PCA9685 16-channel PWM driver: specs and pinout
16-channel, 12-bit PWM LED and servo driver controlled over I2C in Fast-mode Plus at up to 1 MHz.
Specs
| Spec | Value | Source |
|---|---|---|
| Supply voltage VDD | 2.3 V to 5.5 V | source Features and benefits (p.3) |
| Inputs and outputs | 5.5 V tolerant | source Features and benefits (p.3) |
| I2C bus speed | up to 1 MHz (Fast-mode Plus) | source Features (p.1); p.2 |
| PWM resolution | 12 bit (4096 steps) | source General description (p.1) |
| LED output drive | sink 25 mA, source 10 mA at 5 V (totem pole) | source General description (p.1); features (p.2) |
| Hardware address pins | 6 (up to 62 devices on one bus) | source Features (p.2) |
| Output enable pin | OE, active LOW | source Features (p.2) |
Power
| Value | Source | |
|---|---|---|
| Supply | VDD 2.3-5.5 V (chip ratings) | source Features and benefits (p.3) |
Chip pins
These are the pins of the chip on the module, from the chip datasheet. The module's own header may label or expose them differently. Module header labels come from the Compoden listing, not an official module schematic.
| Pin | Function | Voltage | Notes | Source |
|---|---|---|---|---|
| VDD | Supply voltage | 2.3-5.5 V; absolute max +6.0 V | Module servo power (listing: 5-6 V on the green terminal block) is a board feature not in the datasheet. | source Section 6.2 Table 3 Pin description (p.6-7); Table 13 Limiting values |
| VSS | Supply ground | 0 V | source Section 6.2 Table 3 Pin description (p.6-7) | |
| SDA | Serial data line (I2C), I/O | Inputs and outputs 5.5 V tolerant; pin voltage absolute max VSS - 0.5 V to 5.5 V | source Section 6.2 Table 3 Pin description (p.6-7); Table 13 Limiting values | |
| SCL | Serial clock line (I2C), input | 5.5 V tolerant; pin voltage absolute max VSS - 0.5 V to 5.5 V | Fast-mode Plus, up to 1 MHz. | source Section 6.2 Table 3 Pin description (p.6-7); Table 13 Limiting values |
| A0-A5 | Address inputs 0 to 5 (six address pins, 62 usable addresses) | 5.5 V tolerant inputs | On the module these are the address solder jumpers (listing). | source Section 6.2 Table 3 Pin description (p.6-7) |
| OE | Active-LOW output enable | 5.5 V tolerant input | LEDn outputs follow OE: high = outputs programmable to 1, 0 or high-impedance. | source Section 6.2 Table 3 Pin description (p.6-7) |
| EXTCLK | External clock input | 5.5 V tolerant input | Datasheet: this pin must be grounded when not used. | source Section 6.2 Table 3 Pin description (p.6-7) |
| LED0-LED15 | Sixteen PWM outputs (LED driver) | Output absolute max 25 mA; open-drain 25 mA sink at 5 V or totem pole 25 mA sink / 10 mA source at 5 V | On the module these are the servo header channels (board fact). | source Section 6.2 Table 3 Pin description (p.6-7); Table 13 Limiting values |
Common mistakes
- Running the I2C bus at 1 kHz: the device is Fast-mode Plus, up to 1 MHz (source)
- Sinking more than 25 mA per LED output: the datasheet rating is 25 mA sink at 5 V (source)
- Putting more than 62 devices on one bus: the six address pins allow 62 addresses (source)
What we could not confirm
- Base I2C address (0x40 default) is unclear in the datasheet; check the address table.
- Module servo supply (5-6 V on listing) is a board claim, not in the datasheet.
- Chip datasheet only; module pinout not covered.
- Pin rows are the PCA9685 chip pins; the module header (listing: SDA, SCL, green terminal block, GND) is third-party and unsourced. The V+ servo power rail, the VCC pin and the board's 5-6 V claim are not in the datasheet.
- Chip logic: datasheet states inputs/outputs are 5.5 V tolerant and VDD 2.3-5.5 V; the listing's 'logic pins are 5V tolerant' is consistent with the chip but not with every board (VDD of the module is set by the module's VCC).
Sources
Building with the PCA9685 16-channel PWM driver? Describe your project on Soldr: it assigns pins from the board's published pinout, checks power and logic levels, and shows how to wire every part.