LTC1701 LINER [Linear Technology], LTC1701 Datasheet
LTC1701
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LTC1701 Summary of contents
Page 1
... A built-in 0.28 switch allows up to 0.5A of output current at high efficiency. OPTI-LOOP allows the transient response to be optimized over a wide range of loads and output capacitors. The LTC1701 incorporates automatic power saving Burst TM Mode operation to reduce gate charge losses when the load current drops below the level required for continuous operation ...
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... ITH/RUN FB Note 3: The LTC1701 is tested in a feedback loop which servos V midpoint for the error amplifier (V Note 4: Dynamic supply current is higher due to the internal gate charge being delivered at the switching frequency. Note calculated from the ambient T J according to the following formula: ...
Page 3
... Current Comparator. Must be closely decoupled to ground. MIN – 1.25V V REF BANDGAP (1.25V) REFERENCE + 1. COMP SHDN – (1.25V TO 2.25V) PULSE STRETCHER V < 0.6V FB LTC1701 NOMINAL (V) ABSOLUTE MAX (V) TYP MAX MIN V – 0 1.25 1.35 – 0.3 2.25 – 0.3 5.5 – 0.3 + CURRENT + SENSE CURRENT AMP – COMP – ...
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... I TH tion). Low Current Operation When the load is relatively light, the LTC1701 automati- cally switches to Burst Mode operation in which the internal PMOS switch operates intermittently based on load demand. The main control loop is interrupted when the output voltage reaches the desired regulated value. ...
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... The forward voltage drop allowed in the diode is calculated from the maximum short-circuit current as where determined by efficiency and/or thermal requirements (see Efficiency Considerations). Kool registered trademark of Magnetics, Inc. LTC1701 approaches V IN OUT = 0V), the diode OUT at close to 100% duty cycle. SC(PK) V ...
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... LTC1701 U U APPLICATIO S I FOR ATIO Most LTC1701 circuits will be well served by either an MBR0520L or an MBRM120L. An MBR0520L is a good choice for I 500mA, as long as the output OUT(MAX) doesn’t need to sustain a continuous short. Input Capacitor (C ) Selection IN In continuous mode, the input current of the converter is ...
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... TH The I /RUN pin is a dual purpose pin that provides the TH loop compensation and a means to shut down the LTC1701. Soft-start can also be implemented with this pin. Soft-start reduces surge currents from V the internal peak inductor current. Power supply sequenc- ing can also be accomplished using this pin. ...
Page 8
... During normal operation the voltage on the I will vary from 1.25V to 2.25V depending on the load current. Pulling the I /RUN pin below 0.8V puts the TH LTC1701 into a low quiescent current shutdown mode (I < 1 A). This pin can be driven directly from logic as Q shown in Figures 3(a) and 3(b). ...
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... W U The junction temperature is given by RISE As an example, consider the case when the LTC1701 is in dropout at an input voltage of 3.3V with a load current of 0.5A. The ON resistance of the P-channel switch is ap- proximately 0.30 . Therefore, power dissipated by the part is The SOT package junction-to-ambient thermal resistance, , will be in the range of 125 C/W to 150 C/W ...
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... C4: TAIYO YUDEN LMK212BJ105MG C5: TAIYO YUDEN JMK212BJ475MG D1: MBRM120L L1: MURATA LQH3C4R7M24 OUT + and all C C OUT BOLD LINES INDICATE HIGH CURRENT PATHS Figure 4. LTC1701 Layout Diagram (See Board Layout Checklist 4-Cell NiCd/NiMH to 2.5V Converter LTC1701 0 /RUN V TH ...
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... REF (0.102 – 0.118) 1.50 – 1.75 0.00 – 0.15 (0.059 – 0.069) (0.00 – 0.006) 0.35 – 0.50 0.09 – 0.20 (0.014 – 0.020) (0.004 – 0.008) FIVE PLACES (NOTE 2) (NOTE 2) LTC1701 L1 4 OUT (3.3V/0.5A 34k 20.5k 1701 TA03 0.95 (0.037) REF 0.90 – ...
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... Low Input Voltage Current Mode Step-Down DC/DC Controller Linear Technology Corporation 12 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 www.linear-tech.com Single Cell Li-Ion to 3.3V Buck Boost Converter C6 L1 4 LTC1701 R2 34k I /RUN GND R3 R1 20.5k C3 330pF V OUT (3.3V) + ...