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Part Number: UCC3946 Other Parts Discussed in Thread: TPS3851
Hi Team, Is it acceptable and safe to drive the WDI pin of UCC3946 to 3.3V when VDD is not supplied to the device (UCC3946 is powered-off)? The datasheet does not specify a VIH maximum for this…
Please allow me to chime in. Since I came from Unitrode I have in depth familiarity with those parts.
UCC3946 has been shown to work in applications requiring long watchdog periods. https://e2e.ti.com/support/power_management/svs_and_sequencers/f/212/p/56000…
Hello David
The UCC3946 is for temperature of 0-70C while the UCC2946 is for -40-85C, so that’s probably the reason for the tighter accuracy of UCC3946 .
I can only guess that the accuracy of the UCC2946 is basically similar to the UCC3946 within the…
Hi Jackie,
The ±25% variation of the part itself, and it does not take into account the variation in the capacitor you might use, also, we do not recommend going outside of the specified C WP value range (i.e. 155 pF ≤ C WP ≤ 63 nF). Perhaps…
Hi Toshio,
In the Watchdog section of the Electrical Characteristics table we have the minimum Watchdog period for UCC2946 as 0.96s and UCC3946 as 1.12s. 10ms will not work with these parts.
Very Respectfully,
Ryan
The only device we have that will do a 40s delay is the UCC3946. You will need to use a 12.6uF timing capacitor on the RP pin to get 40 seconds of delay. This capacitor will need to be low leakage current so stick with ceramics. The UCC3946 also has a…
In the electrical characteristics on page 3, an output low level is given for the RESET and WDO pins. This voltage is spec'd at 2 mA sink current. So, the pin can handle at least 2 mA. Is this what you need?
