BD6067GU_11 ROHM [Rohm], BD6067GU_11 Datasheet - Page 16

• Manufacturer Part Number: BD6067GU_11
• Description: White Backlight LED Drivers for Small to Medium LCD Panels (Switching Regulator Type)
• Manufacturer: ROHM [Rohm]

© 2011 ROHM Co., Ltd. All rights reserved.
BD6067GU, BD6069GUT, BD6071HFN, BD6072HFN
►BD6071HFN
●Selection of external parts
●PCB Layout
www.rohm.com
RFB
Recommended external parts are as shown below.
When to use other parts than these, select the following equivalent parts.
・Coil
・Capacitor
・Resistor
The coil is the part that is most influential to efficiency. Select the coil whose direct current resistor (DCR) and current -
inductance characteristic is excellent. The BD6068GUT/BD6071HFN is designed for the inductance value of 22µH. Do not
use other inductance value. Select a capacitor of ceramic type with excellent frequency and temperature characteristics.
Further, select Capacitor to be used for CIN/COUT with small direct current resistance, and pay sufficient attention to the
PCB layout shown in the next page.
Please refer to the reference data of p.11 for the change in the efficiency when the coil is changed.
<CIN>
<COUT>
Fig.47 PCB Layout Image
Value
22μH
22μH
22μH
22μH
Value
Value
1µF
1µF
24Ω
GNDA
EN
TEST
VFB
MURATA
MURATA
Tolerance
Tolerance
±10%
±20%
±20%
±20%
±1%
To battery power source
VOUT
GND
VIN
SW
CIN
Manufacturer
MURATA
TDK
Coil Craft
TDK
ROHM
Manufacturer
Manufacturer
COUT
To battery GND
L1
LQH32CN220K53
VLF3012AT220MR33
DO1608
VLF3010AT220MR33
GRM188B11A105K
GRM188B31E105K
MCR006YZPF24R0
Product number
Product number
Product number
<R
In order to make the most of the performance of this IC, its PCB layout is
very important. Characteristics such as efficiency and ripple and the likes
change greatly with layout, which please note carefully.
Connect the input bypath capacitor CIN nearest to between VIN and
GNDA pin, as shown in the upper diagram. Thereby, the input voltage
ripple of the IC can be reduced. And, connect the output capacitor COUT
nearest to between VOUT and GND pin. Thereby, the output voltage ripple
of the IC can be reduced. Connect the current setting RFB nearest to VFB
pin. Connect the GND connection side of RFB directly to GND pin.
Connect the GNDA pin directly to GND pin. When those pins are not
connected directly near the chip, influence is given to the performance of
BD6068/BD6071HFN and may limit the current drive performance. As for
the wire to the inductor, make its resistance component small so as to
reduce electric power consumption and increase the entire efficiency. And
keep the pins that are subject to the influence like VFB pin away from the
wire to SW. The PCB layout in consideration of these is shown in the
Fig.49.
FB
>
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4.45
2.5
2.6
2.6
1.6
1.6
0.6
W
L
L
Size (mm)
Size (mm)
Size (mm)
3.2
2.8
6.6
2.8
0.8
0.8
0.3
W
W
L
1.55
2.92
0.23
1.2
1.0
0.8
0.8
H
H
H
-25deg~+85deg
-25deg~+85deg
2011.01 - Rev.C
Technical Note
Temperature
DCR(Ω)
range
0.71
0.66
0.37
1.30