12-Lead (4mm × 3mm) Plastic DFN 12-Lead (4mm × 3mm) Plastic DFN 12-Lead (4mm × 3mm) Plastic DFN 12-Lead (4mm × 3mm) Plastic DFN 8-Lead Plastic SO 8-Lead Plastic SO 8-Lead Plastic SO 8-Lead Plastic SO 8-Lead Plastic SO 8-Lead Plastic SO 8-Lead Plastic SO 8-Lead Plastic SO 8-Lead Plastic SO 8-Lead Plastic SO 8-Lead Plastic SO 8-Lead Plastic SO 8-Lead Plastic SO 8-Lead Plastic SO 8-Lead Plastic SO TEMPERATURE RANGE –40°C to 125°C –40°C to 125°C –40°C to 125°C –40°C to 125°C –40°C to 125°C –40°C to 125°C –40°C to 125°C –40°C to 125°C –40°C to 125°C –40°C to 125°C –40°C to 125°C –40°C to 125°C TEMPERATURE RANGE –40°C to 125°C –40°C to 125°C –40°C to 125°C –40°C to 125°C –40°C to 125°C –40°C to 125°C –40°C to 125°C –40°C to 125°C –40°C to 125°C –55°C to 125°C –40°C to 125°C –40°C to 125°C –40°C to 125°C –40°C to 125°C –40°C to 125°C –40°C to 125°C –40°C to 125°C –40°C to 125°C –40°C to 125°C –40°C to 125°C –40°C to 125°C –40°C to 125°C Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/ 1763fe 3 LT1763 Series ELECTRICAL CHARACTERISTICS PARAMETER Minimum Operating Voltage Regulated Output Voltage (Note 4) CONDITIONS C, I Grade: ILOAD = 500mA (Notes 3, 11) MP Grade: ILOAD = 500mA (Notes 3, 11) LT1763-1.5 LT1763-1.8 LT1763-2.5 LT1763-3 LT1763-3.3 LT1763-5 ADJ Pin Voltage (Notes 3, 4) Line Regulation LT1763 VIN = 2V, ILOAD = 1mA 2.5V < VIN < 20V, 1mA < ILOAD < 500mA VIN = 2.3V, ILOAD = 1mA 2.8V < VIN < 20V, 1mA < ILOAD < 500mA VIN = 3V, ILOAD = 1mA 3.5V < VIN < 20V, 1mA < ILOAD < 500mA VIN = 3.5V, ILOAD = 1mA 4V < VIN < 20V, 1mA < ILOAD < 500mA VIN = 3.8V, ILOAD = 1mA 4.3V < VIN < 20V, 1mA < ILOAD < 500mA VIN = 5.5V, ILOAD = 1mA 6V < VIN < 20V, 1mA < ILOAD < 500mA VIN = 2.2V, ILOAD = 1mA C, I Grade: 2.3V < VIN < 20V, 1mA < ILOAD < 500mA MP Grade: 2.35V < VIN < 20V, 1mA < ILOAD < 500mA ΔVIN = 2V to 20V, ILOAD = 1mA ΔVIN = 2.3V to 20V, ILOAD = 1mA ΔVIN = 3V to 20V, ILOAD = 1mA ΔVIN = 3.5V to 20V, ILOAD = 1mA ΔVIN = 3.8V to 20V, ILOAD = 1mA ΔVIN = 5.5V to 20V, ILOAD = 1mA C, I Grade: ΔVIN = 2V to 20V, ILOAD = 1mA MP Grade: ΔVIN = 2.1V to 20V, ILOAD = 1mA VIN = 2.5V, ΔILOAD = 1mA to 500mA VIN = 2.5V, ΔILOAD = 1mA to 500mA VIN = 2.8V, ΔILOAD = 1mA to 500mA VIN = 2.8V, ΔILOAD = 1mA to 500mA VIN = 3.5V, ΔILOAD = 1mA to 500mA VIN = 3.5V, ΔILOAD = 1mA to 500mA VIN = 4V, ΔILOAD = 1mA to 500mA VIN = 4V, ΔILOAD = 1mA to 500mA VIN = 4.3V, ΔILOAD = 1mA to 500mA VIN = 4.3V, ΔILOAD = 1mA to 500mA VIN = 6V, ΔILOAD= 1mA to 500mA VIN = 6V, ΔILOAD = 1mA to 500mA l l l l l l l l l l l l l l l l l l l l l l l l l l l l l l The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (Note 2) MIN TYP 1.8 1.8 1.485 1.462 1.782 1.755 2.475 2.435 2.970 2.925 3.267 3.220 4.950 4.875 1.208 1.190 1.190 1.5 1.5 1.8 1.8 2.5 2.5 3 3 3.3 3.3 5 5 1.220 1.220 1.220 1 1 1 1 1 1 1 1 3 4 5 7 7 12 2 MAX 2.3 2.35 1.515 1.538 1.818 1.845 2.525 2.565 3.030 3.075 3.333 3.380 5.050 5.125 1.232 1.250 1.250 5 5 5 5 5 5 5 5 8 15 9 18 12 25 15 30 17 33 25 50 6 12 12 0.19 0.25 0.22 0.32 0.24 0.34 0.35 0.45 UNITS V V V V V V V V V V V V V V V V V mV mV mV mV mV mV mV mV mV mV mV mV mV mV mV mV mV mV mV mV mV mV mV V V V V V V V V LT1763-1.5 LT1763-1.8 LT1763-2.5 LT1763-3 LT1763-3.3 LT1763-5 LT1763 (Note 3) LT1763 (Note 3) LT1763-1.5 LT1763-1.8 LT1763-2.5 LT1763-3 LT1763-3.3 LT1763-5 Load Regulation LT1763 (Note 3) VIN = 2.3V, ΔILOAD = 1mA to 500mA C, I Grade: VIN = 2.3V, ΔILOAD = 1mA to 500mA MP Grade: VIN = 2.35V, ΔILOAD = 1mA to 500mA Dropout Voltage VIN = VOUT(NOMINAL) (Notes 5, 6, 11) ILOAD = 10mA ILOAD = 10mA ILOAD = 50mA ILOAD = 50mA ILOAD = 100mA ILOAD = 100mA ILOAD = 500mA ILOAD = 500mA 0.13 0.17 0.20 0.30 