CISPR 25 Class 4 Rated Design for Dual Automotive USB Charger Reference Design


Design files


PMP20249 is an EMI optimized design for dual automotive USB charger system utilizing the LMS3635 and LMS3655 regulator ICs (400kHz fully-integrated synchronous buck for automotive application) and TPS2549 USB switch (TPS2549-Q1 automotive USB charging port controller with integrated power switch & cable compensation). The design accepts an input voltage range of 6V to 18V and provides the outputs of 5V@3.5A and 5V@2.5A. The design has a differential EMI filter, and has been tested for and passed CISPR25 Class 4 conducted EMI limits without shileding, a common mode choke, or a ferrite bead.

  • Wide-Vin front end power supply for automotive USB charger system with dual 12.5W outputs
  • Off-battery operation with positive and negative over-voltage transient protection
  • Passed CISPR25 Class 4 conducted EMI test
  • All devices have an AEC-Q100 qualified version available
  • All devices switch outside of the AM and FM bands
Output voltage options PMP20249.1
Vin (Min) (V) 6
Vin (Max) (V) 18
Vout (Nom) (V) 3.5
Iout (Max) (A) 2.5
Output Power (W) 8.75
Isolated/Non-Isolated Isolated
Input Type DC
Topology Buck- Synchronous
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A fully assembled board has been developed for testing and performance validation only, and is not available for sale.

Design files & products

Design files

Download ready-to-use system files to speed your design process.

TIDUCU2.PDF (1234 K)

Test results for the reference design, including efficiency graphs, test prerequisites and more


Detailed schematic diagram for design layout and components


Complete listing of design components, reference designators, and manufacturers/part numbers


Detailed overview of design layout for component placement

TIDRSL7.ZIP (5418 K)

Files used for 3D models or 2D drawings of IC components


Design file that contains information on physical board layer of design PCB

TIDRSL6.PDF (1023 K)

PCB layer plot file used for generating PCB design layout


Includes TI products in the design and potential alternatives.

AC/DC & DC/DC converters (integrated FET)

LMS3635-Q13.5-A, 36-V synchronous, 400-kHz, step-down converter

Data sheet: PDF | HTML
AC/DC & DC/DC converters (integrated FET)

LMS36555.5A, 36V Synchronous, 400kHz, Step-Down Converter

Data sheet: PDF | HTML
AC/DC & DC/DC converters (integrated FET)

LMS3655-Q15.5-A, 36-V synchronous, 400-kHz, step-down converter

Data sheet: PDF | HTML
USB power switches & charging port controllers

TPS2549-Q1Automotive USB Charge port controller with droop compensation

Data sheet: PDF | HTML

Technical documentation

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Type Title Date
* Test report CISPR 25 Class 4 Rated Design for Dual Automotive USB Charger Reference Design Sep. 11, 2017

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