LTC3557 LINER [Linear Technology], LTC3557 Datasheet
LTC3557
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LTC3557 Summary of contents
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... Bat-Track that allows effi cient charging from supplies as high as 38V. The LTC3557/LTC3557-1 is available in a low profi le 4mm × 4mm × 0.75mm 28-pin QFN package LTC, LTM and Burst Mode are registered trademarks of Linear Technology Corporation ...
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... TAPE AND REEL LTC3557EUF#PBF LTC3557EUF#TRPBF LTC3557EUF-1#PBF LTC3557EUF-1#TRPBF Consult LTC Marketing for parts specifi ed with wider operating temperature ranges. Consult LTC Marketing for information on non-standard lead based fi nish parts. For more information on lead free part marking, go to: For more information on tape and reel specifi cations, go to: ...
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... Closed-Loop Output Resistance CL(LDO3V3) = 2k, R PROG CONDITIONS Rising Threshold Falling Threshold ) OUT LTC3557 LTC3557, 0°C ≤ T ≤ 85°C A LTC3557-1 LTC3557-1, 0°C ≤ T ≤ 85° 1k, Input Current Limit = 2A PROG R = 2k, Input Current Limit = 1A PROG R = 5k, Input Current Limit = 400mA PROG V > Charger Off 0μ ...
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... LTC3557/LTC3557-1 POWER MANAGER ELECTRICAL CHARACTERISTICS The denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at T ● 5V 3.8V, ILIM0 = ILIM1 = 5V, WALL = EN1 = EN2 = EN3 = 0V, R BUS BAT SYMBOL PARAMETER Wall Adapter ACPR Pin Output High Voltage ...
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... Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2. The LTC3557/LTC3557-1 is guaranteed to meet performance specifi cations from 0°C to 85°C. Specifi cations over the −40°C to 85°C operating temperature range are assured by design, characterization and correlation with statistical process controls ...
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... MODE 500 400 300 200 1x MODE 100 0 50 –50 – 100 TEMPERATURE (°C) 35571 G04 Battery Current and Voltage vs Time (LTC3557) 600 CHRG 500 V BAT 400 300 SAFETY 200 TIMER 1450mAhr TERMINATION CELL C/ 100 BUS ...
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... WALL Connect Waveform WALL 5V/DIV V OUT 5V/DIV I WALL 0.5A/DIV I BAT 0.5A/DIV V = 3.75V 1ms/DIV BAT I = 100mA OUT PROG LTC3557/LTC3557 25°C unless otherwise specifi Forward Voltage vs Ideal Diode Current (with Si2333DS External FET 3.8V BAT BUS T = 25° 4. ...
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... LTC3557/LTC3557-1 TYPICAL PERFORMANCE CHARACTERISTICS Oscillator Frequency vs Temperature 2.5 2 3.8V 2 2.2 IN 2.1 2.0 1 2. 2.7V IN 1.7 1.6 1.5 – 125 –25 100 TEMPERATURE (°C) 35571 G13 Step-Down Switching Regulator 3 1.8V Output Effi ciency vs I OUT3 100 90 Burst Mode 80 OPERATION 70 60 PULSE SKIP 1.8V OUT3 V = 3.8V 10 IN3 ...
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... It can be used as a power on reset for the primary . OUT microprocessor or to enable the other buck regulators for supply sequencing. SW2 (Pin 15): Power Transmission (Switch) Pin for Step-Down Switching Regulator 2. LTC3557/LTC3557-1 = 25°C unless otherwise specifi Step-Down Switching Regulator Start-Up Waveform V OUT2 ...
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... Output Voltage of the PowerPath Controller OUT and Input Voltage of the Battery Charger. The majority of the portable product should be powered from V LTC3557/LTC3557-1 will partition the available power between the external load on V and the internal battery OUT charger. Priority is given to the external load and any extra power is used to charge the battery ...
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... DIODE CHARGER INPUT CURRENT – LIMIT + TEMP BUCK REGULATOR OSC REF EN MODE ILIM LOGIC BUCK REGULATOR OSC EN EN LOGIC MODE BUCK REGULATOR OSC EN MODE GND 29 LTC3557/LTC3557 CONTROL V OUT 23 + GATE 21 – 15mV BAT 22 PROG 20 LDO3V3 3.3V 4 LDO V IN1 6 600mA, 2.25MHz SW1 ...
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... USB BUS 24 12 The LTC3557/LTC3557-1 has the unique ability to use the output, which is powered by an external supply, to charge the battery while providing power to the load. A comparator on the WALL pin is confi gured to detect the presence of the wall adapter and shut off the connection to the USB ...
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... Ideal Diode from BAT CLPROG The LTC3557/LTC3557-1 has an internal ideal diode as well as a controller for an optional external ideal diode. Both the internal and the external ideal diodes respond quickly whenever V drops below BAT. ...
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... However, if more conductance is needed, an external P-channel MOSFET can be added from BAT OUT The GATE pin of the LTC3557/LTC3557-1 drives the gate of the external P-channel MOSFET for automatic ideal diode control. The source of the MOSFET should be connected to V and the drain should be connected to BAT. Capable ...
