LTC3730_15 Datasheet, PDF (1/28 Pages) Linear Technology – 3-Phase, 5-Bit Intel Mobile VID, 600kHz, Synchronous Buck Controller

LTC3730
3-Phase, 5-Bit Intel
Mobile VID, 600kHz,
Synchronous Buck Controller
FEATURES
■ _{3-Phase Current Mode Controller with Onboard}
MOSFET Drivers
■ _{±5% Output Current Match Optimizes Thermal}
Performance and Size of Inductors and MOSFETs
■ _{Operational Amplifier Accomodates Mode Switching}
■ _{±1% VREF Accuracy Over Temperature}
■ _{Reduced Input and Output Capacitance}
■ _{Reduced Power Supply Induced Noise}
■ _{VOUT Programmable from 0.6V to 1.75V (IMVP III)}
■ _{±10% Power Good Output Indicator}
■ _{250kHz to 600kHz Per Phase, PLL, Fixed Frequency}
■ _{PWM, Stage Shedding}^TM _{or Burst Mode}^® _Operation
■ _OPTI-LOOP^® _{Compensation Minimizes COUT}
■ _{Adjustable Soft-Start Current Ramping}
■ _{4V, VIN, Undervoltage RUN/SS Reset/Reattempt Circuit}
■ _{Short-Circuit Shutdown Timer with Defeat Option}
■ _{Overvoltage Soft Latch}
■ _{Small 36-Lead Narrow (0.209”) SSOP Package}
U
APPLICATIO S
■ _{Tablet Computers}
■ _{High Performance Notebook Computers}
■ _{High Output Current DC/DC Power Supplies}
DESCRIPTIO
The LTC^®3730 is a PolyPhase^® synchronous step-down
switching regulator controller that drives all N-channel
external power MOSFET stages in a phase-lockable fixed
frequency architecture. The 3-phase controller drives its
output stages with 120° phase separation at frequencies of
up to 600kHz per phase to minimize the RMS losses in both
the input and output filter capacitors. The 3-phase tech-
nique effectively triples the fundamental frequency, im-
proving transient response while operating each controller
at an optimal frequency for efficiency and ease of thermal
design. Light load efficiency is optimized by using a choice
of output Stage Shedding or Burst Mode technology.
An internal operational amplifier provides mode selectable
output voltage programming in conjunction with the inter-
nal VID voltage control DAC.
Soft-start and a defeatable, timed short-circuit shutdown
protect the MOSFETs and the load. Current foldback
provides protection for the external MOSFETs under
short-circuit or overload conditions.
, LTC and LT are registered trademarks of Linear Technology Corporation. Burst Mode,
OPTI-LOOP and PolyPhase are registered trademarks of Linear Technology Corporation.
Stage Shedding is a trademark of Linear Technology Corporation. All other trademarks are
the property of their respective owners. Protected by U.S. Patents including 5481178,
5929620, 6177787, 6144194, 6100678, 5408150, 6580258, 6462525, 6304066, 5705919.
TYPICAL APPLICATIO
V_CC
4.5V TO 7V
10µF
0.1µF
SW3 SW2 SW1
POWER GOOD INDICATOR
OPTIONAL SYNC IN
5 VID BITS
680pF
5k
0.1µF
100pF
V_CC
TG1
LTC3730 _SW1
BOOST1
BOOST2
BG1
BOOST3
SENSE1⁺
SENSE1^–
PGOOD
PLLIN
PLLFLTR
VID0-VID4
I_TH
RUN/SS
SGND
EAIN
AMPOUT
IN^–
IN⁺
TG2
SW2
BG2
PGND
SENSE2⁺
SENSE2^–
TG3
SW3
BG3
SENSE3⁺
SENSE3^–
1µH
0.003Ω
V_IN
+
5V TO 28V
22µF
35V
V_IN
1µH
0.003Ω
V_OUT
1.2V
50A
V_IN
1µH
0.003Ω
+ COUT
470µF
x4
2.5V 3730 F01
Figure 1. High Current Triple Phase Step-Down Converter
3730fa
1