Datasheet LTC3811 (Analog Devices)
| Manufacturer | Analog Devices |
| Description | High Speed Dual, Multiphase Step-Down DC/DC Controller |
| Pages / Page | 48 / 1 — FEATURES. DESCRIPTION. Fixed Frequency, Peak Current Mode Control. ±0.5% … |
| File Format / Size | PDF / 552 Kb |
| Document Language | English |
FEATURES. DESCRIPTION. Fixed Frequency, Peak Current Mode Control. ±0.5% Output Accuracy Over Temperature
Model Line for this Datasheet
Text Version of Document
LTC3811 High Speed Dual, Multiphase Step-Down DC/DC Controller
FEATURES DESCRIPTION
■
Fixed Frequency, Peak Current Mode Control
The LTC®3811 is a dual, PolyPhase® synchronous step- ■
±0.5% Output Accuracy Over Temperature
down switching regulator controller optimized for output ■
Optimized for Low VOUT Applications (Up to 3.3V)
voltages up to 3.3V. The LTC3811 includes high bandwidth ■
Dual or Single Output, Multiphase Operation
error amplifi ers as well as a high speed differential remote ■
Wide VIN Range: 4.5V to 30V Operation
sense amplifi er. The sense voltage range is programmable ■
High Speed Differential Remote Sense Amplifi er
from 24mV to 85mV, allowing the use of either the inductor ■
Inductor DCR or Sense Resistor Capable
DCR or a discrete sense resistor. Multiphase operation is ■
Adjustable Peak Current Sense Voltage:
made possible using the MODE/SYNC input, the CLKOUT
24mV to 85mV
output and the PHASEMODE control pin, allowing 1-, 2-, ■
Very Low Duty Cycle Operation: tON(MIN) = 65ns (Typ)
3-, 4-, 6- or 12-phase operation. ■ Powerful Internal Gate Drivers Large internal gate drivers minimize switching losses and ■ Output Voltage Soft-Start, Tracking and Sequencing allow the use of multiple power MOSFETs connected in ■ Programmable Load Line for Reduced COUT parallel for high current applications. ■ Clock Input and Output for Up to 12-Phase Operation ■ Fixed Frequency Operation from 250kHz to 750kHz The operating frequency of the LTC3811 can be programmed ■ PLL Synchronization from 150kHz Up to 900kHz from 250kHz to 750kHz and can also be synchronized to ■ Selectable CCM or DCM Operation an external clock using the internal PLL. ■ Available in 5mm × 7mm QFN and G36 Packages Tracking and sequencing are possible with the LTC3811,
APPLICATIONS
and soft-start is programmed with an external capacitor. Shutdown reduces supply current to 20μA. ■ Network Servers , LT, LTC, LTM and PolyPhase are registered trademarks of Linear Technology ■ High Current ASIC Supplies Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 5481178, 6304066, 5929620, 6177787, 6144194, ■ Low Voltage Power Distribution 6580258, 5705919.
TYPICAL APPLICATION Dual Output, 2-Phase Tracking Core and I/O Supply
VIN
Load Step
4.5V TO 14V VIN INTV DRV CC CC TG1 TG2 V BOOST1 BOOST2 OUT 100mV/DIV SW1 SW2 BG1 BG2 RUN1 PGND RUN2 LTC3811 SENSE1+ SENSE2+ IL SENSE1– SENSE2– 5A/DIV DIFF/IN+ RNG1 DIFF/IN– RNG2 V DIFF/OUT OUT1 2V FB1 FB2 VOUT2 15A 20μs/DIV 3811 TA01b VIN = 12V COMP1 COMP2 1.5V VOUT = 2V SS/TRACK1 SGND SS/TRACK2 15A IOUT = 0A to 12.5A 3811 TA01a 3811f 1
FEATURES DESCRIPTION
■
Fixed Frequency, Peak Current Mode Control
The LTC®3811 is a dual, PolyPhase® synchronous step- ■
±0.5% Output Accuracy Over Temperature
down switching regulator controller optimized for output ■
Optimized for Low VOUT Applications (Up to 3.3V)
voltages up to 3.3V. The LTC3811 includes high bandwidth ■
Dual or Single Output, Multiphase Operation
error amplifi ers as well as a high speed differential remote ■
Wide VIN Range: 4.5V to 30V Operation
sense amplifi er. The sense voltage range is programmable ■
High Speed Differential Remote Sense Amplifi er
from 24mV to 85mV, allowing the use of either the inductor ■
Inductor DCR or Sense Resistor Capable
DCR or a discrete sense resistor. Multiphase operation is ■
Adjustable Peak Current Sense Voltage:
made possible using the MODE/SYNC input, the CLKOUT
24mV to 85mV
output and the PHASEMODE control pin, allowing 1-, 2-, ■
Very Low Duty Cycle Operation: tON(MIN) = 65ns (Typ)
3-, 4-, 6- or 12-phase operation. ■ Powerful Internal Gate Drivers Large internal gate drivers minimize switching losses and ■ Output Voltage Soft-Start, Tracking and Sequencing allow the use of multiple power MOSFETs connected in ■ Programmable Load Line for Reduced COUT parallel for high current applications. ■ Clock Input and Output for Up to 12-Phase Operation ■ Fixed Frequency Operation from 250kHz to 750kHz The operating frequency of the LTC3811 can be programmed ■ PLL Synchronization from 150kHz Up to 900kHz from 250kHz to 750kHz and can also be synchronized to ■ Selectable CCM or DCM Operation an external clock using the internal PLL. ■ Available in 5mm × 7mm QFN and G36 Packages Tracking and sequencing are possible with the LTC3811,
APPLICATIONS
and soft-start is programmed with an external capacitor. Shutdown reduces supply current to 20μA. ■ Network Servers , LT, LTC, LTM and PolyPhase are registered trademarks of Linear Technology ■ High Current ASIC Supplies Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 5481178, 6304066, 5929620, 6177787, 6144194, ■ Low Voltage Power Distribution 6580258, 5705919.
TYPICAL APPLICATION Dual Output, 2-Phase Tracking Core and I/O Supply
VIN
Load Step
4.5V TO 14V VIN INTV DRV CC CC TG1 TG2 V BOOST1 BOOST2 OUT 100mV/DIV SW1 SW2 BG1 BG2 RUN1 PGND RUN2 LTC3811 SENSE1+ SENSE2+ IL SENSE1– SENSE2– 5A/DIV DIFF/IN+ RNG1 DIFF/IN– RNG2 V DIFF/OUT OUT1 2V FB1 FB2 VOUT2 15A 20μs/DIV 3811 TA01b VIN = 12V COMP1 COMP2 1.5V VOUT = 2V SS/TRACK1 SGND SS/TRACK2 15A IOUT = 0A to 12.5A 3811 TA01a 3811f 1
