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 Low Noise: 20VRMS (10Hz to 100kHz) Output Current: 500mA Low Quiescent Current: 30A Wide Input Voltage Range: 1.8V to 20V Low Dropout Voltage: 300mV Very Low Shutdown Current: < 1A 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 3.3F 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 x 3mm) DFN Packages Applications n n n Cellular Phones Battery-Powered Systems Noise-Sensitive Instrumentation Systems The LT(R)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 30A 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 0.01F bypass capacitor, output noise drops to 20VRMS over a 10Hz to 100kHz bandwidth. The LT1763 regulators are stable with output capacitors as low as 3.3F. 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 x 3mm x 0.75mm) DFN packages. L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents including 6144250, 6118263. Typical Application Dropout Voltage 3.3V Low Noise Regulator 400 VIN 3.7V TO 20V IN 1F OUT + SENSE LT1763-3.3 0.01F SHDN BYP GND 1763 TA01 10F DROPOUT VOLTAGE (mV) 350 3.3V AT 500mA 20VRMS NOISE 300 250 200 150 100 50 0 0 100 300 400 200 OUTPUT CURRENT (mA) 500 1763 TA02 1763fh For more information www.linear.com/LT1763 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............................................-40C to 125C MP Grade............................................-55C to 125C Storage Temperature Range S8 Package.........................................-65C to 150C DFN Package.......................................-65C to 150C Lead Temperature (Soldering, 10 sec) S8 Package........................................................ 300C pin configuration TOP VIEW NC 1 12 NC OUT 2 11 IN OUT 3 10 IN NC 4 SENSE/ADJ* BYP 13 GND 9 NC 5 8 SHDN 6 7 GND TOP VIEW OUT 1 8 IN SENSE/ADJ* 2 7 GND GND 3 6 GND BYP 4 5 SHDN S8 PACKAGE 8-LEAD PLASTIC SO DE PACKAGE 12-LEAD (4mm x 3mm) PLASTIC DFN TJMAX = 150C, JA = 70C/W, JC = 35C/W TJMAX = 125C, JA = 40C/W, JC = 5C/W EXPOSED PAD (PIN 13) IS GND, MUST BE SOLDERED TO PCB *PIN 2: SENSE FOR LT1763-1.5/LT1763-1.8/LT1763-2.5/LT1763-3/LT1763-3.3/LT1763-5 ADJ FOR LT1763 *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. SEE THE APPLICATIONS INFORMATION SECTION. order information LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT1763CDE#PBF LT1763CDE#TRPBF 1763 12-Lead (4mm x 3mm) Plastic DFN -40C to 125C LT1763IDE#PBF LT1763IDE#TRPBF 1763 12-Lead (4mm x 3mm) Plastic DFN -40C to 125C LT1763MPDE#PBF LT1763MPDE#TRPBF 1763 12-Lead (4mm x 3mm) Plastic DFN -55C to 125C LT1763CDE-1.5#PBF LT1763CDE-1.5#TRPBF 76315 12-Lead (4mm x 3mm) Plastic DFN -40C to 125C LT1763IDE-1.5#PBF LT1763IDE-1.5#TRPBF 76315 12-Lead (4mm x 3mm) Plastic DFN -40C to 125C LT1763MPDE-1.5#PBF LT1763MPDE-1.5#TRPBF 76315 12-Lead (4mm x 3mm) Plastic DFN -55C to 125C LT1763CDE-1.8#PBF LT1763CDE-1.8#TRPBF 12-Lead (4mm x 3mm) Plastic DFN -40C to 125C 2 76318 1763fh For more information www.linear.com/LT1763 LT1763 Series order information LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT1763IDE-1.8#PBF LT1763IDE-1.8#TRPBF 76318 12-Lead (4mm x 3mm) Plastic DFN -40C to 125C LT1763MPDE-1.8#PBF LT1763MPDE-1.8#TRPBF 76318 12-Lead (4mm x 3mm) Plastic DFN -55C to 125C LT1763CDE-2.5#PBF LT1763CDE-2.5#TRPBF 76325 12-Lead (4mm x 3mm) Plastic DFN -40C to 125C LT1763IDE-2.5#PBF LT1763IDE-2.5#TRPBF 76325 12-Lead (4mm x 3mm) Plastic DFN -40C to 125C LT1763MPDE-2.5#PBF LT1763MPDE-2.5#TRPBF 76325 12-Lead (4mm x 3mm) Plastic DFN -55C to 125C LT1763CDE-3#PBF LT1763CDE-3#TRPBF 17633 12-Lead (4mm x 3mm) Plastic DFN -40C to 125C LT1763IDE-3#PBF LT1763IDE-3#TRPBF 17633 12-Lead (4mm x 3mm) Plastic DFN -40C to 125C LT1763MPDE-3#PBF LT1763MPDE-3#TRPBF 17633 12-Lead (4mm x 3mm) Plastic DFN -55C to 125C LT1763CDE-3.3#PBF LT1763CDE-3.3#TRPBF 76333 12-Lead (4mm x 3mm) Plastic DFN -40C to 125C LT1763IDE-3.3#PBF LT1763IDE-3.3#TRPBF 76333 12-Lead (4mm x 