LTC3411 Linear Technology, LTC3411 Datasheet
LTC3411
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LTC3411 Summary of contents
Page 1
... The LTC3411 can be configured for automatic power saving Burst Mode operation to reduce gate charge losses when the load current drops below the level required for continuous operation ...
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... 3.3V SHDN/ 324k T (Note 7) (Note ITH/RUN FB V Ramping Down IN ORDER PART NUMBER TOP VIEW LTC3411EMS PGOOD PART MARKING MS PACKAGE LTQT = 120 C/ C MIN TYP MAX 2.625 5.5 0.1 0.784 0.8 0.816 0.04 0.2 0.02 0.2 – 0.02 – ...
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... Note 2: The LTC3411E is guaranteed to meet specified performance from Specifications over the – operating ambient termperature range are assured by design, characterization and correlation with statistical process controls. Note 3: The LTC3411 is tested in a feedback loop which servos V midpoint for the error amplifier (V = 0.6V). ITH Note 4: Dynamic supply current is higher due to the internal gate charge being delivered at the switching frequency ...
Page 4
... LTC3411 CTIO S PIN NAME DESCRIPTION 1 SHDN/R Shutdown/Timing Resistor T 2 SYNC/MODE Mode Select/Sychronization Pin 3 SGND Signal Ground 4 SW Switch Node 5 PGND Main Power Ground 6 PV Main Power Supply Signal Power Supply IN 8 PGOOD Power Good Pin 9 V Output Feedback Pin ...
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... OUT 0.10 0. (V) IN Efficiency vs Frequency 100 OUT I OUT 125 FREQUENCY (MHz) LTC3411 Frequency 1.8V OUT 1.25A OUT –2 –4 –6 –8 – (V) IN 3411 G08 R ...
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... LTC3411 W BLOCK DIAGRA 0.8V VOLTAGE REFERENCE + – 0.74V – + – 0.86V PGOOD 8 6 SGND LIMIT BCLAMP B – ERROR + AMPLIFIER V B BURST COMPARATOR HYSTERESIS = 80mV OSCILLATOR LOGIC 1 2 SHDN/R SYNC/MODE PMOS CURRENT COMPARATOR + – SLOPE 4 SW ...
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... For lower output voltage ripple at low currents, pulse skipping mode can be used. In this mode, the LTC3411 continues to switch at a constant frequency down to very low currents, where it will eventually begin skipping pulses. ...
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... The choice of which style induc- tor to use often depends more on the price vs size require- ments and any radiated field/EMI requirements than on what the LTC3411 requires to operate. Table 1 shows some , where I is the peak switch current limit. LIM ...
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... U U APPLICATIO S I FOR ATIO typical surface mount inductors that work well in LTC3411 applications. Table 1. Representative Surface Mount Inductors MANU- FACTURER PART NUMBER VALUE CURRENT DCR HEIGHT Toko A914BYW-2R2M-D52LC 2.2 H Toko A915AY-2ROM-D53LC 2 H Coilcraft D01608C-222 2.2 H Coilcraft LP01704-222M 2.2 H Sumida CDRH4D282R2 2.2 H Sumida CDC5D232R2 2.2 H Taiyo Yuden N06DB2R2M 2 ...
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... Other capacitor types include the Panasonic specialty polymer (SP) capacitors. In most cases, 0 ceramic capacitors should also be placed close to the LTC3411 in parallel with the main capacitors for high frequency decoupling. Ceramic Input and Output Capacitors Higher value, lower cost ceramic capacitors are now becoming available in smaller case sizes ...
Page 11
... Pin Interfacing and External Soft-Start the internal peak inductor current. Power supply sequenc- ing can also be accomplished using this pin. The LTC3411 has an internal digital soft-start which steps up a clamp on I over 1024 clock cycles, as can be seen in Figure 4. TH The soft-start time can be increased by ramping the ...
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... LTC3411 U U APPLICATIO S I FOR ATIO The LTC3411 can also be synchronized to an external clock signal by the SYNC/MODE pin. The internal oscillator frequency should be set to 20% lower than the external clock frequency to ensure adequate slope compensation, since slope compensation is derived from the internal oscillator ...
Page 13
... ...) where L1, L2, etc. are the individual losses as a percentage of input power. Although all dissipative elements in the circuit produce losses, four main sources usually account for most of the losses in LTC3411 circuits: 1) LTC3411 switching losses losses, 4) other losses. W ...
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... RISE AMBIENT As an example, consider the case when the LTC3411 is in dropout at an input voltage of 3.3V with a load current of 1A. From the Typical Performance Characteristics graph of Switch Resistance, the R DS(ON) P-channel switch is 0.11 . Therefore, power dissipated by the part is • ...
Page 15
... R2 is then 887k. The compensation should be optimized for these compo- nents by examining the load step response but a good place to start for the LTC3411 is with a 13k and 1000pF filter. The output capacitor may need to be increased depending on the actual undershoot during a load step. ...
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... SGND NOTE: IN DROPOUT, THE OUTPUT TRACKS THE INPUT VOLTAGE C1, C2: TAIYO YUDEN JMK325BJ226MM L1: TOKO A914BYW-2R2M (D52LC SERIES) Figure 7. General Purpose Buck Regulator Using Ceramic Capacitors 16 R5 100k PGOOD PGOOD IN SW LTC3411 SYNC/MODE SHDN 3.3V 2.5V SGND PGND R4 R1A R1B 324k ...
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... SHDN 324k L1: TOKO A915AY-3R3M (D53LC SERIES) M1: SILICONIX Si2302DS Efficiency vs Load Current 1MHz 2. 3. 100k LOAD CURRENT (mA) 3411 TA03 LTC3411 D1 V OUT 3.3V/ + 400mA 3411 TA02 1000 sn3411 3411fs 17 ...
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... TOKO A914BYW-2R2M (D52LC SERIES) Efficiency vs Load Current 100 95 3.3V 1. 2.4V IN Burst Mode OPERATION 60 10 100 1000 LOAD CURRENT (mA) 3211 TA07 SYNC/MODE 2 PGOOD LTC3411 887k 22 F SHDN SGND PGND 412k 3411 TA06 10000 V OUT 1.8V/1.2A sn3411 3411fs ...
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... TOP AND BOTTOM OF PACKAGE MS10 Package 10-Lead Plastic MSOP (Reference LTC DWG # 05-08-1661) DETAIL “A” 0.254 (.010) 0 – 6 TYP GAUGE PLANE 0.53 0.01 (.021 .006) DETAIL “A” 0.18 (.007) LTC3411 R = 0.115 TYP 6 10 1.65 0.10 3.00 0.10 (2 SIDES) (4 SIDES) 5 0.75 0.05 2.38 0.10 (2 SIDES) 0.00 – 0.05 BOTTOM VIEW—EXPOSED PAD 3 ...
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... ThinSOT is a trademark of Linear Technology Corporation. Linear Technology Corporation 20 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 2mm Height, 2MHz, Li-Ion to 1.8V Converter R5 C1 100k PGOOD PGOOD LTC3411 C4 22pF 1 H SYNC/MODE SGND PGND SHDN/R T 698k 15k R4 C3 154k ...