LTC3614 LINER [Linear Technology], LTC3614 Datasheet
LTC3614
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LTC3614 Summary of contents
Page 1
... Mode operation load, dropping to zero current in shutdown. The 2.25V to 5.5V input supply voltage range makes the LTC3614 ideally suited for single Li-Ion as well as fi xed low voltage input applications. 100% duty cycle capability provides low dropout operation, extending the operating time in battery-powered systems ...
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... LTC3614EUDD#PBF LTC3614EUDD#TRPBF LTC3614IUDD#PBF LTC3614IUDD#TRPBF Consult LTC Marketing for parts specifi ed with wider operating temperature ranges. *The temperature grade is identifi label on the shipping container. 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 ...
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... ITH (Note 4) V from 0.06V to 0.54V, FB TRACK/ (Note RT/SYNC = 370k RT/SYNC 5.5V RUN LTC3614 unless otherwise specifi ed (Notes 1, 2, 11). MIN TYP MAX UNITS 2.25 5.5 1.7 2.25 0.594 0.6 0.606 0.591 0.609 0.288 0.300 0.312 0.488 0.500 0.512 ±30 0.2 %/V 0 ...
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... The LTC3614I is guaranteed to meet specifi cations over the full –40°C to 125°C operating junction temperature range. Note that the maximum ambient temperature is determined by specifi c operating conditions in conjunction with board layout, the rated package thermal resistance and other environmental factors ...
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... OUT MODE Load Step Transient in Pulse-Skipping Mode V OUT 100mV/DIV I LOAD 2A/DIV 100μs/DIV V = 1.8V OUT I = 100mA TO 4A LOAD V = 3.3V MODE COMPENSATION FIGURE 1 LTC3614 V = 3.3V, RT/SYNC = SV unless otherwise noted Load Regulation (V = 1.8V) OUT 1.5 = 3.3V FORCED CONTINUOUS MODE = 1.8V PULSE-SKIPPING MODE 1.3 INTERNAL Burst Mode OPERATION 1.1 0.9 0.7 0.5 0.3 0.1 150nH 330nH – ...
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... LTC3614 TYPICAL PERFORMANCE CHARACTERISTICS Load Step Transient in Forced Continuous Mode without AVP Mode V OUT 100mV/DIV I LOAD 2A/DIV 3614 G13 100μs/DIV V = 1.8V OUT I = 100mA TO 4A 1.5V LOAD MODE COMPENSATION FIGURE 1 Sinking Current V OUT 100mV/DIV SW 2V/DIV I L 2A/DIV 3614 G16 1μs/DIV V = 1.8V OUT I = – ...
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... Dynamic Supply Current vs Temperature without AVP Mode 100 FREQ = 2.25MHz FORCED CONTINUOUS MODE 10 PULSE-SKIPPING MODE 1 Burst Mode OPERATION 0.1 0.01 –50 –30 – TEMPERATURE (°C) LTC3614 V = 3.3V, RT/SYNC = SV unless otherwise noted Frequency vs Temperature 0.8 0.6 0.4 0.2 0 –0.2 –0.4 –0.6 –0.8 –1.0 –1.2 –50 –30 – ...
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... Connecting a resistor from RT/SYNC to ground will set the switching frequency based on the resistor value. 2. Driving the RT/SYNC pin with an external clock signal will synchronize the LTC3614 to the applied frequency. The slope compensation is automatically adapted to the external clock frequency. 3. Tying the RT/SYNC pin ...
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... IN circuit. 2. External soft-start timing can be programmed with a capacitor to ground and a resistor TRACK/SS can be used to force the LTC3614 to track the start-up behavior of another supply. The pin can also be used as external reference input. See the Applications Information section for more information. PGND (Exposed Pad Pin 25): Power Ground. This pin connects to the source of the internal N-channel power MOSFET. This pin should be connected close to the (– ...
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... LTC3614 FUNCTIONAL BLOCK DIAGRAM SV SGND RT/SYNC IN BANDGAP RUN OSCILLATOR AND BIAS R – + FOLDBACK AMPLIFIER – 0. – TRACK/SS SOFT-START + 0.555V – + – 0.645V PGOOD 10 ITH ITH SENSE COMPARATOR + COMPENSATION – SV – 0.3V IN PMOS CURRENT ITH COMPARATOR LIMIT ERROR AMPLIFIER BURST COMPARATOR – ...
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... This increases effi ciency by minimizing switching losses. During the intervals when the switches are idle, the LTC3614 enters sleep state where many of the internal circuits are disabled to save power. During Burst Mode operation, the minimum peak inductor current is internally ...
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... Pulse-Skipping Mode Operation Pulse-skipping mode is similar to Burst Mode operation, but the LTC3614 does not disable power to the internal circuitry during sleep mode. This improves output voltage ripple but uses more quiescent current, compromising light load effi ciency. ...
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... ITH pin drops to 40% of the clamp voltage during normal operation. The short-circuit peak inductor current is determined by the minimum on-time of the LTC3614, the input voltage and the inductor value. This foldback behavior helps in limiting the peak inductor APPLICATIONS INFORMATION The basic LTC3614 application circuit is shown in Figure 1 ...
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... RT/SYNC pin in order to reduce inductor current ripple. AC coupling should be used if the external clock genera- tor cannot provide a continuous clock signal throughout start-up, operation and shutdown of the LTC3614. The size of capacitor C depends on parasitic capacitance SYNC on the RT/SYNC pin and is typically in the range of 10pF to 22pF ...
