LTC3810EG LINER [Linear Technology], LTC3810EG Datasheet
LTC3810EG
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LTC3810EG Summary of contents
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FEATURES n High Voltage Operation 100V n Large 1Ω Gate Drivers n No Current Sense Resistor Required n Dual N-Channel MOSFET Synchronous Drive n Extremely Fast Transient Response n ±0.5% 0.8V Voltage Reference n Programmable Output Voltage Tracking/Soft-Start ...
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... INTV Supply Current Q CC INTV Shutdown Current CC 2 PIN CONFIGURATION PART MARKING PACKAGE DESCRIPTION LTC3810EG 28-Lead Plastic SSOP LTC3810IG 28-Lead Plastic SSOP PART MARKING PACKAGE DESCRIPTION LTC3810EG 28-Lead Plastic SSOP LTC3810IG 28-Lead Plastic SSOP http://www.linear.com/leadfree/ http://www.linear.com/tapeandreel/ l The denotes specifi cations which apply over the full operating = 25° ...
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ELECTRICAL CHARACTERISTICS temperature range, otherwise specifi cations are 10V – + MODE/SYNC SENSE SENSE SYMBOL PARAMETER I BOOST Supply Current BOOST V Feedback Voltage FB ΔV Feedback Voltage Line Regulation ...
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LTC3810 ELECTRICAL CHARACTERISTICS temperature range, otherwise specifi cations are 10V – MODE/SYNC SENSE SENSE SYMBOL PARAMETER V PGOOD Low Voltage PGOOD I PGOOD Leakage Current PGOOD PG Delay PGOOD ...
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TYPICAL PERFORMANCE CHARACTERISTICS Load Transient Response V OUT 100mV/ DIV I OUT 5A/DIV 3810 G01 V = 48V 50μs/DIV LOAD STEP FRONT PAGE CIRCUIT Short-Circuit/ Foldback Operation V OUT 5V/DIV V FB 0.5V/ DIV I L ...
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LTC3810 TYPICAL PERFORMANCE CHARACTERISTICS Frequency vs Load Current 350 300 FORCED CONTINUOUS 250 200 150 PULSE SKIP 100 50 FRONT PAGE CIRCUIT LOAD CURRENT (A) 3810 G10 On-Time vs V Voltage ON 700 I ...
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TYPICAL PERFORMANCE CHARACTERISTICS Driver Peak Source Current vs Temperature 2 10V BOOST INTVCC 2.0 1.5 1 –50 – 100 TEMPERATURE (°C) 3810 G19 Driver Pull-Down R DS(ON) vs Supply Voltage 1.1 1.0 ...
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LTC3810 TYPICAL PERFORMANCE CHARACTERISTICS INTV Shutdown Current CC vs INTV Voltage CC 300 250 200 150 100 INTV VOLTAGE ( Voltage TH vs Load Current 3.0 2.5 2.0 1.5 1.0 0.5 V ...
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PIN FUNCTIONS I (Pin 1): On-Time Current Input. Tie a resistor from this pin to set the one-shot timer current and thereby set the switching frequency. V (Pin 4): On-Time Voltage Input. Voltage trip point for ON ...
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LTC3810 PIN FUNCTIONS BG (Pin 19): Bottom Gate Drive. The BG pin drives the gate of the bottom N-channel synchronous switch MOSFET. This pin swings from BGRTN to DRV BGRTN (Pin 20): Bottom Gate Return. This pin connects to the ...
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FUNCTIONAL DIAGRAM 5V REG UVIN UV1 – UV2 + + 0.8V F MODE/SYNC – 7 PLL/LPF 10 PLL-SYNC VON (76pF) ...
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LTC3810 OPERATION Main Control Loop The LTC3810 is a current mode controller for DC/DC step- down converters. In normal operation, the top MOSFET is turned on for a fi xed interval determined by a one-shot timer (OST). When the top ...
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OPERATION Fault Monitoring/Protection Constant on-time current mode architecture provides ac- curate cycle-by-cycle current limit protection—a feature that is very important for protecting the high voltage power supply from output short circuits. The cycle-by-cycle cur- rent monitor guarantees that the inductor ...
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LTC3810 OPERATION is < 6. external supply in the appropriate range can be used. The LTC3810 will automatically detect which mode is being used and operate properly. The four possible operating modes for generating this supply are summarized ...
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APPLICATIONS INFORMATION The basic LTC3810 application circuit is shown on the fi rst page of this data sheet. External component selection is primarily determined by the maximum input voltage and load current and begins with the selection of the sense ...
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LTC3810 APPLICATIONS INFORMATION The most important parameter in high voltage applications is breakdown voltage BV . Both the top and bottom DSS MOSFETs will see full input voltage plus any additional ringing on the switch node across its drain-to-source dur- ...
