LT3692EUH#PBF

LT3692 Monolithic Dual Tracking 3.5A Step-Down Switching Regulator Description Features Wide Input Range: – Operation from 3V to 36V – OVLO Protects Circuit Through 60V Transients n Independent Supply, Shutdown, Soft-Start, Programmable Current Limit and Programmable Power Good for Each 3.5A Regulator n Die Temperature Monitor n Adjustable/Synchronizable Fixed Frequency Operation from 250kHz to 2.25MHz with Synchronized Clock Output n Independent Synchronized Switching Frequencies Optimize Component Size n Antiphase Switching n Outputs Can Be Paralleled n Flexible Output Voltage Tracking n Enhanced Short-Circuit Protection n Low Dropout: 95% Maximum Duty Cycle n 5mm × 5mm QFN Package 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. n 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 500mV/DIV CHARGE PUMP SCOPE PROBE: 15pF SYNCHRONIZED LT3692 RT/SYNC PIN FET PROBE: 2pF 40ns/DIV FREQUENCY: 1.000MHz 3692 F23 CHARGE PUMP SYNCHRONIZED LT3692 RT/SYNC PIN 500mV/DIV FET PROBE: 2pF 20ns/DIV FREQUENCY: 1.000MHz Figure 23. CLKOUT Rise Time 3692 F24 Figure 24. CLKOUT Fall Time 3692fa For more information www.linear.com/3692 27 VIN 7V TO 36V 28 VOUT1 5V 2A 500kHz 8.06k 100pF 0.47µF For more information www.linear.com/3692 120k 0.1µF 33pF 47µF ×2 4.7µF 36.5k 28.0k 330pF 42.2k 8.2µH VIN2 62k DIV GND 0.1µF TJ CLKOUT ILIM1 VC1 RT/SYNC SS2 ILIM2 VC2 SS1 CMPO2 CMPO1 FB2 VOUT2 CMPI2 LT3692 IND2 SW2 SHDN2 BST2 CMPI1 FB1 VOUT1 IND1 SW1 SHDN1 BST1 VIN1 49.9k 33pF 16.9k 2.2µH 25.5k 330pF 100pF 0.22µF 8.06k 4.7µF 49.9k PG 100k 8.06k 10k CLOCKOUT 1MHz 0.1µF 47µF VOUT2 2.5V 1A 1MHz 8.06k 4.02k VOUT3 1.2V 1A 1MHz 100µF 49.9k 33pF 8.06k 100pF 0.22µF 17.8k 470pF 4.02k 2.2µH 2.2µF DIV SW2 ILIM2 VC2 SS2 CMPO2 CMPI2 FB2 VOUT2 IND2 0.1µF TJ CLKOUT GND RT/SYNC ILIM1 VC1 SS1 VIN2 SHDN2 BST2 LT3692 CMPO1 CMPI1 FB1 VOUT1 IND1 SW1 SHDN1 BST1 VIN1 Quad Output 5V, 2.5V, 1.8V and 2V Multi-Frequency Synchronized, 2-Stage Converter with Output Sequencing, Absolute Tracking and Current Limiting 10k 2.2µH 8.06k 49.9k 33pF 3692 TA03 49.9k VOUT4 1.8V 1A 100µF 1MHz 330pF 25.5k 0.22µF 100pF 4.7µF LT3692 Typical Applications 3692fa LT3692 TYPICAL APPLICATIONS 3.3V and 1.8V 2-Stage Dual Step-Down Multi-Frequency Converter VIN 5V TO 36V 4.7µF SHDN1 BST1 8.2µH 0.47µF 1µF VIN2 VIN1 SHDN2 BST2 SW1 SW2 IND1 IND2 1µH 0.22µF LT3692 VOUT1 3.3V 2.5A 400kHz 100µF 100pF 24.9k 8.06k FB1 FB2 CMPI1 CMPI2 CMPO1 CMPO2 SS1 0.1µF 