Proper PCB layout is critical to achieving the full performance of the ISOTMP35R-Q1 device. Place the device as close as possible to the heat source to minimize thermal gradients and improve measurement accuracy. The TSENSE pins must be positioned to provide direct thermal coupling to the heat-generating element.

If the heat source is located on the opposite side of the PCB, implement a small copper area directly beneath the TSENSE pins and connect the copper area to the heat source using thermal vias. This copper region act as a local thermal interface, while the vias provide a low thermal resistance path between the heat source and the sensor. Use multiple vias in close proximity to improve heat transfer.

Place all filtering components, including bypass capacitors and RC filters, as close as possible to the device pins to minimize parasitic inductance and reduce susceptibility to electromagnetic interference (EMI).

Signal routing must be carefully managed. The V_OUT trace must be routed away from high dv/dt switching nodes and high-current paths, and trace length must be minimized to reduce noise pickup. When long routing distances are required, additional filtering or buffering is recommended to maintain signal integrity (see Section 8.1.2 for more details).

A low-impedance ground connection is required. A continuous ground plane provides a stable reference and reduces noise coupling.

The isolation barrier requires a minimum creepage and clearance distance of 8mm. A minimum of a 2-layer PCB stackup is recommended. In 4-layer PCB designs, signal routing can be implemented on either the top or bottom layers. The region beneath the isolation barrier must remain free of conductive elements, including copper planes, traces, pads, and vias, to maintain the isolation integrity of the device.

See Figure 8-5 for an example of the required keep-out region beneath the device.

Figure 8-5 Isolation Barrier Keep-Out Region (Cross-Section View)