3mm) Plastic DFN -40C to 125C LT1763MPDE-3.3#PBF LT1763MPDE-3.3#TRPBF 76333 12-Lead (4mm x 3mm) Plastic DFN -55C to 125C LT1763CDE-5#PBF LT1763CDE-5#TRPBF 17635 12-Lead (4mm x 3mm) Plastic DFN -40C to 125C LT1763IDE-5#PBF LT1763IDE-5#TRPBF 17635 12-Lead (4mm x 3mm) Plastic DFN -40C to 125C LT1763MPDE-5#PBF LT1763MPDE-5#TRPBF 17635 12-Lead (4mm x 3mm) Plastic DFN -55C to 125C LT1763CS8#PBF LT1763CS8#TRPBF 1763 8-Lead Plastic SO -40C to 125C LT1763IS8#PBF LT1763IS8#TRPBF 1763 8-Lead Plastic SO -40C to 125C LT1763MPS8#PBF LT1763MPS8#TRPBF 1763MP 8-Lead Plastic SO -55C to 125C LT1763CS8-1.5#PBF LT1763CS8-1.5#TRPBF 176315 8-Lead Plastic SO -40C to 125C LT1763IS8-1.5#PBF LT1763IS8-1.5#TRPBF 176315 8-Lead Plastic SO -40C to 125C LT1763CS8-1.8#PBF LT1763CS8-1.8#TRPBF 176318 8-Lead Plastic SO -40C to 125C LT1763IS8-1.8#PBF LT1763IS8-1.8#TRPBF 176318 8-Lead Plastic SO -40C to 125C LT1763CS8-2.5#PBF LT1763CS8-2.5#TRPBF 176325 8-Lead Plastic SO -40C to 125C LT1763IS8-2.5#PBF LT1763IS8-2.5#TRPBF 176325 8-Lead Plastic SO -40C to 125C LT1763MPS8-2.5#PBF LT1763MPS8-2.5#TRPBF 176325 8-Lead Plastic SO -55C to 125C LT1763CS8-3#PBF LT1763CS8-3#TRPBF 17633 8-Lead Plastic SO -40C to 125C LT1763IS8-3#PBF LT1763IS8-3#TRPBF 17633 8-Lead Plastic SO -40C to 125C LT1763CS8-3.3#PBF LT1763CS8-3.3#TRPBF 176333 8-Lead Plastic SO -40C to 125C LT1763IS8-3.3#PBF LT1763IS8-3.3#TRPBF 176333 8-Lead Plastic SO -40C to 125C LT1763CS8-5#PBF LT1763CS8-5#TRPBF 17635 8-Lead Plastic SO -40C to 125C LT1763IS8-5#PBF LT1763IS8-5#TRPBF 17635 8-Lead Plastic SO -40C to 125C LT1763MPS8-5#PBF LT1763MPS8-5#TRPBF 17635 8-Lead Plastic SO -55C to 125C Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. Consult LTC Marketing for information on nonstandard lead based finish parts. 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/ 1763fh For more information www.linear.com/LT1763 3 LT1763 Series Electrical Characteristics The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. (Note 2) PARAMETER CONDITIONS Minimum Operating Voltage C, I Grade: ILOAD = 500mA (Notes 3, 11) MP Grade: ILOAD = 500mA (Notes 3, 11) Regulated Output Voltage (Note 4) LT1763-1.5 LT1763-1.8 LT1763-2.5 LT1763-3 LT1763-3.3 LT1763-5 MIN l l V V VIN = 2.3V, ILOAD = 1mA 2.8V < VIN < 20V, 1mA < ILOAD < 500mA l 1.782 1.755 1.8 1.8 1.818 1.845 V V VIN = 3V, ILOAD = 1mA 3.5V < VIN < 20V, 1mA < ILOAD < 500mA l 2.475 2.435 2.5 2.5 2.525 2.565 V V VIN = 3.5V, ILOAD = 1mA 4V < VIN < 20V, 1mA < ILOAD < 500mA l 2.970 2.925 3 3 3.030 3.075 V V VIN = 3.8V, ILOAD = 1mA 4.3V < VIN < 20V, 1mA < ILOAD < 500mA l 3.267 3.220 3.3 3.3 3.333 3.380 V V VIN = 5.5V, ILOAD = 1mA 6V < VIN < 20V, 1mA < ILOAD < 500mA l 4.950 4.875 5 5 5.050 5.125 V V VIN = 2.2V, ILOAD = 1mA C, I Grade: 2.3V < VIN < 20V, 1mA < ILOAD < 500mA MP Grade: 2.35V < VIN < 20V, 1mA < ILOAD < 500mA l l 1.208 1.190 1.190 1.220 1.220 1.220 1.232 1.250 1.250 V V V 1 1 1 1 1 1 1 1 1 5 5 5 5 5 5 5 5 5 mV mV mV mV mV mV mV mV mV 3 8 15 mV mV 4 9 18 mV mV 5 12 25 mV mV 7 15 30 mV mV 7 17 33 mV mV 12 25 50 mV mV 2 6 12 12 mV mV mV 0.13 0.19 0.25 V V 0.17 0.22 0.32 V V 0.20 0.24 0.34 V V 0.30 0.35 0.45 V V l l l l l l l l l Load Regulation LT1763-1.5 VIN = 2.5V, ILOAD = 1mA to 500mA VIN = 2.5V, ILOAD = 1mA to 500mA l VIN = 2.8V, ILOAD = 1mA to 500mA VIN = 2.8V, ILOAD = 1mA to 500mA l VIN = 3.5V, ILOAD = 1mA to 500mA VIN = 3.5V, ILOAD = 1mA to 500mA l VIN = 4V, ILOAD = 1mA to 500mA VIN = 4V, ILOAD = 1mA to 500mA l VIN = 4.3V, ILOAD = 1mA to 500mA VIN = 4.3V, ILOAD = 1mA to 500mA l VIN = 6V, ILOAD= 1mA to 500mA VIN = 6V, ILOAD = 1mA to 500mA l Dropout Voltage VIN = VOUT(NOMINAL) (Notes 5, 6, 11) 4 V V 1.515 1.538 C, I Grade: VIN = 2V to 20V, ILOAD = 1mA MP Grade: VIN = 2.1V 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 C, I Grade: VIN = 2V to 20V, ILOAD = 1mA MP Grade: VIN = 2.1V to 20V, ILOAD = 1mA LT1763-5 2.3 2.35 1.5 1.5 LT1763-1.5 LT1763-1.5 LT1763-1.8 LT1763-2.5 LT1763-3 