This application note was jointly authored by Volterra Semiconductor and Summit Microelectronics. 

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Tech Support: Applications Note 35
Lossless Tracking Procedure and Results Summary
Reference Design: Volterra VT223 Regulator and SMT4214 TRAKKER™



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Lossless Tracking Procedure and Results Summary
Reference Design: Volterra VT223 Regulator and SMT4214 TRAKKER™

  PAGE 2    

 
Summit Microelectronics: Note 35: Figure 02

Summit Microelectronics: Note 35: Figure 03

Low-Level Tracking
When PCB space is a premium, the SMT4214 can be interfaced with on-board discrete (e.g., monolithic controllers) power supplies to obtain accurate voltage tracking eliminating the series power MOSFET. For example, Volterra's VT223-ADJ step-down switching regulator is readily controlled and monitored by the SMT4214 using a simple and inexpensive 'low-level' tracking interface technique.

VT223-ADJ to SMT4214 Interface
The output voltage of the VT223-ADJ is set by connecting a suitable resistor from the VREF pin to ground. The formula for setting the output voltage is:

Summit Microelectronics: Note 35: Equation 01

The output voltage may be fixed or adjusted by varying the value of RREF (Figure 4).


Summit Microelectronics: Note 35: Figure 04
Figure 4: Simplified Block Diagram of VT223-ADJ with VOUT Adjustment


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SUMMIT Microelectronics, Inc. reserves the right to make changes to the products contained in this publication in order to improve design, performance or reliability. SUMMIT Microelectronics, Inc. assumes no responsibility for the use of any circuits described herein, conveys no license under any patent or other right, and makes no representation that the circuits are free of patent infringement. Charts and schedules contained herein reflect representative operating parameters, and may vary depending upon a user's specific application. While the information in this publication has been carefully checked, SUMMIT Microelectronics, Inc. shall not be liable for any damages arising as a result of any error or omission.

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Revision 1.0 - This document supersedes all previous versions. Please check the Summit Microelectronics Inc. web site at
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