LT3970 LINER [Linear Technology], LT3970 Datasheet
LT3970
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LT3970 Summary of contents
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FeaTures Ultralow Quiescent Current n 2.5µ 12V to 3. OUT Low Ripple Burst Mode Operation ® n Output Ripple < 10mV P-P Wide Input Voltage Range: 4.2V to 42V Operating n Adjustable Switching Frequency: 200kHz to ...
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LT3973/LT3973-3.3/LT3973-5 absoluTe maximum raTings V , EN/UVLO Voltage ...............................................42V IN BOOST Pin Voltage ...................................................55V BOOST Pin Above SW Pin .........................................25V FB/V , RT, PG Voltage ..............................................6V OUT BD Voltage ................................................................25V OUT Voltage ..............................................................14V pin conFiguraTion TOP VIEW *FB/V 1 OUT ...
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LEAD FREE FINISH TAPE AND REEL LT3973EDD-5#PBF LT3973EDD-5#TRPBF LT3973IDD-5#PBF LT3973IDD-5#TRPBF LT3973HDD-5#PBF LT3973HDD-5#TRPBF 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 ...
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LT3973/LT3973-3.3/LT3973-5 elecTrical characTerisTics temperature range, otherwise specifications are at T EN/UVLO Voltage Threshold EN/UVLO Voltage Hysteresis PG Threshold Offset from Feedback Voltage PG Hysteresis Output Voltage PG Leakage PG Sink Current Minimum Switch On-Time Minimum Switch Off-Time ...
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Typical perFormance characTerisTics Efficiency 3.3V OUT 12V 24V V = 36V FRONT PAGE APPLICATION V = 3.3V 30 OUT 576k ...
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LT3973/LT3973-3.3/LT3973-5 Typical perFormance characTerisTics Maximum Load Current 1.6 TYPICAL 1.4 1.2 MINIMUM 1.0 0.8 0.6 0.4 0.2 FRONT PAGE APPLICATION V = 3.3V OUT INPUT VOLTAGE (V) 3973 G10 Load Regulation ...
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Typical perFormance characTerisTics Switch V CESAT 600 500 400 300 200 100 0 0 200 400 600 800 1000 SWITCH CURRENT (mA) 3973 G19 Minimum Input Voltage OUT 6.5 FRONT PAGE APPLICATION OUT 6.0 ...
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LT3973/LT3973-3.3/LT3973-5 Typical perFormance characTerisTics Catch Diode Leakage 250 V = 12V R 200 150 100 –50 – 100 125 TEMPERATURE (°C) 3973 G28 Transient Load Response; Load Current is Stepped from 50mA (Burst Mode ...
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FuncTions FB (Pin 1, LT3973 Only): The LT3973 regulates the FB pin to 1.21V. Connect the feedback resistor divider tap to this pin. V (Pin 1, LT3973-3.3 and LT3973-5 Only): The OUT LT3973-3.3 and LT3973-5 regulate the V and ...
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LT3973/LT3973-3.3/LT3973-5 block Diagram 10 3973fa ...
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The LT3973 is a constant frequency, current mode step- down regulator. An oscillator, with frequency set by RT, sets an RS flip-flop, turning on the internal power switch. An amplifier and comparator monitor the current flowing between the V ...
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LT3973/LT3973-3.3/LT3973-5 applicaTions inFormaTion FB Resistor Network The output voltage is programmed with a resistor divider between the output and the FB pin. Choose the 1% resis- tors according to: V OUT R1= R2 – 1 ...
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This leads to a minimum input voltage of approximately OUT – V IN(MIN1 MAX where V is the output voltage, V OUT drop (~0.7V ...
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LT3973/LT3973-3.3/LT3973-5 applicaTions inFormaTion sheet that show the maximum load current as a function of input voltage for several popular output voltages. Low inductance may result in discontinuous mode operation, which is acceptable but reduces maximum load current. For details of ...
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Table 3. Recommended Ceramic Capacitor Vendors MANUFACTURER AVX Murata Taiyo Yuden Vishay Siliconix TDK Ceramic Capacitors Ceramic capacitors are small, robust and have very low ESR. However, ceramic capacitors can cause problems when used with the LT3973 due ...
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LT3973/LT3973-3.3/LT3973-5 applicaTions inFormaTion than 1.9V above the SW pin for best efficiency. For out- puts of 2.2V and above, the standard circuit (Figure 4a) is best. For outputs between 2.2V and 2.5V, use a 1µF boost capacitor. For output voltages ...
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During dropout conditions when the output is below regula- tion, the output ripple may increase. At very high loads, this ripple can increase to approximately 200mV for the front page application. If lower output ripple is desired during ...
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LT3973/LT3973-3.3/LT3973-5 applicaTions inFormaTion If the EN/UVLO pin is grounded, the SW pin current will drop to 0.75µA. However, if the V IN the output is held high, regardless of EN/UVLO, parasitic diodes inside the LT3973 can pull current from the ...
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Typical applicaTions 3.3V Step-Down Converter V IN 4.2V TO 42V V BOOST IN LT3973 OFF ON EN/UVLO OUT 4.7µF GND 215k f = 600kHz 3.3V Step-Down Converter V IN 4.2V TO 42V V BOOST ...
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LT3973/LT3973-3.3/LT3973-5 Typical applicaTions k + – Input Current During Start- INPUT CURRENT DROPOUT 40 CONDITIONS FRONT PAGE 30 APPLICATION FRONT PAGE 20 APPLICATION WITH UVLO 10 PROGRAMMED – INPUT VOLTAGE ...
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DescripTion Please refer to http://www.linear.com/designtools/packaging/ 3.55 ±0.05 1.65 ±0.05 2.15 ±0.05 (2 SIDES) 0.25 ±0.05 RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS PIN 1 TOP MARK (SEE NOTE 6) 0.200 REF LT3973/LT3973-3.3/LT3973-5 for the most recent package drawings. DD Package ...
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LT3973/LT3973-3.3/LT3973-5 package DescripTion Please refer to http://www.linear.com/designtools/packaging/ 1.88 ±0.102 (.074 ±.004) 5.23 (.206) (.066 ±.004) MIN 0.305 ± 0.038 (.0120 ±.0015) TYP RECOMMENDED SOLDER PAD LAYOUT DETAIL “A” 0.254 (.010) GAUGE PLANE DETAIL “A” 0.18 (.007) NOTE: 1. DIMENSIONS IN ...
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REV DATE DESCRIPTION A 4/12 Title and Features modified to include fixed output versions. Absolute Maximum Ratings, Pin Configuration, and Order Information sections modified to include fixed output versions. Electrical Characteristics table modified to include fixed output versions. ...
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... LT3973/LT3973-3.3/LT3973-5 Typical applicaTion 4.2V TO 25V relaTeD parTs PART NUMBER DESCRIPTION LT3970/LT3970-3.3/ 40V, 350mA, 2.2MHz High Efficiency Micropower Step-Down DC/DC LT3970-5 Converter with I = 2.5µA Q LT3990 62V, 350mA, 2.2MHz High Efficiency Micropower Step-Down DC/DC Converter with I = 2.5µA Q LT3971 38V, 1.2A, 2.2MHz High Efficiency Micropower Step-Down DC/DC Converter with I = 2.8µ ...