LTC1627 Linear Technology, LTC1627 Datasheet
LTC1627
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LTC1627 Summary of contents
Page 1
... The internal synchronous switch increases efficiency and eliminates the need for an external Schottky diode, saving components and board space. The LTC1627 comes in an 8-lead SO package. , LTC and LT are registered trademarks of Linear Technology Corporation. Burst Mode is a trademark of Linear Technology Corporation. ...
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... – 100mA RUN/SS Note 3: The LTC1627 is tested in a feedback loop that servos V balance point for the error amplifier (V Note 4: Dynamic supply current is higher due to the gate charge being delivered at the switching frequency. and power INFORMATION ORDER PART ...
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... Reference Voltage vs Temperature 0.808 0.806 0.804 0.802 0.800 0.798 0.796 0.794 0.792 0.790 – 50 – 125 75 100 TEMPERATURE ( C) 1627 G08 LTC1627 Efficiency vs Load Current 100 V = 3.6V IN Burst Mode V = 2.5V OUT OPERATION SYNCHRONIZED AT 525kHz 80 FORCED CONTINUOUS 75 70 ...
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... LTC1627 W U TYPICAL PERFOR A CE CHARACTERISTICS Oscillator Frequency vs Temperature 390 380 SYNC/FCB 370 360 350 340 330 320 310 300 – 50 – 125 75 100 TEMPERATURE ( C) 1627 G10 Switch Leakage Current vs Temperature 1800 V = 8.4V IN 1600 1400 1200 ...
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... Applications Information SLOPE COMP – EN – + SLEEP + + 0.12V EA – BURST SWITCHING RUN/SOFT Q R START + OVDET – LTC1627 . Grounding Pin 8 forces 0.4V 6 – COMP LOGIC AND ANTI- BLANKING SHOOT-THRU CIRCUIT + I RCMP – ...
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... The top MOSFET turn-on follows the rising edge of the external source. When the LTC1627 is clocked by an external source, Burst Mode operation is disabled; the LTC1627 then operates in PWM pulse skipping mode. In this mode, when the output ...
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... A 150mV hysteresis ensures reliable operation with noisy supplies. Low Supply Operation The LTC1627 is designed to operate down to 2.65V supply voltage. At this voltage the converter is most likely to be running at high duty cycles or in dropout where the main switch is on continuously ...
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... OUT. Inductor Value Calculation The inductor selection will depend on the operating fre- quency of the LTC1627. The internal preset frequency is 350kHz, but can be externally synchronized up to 525kHz. The operating frequency and inductor selection are inter- related in that higher operating frequencies allow the use of smaller inductor and capacitor values ...
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... L Run/Soft-Start Function The RUN/SS pin is a dual purpose pin that provides the soft-start function and a means to shut down the LTC1627. Soft-start reduces surge currents from V increasing the internal current limit. Power supply sequencing can also be accomplished using this pin. An internal 2.25 A current source charges up an external capacitor C the LTC1627 begins operating ...
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... Efficiency = 100% – ( ...) where L1, L2, etc. are the individual losses as a percentage of input power. Although all dissipative elements in the circuit produce losses, two main sources usually account for most of the losses in LTC1627 circuits: V losses. 1. The V IN the DC bias current as given in the electrical character- istics and the internal main switch and synchronous switch gate charge currents ...
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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 LTC1627. These items are also illustrated graphically in the layout diagram of Figure 7. Check the following in your to its steady-state OUT ...
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... This capacitor provides the AC current to the internal power MOSFETs. 4. Keep the switching node SW away from sensitive small- signal nodes. Design Example As a design example, assume the LTC1627 is used in a single lithium-ion battery-powered cellular phone applica- tion. The V will be operating from a maximum of 4.2V IN down to about 2 ...
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... SUMIDA CD54-330 SYNC/FCB AVX TPSD107M010R0100 TH *** AVX TPSC226M016R0375 2 7 RUN/ LTC1627 GND SW R2 422k + 1% R1 80.6k 1% LTC1627 OUT 3. *** 0. OUT ** 16V 100 F 6.3V 1627 TA03 V 8. OUT *** 0. OUT ** 16V 100 F 10V ...
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... GND SW 2.5V 0.5A R2 169k 1% + † C OUT 100 F 6.3V R1 80.6k 1% Single Lithium-Ion to 1.8V/0.3A Regulator * SUMIDA CD54-150 SYNC/FCB AVX TPSC107M006R0150 TH *** AVX TPSC226M016R0375 2 7 RUN/ LTC1627 GND SW R2 100k + C 1% 100 F R1 6.3V 80. 3. †† BAT54S 16V ...
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... TYP 0.014 – 0.019 (0.355 – 0.483) LTC1627 0.150 – 0.157** (3.810 – 3.988 0.004 – 0.010 (0.101 – 0.254) 0.050 (1 ...
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... GND SW R2 169k + C OUT ** 1% 100 F R1 6.3V 80. 249k SYNC/FCB TH *** 80.6k 7 RUN/ † LTC1627 25 H MBR0520LT1 8.5V 1 GND 16V † R1 COILTRONICS CTX25-1 †† 80.6k MMSZ4678T1 ††† 10mA MIN LOAD CURRENT IS RECOMMENDED V 8 ...