1,6mm(min)

0,5mm(typ)

0,33mm(typ)

CDCLVP1102

www.ti.com

SCAS884D – AUGUST 2009 – REVISED DECEMBER 2015

11 Layout

11.1 Layout Guidelines

Power consumption of the CDCLVP1102 can be high enough to require attention to thermal management. For

reliability and performance reasons, the die temperature should be limited to a maximum of 125°C. That is, as an

estimate, ambient temperature (TA) plus device power consumption times RθJA should not exceed 125°C.

The device package has an exposed pad that provides the primary heat removal path to the printed circuit board

(PCB). To maximize the heat dissipation from the package, a thermal landing pattern including multiple vias to a

ground plane must be incorporated into the PCB within the footprint of the package. The exposed pad must be

soldered down to ensure adequate heat conduction out of the package. Figure 24 shows a recommended land

and via pattern.

11.2 Layout Example

Figure 24. Recommended PCB Layout

11.3 Thermal Considerations

The CDCLVP1102 supports high temperatures on the printed circuit board (PCB) measured at the thermal pad.

The system designer needs to ensure that the maximum junction temperature is not exceeded.

Ψjb can allow the

system designer to measure the board temperature with a fine gauge thermocouple and back calculate the

junction temperature using Equation 1. Note that

Ψjb is close to RθJB as 75 to 95% of a device's heat is

dissipated by the PCB. Further information can be found at SPRA953 and SLUA566.

Tjunction = TPCB + ( Ψjb × Power)

(1)

Example:

Calculation of the junction-lead temperature with a 4-layer JEDEC test board using four thermal vias:

TPCB = 105 °C

Ψjb = 21.7 °C/W

PowerinclTerm = Imax × Vmax = 105 mA × 3.6 V = 378 mW (max power consumption including termination

resistors)

PowerexclTerm = 302.5 mW (max power consumption excluding termination resistors, see SLYT127 for

further details)

ΔTJunction = Ψjb × PowerexclTerm = 21.7 °C/W × 302.5 mW = 6.56 °C

TJunction = ΔTJunction + TChassis = 6.56 °C + 105 °C = 111.56 °C (the maximum junction temperature of

125 °C is not violated)

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