SUMMARY
The dependence of volume, mass and size on the number of boards and the distance between them in sealed unit of electronic devices is researched. Mass and size characteristics are calculated excluding the mass of electronic components, wiring harness and connectors. During packaging the total mounting of electronic components does not change. Dimensions of each board are included the rock areas and guard bend at the board boundaries. The square boards are used to reduce the volume. Overall dimensions of the unit are given as the family of block volume dependencies on the number of boards if range of boarddistances is equal from 5 to 40 mm. The minimum volume of the unit is provided from 5–7 boards. Then the volume is reduced by 1,5–2 times in comparison with one-board units. The mass of the block is reduced 1,5–3 times under the same conditions. The dependence of maximal temperature on each board from distance between the boards is analyzed. The temperature mode is the worst if distances between the boards are from 2 to 5 mm. The research of the mass, size and thermal characteristics has allowed to reduce design errors and to improve the quality of the electronic device design simultaneously.