1763fe 4 LT1763 Series ELECTRICAL CHARACTERISTICS PARAMETER GND Pin Current VIN = VOUT(NOMINAL) (Notes 5, 7) CONDITIONS ILOAD = 0mA ILOAD = 1mA ILOAD = 50mA ILOAD = 100mA ILOAD = 250mA ILOAD = 500mA COUT = 10μF, CBYP = 0.01μF, ILOAD = 500mA, BW = 10Hz to 100kHz (Notes 3, 8) VOUT = Off to On VOUT = On to Off VSHDN = 0V VSHDN = 20V VIN = 6V, VSHDN = 0V VIN – VOUT = 1.5V (Avg), VRIPPLE = 0.5VP-P, fRIPPLE = 120Hz, ILOAD = 500mA VIN = 7V, VOUT = 0V C, I Grade: VIN = VOUT(NOMINAL) + 1V or 2.3V (Note 12), ΔVOUT = – 0.1V MP Grade: VIN = 2.35V (Note 12), ΔVOUT = – 0.1V VIN = –20V, VOUT = 0V LT1763-1.5 LT1763-1.8 LT1763-2.5 LT1763-3 LT1763-3.3 LT1763-5 LT1763 (Note 3) 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 l l l l l l l l l l l The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (Note 2) MIN TYP 30 65 1.1 2 5 11 20 30 0.25 0.8 0.65 0.1 1 0.1 50 65 1 100 2 MAX 75 120 1.6 3 8 16 UNITS μA μA mA mA mA mA μVRMS nA V V μA μA μA dB Output Voltage Noise ADJ Pin Bias Current Shutdown Threshold SHDN Pin Current (Note 9) Quiescent Current in Shutdown Ripple Rejection Current Limit 520 520 1 10 10 10 10 10 10 5 20 20 20 20 20 20 10 mA mA mA μA μA μA μA μA μA μA Input Reverse Leakage Current Reverse Output Current (Note 10) 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 LT1763 regulators are tested and specified under pulse load conditions such that TJ ≅ TA. The LT1763 (C grade) 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. The LT1763 (I grade) is guaranteed over the full –40°C to 125°C operating junction temperature range. The LT1763 (MP grade) is 100% tested and guaranteed over the –55°C to 125°C operating junction temperature range. Note 3: The LT1763 (adjustable version) is tested and specified for these conditions with the ADJ pin connected to the OUT pin. Note 4: 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 5: To satisfy requirements for minimum input voltage, the LT1763 (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 6: 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 7: GND pin current is tested with VIN = VOUT(NOMINAL) or VIN = 2.3V (C, I grade) or 2.35V (MP grade), 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 8: ADJ pin bias current flows into the ADJ pin. Note 9: SHDN pin current flows into the SHDN pin. Note 10: 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 11: For the LT1763, LT1763-1.5 and LT1763-1.8 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. Note 12: To satisfy requirements for minimum input voltage, current limit is tested at VIN = VOUT(NOMINAL) + 1V or 2.3V (C, I grade) or 2.35V (MP grade), whichever is greater. 1763fe 5 LT1763 Series TYPICAL PERFORMANCE CHARACTERISTICS Typical Dropout Voltage 500 GUARANTEED DROPOUT VOLTAGE (mV) 450 DROPOUT VOLTAGE (mV) 400 350 300 250 200 150 100 50 0 0 50 100 150 200 250 300 350 400 450 500 OUTPUT CURRENT (mA) 1763 G01 Guaranteed Dropout Voltage 500 450 DROPOUT VOLTAGE (mV) 400 350 300 250 200 150 100 50 0 0 50 100 150 200 250 300 350 400 450 500 OUTPUT CURRENT (mA) 1763 G02 Dropout Voltage 500 450 400 350 300 250 200 150 100 50 0 –50 –25 IL = 50mA IL = 10mA 100 125 IL = 1mA IL = 100mA IL = 250mA IL = 500mA = TEST POINTS TJ = 125°C TJ 125°C TJ 25°C TJ = 25°C 50 25 0 75 TEMPERATURE (°C) 1763 G03 Quiescent Current 50 45 QUIESCENT CURRENT (μA) 40 35 30 25 20 15 10 VIN = 6V 5 RL = , IL = 0 (LT1763-1.5/-1.8/-2.5/-3/-3.3/-5) RL = 250k, IL = 5μA (LT1763) 0 0 25 50 75 100 125 –50 –25 TEMPERATURE (°C) 1763 G04 LT1763-1.5 Output Voltage 1.528 IL = 1mA 1.521 OUTPUT VOLTAGE (V) OUTPUT VOLTAGE (V) 1.514 1.507 1.500 1.493 1.486 1.479 1.472 –50 –25 0 25 50 