Datasheet LTC3729 (Analog Devices)
| Fabricante | Analog Devices |
| Descripción | 550kHz, PolyPhase, High Efficiency, Synchronous Step-Down Switching Regulator |
| Páginas / Página | 30 / 1 — FEATURES. DESCRIPTION. Wide VIN Range: 4V to 36V Operation. Reduces … |
| Formato / tamaño de archivo | PDF / 356 Kb |
| Idioma del documento | Inglés |
FEATURES. DESCRIPTION. Wide VIN Range: 4V to 36V Operation. Reduces Required Input Capacitance and Power. Supply Induced Noise
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LTC3729 550kHz, PolyPhase, High Efficiency, Synchronous Step-Down Switching Regulator
FEATURES DESCRIPTION
n
Wide VIN Range: 4V to 36V Operation
The LTC®3729 is a multiple phase, synchronous n
Reduces Required Input Capacitance and Power
step‑down current mode switching regulator controller
Supply Induced Noise
that drives N‑channel external power MOSFET stages in a n ±
1% Output Voltage Accuracy
phase‑lockable fixed frequency architecture. The PolyPhase n
Phase-Lockable Fixed Frequency: 250kHz to 550kHz
controller drives its two output stages out of phase at n
True Remote Sensing Differential Amplifier
frequencies up to 550kHz to minimize the RMS ripple n PolyPhase® Extends from Two to Twelve Phases currents in both input and output capacitors. The output n Reduces the Size and Value of Inductors clock signal allows expansion for up to 12 evenly phased n Current Mode Control Ensures Current Sharing controllers for systems requiring 15A to 200A of output n 1.1MHz Effective Switching Frequency (2‑Phase) current. The multiple phase technique effectively multiplies n OPTI‑LOOP® Compensation Reduces COUT the fundamental frequency by the number of channels n Power Good Output Voltage Indicator used, improving transient response while operating each n Very Low Dropout Operation: 99% Duty Cycle channel at an optimum frequency for efficiency. Thermal n Adjustable Soft‑Start Current Ramping design is also simplified. n Internal Current Foldback Plus Shutdown Timer An internal differential amplifier provides true remote sens‑ n Overvoltage Soft‑Latch Eliminates Nuisance Trips ing of the regulated supply’s positive and negative output n Available in 5mm × 5mm QFN terminals as required for high current applications. and 28‑Lead SSOP Packages
APPLICATIONS
A RUN/SS pin provides both soft‑start and optional timed, short‑circuit shutdown. Current foldback limits MOSFET n dissipation during short‑circuit conditions when the Desktop Computers/Servers n overcurrent latchoff is disabled. OPTI‑LOOP compensation Large Memory Arrays n allows the transient response to be optimized over a wide DC Power Distribution Systems range of output capacitance and ESR values. The LTC3729 L, LT, LTC, LTM, PolyPhase, OPTI‑LOOP, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their includes a power good output pin that indicates when the respective owners. output is within ±7.5% of the designed set point.
TYPICAL APPLICATION
V 0.1µF IN 10Ω 10µF 5V TO 28V S V M1 IN LTC3729 TG1 S 35V BOOST1 0.002Ω CERAMIC 0.1µF 0.47µF SW1 ×4 L1 RUN/SS S M2 D1 BG1 0.8µH ×2 PGOOD PGND SENSE1+ ITH SENSE1– 3.3k 1000pF TG2 M3 S S SGND BOOST2 0.002Ω V 0.47µF OUT SW2 16k L2 1.6V/40A S S M4 V 0.8µH DIFFOUT BG2 ×2 D2 S EAIN INTVCC S + 10µF + V – COUT 16k OS SENSE2+ 1000µF ×2 V + OS SENSE2– 4V COUT: T510E108K004AS L1, L2: CEPH149-IROMC M1, M3: IRF7811W 3729 TA01 D1, D2: UP5840 M2, M4: IRF7822
Figure 1. High Current Dual Phase Step-Down Converter
3729fb 1 Document Outline Features Description Applications Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions functional Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts
FEATURES DESCRIPTION
n
Wide VIN Range: 4V to 36V Operation
The LTC®3729 is a multiple phase, synchronous n
Reduces Required Input Capacitance and Power
step‑down current mode switching regulator controller
Supply Induced Noise
that drives N‑channel external power MOSFET stages in a n ±
1% Output Voltage Accuracy
phase‑lockable fixed frequency architecture. The PolyPhase n
Phase-Lockable Fixed Frequency: 250kHz to 550kHz
controller drives its two output stages out of phase at n
True Remote Sensing Differential Amplifier
frequencies up to 550kHz to minimize the RMS ripple n PolyPhase® Extends from Two to Twelve Phases currents in both input and output capacitors. The output n Reduces the Size and Value of Inductors clock signal allows expansion for up to 12 evenly phased n Current Mode Control Ensures Current Sharing controllers for systems requiring 15A to 200A of output n 1.1MHz Effective Switching Frequency (2‑Phase) current. The multiple phase technique effectively multiplies n OPTI‑LOOP® Compensation Reduces COUT the fundamental frequency by the number of channels n Power Good Output Voltage Indicator used, improving transient response while operating each n Very Low Dropout Operation: 99% Duty Cycle channel at an optimum frequency for efficiency. Thermal n Adjustable Soft‑Start Current Ramping design is also simplified. n Internal Current Foldback Plus Shutdown Timer An internal differential amplifier provides true remote sens‑ n Overvoltage Soft‑Latch Eliminates Nuisance Trips ing of the regulated supply’s positive and negative output n Available in 5mm × 5mm QFN terminals as required for high current applications. and 28‑Lead SSOP Packages
APPLICATIONS
A RUN/SS pin provides both soft‑start and optional timed, short‑circuit shutdown. Current foldback limits MOSFET n dissipation during short‑circuit conditions when the Desktop Computers/Servers n overcurrent latchoff is disabled. OPTI‑LOOP compensation Large Memory Arrays n allows the transient response to be optimized over a wide DC Power Distribution Systems range of output capacitance and ESR values. The LTC3729 L, LT, LTC, LTM, PolyPhase, OPTI‑LOOP, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their includes a power good output pin that indicates when the respective owners. output is within ±7.5% of the designed set point.
TYPICAL APPLICATION
V 0.1µF IN 10Ω 10µF 5V TO 28V S V M1 IN LTC3729 TG1 S 35V BOOST1 0.002Ω CERAMIC 0.1µF 0.47µF SW1 ×4 L1 RUN/SS S M2 D1 BG1 0.8µH ×2 PGOOD PGND SENSE1+ ITH SENSE1– 3.3k 1000pF TG2 M3 S S SGND BOOST2 0.002Ω V 0.47µF OUT SW2 16k L2 1.6V/40A S S M4 V 0.8µH DIFFOUT BG2 ×2 D2 S EAIN INTVCC S + 10µF + V – COUT 16k OS SENSE2+ 1000µF ×2 V + OS SENSE2– 4V COUT: T510E108K004AS L1, L2: CEPH149-IROMC M1, M3: IRF7811W 3729 TA01 D1, D2: UP5840 M2, M4: IRF7822
Figure 1. High Current Dual Phase Step-Down Converter
3729fb 1 Document Outline Features Description Applications Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions functional Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts