LT3692EUHPBF

FEATURES n LT3692 Monolithic Dual Tracking 3.5A Step-Down Switching Regulator DESCRIPTION The LT®3692 is a dual current mode PWM step-down DC/DC converter with two internal 3.8A switches. Independent input voltage, shutdown, feedback, soft-start, current limit and comparator pins for each channel simplify complex power supply tracking and sequencing requirements. To optimize efficiency and component size, both converters have a programmable maximum current limit and are synchronized to either a common external clock input, or a resistor settable fixed 250kHz to 2.25MHz internal oscillator. A frequency divider is provided for channel 1 to further optimize component size. At all frequencies, a 180° phase relationship between channels is maintained, reducing voltage ripple and component size. A clock output is available for synchronizing multiple regulators. Minimum input to output voltage ratios are improved by allowing the switch to stay on through multiple clock cycles only switching off when the boost capacitor needs recharging. Independent channel operation can be programmed using the SHDN pin. Disabling both converters reduces the total quiescent to 1Min) as well as impulse conditions. CLKOUT Capacitive Loading A minor drawback to generating a negative rail from the CLKOUT pin is that the charge pump adds capacitance to the CLKOUT pin, resulting in an output synchronization clock signal phase delay. Figures 23 and 24 show the impact of capacitive loading on the CLKOUT signal rise and fall times. Note that a typical 10:1 150MHz oscilloscope probe contributes significant capacitance to the CLKOUT node, necessitating a low capacitance probe for accurate measurements. Applications requiring CLKOUT to generate the negative supply voltage and provide the synchronization clock to other regulators may benefit from buffering CLKOUT prior to the charge pump circuitry. Other Linear Technology Publications Application notes AN19, AN35 and AN44 contain more detailed descriptions and design information for buck regulators and other switching regulators. The LT1376 data sheet has a more extensive discussion of output ripple, loop compensation and stability testing. Design Note DN100 shows how to generate a dual (+ and –) output supply using a buck regulator. SCOPE PROBE: 15pF CHARGE PUMP SCOPE PROBE: 15pF SYNCHRONIZED LT3692 RT/SYNC PIN FET PROBE: 2pF CHARGE PUMP SYNCHRONIZED LT3692 RT/SYNC PIN 500mV/DIV FET PROBE: 2pF 500mV/DIV 40ns/DIV FREQUENCY: 1.000MHz 3692 F23 20ns/DIV FREQUENCY: 1.000MHz 3692 F24 Figure 23. CLKOUT Rise Time Figure 24. CLKOUT Fall Time 3692f 27 LT3692 TYPICAL APPLICATIONS 28 Quad Output 5V, 2.5V, 1.8V and 2V Multi-Frequency Synchronized, 2-Stage Converter