AN1625 datasheet(20/39 Pages) STMICROELECTRONICS

20 / 39 page

AN1625 APPLICATION NOTE

20/39

2.13 Power Management

Even when operating at current levels well below the maximum ratings of the device, the operating junction tem-

perature must be kept below 125 °C.

Figure 20 shows the IC dissipated power versus the r.m.s. load current, in 4 different driving sequences, assum-

ing the supply voltage is 24V.

Figure 20. IC Dissipated Power versus Output Current.

2.13.1 Maximum output current vs. selectable devices

Figure 21 reports a performance comparison between L6229 (std. power) and L6235 (high power) for different

packages, with the following assumptions:

- Supply voltage: 24 V; Switching frequency: 30 kHz.

- Tamb = 25 °C, TJ = 125 °C.

- Maximum RDS(ON) (taking into account process spread) has been considered, @ 125 °C.

- Maximum quiescent current IQ (taking into account process spread) has been considered.

- PCB is a FR4 with a dissipating copper surface on the top side of 6 cm2 (with a thickness of 35 µm) for

SO and PowerDIP packages (D, N suffixes).

- PCB is a FR4 with a dissipating copper surface on the top side of 6 cm2 (with a thickness of 35 µm), 16

via holes and a ground layer for the PowerSO package (PD suffix).

- For each device (on the x axis) y axis reports the maximum output current.

No PWM

SW = 30 kHz (slow decay)

Test Condition s:

Supply Voltage = 24 V

0.5

1.5

2.5

OUT

[A]

D [W]

IOUT

AN1625 Datasheet(PDF) 20 Page - STMicroelectronics