16.5k ILIM2 VC2 RT/SYNC DIV 47.5k CLKOUT TJ GND 33pF 120k 10k 100pF 100k 8.06k PG SS2 ILIM1 VC1 470pF VOUT2 1.8V 1A 47µF 1600kHz VOUT2 VOUT1 0.1µF CLOCKOUT 1600kHz 33pF 49.9k 100k 330pF 36.5k 0.1µF 40.2k 3692 TA02 12V to 3.3V and 2.5V Converter with Start-Up Current Limiting VIN 12V 4.7µF 4.7µF VIN2 VIN1 SHDN1 BST1 2.2µH 0.22µF SHDN2 BST2 SW1 SW2 IND1 IND2 0.22µF LT3692 VOUT1 2.5V 3A 1MHz VOUT2 VOUT1 47µF 8.06k 100pF 16.9k FB1 FB2 CMPI1 CMPI2 CMPO1 CMPO2 ILIM2 VC2 ILIM1 VC1 0.1µF RT/SYNC 330pF DIV 33pF 0.1µF 21.0k 28.0k 100pF 24.9k 8.06k VOUT2 3.3V 3A 47µF 1MHz SS2 SS1 120k 2.2µH CLKOUT GND TJ CLOCKOUT 1MHz 0.1µF 33pF 0.1µF 330pF 49.9k 24.9k 0.1µF 120k 3692 TA04 3692fa For more information www.linear.com/3692 29 LT3692 TYPICAL APPLICATIONS 3.3V/6A Single Output with UVLO and 100°C Temperature Warning VIN 6V TO 30V 4.7µF 4.7µF 80.6k VIN2 VIN1 6.5V UVLO RISING 6V UVLO FALLING SHDN1 BST1 10k 6.8µH 0.22µF SHDN2 BST2 SW1 SW2 IND1 IND2 6.8µH 0.22µF VOUT 3.3V 6A 800kHz EFFECTIVE RIPPLE LT3692 VOUT VOUT2 VOUT1 47µF 100pF 8.06k 24.9k FB1 FB2 CMPI1 CMPI2 CMPO1 SS1 CMPO2 SS2 ILIM2 VC2 ILIM1 VC1 0.1µF RT/SYNC 680pF DIV 10k 100°C TEMP FLAG SS1 ILIM1 VC1 CLOCKOUT 400kHz TJ GND 33pF 60.4k CLKOUT 47µF 100k FB1 28k R3 73.2k 0.1µF 10.2k 3692 TA05 Power Supply Dual Input Single 3.3V/4A Output Step-Down Converter VIN1 5V TO 36V 4.7µF SHDN1 BST1 5.6µH 0.22µF VOUT1 3.3V 4A 2.2µF VIN2 VIN1 VIN2 5V TO 36V 1A MAX SHDN2 BST2 SW1 SW2 IND1 IND2 6.8µH 0.22µF LT3692 100pF 8.06k 24.9k FB1 CMPI1 CMPI2 CMPO1 SS1 CMPO2 DIV 33pF 120k 24.9k 10.2k FB1 100k PG SS2 ILIM2 VC2 RT/SYNC 330pF 47µF FB2 ILIM1 VC1 0.1µF VOUT1 VOUT2 VOUT1 47µF CLKOUT GND VC1 CLOCKOUT 400kHz TJ 0.1µF 49.9k 0.1µF 3692 TA07 30 3692fa For more information www.linear.com/3692 LT3692 TYPICAL APPLICATIONS 5V and 1.8V Dual 2-Stage Converter VIN 6V TO 36V 1µF 4.7µF VIN2 VIN1 SHDN1 BST1 0.22µF VOUT1 5V 2A 500kHz 8.2µH SHDN2 BST2 SW1 SW2 IND1 IND2 1µH 0.22µF LT3692 VOUT2 VOUT1 47µF ×2 R9 100k 220pF 42.2k 8.06k PG FB1 CMPI2 CMPO1 CMPO2 SS1 0.1µF 47pF 120k 36.5k 61.9k 100k 100pF 47µF 8.06k ILIM2 VC2 RT/SYNC DIV FB1 SS2 ILIM1 VC1 330pF 10k FB2 CMPI1 VOUT2 1.8V 2A 2MHz CLKOUT GND 33pF TJ 0.1µF 0.1µF 330pF 49.9k 39.2k 120k 3692 TA10 3692fa For more information www.linear.com/3692 31 32 VOUT1 12V 1A 750kHz For more information www.linear.com/3692 120k 0.1µF 47µF 30.1k 33pF 330pF 8.06k 100pF 0.47µF VIN 15V TO 36V 120k 113k 1k 8.2µH 4.7µF DIV GND 0.1µF TJ CLKOUT ILIM1 VC1 