ltc3612 Linear Technology Corporation, ltc3612 Datasheet
ltc3612
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ltc3612 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 LTC3612 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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... LTC3612IUDC#PBF LTC3612IUDC#TRPBF LTC3612EFE#PBF LTC3612EFE#TRPBF LTC3612IFE#PBF LTC3612IFE#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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... Forced Continuous Mode –5μA < I < 5μA (Note 4) ITH (Note 4) V from 0.06V to 0.54V, FB TRACK/ (Note RT/SYNC = 370k RT/SYNC 5.5V RUN LTC3612 MIN TYP MAX UNITS 2.25 5.5 1.7 2.25 0.594 0.6 0.606 0.591 0.609 0.289 0.3 0.311 0.489 0.5 0.511 ±30 nA 0.2 %/V 0. ...
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... Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: The LTC3612E is guaranteed to meet performance specifi cations from 0°C to 85°C. Specifi cations over the –40°C to 85°C operating junction temperature range are assured by design, characterization and correlation with statistical process controls. The LTC3612I is guaranteed over the full – ...
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... MODE 5.50 Load Step Transient in Pulse-Skipping Mode V OUT 200mV/DIV I L 1A/DIV V = 1.8V 50μs/DIV OUT I = 100mA TO 3A LOAD V = 3.3V MODE COMPENSATION FIGURE 1 LTC3612 V = 3.3V, RT/SYNC = SV unless otherwise noted Load Regulation 1.5 = 1.8V FORCED CONTINUOUS MODE INTERNAL Burst Mode OPERATION 1.3 PULSE-SKIPPING MODE 1.1 0.9 0.7 0.5 0.3 0.1 1μH 0.68μH –0.1 0.33μ ...
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... LTC3612 TYPICAL PERFORMANCE CHARACTERISTICS Load Step Transient in Forced Continuous Mode without AVP Mode V OUT 200mV/DIV I L 1A/DIV 3612 G13 V = 1.8V 50μs/DIV OUT I = 100mA TO 3A LOAD V = 1.5V MODE COMPENSATION FIGURE 1 Sinking Current V OUT 20mV/DIV SW 2V/DIV I L 500mA/DIV 3612 G16 V = 1.2V 1μs/DIV ...
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... TEMPERATURE (°C) Dynamic Supply Current vs Temperature without AVP Mode 100 FORCED CONTINUOUS MODE 10 PULSE-SKIPPING MODE 1 Burst Mode OPERATION 0.1 0.01 –50 –30 – TEMPERATURE (°C) LTC3612 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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... RUN (Pin 15/Pin 2): Enable Pin. Forcing this pin to ground shuts down the LTC3612. In shutdown, all functions are disabled and the chip draws <1μA of supply current 3.3V, RT/SYNC = SV unless otherwise noted. ...
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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 LTC3612 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. Exposed Pad (Pin 21/Pin 21): Power Ground (PGND). ...
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... LTC3612 FUNCTIONAL BLOCK DIAGRAM SV SGND RT/SYNC IN BANDGAP RUN AND OSCILLATOR BIAS R – + FOLDBACK AMPLIFIER – 0. – TRACK/SS SOFT-START + 0.55V – + – 0.65V PGOOD 10 ITH ITH SENSE COMPARATOR + INTERNAL 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 LTC3612 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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... ITH pin is externally set by the voltage on the MODE pin. Pulse-Skipping Mode Operation Pulse-skipping mode is similar to Burst Mode operation, but the LTC3612 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 LTC3612, the input voltage and the inductor value. This foldback behavior helps in limiting the peak inductor APPLICATIONS INFORMATION The basic LTC3612 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 LTC3612. The size of capacitor C depends on parasitic capacitance SYNC on the RT/SYNC pin and is typically in the range of 10pF ...
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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 LTC3612 applications. Input Capacitor (C ) Selection IN In continuous mode, the source current of the top P-chan- ...
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... LTC3612 APPLICATIONS INFORMATION where f = operating frequency, C OSC tance and ΔI = ripple current in the inductor. The output L ripple is highest at maximum input voltage since ΔI increases with input voltage. In surface mount applications, multiple capacitors may have to be paralleled to meet the capacitance, ESR or RMS current handling requirement of the application ...
