LINEAR 2-Phase Synchronous Buck Controller Features:
Summary
The LTC3856 is a high-efficiency, single-output, two-phase synchronous buck DC/DC controller designed for demanding power supplies in datacenter, telecom, and industrial applications. This manual details advanced features like Stage Shedding Mode and Active Voltage Positioning, which ensure superior efficiency at light loads and excellent transient response across wide input ranges. It provides technical guidance on implementing DCR sensing with temperature compensation and utilizing remote voltage sensing to maintain tight load regulation accuracy for modern power distribution systems.
Page 1 Text Content
2-Phase Synchronous Buck Controller Features Light Load Stage Shedding Mode, Active Voltage Positioning, Low RSENSE and Remote VOUT Sensing Design Note 486 Charlie Zhao and Jian Li Introduction age sensing, Stage Shedding™ mode for improved light
Today’s computer, datacom, and telecom systems de- load effi ciency and adaptive voltage positioning for fast mand power supplies that are effi cient, respond quickly transient response. The LTC3856 can convert a wide input to load transients and accurately regulate the voltage voltage range, 4.5V to 38V, to outputs from 0.6V to 5V. at the load. For example, load current can be measured Despite the many features, the chip is small, available in by using the inductor DCR, thus eliminating the need 32-pin 5mm × 5mm QFN and 38-pin TSSOP packages.
for a dedicated sense resistor. Inductor DCR sensing
High Effi ciency, 2-Phase, 4.5V to 14V Input,
increases effi ciency—especially at heavy load—while
1.5V/50A Output Converter
reducing component cost and required board space.
Figure 1 shows a typical LTC3856 application in a 4.5V
The LTC®3856 single-output 2-phase synchronous buck
to 14V input, 1.5V/50A output converter. The LTC3856’s
controller improves the accuracy of inductor DCR sensing
two channels operate out-of-phase, which reduces the
by compensating for changes in DCR due to temperature.
input RMS current ripple and thus the required input
DCR temperature compensation is just one of many capacitance. Up to six LTC3856s can be paralleled for performance enhancing features offered in the LTC3856.
L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered It also includes on-chip gate drivers, remote output volt- trademarks and Stage Shedding is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners.
1n F VIN VIN
VIN 4.5V
180μF TO 14V
RJK0305DPB 22μF
L1 GND
CLKOUT VIN SENSE1– RJK0305DPB 0.001Ω VOUT
PLLIN SENSE1+ 1.5V/
FREQ TG1 Q6
RJK0330DPB 330μF
RUN SW1 RJK0330DPB
TK/SS INTVCC 4.7μF
ITH BOOST1
20k D1, CMDSH-3 VIN
LTC3856 INTVCC
AVP INTVCC 22μF
RJK0305DPB 4.7μF 22μF
30.1k ITEMP PHASMD Q7
D2, CMDSH-3 RJK0305DPB
DIFFOUT
BOOST2 0.22μH
INTVCC 0.001Ω
DIFFN DIFFP 0.1μF
ISET SW2
RJK0330DPB RJK0330DPB
EXTVCC BG2
INTVCC
ILIM SENSE2+
MODE 1n F 100Ω
PGOOD PGOOD PGND SGND SENSE2–
Figure 1. 1.5V/50A, 2-Phase Synchronous Buck Converter Featuring the LTC3856
Page Summary Contents For LINEAR 2-Phase Synchronous Buck Controller Features:
Manual Details
| Brand | Linear |
|---|---|
| Pages | 2 |
| File Size | 94.02 KB |
| Published | May 31, 2026 |
Enter the captcha to get the download link:
Frequently Asked Questions
Do I need a dedicated sense resistor to measure load current?
No, it uses inductor DCR sensing, which eliminates the need for a separate sense resistor.
How does this converter improve efficiency when operating at light loads?
It features Stage Shedding™ mode and Burst Mode operation to significantly reduce switching related loss at low current levels.
What features help ensure accurate voltage regulation over long PCB runs?
The LTC3856 includes remote output voltage sensing for true load regulation, rejecting common-mode noise and ground loop disturbances.
Does the controller support varying power stages and high current needs?
Yes, it is a 2-phase synchronous buck controller that can synchronize between 1-phase and 2-phase operation and supports up to 12-phase operation.