LTC3550 Linear Technology, LTC3550 Datasheet
LTC3550
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LTC3550 Summary of contents
Page 1
... With power applied to both inputs, the LTC3550 can be put into shutdown mode reducing the DCIN supply current to 20μA, the USBIN supply current to 10μA, and the battery drain current to less than 2μ ...
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... T JMAX EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB ORDER PART NUMBER LTC3550EDHC Order Options Tape and Reel: Add #TR Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF Lead Free Part Marking: Consult LTC Marketing for parts specifi ed with wider operating temperature ranges. ...
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... Drops Below Termination Threshold BAT I = 10% to 90% Full-Scale BAT T = 25°C A 0°C ≤ T ≤ 85°C A –40°C ≤ T ≤ 85° 3V 0. LTC3550 MIN TYP MAX UNITS ● 250 800 µA ● 50 100 µ µA ● 250 800 µ ...
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... Note 2: Guaranteed by long term current density limitations. Note 3: The LTC3550E is guaranteed to meet the 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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... DCIN USBIN 10k 1.2 V (V) PWR 3550 G06 LTC3550 T = 25°C, unless otherwise noted. A IDC Pin Voltage vs Temperature (Constant-Current Mode) 1.008 1.006 1.004 1.002 DCIN 1.000 V = 4.3V DCIN 0.998 0.996 0.994 0.992 75 100 –50 –25 ...
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... LTC3550 W TYPICAL PERFOR A CE CHARACTERISTICS Charge Current vs Ambient Temperature www.datasheet4u.com 1000 ONSET OF THERMAL REGULATION 800 R = 1.25k IDC 600 IDC IUSB 400 200 DCIN USBIN BAT θ = 40°C –50 – 100 TEMPERATURE (°C) DCIN Power FET On-Resistance ...
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... V = 1.8V OUT OUTPUT CURRENT (mA) 3550 G23 LTC3550 T = 25°C, unless otherwise noted. A Undervoltage Lockout Threshold vs Temperature 4.25 4.20 DCIN UVLO 4.15 4.10 4.05 4.00 USBIN UVLO 3.95 3.90 3.85 –50 – 100 TEMPERATURE (°C) 3550 G18 Charge Current During Turn-On and Turn-Off ...
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... LTC3550 W TYPICAL PERFOR A CE CHARACTERISTICS Buck Regulator Effi ciency vs Output Current www.datasheet4u.com 100 V = 2.5V OUT 100 OUTPUT CURRENT (mA) Oscillator Frequency 1.8 1.7 1.6 1.5 1.4 1.3 1 (V) CC Buck Regulator Switches R DS(0N) vs Temperature 0 2. 4.2V CC 0.5 0.4 0.3 0.2 0.1 MAIN SWITCH ...
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... LOAD Load Step V OUT 100mV/DIV AC COUPLED I L 500mA/DIV I LOAD 500mA/DIV 3550 G40 V = 3.6V 20µs/DIV 1.8V OUT I = 100mA TO 600mA LOAD LTC3550 T = 25°C, unless otherwise noted. A Switch Leakage Current 120 RUN = 0V 100 SYNCHRONOUS SWITCH 80 60 MAIN SWITCH ...
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... LED. ⎯ C ⎯ H ⎯ R ⎯ G (Pin 5): Open-Drain Charge Status Output. When the LTC3550 is charging, the ⎯ C ⎯ H ⎯ R ⎯ G pin is pulled low by an internal N-channel MOSFET. When the charge cycle is completed, ⎯ C ⎯ H ⎯ R ⎯ G becomes high impedance. This output is capable of sinking up to 10mA, making it suitable for driving an LED ...
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... USB_ENABLE THERMAL CHARGER CONTROL REGULATION 2.9V 100mV BAT BAT BAT /1000 /1000 /1000 ITERM IDC IUSB ITERM IDC IUSB LTC3550 USBIN 1 OSC SLOPE COMP + 3.95V – BURST CLAMP BAT + – I COMP LATCH ANTI- SHOOT- THRU SWITCHING ...
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... REMOVED OR DCIN POWER APPLIED EN EN DRIVEN HIGH DRIVEN HIGH USBIN POWER DCIN POWER REMOVED OR REMOVED DCIN POWER APPLIED Figure 1. LTC3550 State Diagram of a Charge Cycle > DCIN USBIN TRICKLE CHARGE MODE BAT < 2.9V 1/10th FULL CURRENT CHRG STATE: PULLDOWN BAT > 2.9V CHARGE 2.9V < BAT MODE Þ ...
