Specifications

AMP2-T assembly instructions. © 41Hz Audio / www.41hz.com Revision 1.0T boards
APPENDIX 3: Mounting the TP2350B chip
The TP2350B driver chip can produce some heat, especially if driving MOSFETs with high gate
charges and / or at high rail voltages. The chip has a slug on the bottom side that enhances the
heat transfer from the chip. The AMP2 PCB has a corresponding area with a number of holes /
vias that lead heat from the chip to the back of the PCB. There are also four larger mounting
holes around the chip so a heat sink can be mounted with screws on top of the chip. So to
enhance the heat transferal, it is possible to
- Use heat conductive paste on the bottom of the chip
- Solder the chip slug to the PCB.
- Use a heat sink on top of the chip and also under the chip.
It is recommended that at least one of these methods is used, especially at high power outputs
and high rail voltages.
The use of heat conductive paste on the bottom of the chip is probably the most straight forward
method and this method can be used for light and medium loaded amplifier boards. It also has
the advantage that it is possible to replace the chip without too much trouble. For higher power
applications, such as woofer amplifiers and highly loaded pro amplifiers it is recommended to
solder the slug to the PCB or / and use a heat sink.
Soldering the heat slug
The chip heat slug can not be soldered with a solder iron as it is at the bottom of the chip. A
solder oven or similar must be used. Even a domestic electric oven can be used if no solder oven
is available. Do as follows:
1. Make sure your solder material has a melting point that is not higher than 190 ºC. Most
60%Zn 40%Pb will melt at around 180ºC
2. Heat an oven to about 230-240 ºC
3. Scrape of the solder mask in the rectangle in the middle of the U1 chip position on the
PCB with a sharp knife. Make sure you remove all solder mask varnish in this area.
4. Place about 20 mm (3/4”) long bit of solder with a diameter of 0.6 mm or the equivalent
amount, bent into a circle, on the cleaned PCB area. Place the PCB in the oven and
measure the time it takes before the solder has melted and flowed out on the solder area.
It may take about 2-3 minutes.
5. Remove the PCB from the oven and let the PCB cool down.
6. Spread some “no-clean” non aggressive solder flux on the solder area. A solder flux pen
is handy for this.
7. Place the TP2350B chip perfectly in place on the PCB. Make sure all chip leads are
aligned to the solder pads of the PCB.
8. Place the PCB in the oven and allow as much time as before, but add 20 seconds for the
chip to heat up. After this time shut of the oven power, open the oven door and gently
fan cool air into the oven.
9. Let the PCB cool down and inspect it.
10. If everything is OK, solder the chip legs to the PCB pads.