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LTC5594 power dissipation

According to datasheet typical power dissipation is 5*0.47=2.3W and it's a problem for us.

Can anyone tell actual temp diode reading from evaluation board or other temperature measurements (board near chip or chip itself)?

I'm asking because we can't use aircooling or heatsink. So it's only ground layers of the board (up to 10) and convection which can help to dissipate heat from 5x5mm package of the chip.

I checked evaluation board design files and  can say that using many 0.006inch(0.152mm) thermal vias under the chip is not an option for my design due to production limitations.

Obvious way to reduce current consumption is to disable amplifiers and i think it's the only way for us. But data in this regime is few (there is only one figure 5594 G46 in TPC section). And question about noise figure https://ez.analog.com/rf/f/q-a/534796/ltc5594-mixer-noise-figure was not ansered...

Any piece of advice would be apriciated.

Yuri

Measured on a standard DC2645A demo board (62-mil Nelco 4000-13 EP SI) at room temperature (20degC), no cooling, Vcc = 5V:

IC package top = 47.4degC

PCB bottom directly below IC = 46.2degC

Icc = 458mA

Pd = 2.3W

Theta_JC = 7.7degC/W

Tj = 65degC

  • Below is LTC5594 mixer-only DSB noise figure measured at I-channel output on one sample. The mixer differential output pins are pulled up to Vcc through 100 ohm resistors. They are then DC-blocked and converted to single-ended through a 180-degree combiner. The output is measured at 15MHz.