LTC3832-1ES8#TR Linear Technology, LTC3832-1ES8#TR Datasheet
LTC3832-1ES8#TR
Specifications of LTC3832-1ES8#TR
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LTC3832-1ES8#TR Summary of contents
Page 1
... In shutdown mode, the LTC3832 supply current drops to <10 A. The LTC3832-1 is the SO-8 version without current limit, frequency adjustment and shutdown functions. , LTC and LT are registered trademarks of Linear Technology Corporation. ...
Page 2
... 5V, unless otherwise noted. (Note CC1 CC2 CONDITIONS (Note 1.25V COMP V = 1.25V COMP 10A (Note 6) OUT V = 4.75V to 5.25V CC ORDER PART NUMBER TOP VIEW LTC3832-1ES8 / CC2 3 6 COMP PART MARKING S8 PACKAGE 8-LEAD PLASTIC SO 38321 = 125 C, = 130 MIN TYP ...
Page 3
... Note 3: Supply current in normal operation is dominated by the current needed to charge and discharge the external FET gates. This will vary with the LTC3832 operating frequency, operating voltage and the external FETs used. Note 4: The open-loop DC gain and transconductance from the SENSE – ...
Page 4
... LTC3832/LTC3832 TYPICAL PERFOR A CE CHARACTERISTICS Load Regulation 2. REFER TO FIGURE 12 2.53 2.52 2.51 2.50 2.49 2.48 2.47 2.46 –10 –5 5 – OUTPUT CURRENT (A) 3832 G01 Output Voltage Temperature Drift 2.55 REFER TO FIGURE 12 2.54 OUTPUT = NO LOAD 2.53 2.52 2.51 2.50 2.49 2.48 2.47 2 ...
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... 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) 3832 G17 LTC3832/LTC3832-1 Output Overcurrent Protection 3 REFER TO FIGURE 12 2.5 2.0 1.5 1.0 0 OUTPUT CURRENT (A) 3832 G12 Soft-Start Sink Current vs (V – ...
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... FB. The internal . It remains low if G2 resistor divider is not included in the LTC3832-1. SHDN (Pin 8/NA): Shutdown. A TTL compatible low level at SHDN for longer than 100 s puts the LTC3832 into + V . This shutdown mode. In shutdown, G1 and G2 go low, all ...
Page 7
... CC I (Pin 12/NA): Current Limit Threshold Set. I MAX the threshold for the internal current limit comparator drops below I with G1 on, the LTC3832 goes into FB MAX current limit. I has an internal 12 A pull-down to GND. MAX Connect this pin to the main V supply at the drain of Q1, ...
Page 8
... The PWM loop nominally runs at 300kHz. The LTC3832 includes a current limit sensing circuit that uses the topside external N-channel power MOSFET as a current sensing element, eliminating the need for an external sense resistor. ...
Page 9
... C, after which, the chip resumes normal operation. Soft-Start and Current Limit The LTC3832 includes a soft-start circuit that is used for start-up and current limit operation. The LTC3832-1 only has the soft-start function; the current limit function is disabled. The SS pin requires an external capacitor GND with the value determined by the required soft- start time ...
Page 10
... The R DS(ON) low. This occurs during power up when PV pin to the main V up. To prevent the high determined limit, the LTC3832 will disable the current limit circuit if IMAX PV is less than 2.5V above V CC1 operation of the current limit circuit, PV least 2.5V above V when G1 is low, allowing the use of the external charge ...
Page 11
... V internal circuitry (Figure 6). The LTC3832-1 has the PV and V pins tied together inside the package (Figure 7). CC This pin, brought out as V ripple requirements as the LTC3832, but must also be able to supply the gate drive current to Q2. LTC3832/LTC3832-1 SHDN 300kHz RAMP SIGNAL ...
Page 12
... F usually provide ad- equate filtering for V . For best performance, connect the CC 4.7 F bypass capacitor as close to the LTC3832 V possible. Gate drive for the top N-channel MOSFET Q1 is supplied from PV . This supply must be above V CC1 power supply input least one power MOSFET V for efficient operation ...
Page 13
... DS(ON) – while Q1 F CC1 allowable power dissipation and maximum output current typical LTC3832 circuit, operating in continuous mode the average inductor current is equal to the output load current. This current flows through either with the power dissipation split up according to the duty cycle ...
