I2C-ADCTM I2C 12-Bit, 8-CH ANALOG-TO-DIGITAL CONVERTER User Manual GRAVITECH.US uResearch GRAVITECH GROUP Copyright © 2007 MicroResearch GRAVITECH GROUP WWW.GRAVITECH.US I2C-ADCTM I2C 12-Bit, 8-CH ANALOG-TO-DIGITAL CONVERTER User Manual Description Features The I2C-ADC board is a 14-pin CMOS device that provides 8-CH, 12-bit of Analog to Digital Converter (ADC) using I2C bus. There are no external components required. Only two signal lines SDA and SCL plus supply voltage and ground are required to be connected. This makes it perfect for embedded systems that require analog-to-digital converter. • This board features innovations that set it apart from other ADC module. Innovations feature like on-board I2C address jumpers, pull-up resistors, power LED and 2.5V reference. The module can be quickly connected directly on to the breadboard. The board is small and compact in size 0.70 x 0.70 inches. • • • • • • • • • • • • • The I2C-ADC is designed base on ADS7828 IC. It is a single-supply, lowpower, 12-bit data acquisition device that features a serial I2C interface and an 8channel multiplexer. The Analog-to-Digital (A/D) converter features a sample-andhold amplifier and internal, asynchronous clock. The combination of an I2C serial, 2wire interface and micropower consumption makes the I2C-ADC ideal for applications requiring the A/D converter to be close to the input source in remote locations and for applications requiring isolation. Stand alone module, no external components required On-board I2C address jumpers, pull-up resistors, power LED and 2.5V reference Decoupling supply voltage Design easy for breadboard High quality double sided PCB All SMT components Small and compact in size 0.70 x 0.70 inches Dual row 0.6” width, 0.1” pitch header pins Operating power supply voltage range of 2.7V to 5V Suitable for 3.3V or 5.0V microcontroller 8-Channel multiplexer 50kHz sampling rate Internal 2.5V reference I2C interface supports: Standard, Fast and High-Speed Modes Applications • • • • • • Voltage-supply monitoring Isolated data acquisition Transducer interfaces Battery-operated systems Remote data acquisition And much more… Two jumper pins vary the fixed I2C address and allow up to four devices to share the same I2C bus. That is total of 32 channels. 2 * I C is a trademark of Philips Semiconductors Corporation. Copyright © 2007 MicroResearch GRAVITECH GROUP WWW.GRAVITECH.US I2C-ADCTM I2C 12-Bit, 8-CH ANALOG-TO-DIGITAL CONVERTER User Manual Pin Configuration CH0 (1) CH1 (2) CH2 (3) CH3 (4) CH4 (5) CH5 (6) GND (7) Pin No. 1-6 7 8-9 10 11 12 13 14 Name CH0 – CH5 GND CH6 – CH7 NC SCL SDA REF VCC (14) VCC (13) REF (12) SDA (11) SCL (10) NC (9) CH7 (8) CH6 Type Input PWR Input NC Input I/O Input PWR Interfaces Power: The I2C-ADC board needs an external 2.7VDC – 5.0VDC supply. • VCC: is an input power 2.7VDC – 5.0VDC to I2C-ADC board. • GND: is a common ground for every pin. This pin MUST be connected to ground of the external power supply. Description Analog input channel 0 to 5 Supply ground Analog input channel 6 to 7 No connect Serial clock line Serial data line External reference input Supply voltage Analog input pins: There are eight analog input pins. When the converter enters the hold mode, the voltage on the selected CHx pin is captured on the internal capacitor array. During the sample period, the source must charge the internal sampling capacitor (typically 25pF). The amount of charge transfer from the analog source to the converter is a function of conversion rate. Copyright © 2007 MicroResearch GRAVITECH GROUP WWW.GRAVITECH.US I2C-ADCTM I2C 12-Bit, 8-CH ANALOG-TO-DIGITAL CONVERTER User Manual REF pin: The I2C-ADC can operate with an internal 2.5V reference or an external reference. If a +5V supply is used, an external +5V reference is required in order to provide full dynamic range for a 0V to +VDD analog input. This external reference can be as low as 50mV. I2C pins: The I2C-ADC operates as a slave on the I2C bus. Only two signal lines SDA and SCL are required for I2C bus. Please refer to I2C specification for more information. Power-on LED: The green LED on the module is illuminating when the power applied. The power-on LED is enabled from the manufacture. It can be disabling for light sensitive or low current requirement application by remove the solder bridge on “PW” at the bottom of the module. Module Configuration I2C address: Default address shipped from the manufacture is 0x90 for write and 0x91 for read. A1 = 0 A0 = 0 I2C pull-up resistors: I2C bus specification required to have pullup resistors on SDA and SCL pin. I2CADC come with these two pull-up resistors enabled from the manufacture. It can be disabling when connect to I2C bus that already have pull-up resistors by remove the solder bridge on “PU” at the bottom of the module. The address can be easily change by solder the bridge between the corresponding address pin to VCC or GND at the bottom of the module. These four combinations allow up to four devices to share the same I2C bus. That is total of 32 channels. Copyright © 2007 MicroResearch GRAVITECH GROUP WWW.GRAVITECH.US I2C-ADCTM I2C 12-Bit, 8-CH ANALOG-TO-DIGITAL CONVERTER User Manual Internal/External reference: The I2C-ADC can operate with an internal 2.5V reference by solder the bridge between the middle pad of EX/IN row to “IN”. An external reference can be select by solder the bridge between the middle pad of EX/IN row to “EX”. It may NOT exceed the supply voltage to the module. The device shipped with an internal reference option from the manufacture. Below is the default setting from the manufacture. Copyright © 2007 MicroResearch GRAVITECH GROUP WWW.GRAVITECH.US I2C-ADCTM I2C 12-Bit, 8-CH ANALOG-TO-DIGITAL CONVERTER User Manual Notes Contact Us We maintain a website where you can get information on our products, obtain literature and download support files. Visit us online at: WWW.GRAVITECH.US For sales questions or to place and order, direct your e-mails to [email protected]. Refer to our website for product pricing, shipping rates, payment instructions, and for other info we need to complete your order. Use our online Forum or e-mail your technical support questions to [email protected]. We try to respond to your questions the same day. Disclaimer: MicroResearch reserves the right to modify its products or literature, or to discontinue any product at any time without prior notice. The customer is responsible for determining the suitability of any device for any application developed using MicroResearch components. Copyright © 2007 MicroResearch GRAVITECH GROUP WWW.GRAVITECH.US Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: Gravitech: I2C-ADC