PCA9685 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2015. All rights reserved.
Product data sheet Rev. 4 — 16 April 2015 7 of 52
NXP Semiconductors
PCA9685
16-channel, 12-bit PWM Fm+ I
2
C-bus LED controller
[1] HVQFN28 package die supply ground is connected to both V
SS
pin and exposed center pad. V
SS
pin must
be connected to supply ground for proper device operation. For enhanced thermal, electrical, and board
level performance, the exposed pad needs to be soldered to the board using a corresponding thermal pad
on the board and for proper heat conduction through the board, thermal vias need to be incorporated in the
PCB in the thermal pad region.
[2] This pin must be grounded when this feature is not used.
7. Functional description
Refer to Figure 1 “Block diagram of PCA9685”.
7.1 Device addresses
Following a START condition, the bus master must output the address of the slave it is
accessing.
There are a maximum of 64 possible programmable addresses using the 6 hardware
address pins. Two of these addresses, Software Reset and LED All Call, cannot be used
because their default power-up state is ON, leaving a maximum of 62 addresses. Using
other reserved addresses, as well as any other subcall address, will reduce the total
number of possible addresses even further.
7.1.1 Regular I
2
C-bus slave address
The I
2
C-bus slave address of the PCA9685 is shown in Figure 4. To conserve power, no
internal pull-up resistors are incorporated on the hardware selectable address pins and
they must be pulled HIGH or LOW.
Remark: Using reserved I
2
C-bus addresses will interfere with other devices, but only if
the devices are on the bus and/or the bus will be open to other I
2
C-bus systems at some
later date. In a closed system where the designer controls the address assignment these
addresses can be used since the PCA9685 treats them like any other address. The
LED All Call, Software Reset and PCA9564 or PCA9665 slave address (if on the bus) can
never be used for individual device addresses.
• PCA9685 LED All Call address (1110 000) and Software Reset (0000 0110) which are
active on start-up
LED12 19 16 O LED driver 12
LED13 20 17 O LED driver 13
LED14 21 18 O LED driver 14
LED15 22 19 O LED driver 15
OE
23 20 I active LOW output enable
A5 24 21 I address input 5
EXTCLK 25 22 I external clock input
[2]
SCL 26 23 I serial clock line
SDA 27 24 I/O serial data line
V
DD
28 25 power supply supply voltage
Table 3. Pin description …continued
Symbol Pin Type Description
TSSOP28 HVQFN28
