lt3693 Linear Technology Corporation, lt3693 Datasheet
lt3693
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lt3693 Summary of contents
Page 1
... RUN/SS pin provide a controlled output voltage ramp (soft-start). A power good fl ag signals when V 91% of the programmed output voltage. The LT3693 is available in 10-Pin MSOP and 3mm × 3mm DFN packages with exposed pads for low thermal resistance. ...
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... Minimum Input Voltage Quiescent Current from V IN Quiescent Current from (Note 1) Operating Junction Temperature Range (Note 2) LT3693E ............................................. –40°C to 125°C LT3693I.............................................. –40°C to 125°C Storage Temperature Range ................... –65°C to 150°C Lead Temperature (Soldering, 10 sec) (MSE Only) ....................................................... 300° ...
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... Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: The LT3693E is guaranteed to meet performance specifi cations from 0°C to 125°C. Specifi cations over the –40°C to 125°C operating temperature range are assured by design, characterization and correlation with statistical process controls. The LT3693I specifi ...
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... LT3693 W U TYPICAL PERFOR A CE CHARACTERISTICS Effi ciency 100 V = 12V 34V 24V OUT L = 4.7μ 600kHz 50 0 0.5 1 1.5 2 2.5 3 OUTPUT CURRENT (A) 3693 G01 Maximum Load Current 5.5 TYPICAL 5.0 4.5 MINIMUM 4.0 3 3.3V OUT T = 25° 4.7μ 600kHz 2 INPUT VOLTAGE (V) 3693 G06 Switch Current Limit 6 ...
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... RUN/SS PIN VOLTAGE (V) Error Amp Output Current –10 –20 –30 –40 –50 2.0 –200 –100 0 100 FB PIN ERROR VOLTAGE (mV) LT3693 T = 25°C unless otherwise noted. A Frequency Foldback 1200 R = 34.0k T 1000 800 600 400 200 0 125 150 0 100 200 300 ...
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... LT3693 W U TYPICAL PERFOR A CE CHARACTERISTICS Minimum Input Voltage 6.5 6.0 5.5 5 OUT 4 4 600kHz 4 100 1000 10000 LOAD CURRENT (mA) 3693 G21 Switching Waveforms; Discontinuous Operation V SW 5V/DIV I L 0.2A/DIV V OUT 10mV/DIV V = 12V 1μs/DIV 3.3V OUT I = 110mA LOAD 25°C unless otherwise noted. ...
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... PG remains low until the FB pin is within 9% of the fi nal regulation voltage. PG output is valid when V is above 3.6V and RUN/SS is high (Pin 8): The LT3693 regulates the FB pin to 0.790V. Connect the feedback resistor divider tap to this pin. V (Pin 9): The V C amplifi er. The voltage on this pin controls the peak switch current ...
Page 8
... The LT3693 contains a power good comparator which trips when the FB pin is at 91% of its regulated value. The PG output is an open-collector transistor that is off when the pin, IN output is in regulation, allowing an external resistor to pull the PG pin high. Power good is valid when the LT3693 is enabled and V is above 3.6V. IN 3693f ...
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... The reason input voltage range depends on the switching frequency is because the LT3693 switch has fi nite minimum on and off times. The switch can turn on for a minimum of ~150ns and turn off for a minimum of ~150ns. ...
Page 10
... L OUT(MAX) where I is the maximum output load current. To OUT(MAX) guarantee suffi cient output current, peak inductor current must be lower than the LT3693’s switch current limit (I The peak inductor current is: + Δ L(PEAK) OUT(MAX) L where I is the peak inductor current, I L(PEAK) the maximum output load current, and Δ ...
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... Output Capacitor and Output Ripple The output capacitor has two essential functions. Along with the inductor, it fi lters the square wave generated by the LT3693 to produce the DC output. In this role it determines the output ripple, and low impedance at the switching frequency is important. The second function is to store energy in order to satisfy transient loads and stabilize the LT3693’ ...
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... LT3693 APPLICATIONS INFORMATION Table 2. Capacitor Vendors VENDOR PHONE Panasonic (714) 373-7366 Kemet (864) 963-6300 Sanyo (408) 749-9714 Murata (408) 436-1300 AVX Taiyo Yuden (864) 963-6300 When choosing a capacitor, look carefully through the data sheet to fi nd out what the actual capacitance is under operating conditions (applied voltage and temperature) ...
