LTC3830-1 Linear Technology, LTC3830-1 Datasheet
LTC3830-1
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LTC3830-1 Summary of contents
Page 1
... In shutdown mode, the LTC3830 supply current drops to <10 A. The LTC3830-1 differs from the LTC3830 S8 ver- sion by replacing shutdown with a soft-start function. For a similar, pin compatible DC/DC converter with an output voltage as low as 0.6V, please refer to the LTC3832. ...
Page 2
... S8 PV CC1 PART MARKING PGND GND 3830 – SENSE FB ORDER PART + SENSE NUMBER SHDN LTC3830-1ES8 GN PACKAGE 16-LEAD PLASTIC SSOP T S8 JMAX T JMAX PART MARKING 38301 The denotes specifications that apply over the full operating temperature = 5V, unless otherwise noted. (Note 2) ...
Page 3
... Note 8: The current limiting amplifier can sink but cannot source current. Under normal (not current limited) operation, the output current will be zero. Note 9: The LTC3830E/LTC3830-1E are guaranteed to meet performance specifications from Specifications over the – operating temperature range are assured by design, characterization and correlation with statistical process controls ...
Page 4
... LTC3830/LTC3830 TYPICAL PERFOR A CE CHARACTERISTICS Load Regulation 3. REFER TO FIGURE 12 3.33 3.32 3.31 3.30 3.29 3.28 3.27 3.26 –10 – –15 0 OUTPUT CURRENT (A) 3830 G02 Output Voltage Temperature Drift 3.34 REFER TO FIGURE 12 OUTPUT = NO LOAD 3.33 3.32 3.31 3.30 3.29 3.28 3.27 3.26 –50 – 100 125 TEMPERATURE ( C) 3830 G04 Oscillator Frequency vs Temperature 250 ...
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... G15 V Operating Supply Current CC vs Temperature 1.6 FREQSET FLOATING 1.5 1.4 1.3 1.2 1.1 1.0 0.9 0.8 0.7 0.6 0.5 0.4 –50 – 100 125 TEMPERATURE ( C) 3830 G18 LTC3830/LTC3830-1 Output Overcurrent Protection 3 3.0 REFER TO FIGURE 20k IMAX 2.5 2.0 1.5 1.0 0 OUTPUT CURRENT (A) 3830 G13 Soft-Start Sink Current vs (V – V ...
Page 6
... GATE CAPACITANCE AT G1 AND G2 (nF) resistor divider to set the output voltage, float SENSE – SENSE . It remains low if The internal resistor divider is not included in the LTC3830-1 CC1 and the 8-lead LTC3830. SHDN (Pin 8/Pin 5/NA): Shutdown. A TTL compatible low + V . level at SHDN for longer than 100 s puts the LTC3830 into ...
Page 7
... Power Supply Input. All low CC power internal circuits draw their supply from this pin. Connect this pin to a clean power supply, separate from the main V 4.7 F bypass capacitor. The LTC3830-1 and the 8-lead LTC3830 have V MAX require bypass capacitor to GND. PV (Pin 15/Pin 7/Pin 7): Power Supply Input for G2 ...
Page 8
... N-channel power MOSFET as a current sensing element, eliminating the need for an external sense resistor. Also included in the 16-lead version and the LTC3830 internal soft-start feature that requires only a single external capacitor to operate. In addition, 16-lead parts ...
Page 9
... COMP pin is clamped to a diode drop (B-E junction of QSS in the Block Diagram) above the voltage at the SS pin. This prevents the error amplifier from forcing the loop to maximum duty cycle. The LTC3830/LTC3830-1 operate at low duty cycle as the SS pin rises above 0.6V (V 1.2V continues to rise, QSS turns off and COMP the error amplifier takes over to regulate the output ...
Page 10
... SHDN pin resets the internal oscillator and pulls the ramp V OUT + signal low, this forces the LTC3830 internal oscillator OUT lock to the external clock frequency. The LTC3830-1 does 3830 F04 not have this external synchronization function. forces the chip to run CC sn3830 3830fs ...
Page 11
... Input Supply Considerations/Charge Pump The 16-lead LTC3830 requires four supply voltages to operate: V MOSFET gate drive and a clean, low ripple V LTC3830 internal circuitry (Figure 6). The LTC3830-1 and the 8-lead LTC3830 have the PV together inside the package (Figure 7). This pin, brought out the 16-lead part, but must also be able to supply the gate drive current to Q2 ...
Page 12
... Gate drive for the bottom MOSFET Q2 is provided through PV for the 16-lead LTC3830 or V CC2 LTC3830-1 and the 8-lead LTC3830. This supply only needs to be above the power MOSFET V operation. PV can also be driven from the same supply/ CC2 ...
