OSDZU3 Thermal Management Application Note
Published On: September, 19, 2023 By: Eshtaartha Basu | Updated: October 27, 2023 by Greg Sheridan
The temperature of a device during operation in a system is an important parameter as it affects many properties of the device such as functionality, reliability, and operational lifetime. Since the OSDZU3 is a System-In-Package (SiP) with several ICs and passive components, its thermal characteristics are different than that of any particular component integrated within the SiP.
This document will provide data on the thermal resistance of OSDZU3 SiP. It will also provide data on an example heatsink that meets the target thermal resistance for higher power dissipation use cases.
Table of Contents
OSDZU3 Thermal Resistance
To determine the thermal resistance of the OSDZU3, the on-die temperature sensors of the PMIC and the XCZU3’s SYSMON were used to measure junction temperature. The thermal resistance was calculated using the following formula:
: Measured Junction to Ambient Air Thermal Resistance of SiP on a Specific Printed Circuit Board- : Junction Temperature of the highest Temperature Devices in the SiP
- : Ambient Temperature
- : Power Dissipated by the SiP
is the calculated Thermal Resistance from Junction to Ambient when the OSDZU3 is mounted on an example 4-layer printed circuit board in still air, running in JTAG mode, and other components operating per spec.
The measured Thermal Parameters of OSDZU3 are given in this table. The heatsink information is described in the next section.
Theta JA Calculation
To measure junction temperature, you can access XCZU3’s SYSMON using AMD Vivado. To learn more, refer “On Vivado” sub section of JTAG section in OSDZU3 Getting Started Guide. To access the on-die temperature sensors of the PMICs for junction temperature, see PMIC Programming Guide. To measure case temperature of the ZU3, use a low thermal mass thermocouple.
OSDZU3 Thermal Parameters
The thermal parameters of OSDZU3 are listed in the table below.
| Thermal Parameters | Value (OC/W) |
|---|---|
 | 10.2 |
 * | 4.2 |
* Heat Sink (HS) Information is Provided in the Heatsink Information Section
Heatsink Information
The components of the Heatsink (Figure Below) that were used when taking measurements are listed in the below table.
| Heatsink P/N | ATS-CPX040040010-113-C2-R0 |
| Heatsink Thermal Resistance | 2.9 C/W (using fan indicated below) |
| Thermal Pad P/N | Arctic Thermal Pad APT2560 |
| Heatsink Fan P/N | AFB0405HHA-A (7000rpm, 8.154 CFM/473 LFM airflow) https://www.digikey.com/en/products/detail/delta-electronics/AFB0405HHA-A/2560636 |
Revision History
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| Revision Number | Revision Date | Changes | Author |
| 1 | 11/18/2021 | Initial Release | Eshtaartha Basu |
| 2 | 09/26/2023 | Production Release | Eshtaartha Basu |