ltc1624 Linear Technology Corporation, ltc1624 Datasheet
ltc1624
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ltc1624 Summary of contents
Page 1
... Burst Mode is a trademark of Linear Technology Corporation. 4.8V TO 28V 1000pF – SENSE V IN BOOST I /RUN TH M1 LTC1624 Si4412DY 100pF 0 GND D1 MBRS340T3 Figure 1. High Efficiency Step-Down Converter LTC1624 High Efficiency SO-8 Regulator Controller RUN) allows external SENSE 0.05 35V OUT 3. 35.7k ...
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... 2mA to 20mA BOOST Note 2: The LTC1624 is tested in a feedback loop which servos V the midpoint for the error amplifier (V Note 3: Dynamic supply current is higher due to the gate charge being and power delivered at the switching frequency. See Applications Information ...
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... G11 Boost Load Regulation 15V BOOST LOAD CURRENT (mA) 1624 G06 LTC1624 Efficiency vs Load Current OUT 100 OUT V = 10V 0.033 SENSE 0.001 0.01 0 LOAD CURRENT (A) ...
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... LTC1624 W U TYPICAL PERFORMANCE CHARACTERISTICS V vs Output Current ITH 2.4 ACTIVE MODE 1.2 0.8 SHUTDOWN OUT(MAX) OUT(MAX) I OUT (a) 1624 G01 Frequency vs Feedback Voltage 250 200 150 100 0.25 0.50 0.75 1.00 1.25 FEEDBACK VOLTAGE 1624 G03 PIN FUNCTIONS – SENSE (Pin 1): Connects to the (–) input for the current comparator ...
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... TH pin, Low Current Operation FB The LTC1624 is capable of Burst Mode operation in which the external MOSFET operates intermittently based on load demand. The transition to low current operation begins when comparator B detects when the I voltage is below 1.5V. If the voltage across R not exceed the offset of I full cycle, then on following cycles the top and internal bottom drives are disabled ...
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... LTC1624 U U FUNCTIONAL DIAGRA 6 W (Shown in a step-down application) ...
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... U U APPLICATIONS INFORMATION The LTC1624 can be used in a wide variety of switching regulator applications, the most common being the step- down converter. Other switching regulator architectures include step-up, SEPIC and positive-to-negative converters. The basic LTC1624 step-down application circuit is shown in Figure 1 on the first page. External component selection ...
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... INFORMATION Step-Down Converter: Power MOSFET Selection One external N-channel power MOSFET must be selected for use with the LTC1624 for the top (main) switch. The peak-to-peak gate drive levels are set by the INTV voltage. This voltage is typically 5V. Consequently, logic level threshold MOSFETs must be used in most LTC1624 applications ...
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... MOSFET gate drivers. High input voltage applications in which large MOSFETs are being driven at high frequencies may cause the maxi- mum junction temperature rating for the LTC1624 to be exceeded. The supply current is dominated by the gate charge supply current as discussed in the Efficiency Considerations section ...
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... Function TH The I /RUN pin is a dual purpose pin that provides the TH loop compensation and a means to shut down the LTC1624. Soft start can also be implemented with this pin. Soft start reduces surge currents from V by gradually increasing IN the internal current limit. Power supply sequencing can also be accomplished using this pin ...
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... Percent efficiency can be expressed as: %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, four main sources usually account for most of the losses in LTC1624 circuits: 1. LTC1624 V current losses 3 ...
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... The point when the minimum on-time (450ns) is reached determines the load current when cycle skipping begins at approximately 1% of maximum output current. Using the circuit in Figure 5 the LTC1624 will begin to skip cycles but stays in regula- tion when I I OUT MIN ...
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... MAX SENSE times of the internal circuitry the minimum recommended on-time is 450ns. Since the LTC1624’s frequency is inter- nally set to 200kHz a potential duty cycle limitation exists. When the duty cycle is less than 9%, cycle skipping may occur which increases the inductor ripple current but does ...
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... Boost Converters: Power MOSFET Selection One external N-channel power MOSFET must be selected for use with the LTC1624 for the switch. In boost applica- tions the source of the power MOSFET is grounded along with the SW pin. The peak-to-peak gate drive levels are set by the INTV voltage ...
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... The input voltage source imped- ance determines the size of the capacitor that is typically 100 F. A low ESR is recommended although not as critical as the output capacitor and can be on the order of 0.3 . Input capacitor ripple current for the LTC1624 used as a boost converter is ...
