LTC3788-1_1 LINER [Linear Technology], LTC3788-1_1 Datasheet
LTC3788-1_1
Related parts for LTC3788-1_1
LTC3788-1_1 Summary of contents
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... For a leadless 32-pin QFN package with additional features of adjustable current limit, clock out, phase modulation and two PGOOD outputs, see the LTC3788 data sheet. L, LT, LTC, LTM, Linear Technology, OPTI-LOOP , Burst Mode and the Linear logo are registered trademarks and No R All other trademarks are the property of their respective owners ...
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... PIN CONFIGURATION SENSE1 SENSE1 PLLIN/MODE SENSE2 SENSE2 CC PART MARKING* PACKAGE DESCRIPTION LTC3788GN-1 28-Lead Plastic SSOP LTC3788GN-1 28-Lead Plastic SSOP http://www.linear.com/leadfree/ http://www.linear.com/tapeandreel/ l The denotes the specifi cations which apply over the full operating = 25°C, VBIAS = 12V, unless otherwise noted (Note 2). ...
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... 1. 1. 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 μ μ ...
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... Continuous operation above the specifi ed absolute maximum operating junction temperature may impair device reliability or permanently damage the device. 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 37881 G03 FIGURE 9 CIRCUIT 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 5μs/DIV 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 1.188 – ...
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... TEMPERATURE (°C) Oscillator Frequency vs Input Voltage 360 FREQ = GND 358 356 354 352 350 348 346 344 342 340 130 INPUT VOLTAGE (V) 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 3.4 105 130 –45 – TEMPERATURE (° ...
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... LTC3788-1 TYPICAL PERFORMANCE CHARACTERISTICS SENSE Pin Input Current vs Temperature 260 V = 12V SENSE 240 220 + SENSE PIN 200 180 160 140 120 100 – SENSE PIN 0 – 105 –20 TEMPERATURE (°C) 37881 G22 Maximum Current Sense Threshold vs Duty Cycle ...
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... When not synchronizing to an external clock, this input, which acts on both controllers, determines how the LTC3788-1 operates at light loads. Pulling this pin to ground selects Burst Mode operation. An internal 100k resistor to ground also invokes Burst Mode operation when the pin is fl ...
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... LTC3788-1 BLOCK DIAGRAM PGOOD1 + 1.32V – VFB1 + – 1.08V 20μA FREQ CLK2 VCO CLK1 PFD PLLIN/ MODE SYNC DET 100k VBIAS SHDN EXTV CC 5.4V 5.4V LDO LDO + – 3.8V + INTV SGND CC 4.8V – 10 DUPLICATE FOR SECOND CONTROLLER CHANNEL SHDN SWITCHING LOGIC CHARGE PUMP + 0 ...
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... INTV to its fi nal value. 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 EXTV is taken low load currents ...
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... If one channel is shut down and the other channel is in sleep mode, the LTC3788-1 draws only 125μA of quiescent current. If both channels are in sleep mode, the LTC3788-1 draws only 200μA of quiescent current. In sleep mode, the load current is supplied by the output capacitor. As the output voltage decreases, the EA’ ...
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... OPERATION 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. The typical input clock thresholds on the PLLIN/MODE pin are 1.6V (rising) and 1.2V (falling). Operation When V > ...
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... R is used) 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 for high current inductors high current application requiring such an inductor, conduction loss through a sense resistor could reduce the effi ...
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... Do not allow the core to saturate! Power MOSFET Selection Two external power MOSFETs must be selected for each 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. ...
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... ESR device DS(ON) 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 causing the INTV down the entire LTC3788-1 chip. Once the junction tem- perature drops back to approximately 155°C, the INTV LDO turns back on. Long term overstress (T LDO than CC should be avoided as it can degrade the performance or shorten the life of the part ...
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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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... LTC3788-1 APPLICATIONS INFORMATION f IN Figure 7. Recommended Printed Circuit Layout Diagram 24 – SENSE1 + V SENSE1 PGOOD1 PULL-UP SS1 SW1 TG1 LTC3788 BOOST1 ITH1 BG1 VFB1 VBIAS PGND FREQ EXTV CC PLLIN/MODE INTV CC SGND RUN1 BG2 RUN2 C B2 VFB2 BOOST2 ITH2 TG2 SW2 SS2 ...
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... APPLICATIONS INFORMATION BOLD LINES INDICATE HIGH SWITCHING CURRENT. KEEP LINES TO A MINIMUM LENGTH SENSE1 C SW1 OUT1 L2 R SENSE2 C SW2 OUT2 Figure 8. Branch Current Waveforms LTC3788-1 V OUT1 OUT2 R L2 37881 F08 37881fa 25 ...
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... SGND pin of the IC. An embarrassing problem, which can be missed in an otherwise properly working switching regulator results R – B1 SENSE1 232k + R SENSE1 A1 12.1k VFB1 LTC3788-1 C ITH1 220pF C ITH1 R ITH1 15nF 8.66k ITH1 C SS1 0.1μF SS1 SS2 ...
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... BG2 C , 0.1μF B1 RUN2 BOOST2 FREQ SS2 SW2 ITH2 TG2 VFB2 + SENSE2 – SENSE2 42.2k, 1% MBOT1, MTOP1: RENESAS RJK0305 MBOT2A, MBOT2B, MTOP2: RENESAS RJK0652 D3: DIODES INC B340B D4: DIODES INC B360A LTC3788 OUTA1 6.8μ MTOP1 10.2μH MBOT1 + C INA 22μF 4 MBOT2B MBOT2A L2 16μH D4 ...
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... LTC3788-1 PACKAGE DESCRIPTION .254 MIN .0165 ± .0015 RECOMMENDED SOLDER PAD LAYOUT .0075 – .0098 (0.19 – 0.25) .016 – .050 (0.406 – 1.270) NOTE: 1. CONTROLLING DIMENSION: INCHES 2. DIMENSIONS ARE IN (MILLIMETERS) 3. DRAWING NOT TO SCALE *DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE **DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" ...
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... Updated Related Parts Table Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights. LTC3788-1 PAGE NUMBER ...
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... McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 ● High Effi ciency Dual 12V/24V Boost Converter – SENSE1 100k + SENSE1 PGOOD1 INTV CC VFB1 TG1 SW1 BOOST1 LTC3788 0.1μF B1 BG1 ITH1 D1 VBIAS SS1 INTV CC C INT 4.7μF PGND PLLIN/MODE D2 SGND ...