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... Figure 2 shows an equivalent circuit for the LT3693 control loop. The error amplifi transconductance amplifi er with fi nite output impedance. The power section, consisting of the modulator, power switch and inductor, is modeled as a transconductance amplifi ...
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... LT3693 GND 4.7 F (4b) For 2.5V < V OUT BD BOOST LT3693 GND 4.7 F (4c) For V < 2.5V; V IN(MAX) OUT Figure 4. Three Circuits For Generating The Boost Voltage BOOST and BIAS Pin Considerations Capacitor C3 and the internal boost Schottky diode (see the Block Diagram) are used to generate a boost volt- age that is higher than the input voltage. In most cases a 0.47μ ...
Page 15
... For proper startup, the minimum input voltage is also limited by the boost circuit. If the input voltage is ramped slowly, or the LT3693 is turned on with its RUN/SS pin when the output is already in regulation, then the boost capacitor may not be fully charged. Because the boost capacitor is ...
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... LT3693 is absent. This may occur in battery charging ap- plications or in battery backup systems where a battery or some other supply is diode OR-ed with the LT3693’s output. If the V pin is allowed to fl oat and the RUN/SS ...
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... Figure 9. A Well Chosen Input Network Prevents Input Voltage Overshoot and Ensures Reliable Operation when the LT3693 is Connected to a Live Supply energized supply, the input network should be designed to prevent this overshoot. Figure 9 shows the waveforms that result when an LT3693 circuit is connected to a 24V supply through six feet of 24-gauge twisted pair. The fi ...
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... LFPM airfl ow, this resistance can fall by another 25%. Further increases in airfl ow will lead to lower thermal re- sistance. Because of the large output current capability of the LT3693 possible to dissipate enough heat to raise the junction temperature beyond the absolute maximum of 125°C. When operating at high ambient temperatures, the maximum load current should be derated as the ambient temperature approaches 125° ...
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... IN ON OFF RUN/SS BOOST LT3693 RT 19k PG SYNC 63.4k FB GND f = 600kHz 2.5V Step-Down Converter RUN/SS BOOST ON OFF LT3693 RT 15.4k PG SYNC FB 63.4k GND f = 600kHz LT3693 V OUT 3.3V 3.5A L 0. 316k 100k 47 F 3693 TA03 V OUT 2. 215k 47 F 100k 3693 TA04 3693f 19 ...
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... L: NEC MBP107558R2P 20 5V, 2MHz Step-Down Converter RUN/SS BOOST ON OFF LT3693 RT 15k PG SYNC FB 12.7k GND f = 2MHz 12V Step-Down Converter RUN/SS BOOST ON OFF LT3693 RT 17.4k PG SYNC FB 63.4k GND f = 600kHz V OUT 5V 2.5A L 0. 536k 22 F 100k 3693 TA05 V OUT 12V 3.5A L 0. 715k 47 F ...
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... TYPICAL APPLICATIONS V IN 3.6V TO 27V 4.7 F 680pF D: ON SEMI MBRA340 L: NEC MPLC0730L3R3 1.8V Step-Down Converter OFF RUN/SS BOOST LT3693 RT 16.9k PG SYNC FB 78.7k GND f = 500kHz LT3693 V OUT 1.8V 3.5A L 0. 127k 100k 47 F 3693 TA08 3693f 21 ...
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... LT3693 PACKAGE DESCRIPTION 3.50 ±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 Package 10-Lead Plastic DFN (3mm × 3mm) (Reference LTC DWG # 05-08-1699) 0.675 ±0.05 PACKAGE OUTLINE 0.50 BSC 2.38 ±0.05 (2 SIDES) 3.00 ±0.10 1.65 ± 0.10 (2 SIDES) (4 SIDES) 0.75 ± ...
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... MAX DETAIL “A” SEATING PLANE 0.17 – 0.27 (.007 – .011) 0.50 TYP (.0197) BSC LT3693 2.06 ± 0.102 (.081 ± .004) 1.83 ± 0.102 (.072 ± .004) 0.497 ± 0.076 (.0196 ± .003 REF 3.00 ± 0.102 (.118 ± .004) (NOTE 4) 0 ...
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... High Effi ciency Step-Down DC/DC Converter Linear Technology Corporation 24 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 ● 1.2V Step-Down Converter RUN/SS BOOST ON OFF LT3693 RT 17k PG SYNC FB 78.7k GND 470pF f = 500kHz D: ON SEMI MBRA340 L: NEC MPLC0730L3R3 COMMENTS V TSSOP16/E Package V ThinSOT V 3mm × ...