LTC1475 Linear Technology, LTC1475 Datasheet
LTC1475
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LTC1475 Summary of contents
Page 1
... LTC1475 fea- tures pushbutton on/off. The low supply current coupled with Burst Mode tion enables the LTC1474/LTC1475 to maintain high effi- ciency over a wide range of loads. These features, along with their capability of 100% duty cycle for low dropout ...
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... TOP VIEW RUN OUT LBO SENSE LBI/OFF GND 4 S8 PACKAGE S8 PACKAGE 8-LEAD PLASTIC SO = 110 125 C, = 110 JMAX JA ORDER PART NUMBER LTC1475CS8 LTC1475IS8 LTC1475CS8-3.3 LTC1475CS8-5 S8 PART MARKING 1475 1475I 14753 14755 SENSE 5 SW ...
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... Voltage Comparator Hysteresis HYST t Switch Off-Time OFF V Low Battery Comparator Threshold LBI, TRIP V Run/ON Pin Threshold RUN V OFF Pin Threshold (LTC1475 Only) LBI, OFF I Sink Current into Pin 2 LBO, SINK I Source Current from Pin 8 RUN, SOURCE I Switch Leakage Current SW, LEAK I Leakage Current into Pin 3 ...
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... LTC1474/LTC1475 W U TYPICAL PERFORMANCE CHARACTERISTICS Efficiency vs Input Voltage 100 FIGURE 1 CIRCUIT L: CDRH73-101 25mA LOAD I = 200mA LOAD 1mA LOAD INPUT VOLTAGE (V) 1474/75 G01 Current Trip Threshold vs Temperature 500 V = 10V SENSE 400 300 200 R = 1.1 SENSE 100 0 40 ...
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... Main Supply Pin. IN RUN/ON (Pin 8): On LTC1474, voltage level on this pin controls shutdown/run mode (ground = shutdown, open/ high = run). On LTC1475, a momentary ground on this pin puts regulator in run mode. A 100k series resistor must be used between Pin 8 and the switch or control voltage. W 100mV – ...
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... FB until it reaches the lower threshold of the voltage com- parator (about 5mV below the upper threshold). The voltage comparator then trips again, signaling the LTC1474/ LTC1475 to turn on the circuitry necessary to begin a new burst cycle. 6 Peak Inductor Current Programming The current comparator provides a means for program- ming the maximum inductor/switch current for each switch cycle ...
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... The maximum average output SENSE current I is equal to this peak value less half the peak- MAX to-peak ripple current Allowing a margin for variations in the LTC1474/LTC1475 and external components, the required R calculated from Figure 2 and the following equation (0.067/I ) – 0.25 SENSE MAX for 10mA < ...
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... LTC1474/ 1474/75 F03 LTC1475 supply current. Low forward drop is critical for high current efficiency since loss is proportional to for- ward drop. These are conflicting parameters (see Table 1), but a good compromise is the MBR0530 0.5A Schottky diode specified in the application circuits ...
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... L1, L2, etc. are the individual losses as a percentage of input power. Although all dissipative elements in the circuit produce losses, three main sources usually account for most of the losses in LTC1474/LTC1475 circuits: V losses and catch diode losses. 1. The V IN current and the internal P-channel switch gate charge current ...
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... SENSE Figure 4. LTC1474/LTC1475 Adjustable Configuration Low Battery Comparator The LTC1474/LTC1475 have an on-chip low battery com- I loss as the diode parator that can be used to sense a low battery condition D D when implemented as shown in Figure 5. The resistive ...
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... Figure 6, if both pins are grounded simultaneously, run mode wins. Figure 18 in the Typical Applications section shows an example for the use of the LTC1475 to control on/off of a microcontroller with a single pushbutton. With both the microcontroller and LTC1475 off, depressing the pushbutton grounds the LTC1475 ON pin and starts up the LTC1475 regulator which then powers up the microcon- troller ...
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... The junction temperature is given by example consider the LTC1474/LTC1475 in dropout at which OUT at an input voltage of 3.5V, a load current of 300mA, and ) potential to less IN an ambient temperature From the typical perfor- mance graph of switch resistance, the on-resistance of the P-channel switch ...
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... U APPLICATIONS INFORMATION V OUT Figure 9. LTC1474/LTC1475 Layout Diagram (See Board Layout Checklist) 5. Are the signal and power grounds segregated? The signal ground consists of the (–) plate of C the LTC1474/LTC1475 and the resistive divider. The power ground consists of the Schottky diode anode, the (–) plate of C and the 0 ...
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... LTC1474/LTC1475 U TYPICAL APPLICATIONS V IN 3.5V TO 18V + † 4 35V * SUMIDA CDRH73-271 ** 3 PARALLEL STANDARD RESISTORS PROVIDE LEAST EXPENSIVE SOLUTION (SEE R SELECTION SECTION) SENSE † AVX TPSC475M035 †† AVX TPSC107M006 Figure 10. High Efficiency 3V/100mA Regulator (Design Example 4mA TO 20mA †† D2 12V † ...
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... Figure 12 12V Regulator 0 SENSE V OUT LTC1474 LBI LBO 10 F** 25V + 8 5 RUN SW GND 4 L* 100 H Figure 13. 5V Buck-Boost Converter LTC1474/LTC1475 MBR0530 V OUT –12V 70mA †† 25V + V OUT 12V 70mA + †† 200 H 25V V ( LOAD(MAX) 3.5 ...
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... LTC1474/LTC1475 U TYPICAL APPLICATIONS V IN 3.5V TO 12V + 10 F** 25V †† TP0610 ON/OFF 10M * SUMIDA CDRH74-101 ** AVX TPSC106M025 † AVX TPSC336M010 †† RUN: ON/OFF = 0, SHUTDOWN: 0N/OFF = 18V + 4.7 F** 35V CHARGER ON/OFF * SUMIDA CDRH73-101 ** AVX TPSC475M035 † AVX TPSD476M016 16 0 ...
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... AVX TPSC107M006 Figure 16. High Efficiency 3.3V Regulator with Low Battery Lockout V IN 5.7V TO 18V + 4.7 F** 35V OFF 18V MMBD914LT1 C * SUMIDA CDRH73-101 ** AVX TPSC475M035 † Figure 18. LTC1475 Regulator with 1-Button Toggle On/Off 2. SENSE V OUT LTC1474-3.3 3 LBI LBO 100k 1M 8 RUN RUN ...
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... LTC1474/LTC1475 PACKAGE DESCRIPTION 0.007 (0.18) * DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE ** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE ...
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... TYP 0.014 – 0.019 (0.355 – 0.483) LTC1474/LTC1475 0.150 – 0.157** (3.810 – 3.988 0.004 – 0.010 (0.101 – 0.254) 0.050 (1 ...
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... LT1634-1.25 Micropower Precision Shunt Reference Linear Technology Corporation 20 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 TELEX: 499-3977 www.linear-tech.com 7 1. SENSE V FB 100k LBO LTC1475 5 3 LBI/OFF SW GND 1M 4 OFF 10pF 0.1 F 1.02M V 1% OUT 2.5V + 250mA 1M † 100 F ...