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... LTC3557/LTC3557-1 battery is always topped off, a charge cycle will automati- cally begin when the battery voltage falls below V (typically 4.1V for the LTC3557 or 4V for LTC3557-1). In the event that the safety timer is running when the battery voltage falls below V , the timer will reset back to RECHRG zero ...
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... LED while a microprocessor would be able to decode either the 12.5% or 87.5% duty cycles as a bad battery fault. Note that the LTC3557/LTC3557 3-terminal PowerPath product where system load is always prioritized over battery charging. Due to excessive system load, there may not be suffi ...
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... As the temperature drops, the resistance of the NTC thermistor rises. The LTC3557/ LTC3557-1 is also designed to pause charging when the value of the NTC thermistor increases to 3.25 times the value of R25. For a Vishay “Curve 1” thermistor this resistance, 325k, corresponds to approximately 0° ...
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... LTC3557/LTC3557-1 OPERATION Step-Down Switching Regulator RST2 Operation The RST2 pin is an open-drain output used to indicate that step-down switching regulator 2 has been enabled and has reached its fi nal voltage. A 230ms delay is included from the time switching regulator 2 reaches 92% of its regulation value to allow a system controller ample time to reset itself ...
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... V pin, the regulators should not be operate OUT LTC3557/LTC3557-1 outside the specifi ed operating range as operation is not guaranteed beyond this range. Step-Down Switching Regulator Inductor Selection Many different sizes and shapes of inductors are avail- able from numerous manufacturers ...
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... LTC3557/LTC3557-1 OPERATION The inductor value also has an effect on Burst Mode operation. Lower inductor values will cause Burst Mode switching frequency to increase. Table 3 shows several inductors that work well with the step-down switching regulators. These inductors offer a good compromise in current rating, DCR and physical size ...
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... WALL ACPR OUT LTC3557 21 GATE LTC3557-1 22 BAT (800kHz Switching) C LTC3557/LTC3557-1 pin is regulated to the larger of OUT control of the LTC3557 overdrives the local C control is enabled, the output voltage is set C 499k 22μF 100k Si2333DS OUT C OUT Si2333DS (OPT) BAT + Li-Ion ...
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... LTC3557/LTC3557-1 APPLICATIONS INFORMATION 36V 1μF LT3505 HIGH VOLTAGE BUCK CIRCUITRY Figure 5. LT3505 Buck Control Using V 5.0 4.5 4.0 3.5 3.0 2.5 2.5 3 3.5 BAT (V) Figure 6. LTC3557 V Voltage vs Battery Voltage OUT with the LT3480 5.0 4.5 4.0 3.5 3.0 2.5 2.5 3 3.5 BAT (V) Figure 7. LTC3557-1V Voltage vs Battery Voltage OUT with the LT3505 BOOST ...
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... R = Primary thermistor bias resistor (see Figure 8) NOM R1 = Optional temperature range adjustment resistor (see Figure 9) The trip points for the LTC3557/LTC3557-1’s temperature qualifi cation are internally programmed at 0.349 • V LTC3557/LTC3557-1 for the hot threshold and 0.765 • V threshold. Therefore, the hot trip point is set when: ...
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... NOM Battery Charger Stability Considerations The LTC3557/LTC3557-1’s battery charger contains both a constant voltage and a constant current control loop. The constant voltage loop is stable without any compensation when a battery is connected with low impedance leads. ...
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... D(SW1) dissipation is: = (5V – 3.3V) • 0.15W = 1.85W P D The ambient temperature above which the LTC3557/ LTC3557-1 will begin to reduce the 1A charge current, is approximately 110°C – 1.85W • 37°C/W = 42°C A The LTC3557/LTC3557-1 can be used above 42°C, but the charge current will be reduced below 1A. The charge current at a given ambient temperature can be approximated by: 110° ...
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... If an external buck switching regulator controlled by the LTC3557/LTC3557-1 V pin is used instead wall C adapter we see a signifi cant reduction in power dissipated by the LTC3557/LTC3557-1. This is because the external buck switching regulator will drive the PowerPath output ( about 3.6V with the battery at 3.3V. If you go OUT through the example above and substitute 3 ...
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... ILIM1 7 9 EN1 FB1 PMIC 10 CONTROL 4.7μH EN2 17 11 SW3 EN3 8 MODE 12 FB3 14 RST2 4.7μH 15 SW2 13 FB2 GND 29 LTC3557/LTC3557-1 BUCK INPUT 499k 22μF 100k Si2333DS V OUT 510Ω Si2333DS (OPT) BAT + Li-Ion V OUT1 3.3V 600mA 10pF 1.02M 10μF 324k V OUT3 1.8V 400mA 10pF 806k 10μ ...
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... LTC3557/LTC3557-1 PACKAGE DESCRIPTION 0.70 0.05 PACKAGE OUTLINE 0.20 0.05 0.40 BSC DED SOLDER PAD PITCH AND DIMENSIONS R MASK TO AREAS THAT ARE NOT SOLDERED 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE S NOT A JEDEC PACKAGE OUTLINE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE, IF PRESENT NOT TO SCALE 5 ...