LT1763-3.3 LT1763-5 LT1763 (Note 3) LT1763 (Note 3) LT1763-3.3 1.8 1.8 1.485 1.462 Line Regulation LT1763-3 UNITS l LT1763 LT1763-2.5 MAX VIN = 2V, ILOAD = 1mA 2.5V < VIN < 20V, 1mA < ILOAD < 500mA ADJ Pin Voltage (Notes 3, 4) LT1763-1.8 TYP LT1763 (Note 3) VIN = 2.3V, ILOAD = 1mA to 500mA C, I Grade: VIN = 2.3V, ILOAD = 1mA to 500mA MP Grade: VIN = 2.35V, ILOAD = 1mA to 500mA l l ILOAD = 10mA ILOAD = 10mA l ILOAD = 50mA ILOAD = 50mA l ILOAD = 100mA ILOAD = 100mA l ILOAD = 500mA ILOAD = 500mA l 1763fh For more information www.linear.com/LT1763 LT1763 Series Electrical Characteristics The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. (Note 2) PARAMETER CONDITIONS GND Pin Current VIN = VOUT(NOMINAL) (Notes 5, 7) ILOAD = 0mA ILOAD = 1mA ILOAD = 50mA ILOAD = 100mA ILOAD = 250mA ILOAD = 500mA MIN Output Voltage Noise COUT = 10F, CBYP = 0.01F, ILOAD = 500mA, BW = 10Hz to 100kHz 20 ADJ Pin Bias Current (Notes 3, 8) 30 100 nA Shutdown Threshold VOUT = Off to On VOUT = On to Off 0.8 0.65 2 V V SHDN Pin Current (Note 9) VSHDN = 0V VSHDN = 20V 0.1 1 Quiescent Current in Shutdown VIN = 6V, VSHDN = 0V 0.1 Ripple Rejection VIN - VOUT = 1.5V (Avg), VRIPPLE = 0.5VP-P, fRIPPLE = 120Hz, ILOAD = 500mA Current Limit VIN = 7V, VOUT = 0V C, I Grade: VIN = VOUT(NOMINAL) + 1V or 2.3V (Note 12), VOUT = -0.1V MP Grade: VIN = 2.35V (Note 12), VOUT = -0.1V l l Input Reverse Leakage Current VIN = -20V, VOUT = 0V l Reverse Output Current (Note 10) LT1763-1.5 LT1763-1.8 LT1763-2.5 LT1763-3 LT1763-3.3 LT1763-5 LT1763 (Note 3) l l l l l l l l 50 MAX UNITS 30 65 1.1 2 5 11 75 120 1.6 3 8 16 A A mA mA mA mA VRMS A A 1 65 A dB 520 520 mA mA 10 10 10 10 10 10 5 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: 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 = 25C; performance at -40C and 125C is assured by design, characterization and correlation with statistical process controls. The LT1763 (I grade) is guaranteed over the full -40C to 125C operating junction temperature range. The LT1763 (MP grade) is 100% tested and guaranteed over the -55C to 125C 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 5A DC load on the output. 0.25 TYP 1 mA 20 20 20 20 20 20 10 A A A A A A A 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. 1763fh For more information www.linear.com/LT1763 5 LT1763 Series Typical Performance Characteristics DROPOUT VOLTAGE (mV) 450 TJ = 125C 350 300 250 TJ = 25C 200 150 100 50 0 = TEST POINTS 450 450 400 TJ 125C 350 300 TJ 25C 250 200 150 100 1.528 45 1.521 20 15 10 VIN = 6V 5 RL = , IL = 0 (LT1763-1.5/-1.8/-2.5/-3/-3.3/-5) RL = 250k, IL = 5A (LT1763) 0 0 25 50 75 100 125 -50 -25 1.507 1.500 1.493 1.486 1.472 -50 -25 0 25 50 75 2.50 2.49 2.48 2.47 50 75 100 125 125 1.81 1.80 1.79 1.78 -25 0 25 50 75 125 1763 G06 LT1763-3.3 Output Voltage 3.360 IL = 1mA 3.345 3.030 3.015 3.000 2.985 2.970 2.940 -50 100 TEMPERATURE (C) IL = 1mA 3.330 3.315 3.300 3.285 3.270 3.255 -25 0 25 50 75 100 125 3.240 -50 -25 0 25 50 75 100 125 TEMPERATURE (C) TEMPERATURE (C) 1763 G07 100 IL = 1mA 1.76 -50 125 2.955 TEMPERATURE (C) 6 100 OUTPUT VOLTAGE (V) OUTPUT VOLTAGE (V) OUTPUT VOLTAGE (V) 2.51 50 25 0 75 TEMPERATURE (C) IL = 1mA 1.82 LT1763-3 Output Voltage 2.52 IL = 10mA 1763 G05 3.045 25 -25 TEMPERATURE (C) 3.060 0 IL = 50mA 1.77 1.479 IL = 1mA -25 100 1.83 1.514 LT1763-2.5 Output Voltage 2.46 -50 150 1.84 1763 G04 2.53 200 LT1763-1.8 Output Voltage IL = 1mA TEMPERATURE (C) 2.54 250 1763 G03 OUTPUT VOLTAGE (V) OUTPUT VOLTAGE (V) QUIESCENT CURRENT (A) 40 25 IL = 100mA 300 LT1763-1.5 Output Voltage 50 30 350 1763 G02 Quiescent Current VSHDN = VIN IL = 500mA IL = 250mA 0 -50 50 100 150 200 250 300 350 400 450 500 OUTPUT CURRENT (mA) 0 1763 G01 35 400 50 50 0 50 100 150 200 250 300 350 400 450 500 OUTPUT CURRENT (mA) 0 500 DROPOUT VOLTAGE (mV) GUARANTEED DROPOUT VOLTAGE (mV) 500 400 Dropout Voltage Guaranteed Dropout Voltage Typical Dropout Voltage 500 