PCA9685 Application Guide

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I’ll research the PCA9685PW manufacturer documentation and sourcing options, then create a cited Application & Usage Guide in the project files.

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I verified the pinout and operating limits, including an important caveat: OE HIGH does not necessarily turn LEDs off—the state depends on MODE2. I’m documenting that behavior, resistor calculations, and two cross-manufacturer alternatives that require circuit and firmware changes.
Created a project doc

PCA9685PW Application and Usage Guide

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PCA9685PW Application and Usage Guide
The NXP PCA9685PW is a 16-channel I²C-controlled PWM LED controller with 12-bit (4096-step) resolution, supplied in a 28-lead TSSOP package. Its primary application is independent LED brightness control and RGBA color backlighting; all channels share one programmable PWM frequency.
This practical PCA9685PW pinout, LED-driver circuit, PCB-layout, and sourcing guide distinguishes verified manufacturer requirements from engineering recommendations. Reviewed 7 October 2026; it does not certify the current Flux symbol or footprint.
1. Quick Specifications

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Created and checked the PCA9685PW Application and Usage Guide in the project files, covering all seven requested sections with manufacturer citations, the complete pinout, resistor calculations, layout guidance, and sourcing details.
The guide explicitly flags OE startup behavior, mixed-voltage logic risks, and alternatives that are not drop-in replacements; unverified information is clearly identified.
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Files

Pins

Symbol

Layout

3D View

LED6
SDA
A3
LED1
LED2
VDD
LED12
LED15
LED9
A0
A2
LED7
SCL
LED0
A1
~OE
VSS
LED8
LED13
LED11
LED14
LED3
A5
LED4
LED10
A4
LED5
EXTCLK
Name
Pin #
Type
Section
Pin Group
Orientation
Order
Sub-symbol
Current
A0
1
Input
CONTROL
Right
0.025A
A1
2
Input
CONTROL
Right
0.025A
A2
3
Input
CONTROL
Right
0.025A
A3
4
Input
CONTROL
Right
0.025A
A4
5
Input
CONTROL
Right
0.025A
LED0
6
Output
OUTPUT
Left
0.025A
LED1
7
Output
OUTPUT
Left
0.025A
LED2
8
Output
OUTPUT
Left
0.025A
LED3
9
Output
OUTPUT
Left
0.025A
LED4
10
Output
OUTPUT
Left
0.025A
LED5
11
Output
OUTPUT
Left
0.025A
LED6
12
Output
OUTPUT
Left
0.025A
LED7
13
Output
OUTPUT
Left
0.025A
VSS
14
Power In
POWER
Right
0.4A
LED8
15
Output
OUTPUT
Right
0.025A
LED9
16
Output
OUTPUT
Right
0.025A
LED10
17
Output
OUTPUT
Right
0.025A
LED11
18
Output
OUTPUT
Right
0.025A
LED12
19
Output
OUTPUT
Right
0.025A
LED13
20
Output
OUTPUT
Right
0.025A
LED14
21
Output
OUTPUT
Right
0.025A
LED15
22
Output
OUTPUT
Right
0.025A
~OE
23
Input
CONTROL
Left
0.025A

PCA9685PW