RT/SYNC SS2 ILIM2 VC2 SS1 CMPO2 CMPO1 FB2 VOUT2 CMPI2 LT3692 IND2 SW2 SHDN2 BST2 VIN2 CMPI1 FB1 VOUT1 IND1 SW1 SHDN1 BST1 VIN1 24.9k 4.7µH 49.9k 33pF 2.2µF 8.06k 330pF 24.9k 100pF 0.22µF 133k 0.1µF 49.9k PG 47µF 100k VOUT2 3.3V 2A 750kHz OUT1 OUT2 MOD GND SET LTC6908-1 V+ 0.1µF VOUT3 1.2V 3A 375kHz 100µF ×2 120k 33pF 8.06k 220pF 0.22µF 20k 470pF 4.02k 3.3µH 1µF 62.0k DIV SS2 ILIM2 VC2 0.1µF TJ CLKOUT GND RT/SYNC ILIM1 VC1 SS1 CMPO2 CMPI2 FB2 VOUT2 IND2 SW2 SHDN2 BST2 VIN2 LT3692 CMPO1 CMPI1 FB1 VOUT1 IND1 SW1 SHDN1 BST1 VIN1 12V, 3.3V, 2.5V, 1.2V Quad Output with External Synchronization, Output Sequencing and Tracking Application 16.9k 4.7µH 30.1k 33pF 680pF 1µF 8.06k 100pF 100µF VOUT4 2.5V 2A 750kHz 3692 TA07 49.9k 0.22µF LT3692 TYPICAL APPLICATIONS 3692fa LT3692 TYPICAL APPLICATIONS 5V, 3.3V, 2.5V, 1.8V Synchronized Quad Output VOUT1 5V 2A 2.2µF SVIN PVIN2 PVIN DDR 4.7µF ×2 RUN LT3612 MODE RT VIN2 VIN1 SHDN1 BST1 6.8µH 0.22µF SW1 SW2 IND1 IND2 6.8µH 2.2µF 0.22µF 42.2k 8.06k FB1 FB2 CMPI1 CMPI2 CMPO1 SS1 CMPO2 SS2 ILIM2 VC2 ILIM1 VC1 0.1µF RT/SYNC 330pF DIV 33pF 60.4k 24.9k 16k FB 270k ITH TRACK/SS SGND PGND SVIN PVIN2 60.4k TJ 0.1µF RUN LT3612 100k SS1 ILIM1 VC1 MODE 100°C TEMP FLAG RT 3.3µH VOUT3 2.5V 100µF 2A SW PGOOD 47µF FB1 CLKOUT GND PVIN DDR VOUT2 VOUT1 100pF VOUT2 3.3V 100µF 2A SHDN2 BST2 LT3692 47µF 3.3µH SW PGOOD VIN1 7V TO 36V FB 191k ITH TRACK/SS SGND PGND SVIN PVIN2 60.4k CLOCKOUT 600kHz 2.2µF 28k 73.2k R14 49.9k PVIN DDR PGOOD RUN LT3612 MODE RT SGND 0.1µF 3.3µH VOUT4 1.8V 100µF 2A SW FB 121k ITH TRACK/SS PGND 60.4k 3692 TA08 3692fa For more information www.linear.com/3692 33 LT3692 Package Description Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. UH Package 32-Lead Plastic QFN (5mm × 5mm) (Reference LTC DWG # 05-08-1693 Rev D) 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) BOTTOM VIEW—EXPOSED PAD 0.75 ± 0.05 R = 0.05 TYP 0.00 – 0.05 R = 0.115 TYP PIN 1 NOTCH R = 0.30 TYP OR 0.35 × 45° CHAMFER 31 32 0.40 ± 0.10 PIN 1 TOP MARK (NOTE 6) 1 2 3.50 REF (4-SIDES) 3.45 ± 0.10 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 34 0.25 ± 0.05 0.50 BSC 3692fa For more information www.linear.com/3692 LT3692 Revision History REV DATE DESCRIPTION A 3/13 Clarified Shutdown Quiescent Current vs Temperature Graph PAGE NUMBER 5 Clarified SHDN1/2 Pin Function description 9 Clarified SHDN pin operation in Applications Information operation in general description 10 Clarified