1763 G08 1763 G09 1763fh For more information www.linear.com/LT1763 LT1763 Series Typical Performance Characteristics LT1763-5 Output Voltage IL = 1mA 1.235 5.050 ADJ PIN VOLTAGE (V) OUTPUT VOLTAGE (V) 250 1.240 IL = 1mA 5.075 LT1763-1.5 Quiescent Current 5.025 5.000 4.975 4.950 4.925 1.230 1.225 1.220 1.215 1.210 1.205 4.900 -50 0 -25 25 50 75 100 125 1.200 -50 0 -25 25 50 75 100 150 125 100 75 VSHDN = VIN 3 4 5 6 7 INPUT VOLTAGE (V) 200 150 125 100 75 50 8 9 0 10 VSHDN = VIN 0 1 2 3 4 5 6 7 INPUT VOLTAGE (V) 100 75 VSHDN = VIN 8 9 10 1 2 3 4 5 6 7 INPUT VOLTAGE (V) 8 9 10 1763 G16 SHDN TJ = 25C RL = 150 125 100 75 50 VSHDN = VIN VSHDN = 0V 0 1 2 3 4 5 6 7 INPUT VOLTAGE (V) 8 9 10 40 200 150 125 100 75 50 VSHDN = VIN 1 2 3 4 5 6 7 INPUT VOLTAGE (V) 8 30 VSHDN = VIN 25 20 15 10 5 VSHDN = 0V 0 TJ = 25C RL = 250k 35 175 0 10 1763 G15 TJ = 25C RL = 25 VSHDN = 0V 9 8 175 0 QUIESCENT CURRENT (A) QUIESCENT CURRENT (A) QUIESCENT CURRENT (A) 125 3 4 5 6 7 INPUT VOLTAGE (V) LT1763 Quiescent Current 225 150 0 2 25 VSHDN = 0V 250 TJ = 25C RL = 175 0 1 200 LT1763-5 Quiescent Current 250 25 0 1763 G14 LT1763-3.3 Quiescent Current 200 VSHDN = 0V 225 175 1763 G13 225 VSHDN = VIN 250 TJ = 25C RL = 25 VSHDN = 0V 50 50 1763 G12 QUIESCENT CURRENT (A) 175 2 75 LT1763-3 Quiescent Current 225 QUIESCENT CURRENT (A) QUIESCENT CURRENT (A) 200 1 100 0 125 250 TJ = 25C RL = 0 125 LT1763-2.5 Quiescent Current 250 0 150 1763 G11 LT1763-1.8 Quiescent Current 25 175 TEMPERATURE (C) 1763 G10 50 200 25 TEMPERATURE (C) 225 TJ = 25C RL = 225 QUIESCENT CURRENT (A) 5.100 LT1763 ADJ Pin Voltage 9 10 1763 G17 0 VSHDN = 0V 0 2 4 6 8 10 12 14 16 18 20 INPUT VOLTAGE (V) 1763 G18 1763fh For more information www.linear.com/LT1763 7 LT1763 Series Typical Performance Characteristics LT1763-1.8 GND Pin Current LT1763-1.5 GND Pin Current 1200 1200 1200 800 TJ = 25C VIN = VSHDN *FOR VOUT = 1.5V 600 RL = 150 IL = 10mA* 400 RL = 1.5k IL = 1mA* 200 0 1 2 1000 RL = 36 IL = 50mA* 800 8 9 RL = 180 IL = 10mA* 400 0 10 TJ = 25C VIN = VSHDN *FOR VOUT = 1.8V 600 200 3 4 5 6 7 INPUT VOLTAGE (V) RL = 1.8k IL = 1mA* 0 1 2 3 4 5 6 7 INPUT VOLTAGE (V) 8 1763 G19 TJ = 25C VIN = VSHDN *FOR VOUT = 3V 600 400 RL = 300 IL = 10mA* 200 RL = 3k IL = 1mA* 1 2 3 4 5 6 7 INPUT VOLTAGE (V) 8 9 800 400 RL = 330 IL = 10mA* 200 RL = 3.3k IL = 1mA* 0 10 TJ = 25C VIN = VSHDN *FOR VOUT = 3.3V 600 1200 0 1 2 GND PIN CURRENT (mA) GND PIN CURRENT (A) RL = 122 IL = 10mA* 400 RL = 1.22k IL = 1mA* 200 0 1 2 3 4 5 6 7 INPUT VOLTAGE (V) 9 10 1763 G25 8 RL = 3 IL = 500mA* 8 8 9 8 10 TJ = 25C VIN = VSHDN *FOR VOUT = 5V RL = 500 IL = 10mA* 400 RL = 5k IL = 1mA* 0 1 2 3 4 5 6 7 INPUT VOLTAGE (V) 8 12 1 2 10 3 4 5 6 7 INPUT VOLTAGE (V) TJ = 25C VIN = VSHDN *FOR VOUT = 1.8V 10 RL = 15 IL = 100mA* 0 9 1763 G24 TJ = 25C VIN = VSHDN *FOR VOUT = 1.5V 4 0 9 RL = 100 IL = 50mA* 600 0 10 RL = 5 IL = 300mA* 6 2 8 3 4 5 6 7 INPUT VOLTAGE (V) LT1763-1.8 GND Pin Current 10 TJ = 25C VIN = VSHDN *FOR VOUT = 1.22V 2 200 3 4 5 6 7 INPUT VOLTAGE (V) 12 600 1 800 LT1763-1.5 GND Pin Current RL = 24.4 IL = 50mA* 0 1763 G23 LT1763 GND Pin Current 800 RL = 2.5k IL = 1mA* 1000 RL = 66 IL = 50mA* 1763 G22 1000 200 LT1763-5 GND Pin Current GND PIN CURRENT (mA) 0 RL = 250 IL = 10mA* 1763 G21 GND PIN CURRENT (A) GND PIN CURRENT (A) GND PIN CURRENT (A) 800 400 1200 1000 RL = 60 IL = 50mA* TJ = 25C VIN = VSHDN *FOR VOUT = 2.5V 600 0 10 1200 1000 800 LT1763-3.3 GND Pin Current 1200 0 9 RL = 50 IL = 50mA* 1763 G20 LT1763-3 GND Pin Current 0 GND PIN CURRENT (A) 1000 RL = 30 IL = 50mA* GND PIN CURRENT (A) GND PIN CURRENT (A) 1000 0 LT1763-2.5 GND Pin Current RL = 3.6 IL = 500mA* 8 RL = 6 IL = 300mA* 6 4 RL = 18 IL = 100mA* 2 8 9 10 1763 G26 0 0 1 2 3 4 5 6 7 INPUT VOLTAGE (V) 8 9 10 1763 G27 1763fh For more information www.linear.com/LT1763 LT1763 Series Typical Performance Characteristics RL = 5 IL = 500mA* 8 6 RL = 8.33 IL = 300mA* 4 RL = 25 IL = 100mA* 2 0 0 1 