with Output Sequencing, Absolute Tracking and Current Limiting VIN1 SHDN1 BST1 SW1 IND1 IND2 LT3692 VOUT1 42.2k FB1 FB2 CMPI2 8.06k 8.06k PG 0.1µF CMPO2 SS2 ILIM2 VC2 CLKOUT TJ 10k 330pF 49.9k CLOCKOUT 1MHz 25.5k 49.9k 8.06k 8.06k 4.02k 33pF 49.9k 17.8k 0.1µF 33pF 100k CMPI1 CMPO1 SS1 ILIM1 VC1 RT/SYNC DIV GND 62k 16.9k 100pF 47µF 100pF VOUT2 VOUT3 1.2V 1A 1MHz 100µF 4.02k 2.2µH 0.22µF 0.22µF VOUT2 2.5V 1A 1MHz 2.2µH SW2 SW1 IND1 LT3692 VOUT1 FB1 CMPI1 CMPO1 SS1 ILIM1 VC1 470pF RT/SYNC DIV VOUT2 FB2 CMPI2 CMPO2 SS2 ILIM2 VC2 CLKOUT GND TJ 33pF 0.1µF 49.9k 25.5k 49.9k 330pF 10k 100pF 8.06k SHDN2 BST2 SHDN1 BST1 VIN2 VIN1 4.7µF 2.2µF VIN2 SHDN2 BST2 SW2 IND2 2.2µH 0.22µF VOUT4 1.8V 1A 100µF 1MHz 4.7µF 3692 TA03 VIN 7V TO 36V 4.7µF 0.47µF 8.2µH VOUT1 5V 2A 500kHz 47µF ×2 100pF 8.06k 330pF 0.1µF 33pF 28.0k 120k 36.5k 3692f LT3692 TYPICAL APPLICATIONS 3.3V and 1.8V 2-Stage Dual Step-Down Multi-Frequency Converter VIN 5V TO 36V 4.7µF VIN1 SHDN1 BST1 0.47µF VOUT1 3.3V 2.5A 400kHz 100µF 8.2µH SW1 IND1 LT3692 VOUT1 100pF 8.06k 24.9k FB1 CMPI1 CMPO1 SS1 ILIM1 VC1 470pF 0.1µF 120k 33pF 16.5k 47.5k 100k RT/SYNC DIV VOUT2 FB2 CMPI2 CMPO2 SS2 ILIM2 VC2 CLKOUT TJ 0.1µF 0.1µF CLOCKOUT 1600kHz 49.9k 33pF 36.5k 40.2k 10k 100pF 100k 8.06k PG VIN2 SHDN2 BST2 SW2 IND2 1µH 0.22µF VOUT2 1.8V 1A 47µF 1600kHz 1µF 330pF GND 3692 TA02 12V to 3.3V and 2.5V Converter with Start-Up Current Limiting VIN 12V 4.7µF 4.7µF VIN1 SHDN1 BST1 0.22µF VOUT1 2.5V 3A 1MHz 2.2µH SW1 IND1 VIN2 SHDN2 BST2 SW2 IND2 2.2µH 0.22µF VOUT2 3.3V 3A 47µF 1MHz LT3692 VOUT1 47µF 8.06k 100pF 16.9k FB1 CMPI1 CMPO1 SS1 ILIM1 VC1 0.1µF 33pF 330pF RT/SYNC DIV 28.0k VOUT2 FB2 CMPI2 CMPO2 SS2 ILIM2 VC2 CLKOUT TJ 0.1µF 24.9k 100pF 8.06k CLOCKOUT 1MHz 33pF 330pF 0.1µF GND 120k 0.1µF 21.0k 49.9k 24.9k 0.1µF 3692 TA04 120k 3692f 29 LT3692 TYPICAL APPLICATIONS 3.3V/6A Single Output with UVLO and 100°C Temperature Warning VIN 6V TO 30V 80.6k 6.5V UVLO RISING 6V UVLO FALLING 10k 0.22µF VOUT 47µF 8.06k 100pF 24.9k 6.8µH 4.7µF VIN1 SHDN1 BST1 SW1 IND1 LT3692 VOUT1 FB1 CMPI1 CMPO1 SS1 ILIM1 VC1 0.1µF 33pF 60.4k 10k 10.2k 680pF RT/SYNC DIV VOUT2 FB2 CMPI2 CMPO2 SS2 ILIM2 VC2 CLKOUT TJ SS1 ILIM1 VC1 FB1 VIN2 SHDN2 BST2 SW2 IND2 6.8µH 4.7µF 0.22µF 100k 47µF VOUT 3.3V 6A 800kHz EFFECTIVE RIPPLE 100°C TEMP FLAG CLOCKOUT 400kHz 28k 0.1µF R3 73.2k 3692 TA05 GND 3692f 30 LT3692 TYPICAL APPLICATIONS Power Supply Dual Input Single 3.3V/4A Output Step-Down Converter VIN1 5V TO 36V VIN2 5V TO 36V 1A MAX 4.7µF VIN1 SHDN1 BST1 VIN2 SHDN2 BST2 SW2 IND2 6.8µH 2.2µF 0.22µF VOUT1 3.3V 4A 5.6µH SW1 IND1 LT3692 VOUT1 0.22µF VOUT1 47µF VOUT2 FB2 CMPI2 CMPO2 SS2 ILIM2 VC2 CLKOUT TJ 49.9k 0.1µF 3692 TA07 47µF 8.06k 100pF 24.9k FB1 CMPI1 CMPO1 SS1 ILIM1 VC1 FB1 100k PG VC1 