FEDL5401A-02
OKI Semiconductor
ML5401A
Where TJ(max) is the maximum allowable junction temperature (125°C), and TA(max) is the maximum ambient
temperature used in the application.
For printer applications a heatsink is required since the package alone will not dissipate enough heat to satisfy these
requirements (TJ(max) ≤125°C). This heatsink is the combination of the mounting pad directly below the chip and at
least one ground plane at the bottom side of PCB. At least nine vias (12 is preferable) with 0.3-0.33mm diameter and
1.2mm pitch must be used for connecting the mounting pad to bottom plate. Using a 4-layer board according to
JESD51-7 is highly recommended (Figure 6). By using this structure a θJA of 41 °C/W(typical) is achievable.
Figure 6: PCB dimensions according to JESD51-7
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