Datasheet Linear Technology LTC3861

Manufacturer	Linear Technology
Series	LTC3861

Dual, Multiphase Step-Down Voltage Mode DC/DC Controller with Accurate Current Sharing

Datasheets

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PDF, 996 Kb, Language: en, File uploaded: Sep 24, 2017, Pages: 38
Dual, Multiphase Step-Down Voltage Mode DC/DC Controller with Accurate Current Sharing

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Packaging

	LTC3861EUHE#PBF	LTC3861EUHE#TRPBF	LTC3861IUHE#PBF	LTC3861IUHE#TRPBF
N	1	2	3	4
Package	5x6 QFN-36 Package Outline Drawing	5x6 QFN-36 Package Outline Drawing	5x6 QFN-36 Package Outline Drawing	5x6 QFN-36 Package Outline Drawing
Package Code	UHE	UHE	UHE	UHE
Package Index	05-08-1876	05-08-1876	05-08-1876	05-08-1876
Pin Count	36	36	36	36

Parametrics

Parameters / Models	LTC3861EUHE#PBF	LTC3861EUHE#TRPBF	LTC3861IUHE#PBF	LTC3861IUHE#TRPBF
Architecture	Constant Frequency Voltage Mode	Constant Frequency Voltage Mode	Constant Frequency Voltage Mode	Constant Frequency Voltage Mode
Demo Boards	DC1822A	DC1822A	DC1822A	DC1822A
Design Tools	LTspice File,LTpowerCAD File	LTspice File,LTpowerCAD File	LTspice File,LTpowerCAD File	LTspice File,LTpowerCAD File
Export Control	no	no	no	no
Features	Differential Remote Sense, PolyPhase, External Synchronization, Resistor Set Frequency, DCR Current Sense, Power Good, Tracking	Differential Remote Sense, PolyPhase, External Synchronization, Resistor Set Frequency, DCR Current Sense, Power Good, Tracking	Differential Remote Sense, PolyPhase, External Synchronization, Resistor Set Frequency, DCR Current Sense, Power Good, Tracking	Differential Remote Sense, PolyPhase, External Synchronization, Resistor Set Frequency, DCR Current Sense, Power Good, Tracking
Frequency, kHz	2250	2250	2250	2250
Frequency Adjust Range	Up to 2.25MHz	Up to 2.25MHz	Up to 2.25MHz	Up to 2.25MHz
Frequency Sync Range	Up to 2.25MHz	Up to 2.25MHz	Up to 2.25MHz	Up to 2.25MHz
Integrated Inductor	no	no	no	no
Ishutdown, µA	50	50	50	50
Isupply, mA	30	30	30	30
Max Phases	2, 3, 4, 6, 12	2, 3, 4, 6, 12	2, 3, 4, 6, 12	2, 3, 4, 6, 12
Monolithic	no	no	no	no
Number of Outputs	2	2	2	2
Operating Temperature Range, °C	0 to 85	0 to 85	-40 to 85	-40 to 85
Output Current, A	40	40	40	40
Output Current 2, A	40	40	40	40
Polyphase	yes	yes	yes	yes
Sense Resistor	Rsense, DCR	Rsense, DCR	Rsense, DCR	Rsense, DCR
Switch Current, A	40	40	40	40
Switch Current 2, A	40	40	40	40
Synchronous	yes	yes	yes	yes
Topology	Buck	Buck	Buck	Buck
Topology 1	Buck	Buck	Buck	Buck
Topology 2	Buck	Buck	Buck	Buck
Vin Max, V	24	24	24	24
Vin Min, V	3	3	3	3
Vout Max, V	5.5	5.5	5.5	5.5
Vout Maximum	5.5V	5.5V	5.5V	5.5V
Vout Min, V	0.6	0.6	0.6	0.6
Vref Accuracy Over Temp, %	0.75	0.75	0.75	0.75

Eco Plan

	LTC3861EUHE#PBF	LTC3861EUHE#TRPBF	LTC3861IUHE#PBF	LTC3861IUHE#TRPBF
RoHS	Compliant	Compliant	Compliant	Compliant

Application Notes

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Modeling and Loop Compensation Design of Switching Mode Power Supplies &mdash AN149
PDF, 1.4 Mb, File published: Mar 23, 2015
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Application Note 149
January 2015
Modeling and Loop Compensation Design of
Switching Mode Power Supplies
Henry J. Zhang
Introduction Identifying The Problem TodayвЂ™s electronic systems are becoming more and more
complex, with an increasing number of power rails and
supplies. To achieve optimum power solution density,
reliability and cost, often system designers need to design
their own power solutions, instead of just using commercial power supply bricks. Designing and optimizing high
performance switching mode power supplies is becoming
a more frequent and challenging task. A well-designed switching mode power supply (SMPS)
must be quiet, both electrically and acoustically. An undercompensated system may result in unstable operations.
Typical symptoms of an unstable power supply include:
audible noise from the magnetic components or ceramic
capacitors, jittering in the switching waveforms, oscillation
of output voltage, overheating of power FETs and so on. Power supply loop compensation design is usually
viewed as a difficult task, especially for inexperienced
supply designers. Practical compensation design typically
involves numerous iterations on the value adjustment
of the compensation components. This is not only time
consuming, but is also inaccurate in a complicated
system whose supply bandwidth and stability margin …

Articles

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Sub-Milliohm DCR Current Sensing with Accurate Multiphase Current Sharing for High Current Power Supplies &mdash LT Journal
PDF, 2.7 Mb, File published: Jan 17, 2013
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Sub-Milliohm DCR Current Sensing with
Accurate Multiphase Current Sharing for
High Current Power Supplies
Muthu Subramanian, Tuan Nguyen and Theo Phillips The increasing functional complexity of electronic devices, combined with the desire for
higher microprocessor computational speed and the quest for eco-friendly electronics,
places stringent requirements on power supplies. High current supplies are expected
to operate at top efficiency. In order to minimize conduction losses, power supplies
are placed closer to the load, and multiple power stages are used on the same board.
Individual power stages have had to shrink in size to fit the available board area. To
achieve the best performance per board area, controllers must work with external
power stages such as power blocks, DrMOS or external gate drivers with MOSFETs.
SS
VIN
7V TO 14V 20k 4.22k 40.2k VOUT LTC3861 VSNSOUT1
COMP2
FB2 SS CLKIN
500kHz EXTERNAL
SYNC INPUT 1О©
2.2ВµF
16V 53.6k RUN1
ILIM1
SGND
ISNS1P …

Model Line

Series: LTC3861 (4)

LTC3861EUHE#PBF LTC3861EUHE#TRPBF LTC3861IUHE#PBF LTC3861IUHE#TRPBF

Manufacturer's Classification

Power Management > Switching Regulator > Step-Down (Buck) Regulators > Multiple Output Buck | External Power Switch Buck Controllers