SHDN pin operation description in Applications Information 20 3692fa 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 its circuits as described herein will not infringe on existing patent rights. Forofmore information www.linear.com/3692 35 LT3692 Typical Application 1.2MHz, 12V to 3.3V at 3A, 5V at 3A VIN 12V 4.7µF VIN1 SHDN1 BST1 2.2µH 0.22µF 4.7µF VIN2 SHDN2 BST2 SW1 SW2 IND1 IND2 2.2µH 0.22µF LT3692 VOUT1 3.3V 3A 1.2MHz 100pF 47µF 24.9k 100k 8.06k PG1 FB1 CMPI2 CMPO1 CMPO2 120k 24.9k ILIM2 VC2 RT/SYNC DIV 33pF 8.06k 22µF 100k PG SS2 ILIM1 VC1 330pF 100pF 42.2k FB2 CMPI1 SS1 0.1µF VOUT2 5V 3A 1.2MHz VOUT2 VOUT1 CLKOUT GND 42.2k TJ CLOCKOUT 1.2MHz 0.1µF 330pF 0.1µF 33pF 49.9k 30.1k 120k 3692 TA09 Related Parts PART DESCRIPTION COMMENTS LT3507 36V, Triple 2.4A, 1.4A and 1.4A (IOUT), 2.5MHz, High Efficiency Step-Down DC/DC Converter with LDO Controller VIN: 4V to 36V, VOUT(MIN) = 0.8V, IQ = 7mA, ISD = 1µA, (5mm × 7mm) QFN-38 LT3508 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 LT3680 36V, 3A, 2.4MHz High Efficiency Micropower Step-Down DC/DC Converter VIN: 3.6V to 36V, VOUT(MIN) = 0.8V, IQ = 75µA, ISD < 1µA, (3mm × 3mm) DFN-10, MSOP-10E LT3693 36V, 3A, 2.4MHz High Efficiency Step-Down DC/DC Converter VIN: 3.6V to 36V, VOUT(MIN) = 0.8V, IQ = 1.3mA, ISD < 1µA, (3mm × 3mm) DFN-10, MSOP-10E LT3480 36V with Transient Protection to 60V, 2A (IOUT), 2.4MHz, High Efficiency Step-Down DC/DC Converter with Burst Mode® Operation VIN: 3.6V to 38V, Transients to 60V, VOUT(MIN) = 0.78V, IQ = 70µA, ISD < 1µA, (3mm × 3mm) DFN-10, MSOP-10E LT3980 58V with Transient Protection to 80V, 2A (IOUT), 2.4MHz, High Efficiency Step-Down DC/DC Converter with Burst Mode Operation VIN: 3.6V to 58V, Transients to 80V, VOUT(MIN) = 0.79V, IQ = 75µA, ISD < 1µA, (3mm × 4mm) DFN-16, MSOP-16E LT3971 38V, 1.2A (IOUT), 2MHz, High Efficiency Step-Down DC/DC Converter with Only 2.8µA of Quiescent Current VIN: 4.2V to 38V, VOUT(MIN) = 1.2V, IQ = 2.8µA, ISD < 1µA, (3mm × 3mm) DFN-10, MSOP-10E LT3991 55V, 1.2A (IOUT), 2MHz, High Efficiency Step-Down DC/DC Converter with Only 2.8µA of Quiescent Current VIN: 4.2V to 55V, VOUT(MIN) = 1.2V, IQ = 2.8µA, ISD < 1µA, (3mm × 3mm) DFN-10, MSOP-10E 36 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 For more information www.linear.com/3692 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com/3692 3692fa LT 0313 REV A • PRINTED IN USA  LINEAR TECHNOLOGY CORPORATION 2011