Page 13
... CC1 specified The R DS(ON) be calculated by rearranging the relation voltage and IN and CC1 LTC3830/LTC3830 CC2 CC1 0 3906 Q2 LTC3830 Figure 9b. Duty Cycle Clamp Circuit V OUT V IN ...
Page 14
... LTC3830/LTC3830 APPLICATIO S I FOR ATIO P should be calculated based primarily on required MAX efficiency or allowable thermal dissipation. A typical high efficiency circuit designed for 5V input and 3.3V at 10A output might allow no more than 3% efficiency loss at full load for each MOSFET. Assuming roughly 90% efficiency at this current level, this gives a P MAX (3 ...
Page 15
... Further derating of the input capacitor ripple current beyond the manufacturer’s speci- fication is recommended to extend the useful life of the circuit. Lower operating temperature has the largest effect on capacitor longevity. LTC3830/LTC3830-1 sn3830 3830fs 15 ...
Page 16
... LTC3830/LTC3830 APPLICATIO S I FOR ATIO The output capacitor in a buck converter under steady- state conditions sees much less ripple current than the input capacitor. Peak-to-peak current is equal to inductor ripple current, usually 10% to 40% of the total load current. Output capacitor duty places a premium not on power dissipation but on ESR ...
Page 17
... Table 2. Recommended Compensation Network for 5V to 3.3V Applications Using Multiple Paralleled 820 F Sanyo OS-CON 4SP820M Output Capacitors 1.2 1.2 1.2 2.4 2.4 2.4 4.7 4.7 4 FREQUENCY 3830 F10b Figure 10c. Bode Plot of the LTC3830 Overall Transfer Function Using a Low ESR Output Capacitor LTC3830/LTC3830 (nF) C1 (pF) OUT C C 1640 6.2 3.3 470 2460 12 3.3 470 ...
Page 18
... LTC3830/LTC3830 APPLICATIO S I FOR ATIO Table 3 shows the suggested compensation component values for 5V to 3.3V applications based on 470 F Sanyo POSCAP 4TPB470M output capacitors. Table 3. Recommended Compensation Network for 5V to 3.3V Applications Using Multiple Paralleled 470 F Sanyo POSCAP 4TPB470M Output Capacitors ...
Page 19
... LTC3830 I MAX 1k FREQSET SHDN SENSE COMP – SENSE GND PGND LTC3830/LTC3830-1 should be connected as close as IN and power ground IN pins are very sensitive to pickup from FB + and SENSE and I at Q1’s drain and source pins. MAX Q1A Q1B ...
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... LTC3830/LTC3830 APPLICATIO S I FOR ATIO 100 0.1 F 4 SHUTDOWN 33pF 18k C 0. MBR0530T1 + 6. CC2 CC1 0 0 MAX 1k LTC3830 I FB FREQSET G2 SHDN PGND COMP GND + SENSE C : SANYO 6TPB330M – SENSE C : SANYO 4TPB470M OUT ...
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... TYP .015 .004 45 .053 – .068 (0.38 0.10) (1.351 – 1.727) 0 – 8 TYP .008 – .012 (0.203 – 0.305) LTC3830/LTC3830-1 .189 – .196* (4.801 – 4.978) .009 (0.229 REF .150 – .157** (3.810 – 3.988) ...
Page 22
... LTC3830/LTC3830-1 PACKAGE DESCRIPTIO .050 BSC N .245 MIN 1 2 .030 .005 TYP RECOMMENDED SOLDER PAD LAYOUT .010 – .020 (0.254 – 0.508) .008 – .010 (0.203 – 0.254) NOTE: 1. DIMENSIONS IN 2. DRAWING NOT TO SCALE 3. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm) ...
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... N .053 – .069 (1.346 – 1.752) 0 – 8 TYP .014 – .019 (0.355 – 0.483) TYP LTC3830/LTC3830-1 .386 – .394 (9.804 – 10.008) NOTE .150 – .157 (3.810 – 3.988) ...
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... LTC3830/LTC3830-1 U TYPICAL APPLICATIO 10 F 100 0.1 F 4.7 F 130k SHDN C1 33pF RELATED PARTS PART NUMBER DESCRIPTION LTC1430/LTC1430A High Power Step-Down Switching Regulator Controllers LTC1530 High Power Synchronous Switching Regulator Controller LTC1628 Dual High Efficiency 2-Phase Synchronous Step-Down Controller LTC1702 Dual High Efficiency 2-Phase Synchronous Step-Down Controller ...