SLRS059B April 2012 – June 2015 ULN2003LV
Thin traces can be used on the input due to the low current logic that is typically used to drive ULN2003LV. Take care to separate the input channels as much as possible, as to eliminate cross-talk. Thick traces are recommended for the output, in order to drive high currents that may be needed. Wire thickness can be determined by the trace material's current density and desired drive current. Since all of the channels currents return to a common ground, it is best to size that trace width to be very wide. Some applications require up to 1 A.
Use Equation 3 to calculate ULN2003LV on-chip power dissipation PD:
TI recommends to limit ULN2003LV IC’s die junction temperature to less than 125°C. The IC junction temperature is directly proportional to the on-chip power dissipation. Use the following equation to calculate the maximum allowable on-chip power dissipation for a target IC junction temperature:
The package RθJA value under standard conditions on a High-K board is listed in the Dissipation Ratings. RθJA value depends on the PCB layout. An external heat sink and/or a cooling mechanism, like a cold air fan, can help reduce RθJA and thus improve device thermal capabilities. Refer to TI’s design support web page at www.ti.com/thermal for a general guidance on improving device thermal performance.