2 3 4 5 6 7 INPUT VOLTAGE (V) 8 6 RL = 10 IL = 300mA* 4 0 10 RL = 30 IL = 100mA* 0 1 2 3 4 5 6 7 INPUT VOLTAGE (V) 8 1763 G28 12 RL = 10 IL = 500mA* 10 8 RL = 16.7 IL = 300mA* 6 4 RL = 50 IL = 100mA* 2 0 0 1 2 3 4 5 6 7 INPUT VOLTAGE (V) 8 9 RL = 2.44 IL = 500mA* 8 0.3 0.2 0.1 RL = 12.2 IL = 100mA* 100 125 1763 G34 8 0 1 2 3 4 5 6 7 INPUT VOLTAGE (V) 8 9 10 8 6 4 0 10 0 50 100 150 200 250 300 350 400 450 500 OUTPUT CURRENT (mA) 1763 G33 SHDN Pin Input Current 1.4 0.8 IL = 500mA 0.7 0.6 0.5 IL = 1mA 0.4 0.3 0.2 0 -50 9 2 0.1 50 25 0 75 TEMPERATURE (C) 3 4 5 6 7 INPUT VOLTAGE (V) 1763 G32 SHDN PIN THRESHOLD (V) SHDN PIN THRESHOLD (V) 0.4 2 VIN = VOUT(NOMINAL) + 1V 0.9 0.5 1 10 1.0 0.6 0 1763 G30 SHDN Pin Threshold (Off-to-On) 0.7 RL = 33 IL = 100mA* 12 4 0 10 0.8 -25 0 10 RL = 4.07 IL = 300mA* 2 IL = 1mA 0 -50 9 TJ = 25C VIN = VSHDN *FOR VOUT = 1.22V 6 SHDN Pin Threshold (On-to-Off) 0.9 4 GND Pin Current vs ILOAD 1763 G31 1.0 RL = 11 IL = 300mA* 2 SHDN PIN INPUT CURRENT (A) GND PIN CURRENT (mA) 10 6 LT1763 GND Pin Current GND PIN CURRENT (mA) TJ = 25C VIN = VSHDN *FOR VOUT = 5V RL = 6.6 IL = 500mA* 8 1763 G29 LT1763-5 GND Pin Current 12 TJ = 25C VIN = VSHDN *FOR VOUT = 3.3V 10 RL = 6 IL = 500mA* 8 2 9 12 TJ = 25C VIN = VSHDN *FOR VOUT = 3V 10 GND PIN CURRENT (mA) GND PIN CURRENT (mA) 12 TJ = 25C VIN = VSHDN *FOR VOUT = 2.5V 10 LT1763-3.3 GND Pin Current GND PIN CURRENT (mA) 12 LT1763-3 GND Pin Current GND PIN CURRENT (mA) LT1763-2.5 GND Pin Current -25 50 25 0 75 TEMPERATURE (C) 100 125 1763 G35 1.2 1.0 0.8 0.6 0.4 0.2 0 0 1 2 3 4 5 6 7 8 SHDN PIN VOLTAGE (V) 9 10 1763 G36 1763fh For more information www.linear.com/LT1763 9 LT1763 Series Typical Performance Characteristics ADJ Pin Bias Current SHDN Pin Input Current VSHDN = 20V 1.4 Current Limit 1.0 140 1.0 0.8 0.6 0.4 0.8 100 CURRENT LIMIT (A) 1.2 80 60 40 -25 0 25 50 75 100 125 50 25 0 75 TEMPERATURE (C) -25 TEMPERATURE (C) 100 Current Limit REVERSE OUTPUT CURRENT (A) CURRENT LIMIT (A) 100 VIN = 7 VOUT = 0V 1.0 0.8 0.6 0.4 0.2 TJ = 25C, VIN = 0V CURRENT FLOWS INTO OUTPUT PIN VOUT = VADJ (LT1763) 90 80 70 0.3 0 125 50 25 0 75 TEMPERATURE (C) 100 50 40 30 LT1763-2.5 LT1763-3 LT1763-3.3 LT1763-5 0 1 2 3 4 5 6 7 8 OUTPUT VOLTAGE (V) 9 10 8 4 0 -50 10 70 CBYP = 0.01F 66 60 64 10 0 10 100 RIPPLE REJECTION (dB) COUT = 4.7F 1k 10k FREQUENCY (Hz) 100k 40 1M CBYP = 100pF 30 20 IL = 500mA VIN = VOUT(NOMINAL) + 1V + 50mVRMS RIPPLE COUT = 10F 10 1763 G43 10 50 CBYP = 1000pF RIPPLE REJECTION (dB) 70 IL = 500mA VIN = VOUT(NOMINAL) + 1V + 50mVRMS RIPPLE CBYP = 0 50 25 0 75 TEMPERATURE (C) 0 10 100 1k 10k FREQUENCY (Hz) 100 125 Ripple Rejection 68 20 -25 1763 G42 Input Ripple Rejection 30 LT1763 2 80 40 LT1763-1.5/-1.8/ -2.5/-3/-3.3/-5 6 1763 G41 Input Ripple Rejection 7 6 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) 80 50 4 3 2 5 INPUT VOLTAGE (V) 1763 G39 LT1763-1.5 1763 G40 COUT = 10F 1 Reverse Output Current 20 0 125 60 0 20 LT1763 LT1763-1.8 60 10 RIPPLE REJECTION (dB) 0.4 Reverse Output Current 1.2 -25 0.5 1763 G38 1763 G37 0 -50 0.6 0.1 0 -50 REVERSE OUTPUT CURRENT (A) 0 -50 0.7 0.2 20 0.2 VOUT = 0V 0.9 120 ADJ PIN BIAS CURRENT (nA) SHDN PIN INPUT CURRENT (A) 1.6 62 60 58 56 54 100k 1M 52 -50 VIN = VOUT (NOMINAL) + 1V + 0.5VP-P RIPPLE AT f = 120Hz IL = 500mA -25 0 25 50 75 100 125 TEMPERATURE (C) 1763 G44 1763 G45 1763fh For more information www.linear.com/LT1763 LT1763 Series Typical Performance Characteristics LT1763 Minimum Input Voltage 2.25 0 LOAD REGULATION (mV) IL = 500mA 1.75 IL = 1mA 1.50 1.25 1.00 0.75 0.50 LT1763-3 -10 LT1763-3.3 LT1763-5 -15 VIN = VOUT(NOMINAL) + 1V IL = 1mA TO 500mA VOUT = 1.22V 0 -50 50 25 0 75 TEMPERATURE (C) -25 100 -25 -50 125 LT1763-1.8 -5 -20 0.25 LT1763-1.5 -25 0 25 50 75 CBYP = 0.01F OUTPUT NOISE (VRMS) OUTPUT NOISE SPECTRAL DENSITY (V/Hz) LT1763 100 1k 10k FREQUENCY (Hz) LT1763-3.3 100 LT1763-3 80 LT1763-2.5 60 40 LT1763 LT1763-1.8 LT1763-1.5 100k 