Power Management Switching Regulator Digitally Programmable Regulators

LTC3735 - 2-Phase, High Efficiency DC/DC Controller for Intel Mobile CPUs

Features

  • Output Stages Operate Antiphase
  • ±1% Output Voltage Accuracy
  • 6-Bit IMVP-IV VID Code: VOUT = 0.7V to 1.708V
  • Intel Compatible Power Saving Mode (PSIB)
  • Stage Shedding Improves Low Current Efficiency
  • Power Good Output with Adaptive Masking
  • Lossless Voltage Positioning
  • Dual Input Supply Capability for Load Sharing
  • Resistor Programmable VOUT at Boot-Up and Deeper Sleep State
  • Resistor Programmable Deep Sleep Offset
  • Programmable Fixed Frequency: 210kHz to 550kHz
  • Adjustable Soft-Start Current Ramping
  • Foldback Output Current Limit
  • Short-Circuit Shutdown Timer with Defeat Option
  • Overvoltage Protection
  • Available in 36-Lead SSOP (0.209 Wide) and 38-Lead (5mm × 7mm) Packages

Typical Application

LTC3735 Typical Application

Description

The LTC3735 is a 2-phase synchronous step-down switching regulator controller that drives all N-channel power MOSFETs in a constant frequency architecture. The output voltage is programmable by six VID bits during normal operation and by external resistors during initial boot-up and deeper sleep state. The LTC3735 drives its two output stages out-of-phase at frequencies up to 550kHz to minimize the RMS ripple currents in both input and output capacitors. This antiphase technique also doubles the apparent switching frequency, improving the transient response while operating each phase at an optimum frequency for efficiency. Thermal design is further simplified by cycle-by-cycle current sharing between the two phases.

An Intel compatible PSIB input is provided to select between two modes of operation. Fully enhanced synchronous mode achieves a very small output ripple and very fast transient response while power saving mode realizes very high efficiency. OPTI-LOOP® compensation allows the transient response to be optimized for a wide range of output capacitance and ESR values.

Packaging

CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.

For complete and up to date package information and drawings, please refer to our packaging page

Part Number Package Code Temp Package
Drawing		 RoHS
LTC3735EG#PBF SSOP-36 G E 05-08-1640 (G36) Yes
LTC3735EG#TRPBF SSOP-36 G E 05-08-1640 (G36) Yes
LTC3735EUHF#PBF 5x7 QFN-38 UHF E 05-08-1701 Yes
LTC3735EUHF#TRPBF 5x7 QFN-38 UHF E 05-08-1701 Yes


LTC3735 Package Drawing
LTC3735 Package Drawing

Order Info

  • Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
  • Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
  • Please refer to our general ordering information or the product datasheet for more details

Package Variations and Pricing

Part Number Package Temp Price
(1-99)		 Price
(1k)*		 RoHS
LTC3735EG#PBF SSOP-36 E $6.52 $4.45 Yes
LTC3735EG#TRPBF SSOP-36 E $4.55 Yes
LTC3735EUHF#PBF 5x7 QFN-38 E $6.79 $4.60 Yes
LTC3735EUHF#TRPBF 5x7 QFN-38 E $4.70 Yes
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* The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Linear Technology sales office or authorized distributor.

Demo Boards

Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.

Part Number Description Price Documentation
DC529A-B LTC3735EG | IMVP4 Power Supply (Steelcliff Module), Vin = 5V to 24V, Vout = 0.6V-1.75V@32A Contact Factory
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Click here to view our complete list of demo boards

Applications

  • Mobile and Desktop Computers
  • Internet Servers

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Design Tools

Linear Technology provides a variety of custom design simulation tools and device models to allow even novice designers to quickly and easily evaluate circuits using high performance switching regulators, amplifiers, data converters, filters and more. Please visit our Design Tools page to view and download:

  • LTspice - A powerful SPICE simulator, schematic capture and waveform viewer with enhancements and models for easing the simulation of switching regulators
  • LTpowerCAD - A complete power supply selection, synthesis and design tool
  • LTpowerPlay - A development environment supporting Linear Technology's Digital Power System Management (PSM) products
  • PScope & QuikEval - USB-based product demonstration and data acquisition system for use with our ADCs, DACs, and more
  • Linduino - Arduino compatible system for developing and distributing firmware libraries and example code
  • LinearLab Tools - A collection of Matlab and Python programs that provide direct access to Linear Technology’s data converter evaluation boards
  • And More!

Technical Support