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... SEPIC Converter: Power MOSFET Selection One external N-channel power MOSFET must be selected for use with the LTC1624 for the switch boost applications the source of the power MOSFET is grounded along with the SW pin. The peak-to-peak gate drive levels are set by the INTV voltage ...
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... I I less half the peak-to-peak ripple current, I L1(PEAK) divided by the output-input voltage ratio (see equation for I ) L1(PEAK) . Allowing a margin for variations in the LTC1624 (without considering variation assuming 30% ripple SENSE current in the inductor, yields MIN 100 mV ...
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... Positive-to-Negative Converter: Power MOSFET Selection One external N-channel power MOSFET must be selected for use with the LTC1624 for the switch step-down applications the source of the power MOSFET is con- nected to the Schottky diode and inductor. The peak-to- peak gate drive levels are set by the INTV gate drive voltage is equal to approximately 5V for V 5 ...
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... I RSS I less half the peak-to-peak ripple current with the L(PEAK) remainder divided by the duty cycle. Allowing a margin for variations in the LTC1624 (without considering variation in R current in the inductor, yields: R SENSE Positive-to-Negative Converter: Output Diode The output diode conducts current only during the switch off-time ...
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... LTC1624. These items are also illustrated graphically in the layout diagram of Figure 9. Check the following in your IN layout: 1. Are the signal and power grounds segregated? The LTC1624 ground (Pin 4) must return to the (–) plate of C OUT. 2. Does the V resistors? The resistive divider R1, R2 must be con- ...
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... U TYPICAL APPLICATIONS 100pF 4 BOLD LINES INDICATE HIGH CURRENT PATHS Figure 9. LTC1624 Layout Diagram (See Board Layout Checklist 560pF R C 4.7k 100pF *COILTRONICS CTX10-4 Figure 10. 5V/3A Converter with Output Derived Boost Voltage 1000pF 8 – SENSE SENSE 7 BOOST I /RUN TH LTC1624 ...
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... 0 GND Figure 12. 12V/1A Low Dropout Converter V IN 5.2V TO 11V 1000pF 8 – 0 SENSE BOOST /RUN 0. LTC1624 0 Figure 13. 12V/0.75A Boost Converter SENSE 35V 2 L1 OUT 1.8V 1. MBRS340T3 35. ...
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... Figure 15. Inverting – 5V/2A Converter 3.5V TO 18V 1000pF 1 8 – SENSE BOOST I /RUN TH LTC1624 0 GND Figure 16. Low Dropout 3.3V/1.5A Converter LTC1624 + 35V 35V MBRS130LT3 + V M1 OUT 12V Si4412DY L1b* 0.5A R2 35. OUT 1% 100 F 16V R1 2 3.92k 1% ...
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... TO 18V 1000pF R 8 SENSE V 0. CMDSH-3 V OUT 0 0.015 SENSE1 R , 0.015 SENSE2 C4, 0 LTC1624 3.3 F 3.3 F 50V 50V 8 – BOOST /RUN INTERNATIONAL RECTIFIER IRL3803 IRC LR2010-01-R015-F SENSE1 SENSE2 ...
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... LTC1624 1 8 – V SENSE BOOST I /RUN 0 GND SW R2, 1M IRC OAR-3, 0.005 , 5% SENSE Figure 20. 12V to 24V/5A Boost Converter LTC1624 OUT 90V 0. OUT 100 F 100V M1 1624 F19 D1* R5 750 0.5W M1 OUT1 OUT2 ...
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... LTC1624 U TYPICAL APPLICATIONS V IN 13V TO + 28V IN1 IN2 22 F 35V 2 R 0.033 LTC1624 1 C SENSE C 330pF GND C 100pF 3.92k 10k Q2 1 SENSE 2 I OUT 3 GND 4 – KEMET T495X226M035AS IN1 IN2 L1 = SUMIDA CDRH127-270 R = IRC LR2010-01-R033-F ...
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... Dimensions in inches (millimeters) unless otherwise noted. S8 Package 8-Lead Plastic Small Outline (Narrow 0.150) (LTC DWG # 05-08-1610) 8 0.228 – 0.244 (5.791 – 6.197 0.053 – 0.069 (1.346 – 1.752) 0 – 8 TYP 0.014 – 0.019 (0.355 – 0.483) LTC1624 SENSE 0.015 35V 3 M1** L1* ...
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... Ultralow Quiesent Current Step-Down Monolithic Switching Regulators Adaptive Power is a trademark of Linear Technology Corporation. Linear Technology Corporation 28 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 TELEX: 499-3977 www.linear-tech.com R3 SENSE 0.0082 C4, 0.1 F LTC1624 8 – SENSE BOOST I /RUN ...