LTC3703-5 Linear Technology, LTC3703-5 Datasheet
LTC3703-5
Related parts for LTC3703-5
LTC3703-5 Summary of contents
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... Strong 1 LTC3703-5 to drive multiple MOSFETs for higher current applications. The operating frequency is user program- mable from 100kHz to 600kHz and can also be synchro- nized to an external clock for noise-sensitive applications. ...
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... LTC3703 ABSOLUTE AXI U RATI GS Supply Voltages V , DRV .......................................... –0.3V to 15V CC CC (DRV – BGRTN), (BOOST – SW) ...... –0.3V to 15V CC BOOST (Continuous) ............................ –0.3V to 85V BOOST (400ms) ................................... –0.3V to 95V BGRTN ...................................................... – Voltage (Continuous) .......................... –0.3V to 70V IN V Voltage (400ms) ................................. –0.3V to 80V IN SW Voltage (Continuous) ............................ –1V to 70V SW Voltage (400ms) ................................... – ...
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... D LTC3703- • 100 C/W) G Package Note 4: The LTC3703-5 is tested in a feedback loop that servos V reference voltage with the COMP pin forced to a voltage between 1V and 2V. The denotes the specifications which apply over the full operating = DRV = ...
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... LTC3703 TYPICAL PERFOR A CE CHARACTERISTICS Efficiency vs Input Voltage 100 OUT OUT OUT f = 250kHz FORCED CONTINUOUS INPUT VOLTAGE (V) 37035 G01 V Current vs V Voltage CC CC 3.5 V RISING CC COMP = 1.5V 3.0 2.5 2 1.5 1.0 0 2.5 5 7 VOLTAGE (V) CC 37035 G04 ...
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... GATE CAPACITANCE (nF) 37035 G14 RUN/SS Sink Current vs SW Voltage 0.3V MAX –5 –10 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 |SW| VOLTAGE (V) 37035 G17 LTC3703-5 www.DataSheet4U.com Driver Peak Source Current vs Supply Voltage 3.0 2.5 2.0 1.5 1.0 0 2.5 5 7.5 10 12.5 15 DRV /BOOST VOLTAGE (V) CC 37035 G12 RUN/SS Pull-Up Current vs Temperature ...
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... LTC3703 TYPICAL PERFOR A CE CHARACTERISTICS I Current vs Temperature MAX –60 –40 – 100 TEMPERATURE ( C) 37035 G19 Shutdown Threshold vs Temperature 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0 –60 –40 –20 0 TEMPERATURE ( Duty Cycle vs COMP Voltage 100 V = 10V 50V 25V 0.5 1.00 1.25 1.50 1.75 0.75 COMP (V) 160 ...
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... BG output driving the main switch. Below 1V, the controller will operate in step-down (buck) mode. RUN/SS (Pin 7/Pin 13): Run/Soft-Start. Pulling RUN/SS be- low 0.9V will shut down the LTC3703-5, turn off both of the external MOSFET switches and reduce the quiescent sup- ply current capacitor from RUN/SS to ground will control the turn-on time and rate of rise of the output voltage at power-up ...
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... Diagram of the IC and the circuit on the first page of this data sheet. The LTC3703-5 uses voltage mode control in which the duty ratio is controlled directly by the error amplifier output and thus requires no current sense resis- tor. The V is compared to the internal 0.8V reference by the error amplifier, which outputs an error signal at the COMP pin ...
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... Fast Transient Response The LTC3703-5 uses a fast 25MHz op amp as an error am- plifier. This allows the compensation network to be opti- mized for better load transient response. The high bandwidth of the amplifier, along with high switching fre- quencies and low value inductors, allow very high loop crossover frequencies ...
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... This soft-start scheme smoothly ramps the output voltage to its regulated value, with no overshoot. The RUN/SS voltage will continue ramping until it reaches an internal 4V clamp. Then the MIN feedback comparator is enabled and the LTC3703 full operation. When the RUN/SS is low, the supply current is reduced ...
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... Pulse Skip Mode The LTC3703-5 can operate in one of two modes select- able with the MODE/SYNC pin—Pulse Skip Mode or forced continuous mode. Pulse Skip Mode is selected when increased efficiency at light loads is desired. In this mode, the bottom MOSFET is turned off when inductor current reverses to minimize the efficiency loss due to reverse current flow ...
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... With the INV pin grounded, the LTC3703-5 operates in buck mode with TG driving the main (top side) switch and BG driving the synchronous (bottom side) switch. If the INV pin is pulled above 2V, the LTC3703-5 operates in boost mode with BG driving the main (bottom side) switch and TG driving the synchronous (top side) switch ...
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... Figure 7. MODE/SYNC Clock Input and Switching Waveforms for Synchronous Operation Inductor The inductor in a typical LTC3703-5 circuit is chosen for a specific ripple current and saturation current. Given an input voltage range and an output voltage, the inductor value and operating frequency directly determine the ripple current ...
