JAJSJL5F december 2019 – july 2023 TMUX1308-Q1 , TMUX1309-Q1
PRODUCTION DATA
When evaluating the safety and reliability of an automotive grade multiplexer, it is important to note their performance under various operating conditions. In the case of TMUX13xx-Q1, we examine it's response to various short-to-battery conditions to provide insight on system level design for automotive optimization. It is important to design around short-to-battery as failure to do so can result in operational issues. The following section shows a deep dive into three scenarios to demonstrate the behavior of the TMUX1308-Q1 under short-to-battery conditions using a 5V supply voltage.
We begin with the following setup to explore our first scenario with channel S7 selected and channel S0 experiencing a short-to-battery condition.
Table 10-2 indicates values of ∆VOUT, VSBAT and minimum RLIM for various VBAT cases when considering a maximum allotment of 25mAfor IS/ID. Choosing too large of an RLIM will negatively affect ∆VOUT as well as substantially limit current flow. Choosing too small of an RLIM can damage the device.
VBAT | RLIM | ∆VOUT (typ) | VSBAT |
---|---|---|---|
12V | 470 | < 10 uV | 5.6V |
19V | 750 | < 10 uV | 5.6V |
24V | 1K | < 10 uV | 5.6V |
36V | 1.5K | < 10 uV | 5.6V |
48V | 2K | < 10 uV | 5.6V |
60V | 2.4K | < 10 uV | 5.6V |
We then evaluate the scenario of seeing a short to battery condition on all unselected channels at the same time. The below table indicates values when considering a maximum allotment of 12.5mA for IS/ID. If you have the potential to see short to battery on all channels at the same time, then 12.5 mA is the limiting factor. Here again choosing too large of an RLIM will negatively affect ∆VOUT as well as substantially limit current flow. Choosing too small of an RLIM can also damage the device.
VBAT | RLIM | ∆VOUT (typ) | VSBAT |
---|---|---|---|
12V | 1K | < 10 uV | 5.6V |
19V | 1.5K | < 10 uV | 5.6V |
24V | 2K | < 10 uV | 5.6V |
36V | 3K | < 10 uV | 5.6V |
48V | 3.9K | < 10 uV | 5.6V |
60V | 4.7K | < 10 uV | 5.6V |
We then evaluate the scenario of a short to battery occurring when the switch is closed using a 5V supply. As such, input voltage needs to be limited to 6V. The below table indicates values of RLIM needed to keep the voltage of a selected channel under 6V using a standard 5V VDD for all short to battery cases. Choosing too large of an RLIM will negatively affect ∆VOUT as well as substantially limit current flow. Choosing too small of an RLIM can also damage the device.
VBAT | RLIM | ∆VOUT (typ) | VSBAT |
---|---|---|---|
12V | 1.6K | < 10 uV | 5.9V |
18V | 3K | < 10 uV | 5.9V |
19V | 3.3K | < 10 uV | 5.9V |
24V | 4.7K | < 10 uV | 5.9V |
36V | 10K | < 10 uV | 5.9V |
48V | 13K | < 10 uV | 5.9V |
60V | 15K | < 10 uV | 5.9V |
In conclusion, several short-to-battery case studies were observed using a 5V supply. Note that if using a lower supply voltage, the RLim values will change for optimal current flow. It is important to protect against short to battery conditions as a failure to do so can result in system level issues. Caution must be observed to design around these conditions and the electrical characteristics of the device such that proper operation of the device is guaranteed.