75 100 125 1.83 1.82 1.81 1.80 1.79 1.78 1.77 1.84 LT1763-1.8 Output Voltage IL = 1mA VSHDN = VIN 1.76 –50 –25 0 25 50 75 100 125 TEMPERATURE (°C) 1763 G05 TEMPERATURE (°C) 1763 G06 LT1763-2.5 Output Voltage 2.54 IL = 1mA 2.53 OUTPUT VOLTAGE (V) OUTPUT VOLTAGE (V) 2.52 2.51 2.50 2.49 2.48 2.47 2.46 –50 –25 0 25 50 75 100 125 3.045 3.030 3.015 3.000 2.985 2.970 2.955 3.060 LT1763-3 Output Voltage 3.360 IL = 1mA 3.345 OUTPUT VOLTAGE (V) 3.330 3.315 3.300 3.285 3.270 3.255 –25 0 25 50 75 100 125 LT1763-3.3 Output Voltage IL = 1mA 2.940 –50 3.240 –50 –25 0 25 50 75 100 125 TEMPERATURE (°C) 1763 G07 TEMPERATURE (°C) 1763 G08 TEMPERATURE (°C) 1763 G09 1763fe 6 LT1763 Series TYPICAL PERFORMANCE CHARACTERISTICS LT1763-5 Output Voltage 5.100 IL = 1mA 5.075 OUTPUT VOLTAGE (V) ADJ PIN VOLTAGE (V) 5.050 5.025 5.000 4.975 4.950 4.925 4.900 –50 –25 0 25 50 75 100 125 1.235 1.230 1.225 1.220 1.215 1.210 1.205 1.200 –50 –25 0 25 50 75 100 125 1.240 IL = 1mA QUIESCENT CURRENT (μA) LT1763 ADJ Pin Voltage 250 225 200 175 150 125 100 75 50 25 0 LT1763-1.5 Quiescent Current TJ = 25°C RL = VSHDN = VIN VSHDN = 0V 0 1 2 34567 INPUT VOLTAGE (V) 8 9 10 TEMPERATURE (°C) 1763 G10 TEMPERATURE (°C) 1763 G11 1763 G12 LT1763-1.8 Quiescent Current 250 225 QUIESCENT CURRENT (μA) 200 175 150 125 100 75 50 25 0 0 1 2 VSHDN = VIN VSHDN = 0V 34567 INPUT VOLTAGE (V) 8 9 10 TJ = 25°C RL = QUIESCENT CURRENT (μA) 250 225 200 175 150 125 100 75 50 25 0 LT1763-2.5 Quiescent Current 250 TJ = 25°C RL = QUIESCENT CURRENT (μA) 225 200 175 150 125 100 75 50 25 0 9 10 LT1763-3 Quiescent Current TJ = 25°C RL = VSHDN = VIN VSHDN = 0V 0 1 2 34567 INPUT VOLTAGE (V) 8 VSHDN = VIN VSHDN = 0V 0 1 2 34567 INPUT VOLTAGE (V) 8 9 10 1763 G13 1763 G14 1763 G15 LT1763-3.3 Quiescent Current 250 225 QUIESCENT CURRENT (μA) 200 175 150 125 100 75 50 25 0 0 1 2 VSHDN = VIN VSHDN = 0V 34567 INPUT VOLTAGE (V) 8 9 10 TJ = 25°C RL = QUIESCENT CURRENT (μA) 250 225 200 175 150 125 100 75 50 25 0 LT1763-5 Quiescent Current 40 TJ = 25°C RL = QUIESCENT CURRENT (μA) 35 30 25 20 15 10 5 0 9 10 LT1763 Quiescent Current TJ = 25°C RL = 250k VSHDN = VIN VSHDN = VIN VSHDN = 0V 0 1 2 34567 INPUT VOLTAGE (V) 8 VSHDN = 0V 0 2 4 6 8 10 12 14 16 18 20 INPUT VOLTAGE (V) 1763 G18 1763 G16 1763 G17 1763fe 7 LT1763 Series TYPICAL PERFORMANCE CHARACTERISTICS LT1763-1.5 GND Pin Current 1200 1000 GND PIN CURRENT (μA) GND PIN CURRENT (μA) 800 600 400 200 0 RL = 30Ω IL = 50mA* 1200 1000 800 600 400 200 0 RL = 36Ω IL = 50mA* TJ = 25°C VIN = VSHDN *FOR VOUT = 1.8V RL = 180Ω IL = 10mA* RL = 1.8k IL = 1mA* 0 1 2 34567 INPUT VOLTAGE (V) 8 9 10 GND PIN CURRENT (μA) LT1763-1.8 GND Pin Current 1200 1000 800 600 400 200 0 LT1763-2.5 GND Pin Current RL = 50Ω IL = 50mA* TJ = 25°C VIN = VSHDN *FOR VOUT = 2.5V RL = 250Ω IL = 10mA* RL = 2.5k IL = 1mA* 0 1 2 34567 INPUT VOLTAGE (V) 8 9 10 TJ = 25°C VIN = VSHDN *FOR VOUT = 1.5V RL = 150Ω IL = 10mA* RL = 1.5k IL = 1mA* 0 1 2 34567 INPUT VOLTAGE (V) 8 9 10 1763 G19 1763 G20 1763 G21 LT1763-3 GND Pin Current 1200 1000 GND PIN CURRENT (μA) 800 600 400 200 0 RL = 300Ω IL = 10mA* RL = 3k IL = 1mA* 0 1 2 34567 INPUT VOLTAGE (V) 8 9 10 1200 1000 GND PIN CURRENT (μA) 800 600 400 200 0 LT1763-3.3 GND Pin Current 1200 1000 GND PIN CURRENT (μA) 800 600 400 200 0 LT1763-5 GND Pin Current RL = 60Ω IL = 50mA* TJ = 25°C VIN = VSHDN *FOR VOUT = 3V RL = 66Ω IL = 50mA* TJ = 25°C VIN = VSHDN *FOR VOUT = 3.3V RL = 330Ω IL = 10mA* RL = 3.3k IL = 1mA* 0 1 2 34567 INPUT VOLTAGE (V) 8 9 10 RL = 100Ω IL = 50mA* TJ = 25°C VIN = VSHDN *FOR VOUT = 5V RL = 500Ω IL = 10mA* RL = 5k IL = 1mA* 0 1 2 34567 INPUT VOLTAGE (V) 8 9 10 1763 G22 1763 G23 