Information based on thermal simulations
Table 5-1 Transient Thermal Impedance (RθJA) and Current CapabilityRθJA [°C/W](1) | Configuration | Current (A)(2) |
without PWM(3) | with PWM(4) |
0.1 sec | 1 sec | 10 sec | DC | 0.1 sec | 1 sec | 10 sec | DC | 10 sec | DC |
1.8 | 4.7 | 8.4 | 23.3 | Dual H-Bridge (both outputs loaded with same current) | 8 | 5.7 | 4.2 | 2.5 | 4 | 2.2 |
| Dual H-Bridge (only one output loaded) | 8 | 8 | 6 | 3.5 | 5.4 | 3 |
| Single H-Bridge | 16 | 11.3 | 8.4 | 4.9 | 7.9 | 4.4 |
(1) Simulated using 114.3mm x 76.2mm x 1.6mm 4 layer
PCB – 2oz Cu on top and bottom layers, 1oz Cu on internal planes,
16cm2 top and bottom layer Cu area, with 13 x 5 thermal via array
below thermal pad, 1.1mm pitch, 0.2mm diameter, 0.025mm Cu plating.
(2) Estimated transient current capability at 85 °C ambient temperature for junction temperature rise up to 150°C.
(3) Only conduction losses (I2R) and
quiescent current loss at 48V supply voltage are considered. Maximum ON
resistance values at 150°C as per Electrical Characteristics table are
considered to calculate conduction losses.
(4) Switching loss estimated by the equation:
PSW
= VVM x ILoad x fPWM x tRF, where
VVM = 48V, fPWM = 20KHz, tRF = 110ns