9.2.1 Design Requirements

Table 9-1. Design Parameters

PARAMETER

VALUE

+15 V

-15 V

Power board supply voltage

24 V

Input or output signal range non-faulted

-10 V to 10 V

Overvoltage protection levels

-60 V to 60 V

Control logic thresholds

1.8 V compatible, up to 44 V

Temperature range

-40°C to +125°C

9.2.2 Detailed Design Procedure

The TMUX7462F device's normal operation is to provide fault protection for the system while minimizing the

control logic signals required to route across the PCB. The device works as a channel protector by allowing

the signals to pass when in the valid voltage range, and opening the switch if there is a fault case. A fault

protected switch can add extra robustness to the sytem against fault conditions while also reducing the number

of components required to interface with the physical input channels.

The application shows two channels of the TMUX7462F connected as analog outputs and two channels

connected as analog inputs to the PLC system. The analog input channels utilize the TMUX7462F to protect

down stream operational amplifiers that are operating at a lower supply voltage than the multiplexer. The

TMUX7462F only has overvoltage protection on the source pins, therefore these pins are connected to the

external system connector on the analog output channels. If there is a miswiring or wire short issue on the

connectors, the channel protector will open the switch channel to help prevent long term fault conditions from

damaging the DAC.

to match the system requirements on how to handle a fault condition.

9.2.3 Application Performance Plots

The example application utilizes adjustable fault threshold voltages of the TMUX7462F to allow for protection

of downstream components operating on lower supply voltages. Figure 9-2 shows an example of positive

overvoltage fault response with a fast fault ramp rate of 60 V/us. Figure 9-3 shows the extremely flat on-

resistance across source voltage while operating within the fault threshold voltage levels for many supply voltage

scenarios. These features make the TMUX7462F an ideal solution for data acquisition applications that may face

various fault conditions but also require excellent linearity and low distortion.

Figure 9-2. Positive Overvoltage Response

TMUX7462F

SCDS394A – MARCH 2021 – REVISED OCTOBER 2021

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