1763 G24 LT1763 GND Pin Current 1200 1000 GND PIN CURRENT (μA) 800 600 400 200 0 RL = 122Ω IL = 10mA* RL = 1.22k IL = 1mA* 0 1 2 34567 INPUT VOLTAGE (V) 8 9 10 TJ = 25°C VIN = VSHDN *FOR VOUT = 1.22V RL = 24.4Ω IL = 50mA* 12 10 GND PIN CURRENT (mA) 8 6 4 2 0 LT1763-1.5 GND Pin Current 12 TJ = 25°C VIN = VSHDN *FOR VOUT = 1.5V RL = 3Ω IL = 500mA* RL = 5Ω IL = 300mA* GND PIN CURRENT (mA) 10 8 6 4 2 0 LT1763-1.8 GND Pin Current TJ = 25°C VIN = VSHDN *FOR VOUT = 1.8V RL = 3.6Ω IL = 500mA* RL = 6Ω IL = 300mA* RL = 15Ω IL = 100mA* RL = 18Ω IL = 100mA* 0 1 2 34567 INPUT VOLTAGE (V) 8 9 10 0 1 2 34567 INPUT VOLTAGE (V) 8 9 10 1763 G25 1763 G26 1763 G27 1763fe 8 LT1763 Series TYPICAL PERFORMANCE CHARACTERISTICS LT1763-2.5 GND Pin Current 12 10 GND PIN CURRENT (mA) 8 6 4 2 0 RL = 25Ω IL = 100mA* RL = 5Ω IL = 500mA* RL = 8.33Ω IL = 300mA* TJ = 25°C VIN = VSHDN *FOR VOUT = 2.5V GND PIN CURRENT (mA) 12 10 8 6 4 2 0 RL = 30Ω IL = 100mA* RL = 6Ω IL = 500mA* RL = 10Ω IL = 300mA* TJ = 25°C VIN = VSHDN *FOR VOUT = 3V GND PIN CURRENT (mA) LT1763-3 GND Pin Current 12 10 8 6 4 2 0 LT1763-3.3 GND Pin Current TJ = 25°C VIN = VSHDN *FOR VOUT = 3.3V RL = 6.6Ω IL = 500mA* RL = 11Ω IL = 300mA* RL = 33Ω IL = 100mA* 0 1 2 34567 INPUT VOLTAGE (V) 8 9 10 0 1 2 34567 INPUT VOLTAGE (V) 8 9 10 0 1 2 34567 INPUT VOLTAGE (V) 8 9 10 1763 G28 1763 G29 1763 G30 LT1763-5 GND Pin Current 12 10 GND PIN CURRENT (mA) 8 6 4 2 0 RL = 50Ω IL = 100mA* RL = 16.7Ω IL = 300mA* TJ = 25°C VIN = VSHDN *FOR VOUT = 5V RL = 10Ω IL = 500mA* 12 10 GND PIN CURRENT (mA) 8 6 4 2 0 LT1763 GND Pin Current 12 TJ = 25°C VIN = VSHDN *FOR VOUT = 1.22V RL = 2.44Ω IL = 500mA* RL = 4.07Ω IL = 300mA* GND PIN CURRENT (mA) GND Pin Current vs ILOAD VIN = VOUT(NOMINAL) + 1V 10 8 6 4 2 0 RL = 12.2Ω IL = 100mA* 0 1 2 34567 INPUT VOLTAGE (V) 8 9 10 0 1 2 34567 INPUT VOLTAGE (V) 8 9 10 0 50 100 150 200 250 300 350 400 450 500 OUTPUT CURRENT (mA) 1763 G33 1763 G31 1763 G32 SHDN Pin Threshold (On-to-Off) 1.0 0.9 SHDN PIN THRESHOLD (V) 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 –50 –25 50 25 0 75 TEMPERATURE (°C) 100 125 IL = 1mA SHDN PIN THRESHOLD (V) 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 SHDN Pin Threshold (Off-to-On) 1.4 SHDN PIN INPUT CURRENT (μA) 1.2 1.0 0.8 0.6 0.4 0.2 0 –25 50 25 0 75 TEMPERATURE (°C) 100 125 SHDN Pin Input Current IL = 500mA IL = 1mA 0 –50 0 1 2 345678 SHDN PIN VOLTAGE (V) 9 10 1763 G34 1763 G35 1763 G36 1763fe 9 LT1763 Series TYPICAL PERFORMANCE CHARACTERISTICS SHDN Pin Input Current 1.6 VSHDN = 20V SHDN PIN INPUT CURRENT (μA) 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0 –50 –25 0 25 50 75 100 125 ADJ PIN BIAS CURRENT (nA) 120 CURRENT LIMIT (A) 100 80 60 40 20 0 –50 140 ADJ Pin Bias Current 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 –25 50 25 0 75 TEMPERATURE (°C) 100 125 0 Current Limit VOUT = 0V 0 1 TEMPERATURE (°C) 1763 G37 4 3 2 5 INPUT VOLTAGE (V) 6 7 1763 G39 1763 G38 Current Limit 1.2 1.0 CURRENT LIMIT (A) 0.8 0.6 0.4 0.2 0 –50 REVERSE OUTPUT CURRENT (μA) VIN = 7 VOUT = 0V 100 90 80 70 60 50 40 30 20 10 –25 50 25 0 75 TEMPERATURE (°C) 100 125 0 Reverse Output Current 20 REVERSE OUTPUT CURRENT (μA) TJ = 25°C, VIN = 0V CURRENT FLOWS INTO OUTPUT PIN VOUT = VADJ (LT1763) LT1763 LT1763-1.8 LT1763-2.5 LT1763-3 LT1763-3.3 LT1763-1.5 Reverse Output Current VIN = 0V, VOUT = 1.22V (LT1763) 18 VOUT = 1.5V (LT1763-1.5) = 1.8V (LT1763-1.8) V 16 VOUT = 2.5V (LT1763-2.5) OUT 14 VOUT = 3V (LT1763-3) VOUT = 3.3V (LT1763-3.3) 12 VOUT = 5V (LT1763-5) 10 8 6 4 2 10 0 –50 –25 50 25 0 75 TEMPERATURE (°C) 100 125 LT1763-1.5/-1.8/ -2.5/-3/-3.3/-5 LT1763 LT1763-5 0 1 2 345678 OUTPUT