ADP1655 Analog Devices, ADP1655 Datasheet - Page 22

• Manufacturer Part Number: ADP1655
• Description: Dual LED Flash Driver with I2C Compatible Interface
• Manufacturer: Analog Devices

Specifications of ADP1655

• Product Description: Serial 2 WLED Flash Driver
• Led #: 2
• Led Configuration: Serial
• Topology: Inductive
• Application: Flash
• I2c Support: Yes
• Max Iout (ma): 400mA
• Brightness Control: I2C
• Peak Efficiency (%): n/a
• Switching Frequency: 2MHz
• Over Volt Protection (v): 10V
• Vin Min (v): 2.5V
• Vout (v): Current Output
• Synchronous: Yes
• Package: 12-Bump WLCSP

ADP1655
PCB LAYOUT
Poor layout can affect performance, causing electromagnetic
interference (EMI) and electromagnetic compatibility (EMC)
problems, ground bounce, and voltage losses. Poor layout can
also affect regulation and stability. A good layout is implemented
using the following rules and shown in Figure 36:
•
Place the inductor, input capacitor, and output capacitor
close to the IC using short tracks. These components carry
high switching frequencies and large tracks act as antennas.
Figure 36. Example Layout of the ADP1655 Driving Two White LEDs
V
IN
INDUCTOR
CAPACITOR
CAPACITOR
OUTPUT
INPUT
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ADP1655
PGND
•
•
•
Route the output voltage path away from the inductor and
SW node to minimize noise and magnetic interference.
Maximize the size of ground metal on the component side
to help with thermal dissipation.
Use a ground plane with several vias connecting to the
component side ground to further reduce noise interfe-
rence on sensitive circuit nodes.
POWER
POWER
PGND
HIGH
HIGH
LED
LED