TLE6389_07 Datasheet, PDF (28/38 Pages) Infineon Technologies AG – Step-Down DC/DC Controller

TLE 6389
V_IN
R_SENSE=
47mΩ
M1
L₁ = 47 µH
V _OUT
C_IN1=
100 µF
R_SI1=
400kΩ
R_SI2=
100kΩ
C_IN2 =
220nF
C_BDS=
220 nF
to e.g. 5V rail
D1
R_SO=
R_RO=
20kΩ
11
14
12
3
13 ^BDS
VS
CS
GDRV VOUT
SO
TLE6389-2 GV ^FB
SI
7
SI_GND ENABLE
COMP
SYNC GND RO
6
1
5
4 10
9
2
2.2nF
8
680Ω
to µC
ON OFF
to µC
C_OUT =
100 µF
R_FB1=
330kΩ
R_FB2=
47kΩ
M1: Infineon BSO613SPV
Infineon BSP613P
D1: Motorola MBRD360
L1: EPCOS B82479-A1473-M
Coilcraft DO3340P-473
C_IN1: Electrolythic
C_IN2: Ceramic
C_OUT: Low ESR Tantalum
Figure 3 Application circuit TLE6389-2 GV
7.3
Output voltage at adjustable version - feedback divider
The output voltage is sensed either by an internal voltage divider connected to the VOUT
pin (TLE6389-2 GV50 and TLE6389-3 GV50, fixed 5V versions) or an external divider
from the Buck output voltage to the FB pin (TLE6389-2 GV, adjustable version). Pin
VOUT has to be connected always to the Buck converter output regardless of the
selected output voltage for the -2GV version.
To determine the resistors of the feedback divider for the desired output voltage V_OUT at
the TLE6389-2 GV select R_FB2 between 5kΩ and 500kΩ and obtain R_FB1 with the
following formula:
R_FB1
=
R_FB2
⋅


--V----^O----^U----^T--
V_{FB, th}
–
1_
V_FB is the threshold of the error amplifier with its value of typical 1.25V which shows that
the output voltage can be adjusted in a range from 1.25V to 15V. However the integrated
Reset function will only be operational if the output voltage level is adjusted to >7V.
Also the current consumption will be increased in PFM mode in the range between
1.25V and 7V.
Datasheet Rev. 2.1
28
2007-08-13