LT8650S - Dual Channel 4A, 42V, Synchronous Step-Down Silent Switcher 2 with 6.2µA Quiescent Current

Features

  • Silent Switcher®2 Architecture:
    • Ultralow EMI on Any PCB n Eliminates PCB Layout Sensitivity
    • Internal Bypass Capacitors Reduce Radiated EMI
    • Optional Spread Spectrum Modulation
  • 4A DC from Each Channel Simultaneously
  • Up to 6A on Either Channel
  • Ultralow Quiescent Current BurstMode® Operation:
    • 6.2μA IQ Regulating 12VIN to 5VOUT1 and 3.3VOUT2
    • Output Ripple <10mVP-P
  • Optional External VC Pin: Fast Transient Response and Current Sharing (Extra 50µA IQ/Channel)
  • Forced Continuous Mode
  • High Efficiency at High Frequency
  • 94.6% Efficiency at 2A, 5VOUT from 12VIN at 2MHz
  • 93.3% Efficiency at 4A, 5VOUT from 12VIN at 2MHz
  • Fast Minimum Switch-On Time: 40ns
  • Wide Input Voltage Range: 3.0V to 42V
  • Adjustable and Synchronizable: 300kHz to 3MHz
  • Small 4mm × 6mm 32-Pin LQFN Package

Typical Application

LT8650S Typical Application
LT8650S Typical Application

Description

The LT®8650S is a dual step-down regulator that delivers up to 4A of continuous current from both channels and supports loads up to 6A from each channel. The LT8650S features the second generation Silent Switcher architecture to minimize EMI emissions while delivering high efficiency at high switching frequencies. This includes integration of bypass capacitors to optimize high frequency current loops and make it easy to achieve advertised EMI performance by eliminating layout sensitivity.

The fast, clean, low-overshoot switching edges enable high efficiency operation even at high switching frequencies, leading to a small overall solution size. Peak current mode control with a 40ns minimum on-time allows high step down ratios at high switching frequencies.

Burst Mode operation features a 6.2μA quiescent current resulting in high efficiency at low output currents, forced continuous mode allows fixed switching frequency operation over the entire output load range, and spread spectrum operation can further reduce EMI emissions. External VC pins allow optimal loop compensation for fast transient response. The VC pins can also be used for current sharing and the CLKOUT pin enables synchronizing two LT8650S chips to generate a 4-phase, 16A supply.

Packaging

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

Part Number Package Code Temp Package
Drawing
RoHS
LT8650SEV#PBF 6mm × 4mm × 0.94mm LQFN LQFN E 05-08-1665 Yes
LT8650SIV#PBF 6mm × 4mm × 0.94mm LQFN LQFN I 05-08-1665 Yes


LT8650S 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
LT8650SEV#PBF 6mm × 4mm × 0.94mm LQFN E $8.22 $5.75 Yes
LT8650SIV#PBF 6mm × 4mm × 0.94mm LQFN I $9.04 $6.33 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.

Click here to view our complete list of demo boards

Applications

  • General Purpose Step-Down
  • Automotive and Industrial Supplies

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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

To launch a ready to run LTspice demonstration circuit for this part:

  • Step 1: If you have not installed LTspice on this computer, download and install LTspice
  • Step 2: Once LTspice is installed, click on the link(s) below to launch the simulation
  • Step 3: If LTspice does not automatically open after clicking the link above, you can instead run the simulation by right clicking on the link and selecting "Save Target As." After saving the file to your computer, start LTspice and open the demonstration circuit by selecting 'Open' from the 'File' menu

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

Models for the following parts are available in LTspice:
LT8650S

LTpowerCAD

The LTpowerCAD design tool is a complete power supply design tool program that can significantly ease the tasks of power supply design. It guides users to a solution, selects power stage components, provides detailed power efficiency, shows quick loop bode plot stability and load transient analysis, and can export a final design to LTspice for simulation. Click here to download LTpowerCAD

Design tools for the following parts are available in LTpowerCAD:
LT8650S

Technical Support