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... OUT current steps. Since the control loop cannot respond this fast, the output capacitors must supply the load current to its OUT until the control loop can respond. can OUT LTC3612 and C ) shown in Fig and the bandwidth of the loop increased by ...
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... External Reference Input sections. Soft-Start The RUN pin provides a means to shut down the LTC3612. Tying the RUN pin to SGND places the LTC3612 in a low quiescent current shutdown state (I When the LTC3612 is enabled by pulling the RUN pin high, the chip enters a soft start-up state. The type of soft start- up behavior is set by the TRACK/SS pin: 1 ...
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... IN 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 LTC3612 is turned on, the TRACK/SS pin is internally pulled down for ten microseconds in order to discharge the external capacitor. This discharging time is typically adequate for capacitors up to about 33nF ...
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... OUT2 R1/R2 < R5/R6 V FB2 LTC3612 TRACK/SS2 LTC3612 CHANNEL 2 LTC3612 CHANNEL 1 SLAVE Figure 6b. Setup for Ratiometric Tracking External Reference Input (DDR Mode) If the DDR pin is tied to SV (DDR mode), the run state IN is entered when V exceeds 0.3V and tracking TRACK/SS down behavior is possible if the V below 0 ...
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... Figure 7. DDR Pin Not Tied to S EXTERNAL VOLTAGE REFERENCE 0.45V RUN STATE REDUCED STATE SWITCHING t > 1ms FREQUENCY SS DOWN TRACKING STATE . Example DDR Application IN LTC3612 TIME RUN STATE 3612 F07 UP TRACKING STATE VIN TIME RUN STATE 3612 F08 UP TRACKING STATE 3612f 21 ...
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... A RISE where T is the ambient temperature example, consider the case when the LTC3612 is in dropout at an input voltage of 3.3V with a load current ambient temperature of 70°C. From the Typical Performance Characteristics graph of Switch Resistance, the R resistance of the P-channel switch is 0.075Ω. ...
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... SGND pin at one point which is then connected to the PGND pin close to the LTC3612. 2. Connect the (+) terminal of the input capacitor(s close as possible to the PV as close as possible to the exposed pad, PGND. This capacitor provides the AC current into the internal power MOSFETs ...
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... OUTPUT CURRENT (mA 22μF 24Ω 1μ RUN TRACK/SS RT/SYNC LTC3612 R4 100k PGOOD PGOOD ITH C R5A C1 MODE 10pF 1M R5B 1M L1: VISHAY IHLP-1616BZ-01 0.47μH V OUT 200mV/DIV I L 1A/DIV ...
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... C F2 1μ RUN PV TRACK/SS RT/SYNC LTC3612 R7 100k PGOOD PGOOD ITH C4 MODE V L1, L2: VISHAY IHLP-1616BZ-01 1μH V OUT1 V OUT2 500mV/DIV 3612 TA03b LTC3612 IN IN_DRV CHANNEL 1 DDR MASTER L1 1μ O11 O12 SGND 47μF 22μF PGND 715k 464k 22pF 357k ...
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... LTC3612 PACKAGE DESCRIPTION 3.50 ± 0.05 2.10 ± 0.05 1.50 REF 1.65 ± 0.05 0.25 ±0.05 0.50 BSC RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED PIN 1 TOP MARK (NOTE 6) 4.00 ± 0.10 NOTE: 1. DRAWING IS NOT A JEDEC PACKAGE OUTLINE 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4 ...
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... BSC 0.195 – 0.30 (.0077 – .0118) 4. RECOMMENDED MINIMUM PCB METAL SIZE FOR EXPOSED PAD ATTACHMENT MILLIMETERS (INCHES) *DIMENSIONS DO NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.150mm (.006") PER SIDE LTC3612 6.40 – 6.60* (.252 – .260) 3.86 (.152 6.40 2.74 (.252) ( ...
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... LTC3418 5.5V 4MHz, Synchronous Step-Down DC/DC Converter OUT 28 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 ● , 1MHz IN_DRV DDR L1 LTC3612 1μ 0. ±1.5A 100μF 47μF SGND PGND R1 MODE V FB 200k C3 R2 ...