LTC3788-1 Linear Technology, LTC3788-1 Datasheet
LTC3788-1
Related parts for LTC3788-1
LTC3788-1 Summary of contents
Page 1
... OPTI-LOOP compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values. The LTC3788-1 features a precision 1.2V reference and a power good output indicator. A 4.5V to 38V input supply range encompasses a wide range of system architectures and battery chemistries. ...
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... LTC3788-1 ABSOLUTE MAXIMUM RATINGS (Note 1) VBIAS......................................................... –0.3V to 40V BOOST1, BOOST2 ...................................... –0.3V to 76V SW1, SW2 ................................................. –0.3V to 70V RUN1, RUN2 ................................................ –0. Maximum Current Sourced into Pin from Source > 8V..............................................100μA PGOOD1, PLLIN/MODE ............................... –0. INTV , (BOOST1-SW1, BOOST2-SW2) ...... –0. EXTV ......................................................... –0. ...
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... LIM V = 1.1V Float FB LIM C = 3300pF (Note 6) LOAD C = 3300pF (Note 6) LOAD C = 3300pF (Note 6) LOAD C = 3300pF (Note 6) LOAD C = 3300pF (Each Driver) LOAD C = 3300pF (Each Driver) LOAD (Note 7) LTC3788-1 MIN TYP MAX UNITS l 0.01 0 –0.01 –0 mmho 0.9 mA 1.2 mA 125 190 μA 200 300 μA ...
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... V SW1,2 BOOST1,2 FREQ = 0V, Forced Continuous or Pulse-Skipping Mode Note 4: The LTC3788-1 is tested in a feedback loop that servos V output of the error amplifi er while maintaining I current limit range. Note 5: Dynamic supply current is higher due to the gate charge being delivered at the switching frequency. ...
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... V OUT FIGURE 9 CIRCUIT 37881 G03 Load Step Pulse-Skipping Mode LOAD STEP 2A/DIV INDUCTOR CURRENT 5A/DIV V OUT 500mV/DIV 37881 G05 OUT FIGURE 9 CIRCUIT LTC3788-1 10000 1000 100 12V 24V OUT Burst Mode OPERATION FIGURE 9 CIRCUIT 0.1 0.0001 0.001 0.01 0 OUTPUT CURRENT (A) ...
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... LTC3788-1 TYPICAL PERFORMANCE CHARACTERISTICS Inductor Current at Light Load FORCED CONTINUOUS MODE Burst Mode OPERATION 5A/DIV PULSE-SKIPPING MODE V = 12V 24V OUT I = 200μA LOAD FIGURE 9 CIRCUIT Regulated Feedback Voltage vs Temperature 1.212 1.209 1.206 1.203 1.200 1.197 1.194 1.191 www.DataSheet4U.com 1.188 –45 – ...
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... G16 Load Current CC 600 550 = 0V CC 500 450 = 6V CC 400 350 300 100 120 140 160 180 200 37881 G18 LTC3788-1 Undervoltage Lockout Threshold vs Temperature 4.4 4.3 INTV RISING 4.2 CC 4.1 4.0 3.9 INTV FALLING CC 3.8 3.7 3.6 3.5 3.4 80 105 130 –45 – TEMPERATURE (°C) 37881 G14 ...
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... LTC3788-1 TYPICAL PERFORMANCE CHARACTERISTICS Oscillator Frequency vs Input Voltage 360 FREQ = GND 358 356 354 352 350 348 346 344 342 340 INPUT VOLTAGE (V) SENSE Pin Input Current vs I Voltage TH 260 V = 12V SENSE 240 220 SENSE 200 180 160 ...
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... To avoid false trips the output voltage must be outside the range for 25μs before this output is activated. SS1, SS2 (Pin 28, Pin 14): Output Soft-Start Input. A capacitor to ground at this pin sets the ramp rate of the output voltage during start-up. LTC3788-1 and sets the thresholds for IN directly from CC . ...
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... LTC3788-1 BLOCK DIAGRAM PGOOD1 + 1.32V – VFB1 + – 1.08V 20μA FREQ VCO PFD PLLIN/ MODE SYNC DET 100k VBIAS EXTV CC www.DataSheet4U.com 5.4V 5.4V LDO LDO INTV CC 4.8V – 10 DUPLICATE FOR SECOND CONTROLLER CHANNEL CLK2 + CLK1 0.425V – – – 2.8V 0.7V SLOPE COMP + SENS LO – ...
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... Light Load Current Operation—Burst Mode Operation, Pulse-Skipping or Continuous Conduction (PLLIN/MODE Pin) pin. The LTC3788-1 can be enabled to enter high effi ciency CC Burst Mode operation, constant-frequency pulse-skip- ping mode or forced continuous conduction mode at low load currents. To select Burst Mode operation, tie ...
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... BG1. The ability to prebias the loop fi lter allows the PLL to lock-in rapidly without deviating far from the desired frequency. The typical capture range of the LTC3788-1’s PLL is from approximately 55kHz to 1MHz, and is guaranteed to lock to an external clock source whose frequency is be- tween 75kHz and 850kHz ...
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... In forced con- Operation at Low SENSE Pin Common Voltage . The internal OUT The current comparator in the LTC3788-1 is powered di- rectly from the SENSE mode voltage of SENSE low as 2.5V, which is below the UVLO threshold. Figure 1 shows a typical application when the controller’s VBIAS is powered from V 2 ...
