9

Layout guidelines

The RHRPMICL1A simultaneously handles fast switching and medium voltage, which implies specific attention to

the layout. Furthermore, proper layout allows mitigating a heavy ion effect, in particular SET. We recommend that

the user refers as much as possible to the layout guidelines of the EVAL-RHRICL1xV1 demonstration board.

The first priority when components, are placed has to be given to the power section (current path from input,

through current sense resistor and high-side switch, toward output), minimizing the length of each connection and

loop as short as possible.

Also, the path of the gate driver signal (driving ON/OFF the high-side switch) must present the lowest resistance

as possible. A power resistor might be required in series to this path to protect the integrated gate driver.

To minimize noise and voltage spikes (also EMI and losses) power connections must be a part of a power plane

and implemented using wide and thick conductor traces. The loop must be minimized. The inductance effect and,

consequently, leading to ringing of the tracks can be minimized by making it as short as possible. The number of

vias must be minimized to reduce the related parasitic effect.

to the IC to reduce possible loop and parasitic inductance.

Small signal components and connections to critical nodes (e.g. TC_ON/OFF, ISNS+ and ISNS-) of the

application are also important. In fact, the symmetry of the path may impact the sampled value.

To improve heat dissipation, place a copper area under the IC. This copper area may be connected with other

layers (if available) through vias to improve the thermal conductivity. The combination of a copper pad, copper

plane and vias under the driver allows the device to reach its best thermal performance.

It is important to ensure that the power devices, including the IC, have a thermal path compatible with the power

dissipated. It is advisable to mount both the IC and the high-side switch on dedicated heatsinks (for example, the

device should be soldered on the copper area of the PCB, which is in strict thermal contact to an aluminium

frame) gluing each part to the frame (without using any screws for the power MOSFET).

The material used to glue could be the resin ME7158 (space approved resin). Moreover, two small FR4 spacers

could be added in order to ensure the electrical isolation of the package of the device from the frame.

Finally, for reliability reasons it is advisable to use more than one resistor (series connected) between the device

and the main bus ground whose total value is the one obtained by application design considerations.

RHRPMICL1A

Layout guidelines

DS12602 - Rev 3

page 21/31