VOLTAGE (V) 9 1763 G40 1763 G41 1763 G42 Input Ripple Rejection 80 70 RIPPLE REJECTION (dB) RIPPLE REJECTION (dB) 60 50 40 30 20 10 0 10 100 1k 10k FREQUENCY (Hz) 100k 1M 1763 G43 Input Ripple Rejection 80 70 CBYP = 0.01μF RIPPLE REJECTION (dB) 60 50 CBYP = 1000pF 40 30 20 10 0 10 100 1k 10k FREQUENCY (Hz) 100k 1M 1763 G44 Ripple Rejection 68 66 64 62 60 58 56 54 52 –50 VIN = VOUT (NOMINAL) + 1V + 0.5VP-P RIPPLE AT f = 120Hz IL = 500mA –25 0 25 50 75 100 125 COUT = 10μF CBYP = 100pF IL = 500mA VIN = VOUT(NOMINAL) + 1V + 50mVRMS RIPPLE CBYP = 0 COUT = 4.7μF IL = 500mA VIN = VOUT(NOMINAL) + 1V + 50mVRMS RIPPLE COUT = 10μF TEMPERATURE (°C) 1763 G45 1763fe 10 LT1763 Series TYPICAL PERFORMANCE CHARACTERISTICS LT1763 Minimum Input Voltage 2.50 2.25 MINIMUM INPUT VOLTAGE (V) LOAD REGULATION (mV) 2.00 1.75 1.50 1.25 1.00 0.75 0.50 0.25 VOUT = 1.22V –25 50 25 0 75 TEMPERATURE (°C) 100 125 –25 –50 IL = 1mA IL = 500mA 0 –5 –10 –15 –20 LT1763-3 LT1763-3.3 LT1763-5 5 LT1763 LT1763-2.5 LT1763-1.5 LT1763-1.8 Load Regulation VIN = VOUT(NOMINAL) + 1V IL = 1mA TO 500mA –25 0 25 50 75 100 125 0 –50 TEMPERATURE (°C) 1763 G46 1763 G47 Output Noise Spectral Density CBYP = 0 OUTPUT NOISE SPECTRAL DENSITY (μV/ Hz) OUTPUT NOISE SPECTRAL DENSITY (μV/ Hz) 10 LT1763-3 LT1763-5 1 LT1763-3.3 10 Output Noise Spectral Density COUT = 10μF IL = 500mA LT1763-5 1 LT1763 CBYP = 1000pF CBYP = 100pF LT1763 0.1 LT1763-2.5 LT1763-1.5 LT1763-1.8 0.1 CBYP = 0.01μF COUT = 10μF IL = 500mA 0.01 10 100 1k 10k FREQUENCY (Hz) 100k 1763 G48 0.01 10 100 1k 10k FREQUENCY (Hz) 100k 1763 G49 RMS Output Noise vs Bypass Capacitor 160 140 OUTPUT NOISE (μVRMS) 120 100 80 LT1763-2.5 60 40 20 0 10 100 CBYP (pF) 1763 G50 RMS Output Noise vs Load Current (10Hz to 100kHz) 160 140 OUTPUT NOISE (μVRMS) 120 LT1763-5 100 80 60 40 20 1000 10000 0 0.01 0.1 LT1763-5 LT1763 10 100 1 LOAD CURRENT (mA) 1000 1763 G51 COUT = 10μF IL = 500mA f = 10Hz TO 100kHz LT1763-5 LT1763-3.3 LT1763-3 COUT = 10μF CBYP = 0 CBYP = 0.01μF LT1763 LT1763 LT1763-1.8 LT1763-1.5 1763fe 11 LT1763 Series TYPICAL PERFORMANCE CHARACTERISTICS LT1763-5 10Hz to 100kHz Output Noise CBYP = 0 LT1763-5 10Hz to 100kHz Output Noise CBYP = 100pF VOUT 100μV/DIV VOUT 100μV/DIV COUT = 10μF IL = 500mA 1ms/DIV 1763 G52 COUT = 10μF IL = 500mA 1ms/DIV 1763 G53 LT1763-5 10Hz to 100kHz Output Noise CBYP = 1000pF LT1763-5 10Hz to 100kHz Output Noise CBYP = 0.01μF VOUT 100μV/DIV VOUT 100μV/DIV COUT = 10μF IL = 500mA 1ms/DIV 1763 G54 COUT = 10μF IL = 500mA 1ms/DIV 1763 G55 LT1763-5 Transient Response CBYP = 0 OUTPUT VOLTAGE DEVIATION (V) OUTPUT VOLTAGE DEVIATION (V) 0.4 0.2 0 –0.2 –0.4 VIN = 6V CIN = 10μF COUT = 10μF 0.10 0.05 0 –0.05 –0.10 LT1763-5 Transient Response CBYP = 0.01μF VIN = 6V CIN = 10μF COUT = 10μF LOAD CURRENT (mA) 600 400 200 0 0 200 400 600 TIME (μs) 800 1000 1763 G56 LOAD CURRENT (mA) 600 400 200 0 0 10 20 30 40 50 60 70 80 90 100 TIME (μs) 1763 G57 1763fe 12 LT1763 Series PIN FUNCTIONS (DE12/S8) NC (Pins 1, 4, 9, 12) DE12 Only: No Connect. No connect pins have no connection to any internal circuitry. These pins may be tied to either GND or VIN , or left floating. OUT (Pins 2, 3/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. ADJ (Pin 5/Pin 2): Adjust. For the adjustable LT1763, 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 pin (see the curve of ADJ Pin Bias Current vs Temperature in the Typical Performance Characteristics section). The ADJ pin voltage is 1.22V referenced to ground and the output voltage range is 1.22V to 20V. SENSE (Pin 5/Pin 2): Output Sense. For fixed voltage versions of the LT1763 (LT1763-1.5/LT1763-1.8/ LT1763-2.5/LT1763-3/LT1763-3.3/LT1763-5), 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). 