CLOCKOUT 400kHz 0.1µF 0.1µF 33pF 120k 330pF RT/SYNC DIV 10.2k GND 24.9k 3692f 31 LT3692 TYPICAL APPLICATIONS 5V and 1.8V Dual 2-Stage Converter 1µF 4.7µF VIN1 SHDN1 BST1 0.22µF VOUT1 5V 2A 500kHz 8.2µH SW1 IND1 LT3692 47µF ×2 R9 100k VOUT1 220pF 8.06k 42.2k FB1 CMPI1 CMPO1 SS1 ILIM1 VC1 330pF 0.1µF 120k 47pF 36.5k 61.9k 100k RT/SYNC DIV VOUT2 FB2 CMPI2 CMPO2 SS2 ILIM2 VC2 CLKOUT TJ 0.1µF 49.9k 33pF 330pF 39.2k 120k 3692 TA10 VIN 6V TO 36V VIN2 SHDN2 BST2 SW2 IND2 1µH 0.22µF VOUT2 1.8V 2A 2MHz 10k FB1 100pF 8.06k 47µF PG 0.1µF GND 3692f 32 12V, 3.3V, 2.5V, 1.2V Quad Output with External Synchronization, Output Sequencing and Tracking Application VIN 15V TO 36V 4.7µF TYPICAL APPLICATIONS VIN1 VIN1 SHDN1 BST1 4.7µH 0.22µF 0.22µF IND1 LT3692 VOUT1 220pF 8.06k PG 0.1µF 4.02k FB1 CMPI1 CMPO1 SS1 ILIM1 VC1 470pF 33pF 24.9k 49.9k 120k 20k 62.0k RT/SYNC DIV VOUT2 FB2 CMPI2 CMPO2 SS2 ILIM2 VC2 CLKOUT GND TJ 0.1µF VOUT2 3.3V 2A 750kHz VOUT3 1.2V 3A 375kHz 100µF ×2 3.3µH SW1 SW2 IND2 SHDN2 BST2 SHDN1 BST1 SW1 SW2 IND2 LT3692 VOUT1 VOUT2 FB2 CMPI2 8.06k CMPO2 SS2 ILIM2 VC2 CLKOUT TJ 33pF 49.9k 0.1µF 330pF 24.9k 100pF 47µF 100k FB1 CMPI1 CMPO1 SS1 ILIM1 VC1 RT/SYNC DIV GND IND1 SHDN2 BST2 VIN2 2.2µF VIN2 1µF 1µF 0.47µF 8.2µH 4.7µH VOUT1 12V 1A 750kHz 1k 0.22µF VOUT4 2.5V 2A 750kHz 16.9k 100pF 8.06k 100µF 47µF 100pF 113k 8.06k 0.1µF 330pF 680pF 33pF 30.1k 49.9k 33pF 120k 30.1k 120k 3692 TA07 V+ 0.1µF 133k GND SET OUT1 LTC6908-1 OUT2 MOD LT3692 33 3692f LT3692 TYPICAL APPLICATIONS 5V, 3.3V, 2.5V, 1.8V Synchronized Quad Output VOUT1 5V 2A 2.2µF SVIN DDR VIN1 7V TO 36V PGOOD 4.7µF ×2 VIN1 SHDN1 BST1 0.22µF 6.8µH SW1 IND1 LT3692 VOUT1 47µF 8.06k 100pF 42.2k FB1 CMPI1 CMPO1 SS1 ILIM1 VC1 0.1µF 33pF 60.4k 24.9k 16k 330pF RT/SYNC DIV VOUT2 FB2 CMPI2 CMPO2 SS2 ILIM2 VC2 CLKOUT TJ 0.1µF 28k 73.2k R14 49.9k SS1 ILIM1 VC1 FB1 47µF 100k 100°C TEMP FLAG VIN2 SHDN2 BST2 SW2 IND2 6.8µH 0.22µF 2.2µF RUN LT3612 MODE RT SGND PVIN2 PVIN SW FB ITH TRACK/SS PGND 60.4k 270k 3.3µH VOUT2 3.3V 100µF 2A SVIN DDR PGOOD PVIN2 PVIN SW FB ITH TRACK/SS PGND 60.4k 191k 3.3µH VOUT3 2.5V 100µF 2A RUN LT3612 MODE RT SGND CLOCKOUT 600kHz 2.2µF SVIN DDR PGOOD RUN LT3612 MODE RT SGND 0.1µF PVIN2 PVIN SW FB ITH TRACK/SS PGND 60.4k 3692 TA08 GND 3.3µH 121k VOUT4 1.8V 100µF 2A 3692f 34 LT3692 PACKAGE DESCRIPTION (Reference LTC DWG # 05-08-1693 Rev D) UH Package 32-Lead Plastic QFN (5mm × 5mm) 0.70 ±0.05 5.50 ±0.05 4.10 ±0.05 3.50 REF (4 SIDES) 3.45 ± 0.05 3.45 ± 0.05 PACKAGE OUTLINE 0.25 ± 0.05 0.50 BSC RECOMMENDED SOLDER PAD LAYOUT APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED 5.00 ± 0.10 (4 SIDES) PIN 1 TOP MARK (NOTE 6) 0.75 ± 0.05 R = 0.05 TYP 0.00 – 0.05 BOTTOM VIEW—EXPOSED PAD R = 0.115 TYP PIN 1 NOTCH R = 0.30 TYP