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... The choice of which style inductor to use mainly depends on the price versus size requirements and any radiated fi eld/EMI requirements. Table 1 shows some typical surface mount inductors that work well in LTC3614 applications. Input Capacitor (C ) Selection IN In continuous mode, the source current of the top P-channel ...
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... LTC3614 APPLICATIONS INFORMATION Output Capacitor (C ) Selection OUT The selection typically driven by the required OUT ESR to minimize voltage ripple and load step transients (low ESR ceramic capacitors are discussed in the next section). Typically, once the ESR requirement is satisfi ed, the capacitance is adequate for fi ltering. The output ripple Δ ...
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... C1 voltage settings, helps fi lter out any high frequency noise that may couple onto that node. The fi rst circuit in the Typical Applications section uses faster compensation to improve step response. LTC3614 . This sets I IN BURST shifts by an amount equal OUT , where ESR is the effective series resistance ...
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... COMPENSATION FIGURE 1 Figure 3. Load Step Transient Forced Continuous Mode (AVP Inactive) 18 Consider the LTC3614 without AVP with a bank of tantalum output capacitors load step with very fast slew rate occurs, the voltage excursion will be seen in both direc regulator can tions, for full load to minimum load transient and for the OUT minimum load to full load transient ...
Page 19
... SS 3. The TRACK/SS pin can be used to track the output voltage of another supply. Each time the RUN pin is tied high and the LTC3614 is turned on, the TRACK/SS pin is internally pulled down , lower IN for ten microseconds in order to discharge the external capacitor ...
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... LTC3614 APPLICATIONS INFORMATION The LTC3614 allows the user to control the slew rate of the switching node SW by using the SRLIM/DDR pin. Tying this pin to ground selects the fastest slew rate. The slow- est slew rate is selected when the pin is open. Connecting a resistor (between 10k and 100k) from SRLIM pin to ground adjusts the slew rate between the maximum and minimum values ...
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... Other losses including C losses and inductor core losses generally account for less than 2% of the total loss losses. The V IN LTC3614 2 R loss dominates to ground. The resulting dQ/dt is the current due to gate charge, and it is typically larger ; thus, their effects IN ...
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... LTC3614 APPLICATIONS INFORMATION 0.6V V PIN FB VOLTAGE 0V 0.6V TRACK/SS 0.2V PIN VOLTAGE RUN PIN VOLTAGE PIN IN VOLTAGE 0V SHUTDOWN SOFT-START STATE 0.45V 0.3V V PIN FB VOLTAGE 0V 0.45V 0.3V TRACK/SS 0.2V PIN VOLTAGE RUN PIN VOLTAGE PIN IN VOLTAGE 0V SHUTDOWN SOFT-START STATE t Figure 9. DDR Pin Tied to SV ...
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... A RISE where T is the ambient temperature example, consider the case when the LTC3614 is in dropout at an input voltage of 3.3V with a load current ambient temperature of 85°C. From the Typical Performance Characteristics graph of Switch Resistance, the R resistance of the P-channel switch is 0.038Ω. ...
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... LTC3614 PACKAGE DESCRIPTION Design Example As a design example, consider using the LTC3614 in an application with the following specifi cations 2.25V to 5.5V 1.8V OUT OUT(MAX) = 200mA 2.6MHz. Effi ciency is important at both high and low load current, so Burst Mode operation will be utilized. ...
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... C R5A C1 MODE 10pF 1M R5B 1M V OUT 100mV/DIV I OUT 2A/DIV 5.5V IN 10000 3614 TA02b LTC3614 0.33μH V OUT 1. SGND 100μF PGND 392k C3 R2 22pF 196k 3614 TA02a Load Step Response in Forced Continuous Mode V = 3.3V 50μs/DIV ...
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... TRACK/SS SRLIM/DDR RT/SYNC LTC3614 R5 100k PGOOD PGOOD ITH MODE 24Ω 1μ RUN TRACK/SS SRLIM/DDR RT/SYNC LTC3614 R7 100k PGOOD PGOOD ITH C4 MODE V L1, L2: VISHAY IHLP-2525CZ-01 680nH V OUT1 V OUT2 500mV/DIV 3614 TA03b IN CHANNEL 1 MASTER L1 0.68μH V OUT1 SW 1.8V C O12 ...
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... Plastic QFN (3mm × 5mm) (Reference LTC DWG # 05-08-1833) 0.70 ±0.05 3.65 ± 0.05 PACKAGE OUTLINE 3.50 REF 4.10 ± 0.05 5.50 ± 0.05 0.75 ± 0. 0.05 TYP 3.00 ± 0.10 3.50 REF 0.200 REF 0.00 – 0.05 LTC3614 PIN 1 NOTCH R = 0.20 OR 0.25 45° CHAMFER 1.50 REF 23 24 0.40 ± 0. 3.65 ± 0.10 1.65 ± 0.10 (UDD24) QFN 0808 REV Ø 0.25 ± 0. ...
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... LTC3412A 5.5V, 2. 4MHz, Synchronous Step-Down DC/DC OUT Converter 28 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 ● , 1MHz SRLIM/DDR L1 LTC3614 0.33μ 100μF 47μF SGND PGND R1 MODE V FB 200k C3 R2 22pF 200k 3614 TA04a COMMENTS 95% Effi ...