LTC3829_15 Datasheet, PDF (1/40 Pages) Linear Technology – 3-Phase, Single Output Synchronous Step-Down DC/DC Controller with Diffamp

LTC3829
3-Phase, Single Output
Synchronous Step-Down
DC/DC Controller with Diffamp
FEATURES
DESCRIPTION
n _{Optional Nonlinear Control for Fast Response}
n _{±0.75%, 0.6V Reference Accuracy}
n _{PWM, Stage Shedding™ or Burst Mode}^® _Operation
n _{High Efficiency: Up to 95%}
n _{RSENSE or DCR Current Sensing}
n _{Programmable DCR Temperature Compensation}
n _{Phase-Lockable Fixed Frequency: 250kHz to 770kHz}
n _{True Remote Sense Differential Amplifier}
n _{Programmable Active Voltage Positioning (AVP)}
n _{Triple N-Channel MOSFET Synchronous Drive}
n _{Wide VIN Range: 4.5V to 38V Operation}
n _{VOUT Range: 0.6V to 5V without Diffamp}
n _{VOUT Range: 0.6V to 3.3V with Diffamp}
n _{Clock Input and Output for 6-Phase Operation}
n _{Adjustable Soft-Start or VOUT Tracking}
n _{38-Pin (5mm × 7mm) QFN and FE Packages}
APPLICATIONS
n _{Notebook and Palmtop Computers}
n _{Telecom Systems}
n _{Portable Instruments}
n _{DC Power Distribution Systems}
The LTC^®3829 is a high performance 3-phase single output
synchronous step-down DC/DC switching controller that
drives all N‑channel synchronous power MOSFET stages.
A constant frequency current mode architecture allows a
phase-lockable frequency of up to 770kHz. Power loss and
noise due to ESR of the input capacitors are minimized by
operating the three controller output stages out of phase.
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.
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.
The LTC3829 is available in both low profile 38-pin 5mm
× 7mm QFN and Exposed Pad FE packages.
L, LT, LTC, LTM, Burst Mode, OPTI-LOOP, PolyPhase, Linear Technology, the Linear logo are
registered trademarks and Stage Shedding, No R_SENSE are trademarks of Linear Technology
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.
TYPICAL APPLICATION
4.7µF
INTV_CC ^VIN
TG1
SW1
BOOST1
BOOST2
BOOST3
BG1
PGND
SENSE1⁺
SENSE1^–
SW3 SW2 SW1
680pF
TG2
100k
FREQ
SW2
LTC3829 ^BG2
I_TH
5k
0.1µF
TK/SS
SGND
SENSE2⁺
SENSE2^–
DIFFOUT
TG3
SW3
20k
BG3
V_FB
20k
DIFFN
DIFFP
SENSE3⁺
SENSE3^–
0.6µH _0.002Ω
V_IN
+ 22µF ^{6V TO 28V}
35V
×3
V_IN
0.6µH _0.002Ω
V_IN
0.6µH _0.002Ω
V_OUT
1.2V
50A
+
C_OUT
470µF
4V
×4
3829 TA01
Efficiency
100
V_IN = 12V
95 V_OUT = 1.5V
90
85
EFFICIENCY
80
75
70
65
POWER LOSS
60
55
50
0.1
1
10
LOAD CURRENT (A)
16
14
12
10
8
6
4
2
0
100
3829 TA01b
For more information www.linear.com/LTC3829
3829fc
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