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... U APPLICATIO S I FOR ATIO appropriate breakdown specification. Since most MOSFETs in the 30V to 60V range have logic level thresholds (V 4.5V), the LTC3703-5 is designed to be used GS(MIN) with a 4.5V to 15V gate drive supply (DRV For maximum efficiency, on-resistance R capacitance should be minimized. Low R conduction losses and low input capacitance minimizes transition losses ...
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... • 100 % , fCR ) ESR is the ESR of the aluminum capacitor and primarily determined by the ESR OUT 1 I ESR OUT increases with input voltage, the output ripple is until the feedback loop in the LTC3703-5 can 37035f 15 ...
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... ESR, but can be used in cost-driven applications providing that consideration is given to ripple current ratings and long term reliability. Other capacitor types include Pana- sonic SP and Sanyo POSCAPs. Output Voltage The LTC3703-5 output voltage is set by a resistor divider according to the following formula ...
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... F09c Connection Figure 9d. Capacitive Charge Pump for V CC below the UVLO threshold, the LTC3703-5 shuts down and the gate drive outputs remain low. Bottom MOSFET Source Supply (BGRTN) The bottom gate driver, BG, switches from DRV where BGRTN can be a voltage between ground and –5V. ...
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... So far, the AC response of the loop is pretty well out of the user’s control. The modulator is a fundamental piece of the LTC3703-5 design and the external L and C are usually chosen based on the regulation and load current require- ments without considering the AC loop response. The ...
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... ESR causes the LC section to approach 180 phase shift well above the initial LC roll-off. As with a Type 2 circuit, the loop should cross through 0dB in the middle of the phase bump to maximize phase margin. Many LTC3703-5 circuits using low ESR tantalum or OS-CON output capaci- –6dB/OCT ...
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... To measure the modulator gain and phase directly, wire up a breadboard with an LTC3703-5 and the actual MOSFETs, inductor and input and output capacitors that the final design will use. This breadboard ...
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... For the design steps common to both a buck and a boost, see the applicable section in the buck mode section. An example of a boost converter circuit is shown in the Typical Applications section. To operate the LTC3703-5 in boost mode, the INV pin should be tied to the V voltage (or a voltage above 2V). Note that in boost CC mode, pulse-skip operation and the line feedforward com- pensation are disabled ...
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... Be sure to specify surge-tested capacitors! Boost Converter: Current Limit Programming ( ) The LTC3703-5 provides current limiting in boost mode by ) monitoring the V and comparing it to the voltage at I limit, calculate the expected voltage drop across the MOSFET at the maximum desired inductor current and www ...
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... C1 = 1/(2 • f • G • R1) Run/Soft-Start Function The RUN/SS pin is a multipurpose pin that provide a soft- start function and a means to shut down the LTC3703-5. Soft-start reduces the input supply’s surge current by gradually increasing the duty cycle and can also be used for power supply sequencing. ...
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... SS V SEC MIN ( where R1 and R2 are shown in Figure 9c. If the LTC3703-5 is operating in Pulse Skip Mode and the RUN/SS auxiliary output voltage drops below V SYNC pin will trip and the LTC3703-5 will resume continu- C ous operation regardless of the load on the main output. ...
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... Minimum on-time t is the smallest amount of time ON(MIN) that the LTC3703-5 is capable of turning the top MOSFET on and off again determined by internal timing delays and the amount of gate charge required to turn on the top MOSFET. Low duty cycle applications may approach this ...
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... Optimizing Loop Compensation Loop compensation has a fundamental impact on tran- sient recovery time, the time it takes the LTC3703-5 to recover after the output voltage has dropped due to a load step. Optimizing loop compensation entails maintaining the highest possible loop bandwidth while ensuring loop ...
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... LTC3703-5 circuits. Solder the MOSFET and the resistor(s) as close to the output of the LTC3703-5 circuit as possible and set up the signal generator to pulse at a 100Hz rate with a 5% duty cycle. This pulses the LTC3703-5 with 500 s ...
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... Converter, layout is similar with V Check the following in your layout: 1. Keep the signal and power grounds separate. The signal ground consists of the LTC3703-5 GND pin, the ground return of C ground consists of the Schottky diode anode, the source of the bottom side MOSFET, and the (–) terminal of the ( – ...
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... Place the divider resistors near the LTC3703-5 in order to keep the high impedance FB node short. 8. For applications with multiple switching power convert- ...
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... BGRTN C VCC 1 F Single Input Supply 5V/5A Output Step-Down Converter FZT600 + 22 F 25V 1 16 MODE/SYNC V IN 25k 2 15 4.7 FSET BOOST 3 14 COMP LTC3703-5 15k MAX INV DRV RUN/ DRVCC GND BGRTN ...
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... TYP * DIMENSIONS DO NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED .152mm (.006") PER SIDE ** DIMENSIONS DO NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED .254mm (.010") PER SIDE LTC3703-5 www.DataSheet4U.com .189 – .196* (4.801 – 4.978) .009 (0.229 ...
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... FAX: (408) 434-0507 www.linear.com 5V to 24V/5A Synchronous Boost Converter + CMDSH-3 25V 1 16 MODE/SYNC FSET BOOST 3 14 COMP 0 LTC3703 MAX INV DRV RUN/ DRVCC GND BGRTN C VCC ...