Datasheet PCA9685 (NXP) - 7

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NXP Semiconductors PCA9685 16-channel, 12-bit PWM Fm+ I2C-bus LED controller Table 3. Pin description
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Symbol Pin Type Description TSSOP28 HVQFN28
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 VDD 28 25 power supply supply voltage [1] HVQFN28 package die supply ground is connected to both VSS pin and exposed center pad. VSS 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 I2C-bus slave address
The I2C-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 I2C-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 I2C-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.
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PCA9685 LED All Call address (1110 000) and Software Reset (0000 0110) which are active on start-up 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
Document Outline 1. General description 2. Features and benefits 3. Applications 4. Ordering information 4.1 Ordering options 5. Block diagram 6. Pinning information 6.1 Pinning 6.2 Pin description 7. Functional description 7.1 Device addresses 7.1.1 Regular I2C-bus slave address 7.1.2 LED All Call I2C-bus address 7.1.3 LED Sub Call I2C-bus addresses 7.1.4 Software Reset I2C-bus address 7.2 Control register 7.3 Register definitions 7.3.1 Mode register 1, MODE1 7.3.1.1 Restart mode 7.3.2 Mode register 2, MODE2 7.3.3 LED output and PWM control 7.3.4 ALL_LED_ON and ALL_LED_OFF control 7.3.5 PWM frequency PRE_SCALE 7.3.6 SUBADR1 to SUBADR3, I2C-bus subaddress 1 to 3 7.3.7 ALLCALLADR, LED All Call I2C-bus address 7.4 Active LOW output enable input 7.5 Power-on reset 7.6 Software reset 7.7 Using the PCA9685 with and without external drivers 8. Characteristics of the I2C-bus 8.1 Bit transfer 8.1.1 START and STOP conditions 8.2 System configuration 8.3 Acknowledge 9. Bus transactions 10. Application design-in information 11. Limiting values 12. Static characteristics 13. Dynamic characteristics 14. Test information 15. Package outline 16. Handling information 17. Soldering of SMD packages 17.1 Introduction to soldering 17.2 Wave and reflow soldering 17.3 Wave soldering 17.4 Reflow soldering 18. Abbreviations 19. Revision history 20. Legal information 20.1 Data sheet status 20.2 Definitions 20.3 Disclaimers 20.4 Trademarks 21. Contact information 22. Contents