8 IN LT1763 OUT 1 RP supply system where the regulator load is returned to a negative supply) and still allow the device to start and operate. BYP (Pin 6/Pin 4): Bypass. The BYP pin is used to bypass the reference of the LT1763 regulators 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 (Pins 7/Pins 3, 6, 7): Ground. SHDN (Pin 8/Pin 5): Shutdown. The SHDN pin is used to put the LT1763 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 open-collector logic with a pull-up resistor. The pull-up resistor is required to supply the pull-up current of the open-collector gate, normally several microamperes, and the SHDN pin current, typically 1μA. If unused, the SHDN pin must be connected to VIN. The device will be in the low power shutdown state if the SHDN pin is not connected. IN (Pin 10, 11/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 LT1763 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. Exposed Pad (Pin 13) DE12 Only: Ground. The Exposed Pad must be soldered to the PCB ground for rated thermal performance. 1763fe + VIN 5 SHDN SENSE GND 3 2 + LOAD RP 1763 F01 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 13 LT1763 Series APPLICATIONS INFORMATION The LT1763 series are 500mA low dropout regulators with micropower quiescent current and shutdown. The devices are capable of supplying 500mA 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 LT1763 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 LT1763-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 LT1763 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 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. Curves of ADJ Pin Voltage vs Temperature and ADJ Pin Bias Current vs Temperature appear in the Typical Performance Characteristics section. 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 1763fe to 1.22V: VOUT /1.22V. For example, load regulation for an output current change of 1mA to 500mA is –2mV typical at VOUT = 1.22V. At VOUT = 12V, load regulation is: (12V/1.22V)(–2mV) = –19.6mV IN VIN LT1763 OUT VOUT + R2 ADJ R1 1763 F02 GND ⎛ 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 Bypass Capacitance and Low Noise Performance The LT1763 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 500mA 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 500mA load step in less than 10μs, with total output voltage deviation of less than 2.5% (see the LT1763-5 Transient Response curve in the Typical Performance Characteristics section). However, regulator start-up time is proportional to the size of the bypass capacitor, slowing to 15ms with a 0.01μF bypass capacitor and 10μF output capacitor. 14 LT1763 Series APPLICATIONS INFORMATION Output Capacitance and Transient Response The LT1763 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 LT1763-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 LT1763-X, will increase the effective output capacitor value. With larger capacitors used to bypass the reference (for low noise operation), larger values of output capacitors 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 LT1763 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 temperature and applied voltage. The most common dielectrics used are specified with EIA temperature characteristic codes of Z5U, Y5V, X5R and X7R. The Z5U and Y5V dielectrics are good for providing high capacitances in a small package, but they tend to have strong voltage and temperature coefficients, as shown in Figures 4 and 5. When used with a 5V regulator, a 16V 10μF Y5V capacitor can