0 10 100 100 140 120 100k COUT = 10F CBYP = 0 CBYP = 0.01F LT1763-5 100 80 60 LT1763 40 LT1763-5 1000 10000 0 0.01 LT1763 0.1 10 100 1 LOAD CURRENT (mA) 1763 G50 1000 1763 G51 LT1763-5 10Hz to 100kHz Output Noise CBYP = 1000pF LT1763-5 10Hz to 100kHz Output Noise CBYP = 100pF VOUT 100V/DIV VOUT 100V/DIV 1k 10k FREQUENCY (Hz) 1763 G48 CBYP (pF) LT1763-5 10Hz to 100kHz Output Noise CBYP = 0 1ms/DIV 0.01 10 20 1763 G49 COUT = 10F IL = 500mA COUT = 10F IL = 500mA RMS Output Noise vs Load Current (10Hz to 100kHz) LT1763-5 120 20 0.01 10 LT1763-2.5 LT1763-1.5 LT1763-1.8 0.1 COUT = 10F IL = 500mA f = 10Hz TO 100kHz 140 CBYP = 100pF 0.1 LT1763 160 160 COUT = 10F IL = 500mA 1 1 RMS Output Noise vs Bypass Capacitor CBYP = 1000pF LT1763-3.3 1763 G47 Output Noise Spectral Density LT1763-5 LT1763-3 LT1763-5 TEMPERATURE (C) 1763 G46 10 125 100 10 OUTPUT NOISE (VRMS) 2.00 LT1763-2.5 LT1763 OUTPUT NOISE SPECTRAL DENSITY (V/Hz) 5 2.50 MINIMUM INPUT VOLTAGE (V) Output Noise Spectral Density CBYP = 0 Load Regulation VOUT 100V/DIV 1763 G52 COUT = 10F IL = 500mA 1ms/DIV 1763 G53 COUT = 10F IL = 500mA 1ms/DIV 1763 G54 1763fh For more information www.linear.com/LT1763 11 LT1763 Series Typical Performance Characteristics 0.2 OUTPUT VOLTAGE DEVIATION (V) VIN = 6V CIN = 10F COUT = 10F 0.4 0 -0.2 -0.4 600 400 200 0 0 200 400 600 TIME (s) 800 1000 1763 G56 12 VIN = 6V CIN = 10F COUT = 10F 0.10 0.05 0 -0.05 -0.10 LOAD CURRENT (mA) OUTPUT VOLTAGE DEVIATION (V) COUT = 10F IL = 500mA 1763 G55 LOAD CURRENT (mA) VOUT 100V/DIV 1ms/DIV LT1763-5 Transient Response CBYP = 0.01F LT1763-5 Transient Response CBYP = 0 LT1763-5 10Hz to 100kHz Output Noise CBYP = 0.01F 600 400 200 0 0 10 20 30 40 50 60 70 80 90 100 TIME (s) 1763 G57 1763fh For more information www.linear.com/LT1763 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 3.3F 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 VIN + IN OUT 1 RP LT1763 5 SHDN SENSE GND + 2 LOAD 3 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 10A 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. 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 0.01F can be used for reducing output voltage noise to a typical 20VRMS over a 10Hz to 100kHz bandwidth. If not used, this pin must be left unconnected. GND (Pins 7, Exposed Pad Pin 13/Pins 3, 6, 7): Ground. The exposed pad of the DFN package is an electrical connection to GND. To ensure proper electrical and thermal performance, solder Pin 13 to the PCB ground and tie directly to Pin 7. Connect the bottom of the output voltage setting resistor divider directly to the GND pins for optimum load regulation performance. 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 1A. 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 1F to 10F 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. 1763fh For more information www.linear.com/LT1763 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 20VRMS over a 10Hz to 100kHz bandwidth with the addition of a 0.01F 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 (30A) drops to less than 1A 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 25C, 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. 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 OUT IN VIN R2 LT1763 GND ADJ R1 1763 F02 + VOUT R2 VOUT = 1.22V 1 + + (IADJ )(R2) R1 VADJ = 1.22V IADJ = 30nA AT 25C 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 20VRMS with the addition of a 0.01F bypass capacitor. Using a bypass capacitor has the added benefit of improving transient response. With no bypass capacitor and a 10F output capacitor, a 10mA to 500mA load step will settle to within 1% of its final value in less than 100s. With the addition of a 0.01F bypass capacitor, the output will settle to within 1% for a 10mA to 500mA load step in less than 10s, 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 0.01F bypass capacitor and 10F output capacitor. 