LTC3872 Linear Technology, LTC3872 Datasheet
LTC3872
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LTC3872 Summary of contents
Page 1
... High switching frequency of 550kHz allows the use of a small inductor. The LTC3872 is available in an 8-lead low profi le (1mm) ThinSOT DFN package. , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. ...
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... RUN/ IPRG DDB PACKAGE 8-LEAD (3mm × 2mm) PLASTIC DFN = 125°C, θ 76°C/W JMAX JA EXPOSED PAD (PIN 9) IS GND MUST BE SOLDERED TO PCB DDB PART MARKING LTC3872EDDB LCHT MIN TYP ● 2.75 250 8 20 ● 2.3 2.45 ● 2.05 2.3 ● 0.6 0.85 0.7 0.95 ● ...
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... Note 4: The dynamic input supply current is higher due to power MOSFET gate charging (Q Note 5: The LTC3872 is tested in a feedback loop which servos V the reference voltage with the I range (0.7V ≤ V Note 6: Rise and fall times are measured at 10% and 90% levels Voltage Line Regulation 1 ...
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... LTC3872 W TYPICAL PERFOR A CE CHARACTERISTICS Shutdown www.datasheet4u.com (V) IN Gate Drive Rise and Fall Time vs C LOAD 100 RISE TIME 60 FALL TIME 2000 4000 6000 8000 C (pF) LOAD ...
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... Exposed Pad (NA/Pin 9): Ground. Must be soldered to PCB for electrical contact and rated thermal performance VOLTAGE 1.2V REFERENCE + I TH BUFFER – CURRENT LIMIT CLAMP ERROR AMPLIFIER – LTC3872 GND SW SLOPE COMPENSATION – + CURRENT COMPARATOR I LIM 550kHz OSCILLATOR LATCH SWITCHING LOGIC CIRCUIT 1 ...
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... The average inductor current will therefore rise until it equals the load current, thereby maintaining output regulation. The LTC3872 can be used either by sensing the voltage drop across the power MOSFET or by connecting the SW pin to a conventional sensing resistor in the source of the power MOSFET. Sensing the voltage across the power MOSFET maximizes converter effi ...
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... The LTC3872 has a built-in circuit that allows the extension of the maximum duty cycle while keeping the minimum switch off time unchanged. This is accomplished by reducing the clock frequency when the duty cycle is close to 80% ...
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... New designs for surface mount inductors are available from Coiltronics, Coilcraft, Toko and Sumida. Power MOSFET Selection The power MOSFET serves two purposes in the LTC3872: it represents the main switching element in the power path and its R for the control loop. Important parameters for the power ...
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... 100 3872 G03 LTC3872 is the maximum voltage drop across the is typically 270mV, 170mV SENSE(MAX) term accounts for the temperature T of the MOSFET, which is typically DS(ON) over temperature for a typical power MOSFET ...
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... LTC3872 U U APPLICATIO S I FOR ATIO result, some iterative calculation is normally required to determine a reasonably accurate value. Since the controller is using the MOSFET as both a switching and a sensing www.datasheet4u.com element, care should be taken to ensure that the converter is capable of delivering the required load current over all operating conditions (line voltage and temperature), and for the worst-case specifi ...
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... An excellent choice is AVX TPS series of surface mount tantalum. Also, ceramic capacitors are now available with extremely low ESR, ESL and high ripple current ratings. – MIN ( ) IN MIN ( ) LTC3872 OUT OUT L 5a. Circuit Diagram ...
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... Although all dissipative elements in the circuit produce losses, four main sources usually account for the majority of the losses in LTC3872 application circuits: 1. The supply current into V IN sum of the DC supply current I Characteristics) and the MOSFET driver and control cur- rents ...
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... The inductor ripple current is: Δ And so the inductor value is 3872 F06 The component chosen is a 2.2μH inductor made by Sumida (part number CEP125-H 1ROMH). LTC3872 to its steady-state value. During O can be monitored for overshoot causing a nearly instantaneous drop in O ⎛ ⎞ ...
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... For this particular design two 22μF Taiyo Yuden ceramic R ITH C ITH BOLD LINES INDICATE HIGH CURRENT PATHS Figure 7. LTC3872 Layout Diagram (See PC Board Layout Checklist capacitors (JMK325BJ226MM) is required (the input and return lead lengths are kept to a few inches. As with ...
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... NGATE M1 FB 11.8k 1% 107k 1% COUT1: TAIYO YUDEN TMK325BJ226MM L1: COILTRONICS DR125-2R2 M1: FAIRCHILD FDS6064N3 V OUT 12V AC COUPLED I L 5A/DIV I LOAD 1A/DIV STEP FROM 100μs/DIV LTC3872 10μF PDS1040 V OUT 12V + C OUT1 1.5A C OUT2 22μF 120μF ×2 3872 F08 3872 F09 3872fa ...
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... OUT2 ´ 2 3872 TA03 High Effi ciency 5V Input, 24V Output Boost Converter 4.7M 0.068μF I RUN/ IPRG L1 8.2μH LTC3872 GND NGATE FB 1% 232k TAIYO YUDEN GMK316BJ106ML OUT1 L1: WURTH WE-HCF 8.2μH 744392-820 M1: SILICONIX Si4884DY 500mA/DIV STEP FROM 100mA TO 600mA ...
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... OUT1 D1: DIODES, INC. PDS760 L1: SUMIDA CDEP147 M1: VISHAY SILICONIX Si7850DP 200mA/DIV 500mV/DIV AC COUPLED 3872 TA05b Effi ciency 100 100 LOAD (mA) LTC3872 10μ OUT 48V + C OUT1 C 0.5A OUT2 2.2μF 68μF ×3 3872 TA05 Load Step ...
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... LTC3872 PACKAGE DESCRIPTIO www.datasheet4u.com 0.61 ±0.05 (2 SIDES) 2.55 ±0.05 1.15 ±0.05 0.25 ± 0.05 RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS PIN 1 BAR TOP MARK (SEE NOTE 6) 0.200 REF 18 U DDB Package 8-Lead Plastic DFN (3mm × 2mm) (Reference LTC DWG # 05-08-1702 Rev B) 0.70 ±0.05 PACKAGE OUTLINE 0.50 BSC 2.20 ± ...
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... U TS8 Package 8-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1637) 0.65 REF 1.22 REF 1.50 – 1.75 2.80 BSC 1.4 MIN (NOTE 4) 0.65 BSC 0.80 – 0.90 1.00 MAX 0.09 – 0.20 (NOTE 3) LTC3872 2.90 BSC (NOTE 4) PIN ONE ID 0.22 – 0.36 8 PLCS (NOTE 3) 0.01 – 0.10 1.95 BSC TS8 TSOT-23 0802 19 3872fa ...
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... FAX: (408) 434-0507 U 3.3V Input, 5V/2A Output Boost Converter 47pF 1 M 1nF 1.8nF 17.4k I RUN/ IPRG IN LTC3872 GND SW V NGATE M1 FB 11k 1% 34.8k 1% D1: DIODES, INC B320 L1: TOKOFDV0630-1R0 M1: SILICONIX Si3460DV COMMENTS 300kHz Fixed Frequency, Boost, SEPIC, Flyback Topology SO-8; 300kHz Operating Frequency; Buck, Boost, SEPIC Design; ...