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... SENSE SENSE Filter components mutual to the sense lines should be placed close to the LTC3788-1, and the sense lines should run close together to a Kelvin connection underneath the current sense element (shown in Figure 1). Sensing cur- rent elsewhere can effectively add parasitic inductance ...
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... Inductor DCR Sensing For applications requiring the highest possible effi ciency at high load currents, the LTC3788-1 is capable of sensing the voltage drop across the inductor DCR, as shown in Figure 2b. The DCR of the inductor can be less than 1mΩ ...
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... Do not allow the core to saturate! Power MOSFET Selection Two external power MOSFETs must be selected for each decreases with higher L controller in the LTC3788-1: one N-channel MOSFET for : IN the bottom (main) switch, and one N-channel MOSFET for the top (synchronous) switch. The peak-to-peak gate drive levels are set by the INTV voltage ...
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... DS(ON) ΔV ESR The LTC3788-1 can also be confi gured as a 2-phase single output converter where the outputs of the two channels are connected together and both channels have the same duty cycle. With 2-phase operation, the two channels of the dual switching regulator are operated 180 degrees out-of-phase ...
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... Capacitors are now available with low ESR and high ripple current ratings (i.e., OS-CON and POSCAP). Setting Output Voltage The LTC3788-1 output voltages are each set by an exter- nal feedback resistor divider carefully placed across the output, as shown in Figure 4. The regulated output voltage is determined by: ⎛ ...
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... CC the overtemperature circuitry disables the INTV LDO is enabled. The causing the INTV CC down the entire LTC3788-1 chip. Once the junction tem- LDO attempts CC perature drops back to approximately 155°C, the INTV LDO turns back on. Long term overstress (T CC ...
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... Frequency and Resistor Value at the FREQ Pin Minimum On-Time Considerations Minimum on-time, t ON(MIN) that the LTC3788-1 is capable of turning on the bottom MOSFET determined by internal timing delays and the gate charge required to turn on the top MOSFET. Low duty cycle applications may approach this minimum on- time limit ...
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... ...) where L1, L2, etc., are the individual losses as a percent- age of input power. Although all dissipative elements in the circuit produce losses, four main sources usually account for most of the losses in LTC3788-1 circuits regulator current losses, 4) Bottom MOSFET CC transition losses ...
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... LTC3788-1 APPLICATIONS INFORMATION a realistic load step condition. The initial output voltage step resulting from the step change in output current may not be within the bandwidth of the feedback loop, so this signal cannot be used to determine phase margin. This is why it is better to look at the ITH pin signal which is in the feedback loop and is the fi ...
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... The output capacitor (–) terminals should be connected as close as possible to the (–) terminals of the input capacitor by placing the capacitors next to each other the LTC3788-1 VFB pins’ resistive dividers connect to the (+) terminals The resistive divider must be OUT connected between the (+) terminal of C ground and placed close to the VFB pin ...
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... BOLD LINES INDICATE HIGH SWITCHING CURRENT. KEEP LINES TO A MINIMUM LENGTH. 24 – SENSE1 + V SENSE1 PGOOD1 PULL-UP SS1 SW1 TG1 LTC3788 BOOST1 ITH1 BG1 VFB1 VBIAS PGND EXTV FREQ CC f PLLIN/MODE INTV IN CC SGND RUN1 BG2 RUN2 C ...
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... EXTV BG2 0.1μF B1 RUN1 RUN2 BOOST2 FREQ SW2 SS2 TG2 ITH2 VFB2 + SENSE2 – SENSE2 Figure 9. High Effi ciency Dual 12V/24V Boost Converter LTC3788-1 V OUT1 24V OUTA1 OUTB1 L1 22μF 220μF R SENSE1 MTOP1 3.3μH 4 4mΩ MBOT1 V IN ...
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... OUTB2 L1: PULSE PA2050.103NL L2: PULSE PA2050.163NL Figure 10. High Effi ciency Dual 24V/48V Boost Converter with Inductor DCR Current Sensing 53.6k – SENSE1 C1 100k 0.1μF + SENSE1 PGOOD1 INTV CC LTC3788-1 VFB1 TG1 SW1 BOOST1 C , 0.1μF B1 ITH1 BG1 D1 VBIAS SS1 INTV CC PLLIN/MODE C CC INT 4.7μ ...
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... BSC .015 ± .004 × 45° .0532 – .0688 (0.38 ± 0.10) (1.35 – 1.75) 0° – 8° TYP .008 – .012 (0.203 – 0.305) TYP INCHES (MILLIMETERS) LTC3788-1 .386 – .393* (9.804 – 9.982 ...
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... LTC3788-1 RELATED PARTS PART NUMBER DESCRIPTION LTC3788 Multiphase, Dual Output Synchronous Step-Up Controller LTC3862/LTC3862-1 Multiphase Current Mode Step-Up DC/DC Controller LTC3813 100V Maximum V Step-Up DC/DC Controller LTC3814-5 60V Maximum V OUT Step-Up DC/DC Controller LTC1871/LTC1871-1/ Wide Input Range LTC1871-7 Current Flyback, Boost and SEPIC Controller ...