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 14 1763fh For more information www.linear.com/LT1763 LT1763 Series Applications Information 4.0 Output Capacitance and Transient Response 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 10F Y5V capacitor can exhibit an effective value as low as 1F to 2F 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 3.0 STABLE REGION ESR () 2.5 2.0 CBYP = 0 CBYP = 100pF 1.5 1.0 0.5 0 CBYP = 330pF CBYP 1000pF 3 2 4 5 6 7 8 9 10 OUTPUT CAPACITANCE (F) 1763 F03 1 Figure 3. Stability 20 BOTH CAPACITORS ARE 16V, 1210 CASE SIZE, 10F 0 CHANGE IN VALUE (%) 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 3. 3.5 X5R -20 -40 -60 Y5V -80 -100 0 2 4 6 8 10 14 12 DC BIAS VOLTAGE (V) 16 1763 F04 Figure 4. Ceramic Capacitor DC Bias Characteristics 40 20 CHANGE IN VALUE (%) 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 3.3F with an ESR of 3, 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, 4.7F of output capacitor is recommended. With a 1000pF bypass capacitor or larger, a 6.8F output capacitor is recommended. X5R 0 -20 -40 Y5V -60 -80 BOTH CAPACITORS ARE 16V, 1210 CASE SIZE, 10F -100 -50 -25 50 25 75 0 TEMPERATURE (C) 100 125 1763 F05 Figure 5. Ceramic Capacitor Temperature Characteristics 1763fh For more information www.linear.com/LT1763 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. Thermal Considerations 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. 1. Output current multiplied by the input/output voltage differential: (IOUT)(VIN - VOUT), and LT1763-5 COUT = 10F CBYP = 0.01F ILOAD = 100mA The power handling capability of the device will be limited by the maximum rated junction temperature (125C). The power dissipated by the device will be made up of two components: 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 125C 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. VOUT 500V/DIV 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* BACKSIDE BOARD AREA THERMAL RESISTANCE (JUNCTION-TO-AMBIENT) 2500mm2 2500mm2 2500mm2 40C/W 1000mm2 2500mm2 2500mm2 45C/W 225mm2 2500mm2 2500mm2 50C/W 100mm2 2500mm2 2500mm2 60C/W * Device is mounted on topside 16 1763fh For more information www.linear.com/LT1763 LT1763 Series Applications Information Protection Features Table 2. SO-8 Package, 8-Lead SO COPPER AREA TOPSIDE* BACKSIDE BOARD AREA THERMAL RESISTANCE (JUNCTION-TO-AMBIENT) 2500mm2 2500mm2 2500mm2 60C/W 1000mm2 2500mm2 2500mm2 60C/W 225mm2 2500mm2 2500mm2 68C/W 100mm2 2500mm2 2500mm2 74C/W 50mm2 2500mm2 2500mm2 86C/W * 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 50C, 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 60C/W to 86C/W, depending on the copper area. So, the junction temperature rise above ambient will be approximately equal to: 0.71W(75C/W) = 53.3C The maximum junction temperature will then be equal to the maximum junction temperature rise above ambient plus the maximum ambient temperature, or : TJMAX = 50C + 53.3C = 103.3C 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 125C. 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 100A) 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 100A. 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. 1763fh For more information www.linear.com/LT1763 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. 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 2A. 