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APPLICATIONS INFORMATION the period. Since there is no transition loss term in the synchronous MOSFET, optimal effi ciency is obtained by minimizing R — by using larger MOSFETs or paral- DS(ON) leling multiple MOSFETs. Multiple MOSFETs can be used in ...
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LTC3810 APPLICATIONS INFORMATION application. A good starting point is to feed about 25% of the voltage change at the I pin to the V TH shown in Figure 8. Place capacitance on the V fi lter out the I variations ...
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APPLICATIONS INFORMATION diode to be effective, the inductance between it and the bottom MOSFET must be as small as possible, mandating that these components be placed adjacently. The diode can be omitted if the effi ciency loss is tolerable. Input ...
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LTC3810 APPLICATIONS INFORMATION that have been surge tested for use in switching power supplies. Several excellent surge-tested choices are the AVX, TPS and TPSV or the KEMET T510 series. Aluminum electrolytic capacitors have signifi cantly higher ESR, but can be ...
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APPLICATIONS INFORMATION is typically much higher than 14V a separate supply for the IC power (INTV ) and driver power (DRV CC be used. The LTC3810 has integrated bias supply control circuitry that allows the IC/driver supply to be easily ...
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LTC3810 APPLICATIONS INFORMATION The external NMOS for the linear regulator should be a standard 3V threshold type (i.e., not a logic level threshold). The rate of charge of INTV from 0V to 10V is controlled CC by the LTC3810 to ...
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APPLICATIONS INFORMATION Using an External Supply Connected to the INTV DRV Pins external supply is available between 6.2V and 14V, the supply can be connected directly to the INTV pins. In this mode, INTV , EXTV CC ...
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LTC3810 APPLICATIONS INFORMATION FEEDBACK LOOP/COMPENSATION Feedback Loop Types In a typical LTC3810 circuit, the feedback loop consists of the modulator, the output fi lter and load, and the feedback amplifi er with its compensation network. All of these components affect ...
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APPLICATIONS INFORMATION Feedback Component Selection Selecting the R and C values for a typical Type 2 or Type 3 loop is a nontrivial task. The applications shown in this data sheet show typical values, optimized for the power components shown. ...
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LTC3810 APPLICATIONS INFORMATION With the gain/phase plot in hand, a loop crossover fre- quency can be chosen. Usually the curves look something like Figure 13. Choose the crossover frequency about 25% of the switching frequency for maximum bandwidth. Al- though ...
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APPLICATIONS INFORMATION where H(s) was given in Equation 2 and A(s) depends on compensation circuit used: Type • R3 • ( • • R • • ...
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LTC3810 APPLICATIONS INFORMATION voltage V below which continuous operation is OUT2(MIN) forced until V has risen above its minimum. OUT2 OUT2(MIN) R3 Table 1. MODE/SYNC PIN CONDITION DC Voltage 0.75V Forced Continuous Current ...
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APPLICATIONS INFORMATION Output Voltage Tracking The LTC3810 allows the user to program how its output ramps up by means of the TRACK/SS pin. Through this pin, the output can be set up to either coincidentally or ratiometrically track with another ...
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LTC3810 APPLICATIONS INFORMATION error on the tracking voltage depending on the absolute values of the tracking resistive divider. By selecting different resistors, the LTC3810 can achieve different modes of tracking including the two in Figure 15. So which mode should ...
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APPLICATIONS INFORMATION is less than f , current is sunk continuously, pulling down O the PLL/LPF pin. If the external and internal frequencies are the same but exhibit a phase difference, the current sources turn on for an amount of ...
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LTC3810 APPLICATIONS INFORMATION Checking Transient Response The regulator loop response can be checked by looking at the load transient response. Switching regulators take several cycles to respond to a step in load current. When load step occurs, V immediately shifts ...
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APPLICATIONS INFORMATION Since power dissipation at V IN(MIN) 0.4W, calculate R such that fault timeout is NDRV(MAX) always enabled: 36V 10V – 3.5V = 83.3k R NDRV 270μA So, choose R = 80.6k. NDRV C is chosen for an RMS ...
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LTC3810 APPLICATIONS INFORMATION C ON 100pF 20k 80.6k PGOOD 250kHz CLOCK 0.01μF 10k UV1 1000pF 470k SHDN R C UV2 C2 12k 47pF 200k FB2 1k Figure 19. 36V to 72V Input Voltage to ...
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TYPICAL APPLICATIONS 15V to 80V Input Voltage to 3.3V/5A with Fault Timeout 100pF PGOOD C SS 1000pF SHDN C C2 47pF C R 5pF C R FB2 200k 1.89k PACKAGE DESCRIPTION 7.8 – 8.2 0.42 ±0.03 RECOMMENDED SOLDER ...
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LTC3810 TYPICAL APPLICATION 15V to 100V Input Voltage to 12V/5A with Trickle Charger Start- 261k C ON 100pF PGOOD R UV1 470k C SS 1000pF SHDN R C UV2 C2 28k 47pF 5pF C R ...