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... An important detail to remember is that at low input supply voltages, the R DS(ON) (see Typical Performance Characteristics). Therefore, the user should calculate the power dissipation when the LTC3550 is used at 100% duty cycle with low input voltage (See Thermal Considerations in the Applications Information section). Short-Circuit Protection , or ...
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... The charge status output ( ⎯ C ⎯ H ⎯ R ⎯ has two states: pull- down and high impedance. The pull-down state indicates that the LTC3550 charge cycle. Once the charge cycle has terminated or the LTC3550 is disabled, the pin state becomes high impedance. The pull-down state is strong enough to drive an LED and is capable of sinking up to 10mA ...
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... LTC3550 terminates the charge cycle and stops providing any current out of the BAT pin. In this state, any load on the BAT pin must be supplied by the battery. *Any external sources that hold the ITERM pin above 100mV will prevent the LTC3550 from terminating a charged cycle. LTC3550 ...
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... The choice of which style inductor to use often depends more on the price vs size requirements and any radiated fi eld/EMI requirements than on what the LTC3550 requires to operate. Table 2 shows some typical surface mount inductors that work well in LTC3550 applications. ...
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... ESR make them ideal for switching regulator applications. Because the LTC3550’s control loop does not depend on the output capacitor’s ESR for stable operation, ceramic capacitors can be used freely to achieve very low output ripple and small circuit size ...
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... DCIN or USBIN the battery voltage and I BAT rent Example: An LTC3550 operating from a 5V wall adapter J A RISE (on the DCIN input) is programmed to supply 650mA full-scale current to a discharged Li-Ion battery with a voltage of 3V. The charger power dissipation is calculated to be: ...
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... 105°C – 52° 53°C A The LTC3550 can be used above 53°C ambient, but the charge current will be reduced from 650mA. Assum- ing no power dissipation from the buck converter, the approximate current at a given ambient temperature can be approximated by: ° 105 C T – ...
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... PC Board Layout Checklist When laying out the printed circuit board, the following checklist should be used to ensure proper operation of the LTC3550. These items are also illustrated graphically in Figures 6 and 7. Check the following in your layout – ...
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... V CC GND Figure 7. DC-DC Converter Suggested Layout Design Example As a design example, assume the LTC3550 is used in a single lithium-ion battery-powered cellular phone application. The battery is charged by either plugging a wall adapter cable into the phone or putting the phone in and ground. a USB cradle. The optimum charge current for this parti- cular lithium-ion battery is determined to be 800mA ...
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... FB RUN 301k 800mA (WALL 475mA (USB) BAT † 4.7µF ITERM 4.2V + 1.24k SINGLE-CELL 1% Li-Ion BATTERY 3550 F08a U Full Featured Dual Input Charger Plus Step-Down Converter DCIN BAT LTC3550 1k USBIN PWR CHRG EN RUN V IUSB CC IDC SW 2 ITERM FB GND 1.24k ...
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... Plastic DFN (5mm × 3mm) (Reference LTC DWG # 05-08-1706) 0.65 ±0.05 PACKAGE OUTLINE 0.25 ± 0.05 0.50 BSC 4.40 ±0.05 (2 SIDES) 5.00 ±0.10 (2 SIDES 0.20 TYP 3.00 ±0.10 1.65 ± 0.10 (2 SIDES) (2 SIDES) 0.75 ±0.05 0.00 – 0.05 LTC3550 R = 0.115 0.40 ± 0.10 TYP 9 16 PIN 1 NOTCH (DHC16) DFN 1103 8 1 0.25 ± 0.05 0.50 BSC 4.40 ±0.10 (2 SIDES) BOTTOM VIEW—EXPOSED PAD 23 3550fa ...
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... Charger LTC4077 Dual Input Standalone Li-Ion Battery Charger ThinSOT is a trademark of Linear Technology Corporation. Linear Technology Corporation 24 1630 McCarthy Blvd., Milpitas, CA 95035-7417 ● (408) 432-1900 FAX: (408) 434-0507 U EN DCIN LTC3550 1µF RUN V USBIN CC 4.7µF 1µF IUSB BAT 2.2µH SW IDC V ITERM ...