Page 14
... This action causes a temporary voltage droop at the output. To minimize this effect, the inductor value should usually be in the range for most 3.3V input LTC3832 circuits. To optimize performance, different combinations of input and output voltages and expected loads may require different inductor values ...
Page 15
... LTC3832 adjusts the inductor current to the new value. ESR in the output capacitor results in a step in the output voltage equal to the ESR value multiplied by the change in load current load step with a 0.05 ESR output capacitor results in a 250mV output voltage shift ...
Page 16
... LC ESR f CO Figure 10b. Bode Plot of the LTC3832 Overall Transfer Function Loop stability is affected by the values of the inductor, the output capacitor, the output capacitor ESR, the error amplifier transconductance and the error amplifier com- pensation network. The inductor and the output capacitor ...
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... LAYOUT CONSIDERATIONS When laying out the printed circuit board, use the follow- C1 (pF) C2 (pF) ing checklist to ensure proper operation of the LTC3832. 560 1500 These items are also illustrated graphically in the layout 330 1500 diagram of Figure 11. The thicker lines show the high ...
Page 18
... Do not connect these parts to the ground plane! 4. The close to the LTC3832 as possible. The 4.7 F and 1 F bypass capacitors shown at V provide optimum regulation performance. 5. The (+) plate of C possible to the drain of the upper MOSFET, Q1. An additional 1 F ceramic capacitor between V recommended ...
Page 19
... Q1A, Q1B, Q2: FAIRCHILD FDS6670A Figure 12. Typical 3.3V to 2.5V, 14A Application Efficiency vs Load Current 100 3. 2.5V 10 OUT REFER TO FIGURE LOAD CURRENT (A) 3832 F12b LTC3832/LTC3832 3. 330 F 2 1N5817 Q1A, Q1B 2 IN PARALLEL L O 0 OUT 2. 14A OUT Q2 D1 470 F 3 3832 F12a sn3832 3832fs 19 ...
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... F 0. SHUTDOWN 68pF 6. 0. Typical 3.3V to 5V, 5A Synchronous Boost Converter MBR0520 MBR0520 0 CC1 CC2 V 0 MAX 100 LTC3832 I FB FREQSET G1 SHDN PGND COMP GND + SENSE G2 FB – SENSE SANYO POSCAP 6TPB330M IN OUT L : SUMIDA CDEP105-1R3-MC-S O Q1, Q2: SILICONIX Si4864DY 1.3 H MBR330T3 ...
Page 21
... V IN 3.3V MBR0520 3. CC2 CC1 0 0 MAX 1k LTC3832 I FB FREQSET G2 13V SHDN COMP FB + SENSE PGND GND – SENSE SANYO POSCAP 6TPB330M IN OUT L : SUMIDA CDEP105-1R3-MC Q1, Q2: SILICONIX Si7440DP LTC3832/LTC3832 330 1 OUT 10 F 93.1k 330 F 1% 12. OUT –5V 3832 TA04 5A sn3832 3832fs 21 ...
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... LTC3832/LTC3832-1 PACKAGE DESCRIPTIO .254 MIN .0165 .0015 RECOMMENDED SOLDER PAD LAYOUT .007 – .0098 (0.178 – 0.249) .016 – .050 (0.406 – 1.270) NOTE: 1. CONTROLLING DIMENSION: INCHES INCHES 2. DIMENSIONS ARE IN (MILLIMETERS) 3. DRAWING NOT TO SCALE *DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" ...
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... N/2 45 .053 – .069 (1.346 – 1.752) 0 – 8 TYP .016 – .050 .014 – .019 (0.406 – 1.270) (0.355 – 0.483) TYP INCHES (MILLIMETERS) LTC3832/LTC3832-1 .189 – .197 (4.801 – 5.004) NOTE .150 – .157 (3.810 – 3.988) NOTE 3 N/2 1 ...
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... Linear Technology Corporation 24 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 Typical 5V to 3.3V, 10A Application 5V MBR0530T1 20k PV PV CC2 CC1 0 0 MAX 1k I LTC3832 FB FREQSET G2 SHDN PGND COMP GND + SENSE NC FB – SENSE C : SANYO 6TPB330M SANYO 4TPB470M OUT L : SUMIDA CDEP105-1R3-MC-S ...