Datasheet

TLE 6389
Datasheet Rev. 2.1 35 2007-08-13
7.11 Components recommendation - overview
7.12 Layout recommendation
The most sensitive points for Buck converters - when considering the layout - are the
nodes at the input, output and the gate of the PMOS transistor and the feedback path.
For proper operation and to avoid stray inductance paths the external catch diode, the
Buck inductance and the input capacitor C
IN1
have to be connected as close as possible to
the PMOS device. Also the GDRV path from the controller to the MosFet has to be as short
as possible. Best suitable for the connection of the cathode of the catch diode and one
terminal of the inductance would be a small plain located next to the drain of the PMOS.
The GND connection of the catch diode must be also as short as possible. In general the
GND level should be implemented as surface area over the whole PCB as second layer,
if necessary as third layer. The feedback path has to be well grounded also, a ceramic
capacitance might help in addition to the output cap to avoid spikes.
To obtain the optimum filter capability of the input pi-filter it has to be located also as
close as possible to the input. To filter the supply input of the device (VS) the ceramic cap
should be connected directly to the pin.
As a guideline an EMC optimized application board / layout is available.
Device Type Supplier Remark
C
IN1
Electrolytic /Foil type various 100µF, 60V
C
IN2
Ceramic various 220nF, 60V
L1 B82464-A4473 EPCOS 47µH, 1.6A, 145mΩ
B82479-A1473-M EPCOS 47µH, 3.5A, 47mΩ
DO3340P-473 Coilcraft 47µH, 3.8A, 110mΩ
DO5022P-683 Coilcraft 68µH, 3.5A, 130mΩ
DS5022P-473 Coilcraft 47µH, 4.0A, 97mΩ
M1 BSO 613SPV Infineon 60V, 3.44A, 130mΩ, NL
BSP 613P Infineon 60V, 2.9A, 130mΩ, NL
SPD09P06PL Infineon 60V, 9A, 250mΩ, LL
C
BDS
Ceramic various 220nF, 16V
D1 MBRD360 Motorola Schottky, 60V, 3A
MBRD340 Motorola Schottky, 40V, 3A
SS34 various Schottky, 40V, 3A
C
OUT
B45197-A2107 EPCOS Low ESR Tantalum, 100µF, 10V
C
COMP
Ceramic various see 7.10.9.