OR 0.35 × 45° CHAMFER 31 32 0.40 ± 0.10 1 2 3.45 ± 0.10 3.50 REF (4-SIDES) 3.45 ± 0.10 (UH32) QFN 0406 REV D 0.200 REF NOTE: 1. DRAWING PROPOSED TO BE A JEDEC PACKAGE OUTLINE M0-220 VARIATION WHHD-(X) (TO BE APPROVED) 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.20mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE 0.25 ± 0.05 0.50 BSC 3692f 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 representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 35 LT3692 TYPICAL APPLICATION 1.2MHz, 12V to 3.3V at 3A, 5V at 3A VIN 12V 4.7µF 4.7µF VIN1 SHDN1 BST1 0.22µF VOUT1 3.3V 3A 1.2MHz 100k PG1 8.06k 2.2µH SW1 IND1 LT3692 VOUT1 47µF 100pF 24.9k FB1 CMPI1 CMPO1 SS1 ILIM1 VC1 0.1µF 330pF 33pF 120k 24.9k 42.2k RT/SYNC DIV VOUT2 FB2 CMPI2 CMPO2 SS2 ILIM2 VC2 CLKOUT TJ 0.1µF 42.2k 100pF 8.06k 22µF 100k PG VIN2 SHDN2 BST2 SW2 IND2 2.2µH 0.22µF VOUT2 5V 3A 1.2MHz CLOCKOUT 1.2MHz 33pF 49.9k 330pF 0.1µF 30.1k 120k 3692 TA09 GND RELATED PARTS PART LT3507 LT3508 LT3680 LT3693 LT3480 LT3980 LT3971 LT3991 DESCRIPTION 36V, Triple 2.4A, 1.4A and 1.4A (IOUT), 2.5MHz, High Efficiency Step-Down DC/DC Converter with LDO Controller COMMENTS VIN: 4V to 36V, VOUT(MIN) = 0.8V, IQ = 7mA, ISD = 1µA, (5mm × 7mm) QFN-38 36V with Transient Protection to 40V, Dual 1.4A (IOUT), 3MHz, High Efficiency VIN: 3.7V to 37V, VOUT(MIN) = 0.8V, IQ = 4.6mA, ISD = 1µA, Step-Down DC/DC Converter (4mm × 4mm) QFN-24, TSSOP-16E 36V, 3A, 2.4MHz High Efficiency Micropower Step-Down DC/DC Converter 36V, 3A, 2.4MHz High Efficiency Step-Down DC/DC Converter 36V with Transient Protection to 60V, 2A (IOUT), 2.4MHz, High Efficiency Step-Down DC/DC Converter with Burst Mode® Operation 58V with Transient Protection to 80V, 2A (IOUT), 2.4MHz, High Efficiency Step-Down DC/DC Converter with Burst Mode Operation 38V, 1.2A (IOUT), 2MHz, High Efficiency Step-Down DC/DC Converter with Only 2.8µA of Quiescent Current 55V, 1.2A (IOUT), 2MHz, High Efficiency Step-Down DC/DC Converter with Only 2.8µA of Quiescent Current VIN: 3.6V to 36V, VOUT(MIN) = 0.8V, IQ = 75µA, ISD < 1µA, (3mm × 3mm) DFN-10, MSOP-10E VIN: 3.6V to 36V, VOUT(MIN) = 0.8V, IQ = 1.3mA, ISD < 1µA, (3mm × 3mm) DFN-10, MSOP-10E VIN: 3.6V to 38V, Transients to 60V, VOUT(MIN) = 0.78V, IQ = 70µA, ISD < 1µA, (3mm × 3mm) DFN-10, MSOP-10E VIN: 3.6V to 58V, Transients to 80V, VOUT(MIN) = 0.79V, IQ = 75µA, ISD < 1µA, (3mm × 4mm) DFN-16, MSOP-16E VIN: 4.2V to 38V, VOUT(MIN) = 1.2V, IQ = 2.8µA, ISD < 1µA, (3mm × 3mm) DFN-10, MSOP-10E VIN: 4.2V to 55V, VOUT(MIN) = 1.2V, IQ = 2.8µA, ISD < 1µA, (3mm × 3mm) DFN-10, MSOP-10E 3692f 36 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● LT 0111 • PRINTED IN USA FAX: (408) 434-0507 ● www.linear.com  LINEAR TECHNOLOGY CORPORA TION 2011