BD81A24MUV-M Datasheet, PDF (18/40 Pages) Rohm – 4ch White LED Driver with Buck-Boost

BD81A24MUV-M/EFV-M
PCB Application Circuit
SYNC
SHDETEN
PWM
FAIL1
FAIL2
VREG
RFL1
LEDEN1
LEDEN2
RFL2
Datasheet
VCC
U1 BD81A44EFV
1 _VCC
2 _SS
3 _COMP
4 _RT
5 _SYNC
6 _SHDETEN
7 _GND
8 _PWM
9 _FAIL1
10 _FAIL2
11 _LEDEN1
GND
12 _LEDEN2
13 _LED1
14 _LED2
CS ²⁸
EN ²⁷
VREG ²⁶
BOOT ²⁵
OUTH ²⁴
SW ²³
VDISC ²²
DGND ²¹
OUTL ²⁰
PGND ¹⁹
ISET ¹⁸
OVP ¹⁷
LED4 ¹⁶
LED3 ¹⁵
RCS3
EN
RBOOT
M1
L1
VREG
VREG
D2
D1
VOUT
LED4
LED3
LED2
LED1
Figure 23. PCB Application Circuit
・Please arrange RRT resistor closest to RT pin and do not attach capacitor.
・Please arrange RISET resistor closest to ISET pin and do not attach capacitor.
・Please attach the decoupling capacitor of CIN and CREG to IC pin as close as possible.
・Because there is possibility that big current may flow into DGND and PGND, please make the impedance low.
・In pins of ISET, RT and COMP, please pay attention so that noise will not get in.
・Since PWM, OUTH, OUTL, SW, SYNC and LED 1-4 are switching, please pay attention so that it will not affect
the surrounding pattern.
・There is a heat dissipation PAD at the back of package. Please solder the board for the heat dissipation PAD.
・Please set the gate resistor of step-down FET (M1) to 0Ω. If resistor is connected, M1 OFF timing is delayed in M1 parasitic
capacity and gate resistor, and the penetrating current flows to the internal transistor of M1 and SW. OCP may be detected
by penetrating current.
・To reduce noise, please consider the board layout in the shortest MIN impedance for Boost loop
(D2→COUT→DGND→OUTL→D2) and Buck loop (VCC→RCS→M1→D1→DGND→GND→CIN→VCC).
.
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TSZ02201-0T3T0C600070-1-2
2016.10.19 Rev.003