exhibit an effective value as low as 1μF to 2μF for the DC bias voltage applied and 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. Care still must be exercised when using X5R and X7R capacitors; the X5R and X7R codes only specify operating temperature range and maximum capacitance change over temperature. Capacitance change due to DC bias with X5R and X7R capacitors is better than 4.0 3.5 3.0 STABLE REGION 2.5 ESR (Ω) 2.0 1.5 1.0 0.5 0 1 3 2 4 5 6 7 8 9 10 OUTPUT CAPACITANCE (μF) 1763 F03 CBYP = 0 CBYP = 100pF CBYP = 330pF CBYP 1000pF Figure 3. Stability 20 0 CHANGE IN VALUE (%) BOTH CAPACITORS ARE 16V, 1210 CASE SIZE, 10μF X5R –20 –40 –60 Y5V –80 –100 0 2 4 6 8 10 12 14 16 1763 F04 DC BIAS VOLTAGE (V) Figure 4. Ceramic Capacitor DC Bias Characteristics 40 20 CHANGE IN VALUE (%) 0 –20 –40 –60 –80 BOTH CAPACITORS ARE 16V, 1210 CASE SIZE, 10μF 50 25 75 0 TEMPERATURE (°C) 100 125 1763 F05 X5R Y5V –100 –50 –25 Figure 5. Ceramic Capacitor Temperature Characteristics 1763fe 15 LT1763 Series APPLICATIONS INFORMATION Y5V and Z5U capacitors, but can still be significant enough to drop capacitor values below appropriate levels. Capacitor DC bias characteristics tend to improve as component case size increases, but expected capacitance at operating voltage should be verified. 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. 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. LT1763-5 COUT = 10μF CBYP = 0.01μF ILOAD = 100mA VOUT 500μV/DIV 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 section. Power dissipation will be equal to the sum of the two components listed above. The LT1763 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. 100ms/DIV 1763 F06 Figure 6. Noise Resulting from Tapping on a Ceramic Capacitor The following tables list 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. DE Package, 12-Lead DFN COPPER AREA TOPSIDE* 2500mm2 1000mm2 225mm2 100mm2 BACKSIDE 2500mm2 2500mm2 2500mm2 2500mm2 BOARD AREA 2500mm2 2500mm2 2500mm2 2500mm2 THERMAL RESISTANCE (JUNCTION-TO-AMBIENT) 40°C/W 45°C/W 50°C/W 60°C/W * Device is mounted on topside 1763fe 16 LT1763 Series APPLICATIONS INFORMATION Table 2. SO-8 Package, 8-Lead SO COPPER AREA TOPSIDE* 2500mm2 1000mm2 225mm2 100mm2 50mm2 BACKSIDE 2500mm2 2500mm2 2500mm2 2500mm2 2500mm2 BOARD AREA 2500mm2 2500mm2 2500mm2 2500mm2 2500mm2 THERMAL RESISTANCE (JUNCTION-TO-AMBIENT) 60°C/W 60°C/W 68°C/W 74°C/W 86°C/W Protection Features The LT1763 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 LT1763-X 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 100μA. 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 from the 1.22V reference when the output is forced to 20V. 1763fe * 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 250mA 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) = 250mA VIN(MAX) = 6V IGND at (IOUT = 250mA, VIN = 6V) = 5mA So, P = 250mA(6V – 3.3V) + 5mA(6V) = 0.71W The thermal resistance will be in the range of 60°C/W to 86°C/W, depending on the copper area. So, the junction temperature rise above ambient will be approximately equal to: 0.71W(75°C/W) = 53.3°C 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 + 53.3°C = 103.3°C 17 LT1763 Series APPLICATIONS INFORMATION 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 output 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. 