LTC3829
3-Phase, Single Output
Synchronous Step-Down
DC/DC Controller with Diffamp
FeaTures
DescripTion
TheLTC®3829isahighperformance3-phasesingleoutput
synchronous step-down DC/DC switching controller that
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Optional Nonlinear Control for Fast Response
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±±0.75% ±0ꢀ6 Referenꢁe ꢂꢁꢁcraꢁꢃ
PWM% Stage Shedding™ or Bcrst Mode® Operation
High Effiꢁienꢁꢃ: Up to 975
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drives all N-channel synchronous power MOSFET stages.
A constant frequency current mode architecture allows a
phase-lockablefrequencyofupto770kHz.Powerlossand
noise due to ESR of the input capacitors are minimized by
operating the three controller output stages out of phase.
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R
or DCR Ccrrent Sensing
SENSE
Programmable DCR Temperatcre Compensation
Phase-Loꢁkable Fixed Freqcenꢁꢃ: 27±kHz to ..±kHz
Trce Remote Sense Differential ꢂmplifier
The LTC3829 can be configured for 6-phase operation,
has DCR temperature compensation, and output foldback
current limiting. This device features a precision 0.6V
reference and a power good indicator.
Programmable Active Voltage Positioning (AVP)
Triple N-Channel MOSFET Synchronous Drive
Wide V Range: 4.5V to 38V Operation
IN
V
V
Range: 0.6V to 5V without Diffamp
Range: 0.6V to 3.3V with Diffamp
OUT
OUT
Light load efficiency is optimized by using a choice of
output Stage Shedding or Burst Mode operation. A dif-
ferential amplifier provides true remote sensing of the
output voltage at the point of load.
Clock Input and Output for 6-Phase Operation
Adjustable Soft-Start or V Tracking
OUT
38-Pin (5mm × 7mm) QFN and FE Packages
The LTC3829 is available in both low profile 38-pin 5mm
× 7mm QFN and Exposed Pad FE packages.
applicaTions
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Notebook and Palmtop Computers
L, LT, LTC, LTM, Burst Mode, OPTI-LOOP, PolyPhase, Linear Technology, the Linear logo are
registered trademarks and Stage Shedding, No R
are trademarks of Linear Technology
SENSE
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Telecom Systems
Corporation. All other trademarks are the property of their respective owners. Protected by
U.S. Patents, including 5481178, 5705919, 5929620, 6144194, 6177787, 6580258, 6498466,
6674274, 6611136.
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Portable Instruments
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DC Power Distribution Systems
Typical applicaTion
V
IN
6V TO 28V
+
22µF
35V
s3
V
IN
INTV
TG1
SW1
CC
0.6µH
0.002Ω
0.002Ω
0.002Ω
4.7µF
BG1
Effiꢁienꢁꢃ
BOOST1
BOOST2
BOOST3
PGND
100
95
16
14
12
10
8
V
V
= 12V
IN
OUT
+
–
SENSE1
SENSE1
= 1.5V
V
V
90
IN
SW3 SW2 SW1
680pF
TG2
SW2
BG2
85
0.6µH
V
OUT
1.2V
50A
100k
EFFICIENCY
FREQ
80
75
LTC3829
I
TH
70
65
60
55
50
6
TK/SS
+
–
SENSE2
SENSE2
5k
0.1µF
POWER LOSS
10
4
SGND
IN
0.6µH
DIFFOUT
TG3
SW3
BG3
2
20k
20k
0
100
0.1
1
V
FB
LOAD CURRENT (A)
DIFFN
DIFFP
3829 TA01b
+
–
SENSE3
SENSE3
C
OUT
470µF
+
4V
s4
3829 TA01
3829f
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