RT9526A_14 Datasheet, PDF (11/13 Pages) Richtek Technology Corporation – Linear Single Cell Li-Ion Battery Charger

RT9526A
P_D(MAX) = (125°C − 25°C) / (31.5°C/W) = 3.17W for
WDFN-8L 2x3 package
P_D(MAX) = (125°C − 25°C) / (208.2°C/W) = 0.48W for
SOT-23-6 package
The maximum power dissipation depends on the operating
ambient temperature for fixed T_J(MAX) and thermal
resistance, θ_JA. The derating curve in Figure 3 allow the
designer to see the effect of rising ambient temperature
on the maximum power dissipation.
4.0
3.5 _{WDFN-8L 2x3}
Four-Layer PCB
3.0
2.5
2.0
1.5
1.0
SOT-23-6
0.5
0.0
0
25
50
75
100
125
Ambient Temperature (°C)
Figure 3. Derating Curve of Maximum Power Dissipation
Layout Consideration
The RT9526A is a fully integrated low cost single-cell Li-
ion battery charger ideal for portable applications. Careful
PCB layout is necessary. For best performance, place all
peripheral components as close to the IC as possible. A
short connection is highly recommended. The following
guidelines should be strictly followed when designing a
PCB layout for the RT9526A.
 Input capacitor should be placed close to the IC and
connected to the ground plane. The trace of input on
the PCB should be placed far away from the sensitive
devices and shielded by the ground.
 The GND and exposed pad should be connected to a
strong ground plane for heat sinking and noise protection.
 The connection of R_ISET should be isolated from other
noisy traces.
 Output capacitor should be placed close to the IC and
connected to the ground plane to reduce noise coupling.
R1
BATT
BATT
R2
C_IN should be placed near the
IC to improve performance.
VIN
BATT
C_IN ^COUT
The copper area connecting the
resistors of ISET and IMIN should
be minimized and kept far away
from noise sources.
VIN 1
PGB 2
CHG_SB 3
ENB 4
8 BATT RISET
7 ISET
9
6 IMIN
5 GND
R_IMIN
GND
The GND plane should be connected to a strong
ground plane for heat sinking and noise protection.
Figure 4. PCB Layout Guide
Copyright ©2014 Richtek Technology Corporation. All rights reserved.
DS9526A-03 July 2014
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
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