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. REVERSE OUTPUT CURRENT (A) 100 TJ = 25C 90 VIN = 0V CURRENT FLOWS 80 INTO OUTPUT PIN 70 VOUT = VADJ (LT1763) LT1763 60 LT1763-1.8 50 LT1763-2.5 LT1763-1.5 LT1763-3 40 30 20 LT1763-5 10 0 LT1763-3.3 0 1 2 3 4 5 6 7 8 OUTPUT VOLTAGE (V) 9 10 1763 F07 Figure 7. Reverse Output Current 18 1763fh For more information www.linear.com/LT1763 LT1763 Series Package Description DE/UE Package 12-Lead Plastic DFN (4mm x 3mm) (Reference LTC DWG # 05-08-1695 Rev D) 0.70 0.05 3.60 0.05 2.20 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 4.00 0.10 (2 SIDES) 7 R = 0.115 TYP 0.40 0.10 12 R = 0.05 TYP PIN 1 TOP MARK (NOTE 6) 0.200 REF 3.30 0.10 3.00 0.10 (2 SIDES) 1.70 0.10 0.75 0.05 6 0.25 0.05 1 PIN 1 NOTCH R = 0.20 OR 0.35 x 45 CHAMFER (UE12/DE12) DFN 0806 REV D 0.50 BSC 2.50 REF 0.00 - 0.05 BOTTOM VIEW--EXPOSED PAD NOTE: 1. DRAWING PROPOSED TO BE A VARIATION OF VERSION (WGED) IN JEDEC PACKAGE OUTLINE M0-229 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE 1763fh For more information www.linear.com/LT1763 19 LT1763 Series Package Description Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. S8 Package 8-Lead Plastic Small Outline (Narrow .150 Inch) (Reference LTC DWG # 05-08-1610 Rev G) .189 - .197 (4.801 - 5.004) NOTE 3 .045 .005 .050 BSC 8 .245 MIN .160 .005 .010 - .020 x 45 (0.254 - 0.508) 2 .053 - .069 (1.346 - 1.752) 0- 8 TYP .016 - .050 (0.406 - 1.270) .014 - .019 (0.355 - 0.483) 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) 4. PIN 1 CAN BE BEVEL EDGE OR A DIMPLE 20 5 .150 - .157 (3.810 - 3.988) NOTE 3 1 RECOMMENDED SOLDER PAD LAYOUT .008 - .010 (0.203 - 0.254) 6 .228 - .244 (5.791 - 6.197) .030 .005 TYP NOTE: 1. DIMENSIONS IN 7 3 4 .004 - .010 (0.101 - 0.254) .050 (1.270) BSC SO8 REV G 0212 1763fh For more information www.linear.com/LT1763 LT1763 Series Revision History (Revision history begins at Rev G) REV DATE DESCRIPTION G 5/10 Updated Order Information to add MP-grade to all versions of DFN package H 11/14 PAGE NUMBER 2 to 4 Revised Line Regulation section of Electrical Characteristics 5 Consolidated GND and exposed pad descriptions in Pin Descriptions section 14 Added LT3085 to Related Parts 22 Updated Order Information Table to add MP-grade to LT1763-2.5 and LT1763-5 in SO-8 package. 2-3 1763fh 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. For more information www.linear.com/LT1763 21 LT1763 Series Typical Application Paralleling of Regulators for Higher Output Current R1 0.1 VIN > 3.8V + IN C1 10F OUT SENSE LT1763-3.3 C4 0.01F SHDN BYP GND R2 0.1 IN OUT C5 0.01F LT1763 SHDN R3 2.2k SHDN GND R4 2.2k 3 2 + BYP ADJ 8 4 3.3V 1A C2 10F R6 2k R7 1.21k 1/2 LT1490 - + 1 R5 10k C3 0.01F 1763 TA03 Related Parts PART NUMBER DESCRIPTION COMMENTS LT1120 125mA Low Dropout Regulator with 20A IQ Includes 2.5V Reference and Comparator LT1121 150mA Micropower Low Dropout Regulator 30A IQ , SOT-223 Package LT1129 700mA Micropower Low Dropout Regulator 50A Quiescent Current LT1175 500mA Negative Low Dropout Micropower Regulator 45A IQ , 0.26V Dropout Voltage, SOT-223 Package LT1521 300mA Low Dropout Micropower Regulator with Shutdown 15A IQ , Reverse Battery Protection LT1529 3A Low Dropout Regulator with 50A IQ 500mV Dropout Voltage LT1613 1.4MHz Single-Cell Micropower DC/DC Converter SOT-23 Package, Internally Compensated LT1761 Series 100mA, Low Noise, Low Dropout Micropower Regulators in SOT-23 20A Quiescent Current, 20VRMS Noise, ThinSOTTM LT1762 Series 150mA, Low Noise, LDO Micropower Regulators 25A Quiescent Current, 20VRMS Noise, MS8 LT1764A 3A, Fast Transient Response Low Dropout Regulator 340mV Dropout Voltage, DD, TO220 LT1962 300mA, Fast Transient Response Low Dropout Regulator 270mV Dropout Voltage, 20VRML , MS8 LT1963A 1.5A, Fast Transient Response Low Dropout Regulator 340mV Dropout Voltage, 40VRML , DD, TO220, S8, SOT-223 LT3010 50mA, 80V Low Noise, LDO Micropower Regulator 300mV Dropout Voltage, MS8E LT3021 500mA, Low Voltage, Very Low Dropout Linear Regulator 160mV Dropout Voltage, DFN-8 and SOIC-8 Packages LT3085 500mA Parallelable, Low Noise, Low Dropout Linear Regulator 275mV Dropout Voltage (2 Supply Operation), MSOP-8 and 2mm x 3mm DFN-6 Packages 22 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 For more information www.linear.com/LT1763 (408) 432-1900 FAX: (408) 434-0507 www.linear.com/LT1763 1763fh LT 1114 REV H * PRINTED IN USA LINEAR TECHNOLOGY CORPORATION 1999