100 REVERSE OUTPUT CURRENT (μA) TJ = 25°C 90 VIN = 0V CURRENT FLOWS 80 INTO OUTPUT PIN 70 VOUT = VADJ (LT1763) LT1763 60 LT1763-1.8 50 LT1763-2.5 40 30 20 10 0 0 1 2 LT1763-5 LT1763-3.3 345678 OUTPUT VOLTAGE (V) 9 10 1763 F07 When the IN pin of the LT1763-X 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 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. LT1763-1.5 LT1763-3 Figure 7. Reverse Output Current 1763fe 18 LT1763 Series PACKAGE DESCRIPTION DE/UE Package 12-Lead Plastic DFN (4mm × 3mm) (Reference LTC DWG # 05-08-1695 Rev D) 4.00 0.10 (2 SIDES) 0.70 0.05 3.30 0.05 1.70 0.05 PACKAGE OUTLINE 0.25 0.05 0.50 BSC 2.50 REF RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED 0.00 – 0.05 0.200 REF 0.75 0.05 PIN 1 TOP MARK (NOTE 6) 3.00 0.10 (2 SIDES) R = 0.05 TYP 7 R = 0.115 TYP 0.40 12 0.10 3.60 0.05 2.20 0.05 3.30 0.10 1.70 0.10 PIN 1 NOTCH R = 0.20 OR 0.35 45 CHAMFER 6 0.25 1 0.05 0.50 BSC 2.50 REF BOTTOM VIEW—EXPOSED PAD (UE12/DE12) DFN 0806 REV D NOTE: 1. DRAWING PROPOSED TO BE A VARIATION OF VERSION 5. EXPOSED PAD SHALL BE SOLDER PLATED (WGED) IN JEDEC PACKAGE OUTLINE M0-229 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION 2. DRAWING NOT TO SCALE ON THE TOP AND BOTTOM OF PACKAGE 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 S8 Package 8-Lead Plastic Small Outline (Narrow .150 Inch) (Reference LTC DWG # 05-08-1610) .045 ±.005 .050 BSC 8 .189 – .197 (4.801 – 5.004) NOTE 3 7 6 5 .053 – .069 (1.346 – 1.752) .004 – .010 (0.101 – 0.254) .245 MIN .160 ±.005 .228 – .244 (5.791 – 6.197) .150 – .157 (3.810 – 3.988) NOTE 3 .014 – .019 (0.355 – 0.483) TYP .010 – .020 45° (0.254 – 0.508) .008 – .010 (0.203 – 0.254) .050 (1.270) BSC .030 ±.005 TYP RECOMMENDED SOLDER PAD LAYOUT NOTE: 1. DIMENSIONS IN 1 2 3 4 0°– 8° TYP INCHES (MILLIMETERS) 2. DRAWING NOT TO SCALE 3. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm) .016 – .050 (0.406 – 1.270) SO8 0303 1763fe 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. 19 LT1763 Series TYPICAL APPLICATION Paralleling of Regulators for Higher Output Current R1 0.1Ω 3.3V 1A C2 10μF + VIN > 3.8V IN C1 10μF OUT SENSE LT1763-3.3 + C4 0.01μF SHDN BYP GND R2 0.1Ω IN LT1763 SHDN R3 2.2k R4 2.2k 3 SHDN GND BYP ADJ OUT C5 0.01μF R6 2k R7 1.21k + – 8 1 R5 10k 1/2 LT1490 2 4 C3 0.01μF 1763 TA03 RELATED PARTS PART NUMBER LT1120 LT1121 LT1129 LT1175 LT1521 LT1529 LT1613 LT1761 Series LT1762 Series LT1764A LT1962 LT1963A LT3010 LT3021 DESCRIPTION 125mA Low Dropout Regulator with 20μA IQ 150mA Micropower Low Dropout Regulator 700mA Micropower Low Dropout Regulator 500mA Negative Low Dropout Micropower Regulator 300mA Low Dropout Micropower Regulator with Shutdown 3A Low Dropout Regulator with 50μA IQ 1.4MHz Single-Cell Micropower DC/DC Converter 100mA, Low Noise, Low Dropout Micropower Regulators in SOT-23 150mA, Low Noise, LDO Micropower Regulators 3A, Fast Transient Response Low Dropout Regulator 300mA, Fast Transient Response Low Dropout Regulator 1.5A, Fast Transient Response Low Dropout Regulator 50mA, 80V Low Noise, LDO Micropower Regulator 500mA, Low Voltage, Very Low Dropout Linear Regulator COMMENTS Includes 2.5V Reference and Comparator 30μA IQ , SOT-223 Package 50μA Quiescent Current 45μA IQ , 0.26V Dropout Voltage, SOT-223 Package 15μA IQ , Reverse Battery Protection 500mV Dropout Voltage SOT-23 Package, Internally Compensated 20μA Quiescent Current, 20μVRMS Noise, ThinSOT™ 25μA Quiescent Current, 20μVRMS Noise, MS8 340mV Dropout Voltage, DD, TO220 270mV Dropout Voltage, 20μVRML , MS8 340mV Dropout Voltage, 40μVRML , DD, TO220, S8, SOT-223 300mV Dropout Voltage, MS8E 160mV Dropout Voltage, DFN-8 and SOIC-8 Packages ThinSOT is a trademark of Linear Technology Corporation. 1763fe 20 Linear Technology Corporation (408) 432-1900 ● FAX: (408) 434-0507 ● LT 1008 REV E • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 www.linear.com © LINEAR TECHNOLOGY CORPORATION 1999