Hi there:
I'd like to check the application for customer about TMP432ADGSR
1. The DXP1/N1 & DXP2/N using 1800pF, are there correct usage?
2. Using Beta compensation configuration register as 0111, is that correct?
3. What's suggest value for η-Factor Correction Register ?
4. What's suggest setting for Nadjust ?
the following is the schematic of their design.
Hello Kay,
1. 1800 pF is an acceptable differential capacitance for DXP1/N1 & DXP2/N2. Up to 2200pF can be tolerated, however the more you minimize the capacitance between these lines the better your results will be.
2. Setting the Beta compensation register to 0111 will disable beta compensation, and set the η-Factor of the TMP432 to 1.008. Setting it to 1xxx will turn beta compensation on.
3 & 4. The N_adjust value can be found using the equation below, which is equation (3) from the datasheet. This value is what you should load into the η-Factor correction register. We recommend all variants of 3904 and 3906 transistors which typically have an η_eff value of roughly 1.008, meaning that the η-factor correction register should be set to 0. We cannot guarantee the accuracy of any particular transistor, so for best results η-factor should be measured for your transistor.
Hi Brandon:
Thanks again, but if customer using the temperature diode for DPX/DPN, the setting will be the same or else?
Nadjust = 300 – ((300 *1.008) / 1.025)
Kay,
1. If the on chip transistor you are monitoring is diode connected then 0111 is the correct setting. If you want to be sure, you can enable the beta compensation by setting the register to 1xxx, and the TMP432 will automatically choose the correct setting.
2. Yes, based on this information you should set your N-factor correction register to decimal 5. Note that if you choose to use the automatic set function of the TMP432 for the beta compensation register and it chooses any value other than 1111, you will need to use this equation instead:
Best Regards,
Brandon Fisher
