LT3470 LINEAR [Linear Integrated Systems], LT3470 Datasheet
LT3470
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LT3470 Summary of contents
Page 1
... The LT3470 combines Burst Mode and continuous opera- tion to allow the use of tiny inductor and capacitors while providing a low ripple output to loads 200mA. With its wide input range 40V, the LT3470 can regulate a wide variety of power sources, from 2-cell Li-Ion batteries to unregulated wall transformers and lead- acid batteries. Quiescent current in regulation is just 26µ ...
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... FB 4V < V < 40V 100mA ORDER PART NUMBER TOP VIEW 8 FB LT3470ETS8 7 BIAS LT3470ITS8 6 BOOST 5 SW TS8 PART MARKING TS8 PACKAGE LTBDM = 125°C, θ = 140° LTBPW = 25°C. A MIN TYP MAX ● 4 0.1 0.5 ● ...
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... Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: The LT3470E is guaranteed to meet performance specifications from 0°C to 70°C. Specifications over the –40°C to 85°C operating temperature range are assured by design, characterization and correlation with statistical process controls. The LT3470I specifications are guaranteed over the – ...
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... LT3470 W U TYPICAL PERFOR A CE CHARACTERISTICS Top and Bottom Switch Current Limits (V = 0V) vs Temperature FB 400 350 300 250 200 150 100 50 0 – 100 125 – TEMPERATURE (°C) 3470 G04 SHDN Bias Current vs Temperature 36V SHDN ...
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... G16 = 3.3V Minimum Input Voltage, V OUT 25° 150 200 0 3470 G18 LT3470 BOOST Pin Current 100 200 0 300 SWITCH CURRENT (mA) 100 200 50 150 BOOST DIODE CURRENT (mA) 3470 G17 = 5V OUT ...
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... CTIO S SHDN (Pin 1): The SHDN pin is used to put the LT3470 in shutdown mode. Tie to ground to shut down the LT3470. Apply 2V or more for normal operation. If the shutdown feature is not used, tie this pin to the V NC (Pin 2): This pin can be left floating or connected to V ...
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... Burst Mode Operation Figure 1. Operating Waveforms of the LT3470 Converting 12V to 5V Using a 33µH Inductor and 10µF Output Capacitor comparator trips and resets the latch causing the switch to turn off. While the switch is off, the inductor current ramps down through the catch diode ...
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... Electrical Characteristics) such that the average inductor current equals the load current. For safe operation, it must be noted that the LT3470 cannot turn the switch on for less than ~150ns. If the inductor is small and the input voltage is high, the current through the switch may exceed safe operating limit before the LT3470 is able to turn off ...
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... With a high quality capacitor filtering the ripple current from the inductor, the output voltage ripple is determined by the delay in the LT3470’s feedback comparator. This ripple can be reduced further by adding a small (typically 22pF) phase lead capacitor between the output and the feedback pin ...
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... If the LT3470 circuit is plugged into a live supply, the input voltage can ring to twice its nominal value, possibly exceeding the LT3470’s rating. This situation is easily avoided ...
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... Figure 4. Diode D1 Prevents a Shorted Input from Discharging a 3470 G19 Backup Battery Tied to the Output; It Also Protects the Circuit from a Reversed Input. The LT3470 Runs Only When the Input is Present Hot Plugging Safely to start and to run. At light loads, the IN = 40V. There is another situation to consider in ...
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... LT3470 into an energized supply, the input network should be designed to prevent this overshoot. Figure 6 shows the waveforms that result when an LT3470 circuit is connected to a 24V supply through six feet of 24-gauge twisted pair. The first plot is the response with a 2.2µF ceramic capacitor at the input ...
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... AI.EI. 0.1µF Figure 6: A Well Chosen Input Network Prevents Input Voltage Overshoot and Ensures Reliable Operation When the LT3470 is Connected to a Live Supply in the circuit. An alternative solution is shown in Figure 6c. A 1Ω resistor is added in series with the input to eliminate the voltage overshoot (it also reduces the peak input current). A 0.1µ ...
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... V OUT 1.8V OFF ON 200mA R1 22pF 147k C2 22µF R2 332k 3470 TA04 C1: TDK C3216JB1H105M C2: TDK C3216JB1C106M L1: MURATA LQH32CN150K53 5V Step-Down Converter 0.22µF V BOOST IN L1 LT3470 33µ SHDN SW 7 BIAS R1 22pF 604k 1µF GND R2 200k 4 3470 TA04 V OUT 2.5V 200mA R1 200k C2 22µ ...
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... BSC 1.4 MIN (NOTE 4) 0.65 BSC 0.80 – 0.90 1.00 MAX 0.09 – 0.20 (NOTE 3) 4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR 5. MOLD FLASH SHALL NOT EXCEED 0.254mm 6. JEDEC PACKAGE REFERENCE IS MO-193 LT3470 2.90 BSC (NOTE 4) PIN ONE ID 0.22 – 0.36 8 PLCS (NOTE 3) 0.01 – 0.10 1.95 BSC TS8 TSOT-23 0802 15 3470f ...
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