Information based on thermal simulations
Table 7-1 Transient Thermal Impedance (RθJA) and Current
Capability - full-bridge
PART NUMBER |
PACKAGE |
RθJA [°C/W](1) |
Current [A](5) |
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 |
DRV8243-Q1 |
VQFN-HR |
7.3 |
13 |
17.5 |
34.2 |
7.5 |
5.6 |
4.8 |
3.5 |
4.4 |
3.0 |
DRV8243-Q1 |
HVSSOP |
5.8 |
10.5 |
15.3 |
32.4 |
7.8 |
5.8 |
4.8 |
3.3 |
4.4 |
2.9 |
(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.
(5) 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