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©2016-2023 Renesas Electronics Corporation

March 21, 2023

8P34S2108 Datasheet

The ePad provides a low thermal resistance path for heat transfer to the PCB and represents the key pathway to transfer heat away from

the IC to the PCB. It’s critical that the connection of the exposed pad to the PCB is properly constructed to maintain the desired IC case

temperature (TCB). A good connection ensures that temperature at the exposed pad (TCB) and the board temperature (TB) are relatively

the same. An improper connection can lead to increased junction temperature, increased power consumption and decreased electrical

performance. In addition, there could be long-term reliability issues and increased failure rate.

Example Calculation for Junction Temperature (TJ): TJ = TCB + JB x PD

For the variables above, the junction temperature is equal to 106.1°C. Since this is below the maximum junction temperature of 125°C,

there are no long term reliability concerns. In addition, since the junction temperature at which the device was characterized using forced

convection is 122°C, this device can function without the degradation of the specified AC or DC parameters.

Fail-Safe Operation

All clock inputs support fail-safe operation. That is, when the device is powered down, the clock inputs can be held at a DC voltage of up

to 4.6V without damaging the device or the input pins.

Power Considerations

This section provides information on power dissipation and junction temperature for the 8P34S2108.

Equations and example calculations are also provided.

1. Power Dissipation

The following is the power dissipation for VDD = 2.7V, which gives worst case results.

Maximum current at 85°C: VDD_MAX = 525mA.

▪ Power_MAX = VDD_MAX * IDD_MAX = 2.7V * 525mA = 1417.5mW

Package type

48 VFQFPN

Body size (mm)

7 x 7 x 0.8

ePad size (mm)

5.65 x 5.65

Thermal Via

5 x 5 Matrix

JB

1.2oC/W

TCB

105

°C

PD

0.9W

TJ

TCB