LTC3736-1 - Dual 2-Phase, No RSENSE Synchronous Controller with Spread Spectrum

Features

  • Spread Spectrum Operation
  • Tracking Function
  • No Current Sense Resistors Required
  • Out-of-Phase Controllers Reduce Required
  • Input Capacitance
  • Wide VIN Range: 2.75V to 9.8V
  • Current Mode Operation
  • 0.6V ±1.5% Voltage Reference
  • Low Dropout Operation: 100% Duty Cycle
  • Pulse Skipping Operation at Light Loads
  • Internal Soft-Start Circuitry
  • Power Good Output Voltage Monitor
  • Output Overvoltage Protection
  • Micropower Shutdown: IQ = 9µA
  • Tiny Low Profile (4mm × 4mm) QFN and Narrow SSOP Packages

Typical Application

LTC3736-1 Typical Application
LTC3736-1 Typical Application

Description

The LTC3736-1 is a 2-phase dual synchronous stepdown switching regulator controller with tracking that drives external complementary power MOSFETs using few external components. The constant frequency current mode architecture with MOSFET VDS sensing eliminates the need for sense resistors and improves efficiency. Power loss and noise due to the ESR of the input capacitance are minimized by operating the two controllers out of phase.

A unique spread spectrum architecture randomly varies the LTC3736-1’s switching frequency from 450kHz to 580kHz, significantly reducing the peak radiated and conducted noise on both the input and output supplies, making it easier to comply with electromagnetic interference (EMI) standards.

Pulse skipping operation provides high efficiency at light loads. 100% duty cycle capability provides low dropout operation, extending operating time in battery-powered systems. The high switching frequencies allow for the use of small surface mount inductors and capacitors.

The LTC3736-1 is available in the low profile (0.75mm) 24-pin thermally enhanced (4mm × 4mm) QFN package and 24-lead narrow SSOP packages.

No RSENSE is a trademark of Linear Technology Corporation. Protected by U.S. Patents including 5481178, 5929620, 6144194, 6580258, 6304066, 6611131, 6498466.

  Max Current Sense Voltage Burst Mode
Soft Start Spread Spectrum
LTC3736 204mV Yes No No
LTC3736-1 204mV No No Yes
LTC3736-2 345mV No Yes No

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
LTC3736EGN-1#PBF SSOP-24 GN E 05-08-1641 (GN24) Yes
LTC3736EGN-1#TRPBF SSOP-24 GN E 05-08-1641 (GN24) Yes
LTC3736EUF-1#PBF 4x4 QFN-24 UF E 05-08-1697 Yes
LTC3736EUF-1#TRPBF 4x4 QFN-24 UF E 05-08-1697 Yes


LTC3736-1 Package Drawing
LTC3736-1 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
LTC3736EGN-1#PBF SSOP-24 E $6.25 $4.40 Yes
LTC3736EGN-1#TRPBF SSOP-24 E $4.50 Yes
LTC3736EUF-1#PBF 4x4 QFN-24 E $6.43 $4.50 Yes
LTC3736EUF-1#TRPBF 4x4 QFN-24 E $4.60 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
DC803A LTC3736EUF-1 | 2-Phase, Spread Spectrum, 2.75V ≤ Vin ≤ 8V; Vout1 = 2.5V @ 5A, Vout2 = 1.8V @ 5A $150.00
Buy Now
Click here to view our complete list of demo boards

Applications

  • One or Two Lithium-Ion Powered Devices
  • Notebook and Palmtop Computers, PDAs
  • Portable Instruments
  • Distributed DC Power Systems

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Design Tools

LTspice

LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice

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To explore other ready to run LTspice demonstration circuits, please visit our Demo Circuits Collection.

Models for the following parts are available in LTspice:
LTC3736
LTC3736-1
LTC3736-2

Technical Support