Welcome to the Sequencers Section of the TI E2E Support Community. Ask questions, share knowledge, explore ideas, and help solve problems with fellow engineers. To post a question, click on the forum tab then "New Post".
Q: TPS3818_Delay time tolerance by 1300154
What is the delay time tolerance of TPS3818?
In this forum, I found out that there is a formula for calculating the delay time based on the CT pin charge current and threshold voltage.
Could someone please share me that formula?
Thank you in advance.
A: Re: TPS3818_Delay time tolerance by 10449
The TPS3818 delay time is defined by how long it takes the 220nA precision current source to charge the timing capacitor on the CT pin to 1.23V. This is a simple I=C*(dV/dt) calculation. The equation you are looking for is found by rearranging terms to make it dt=C*dV/I = C * 1.23V / 220nA. The datasheet equation for calculating the Ct capacitor value looks a little more complicated because it combines terms and includes a 500us delay time. The 500us delay time is insignificant in most applications and can be ignored to make the calculation a little easier. The tolerance of the RESET pulse is a function of tolerances of the current source (which is specified in the datasheet) and the 1.23V comparator trip voltage (which is specified in the datasheet). The remaining RESET pulse variation is a function of capacitor tolerance. Note 3 on page 3 shows that the RESET time tolerance due to the 1.23V and 220nA tolerances is +/- 15%
All content and materials on this site are provided "as is". TI and its respective suppliers and providers of content make no representations about the suitability of these materials for any purpose and disclaim all warranties and conditions with regard to these materials, including but not limited to all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement of any third party intellectual property right. TI and its respective suppliers and providers of content make no representations about the suitability of these materials for any purpose and disclaim all warranties and conditions with respect to these materials. No license, either express or implied, by estoppel or otherwise, is granted by TI. Use of the information on this site may require a license from a third party, or a license from TI.
TI is a global semiconductor design and manufacturing company. Innovate with 100,000+ analog ICs andembedded processors, along with software, tools and the industry’s largest sales/support staff.