Information based on thermal simulations
Table 6-1 Transient Thermal Impedance (RθJA) and Current
Capability - half-bridge
PART NUMBER |
PACKAGE |
RθJA [°C/W](1) |
Current [A](3) |
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 |
DRV8145-Q1 |
VQFN-HR |
3.8 |
8.8 |
13.1 |
29.7 |
33.5 |
22.0 |
18.1 |
12.0 |
13.6 |
7.9 |
DRV8145-Q1 |
HTSSOP |
2.6 |
6.5 |
11.5 |
28.3 |
36.3 |
22.9 |
17.2 |
11.0 |
13.6 |
7.6 |
(1) Based on thermal simulations using 40 mm x 40
mm x 1.6 mm
4 layer PCB – 2 oz Cu on top and bottom layers, 1 oz Cu on internal
planes with 0.3 mm thermal via drill diameter, 0.025 mm Cu plating, 1 minimum mm
via pitch.
(3) Estimated transient current capability at 85 °C
ambient temperature for junction temperature rise up to 150°C
(3) Only conduction losses (I2R)
considered
(4) Switching loss roughly estimated by the
following equation:
Equation 1. PSW =
VVM x ILoad x fPWM x VVM/SR,
where VVM = 13.5 V, fPWM = 20 KHz, SR = 23
V/µs