Datasheet LTC2489 (Analog Devices) - 8

LTC2489
pin FuncTions fO (Pin 1):
Frequency Control Pin. Digital input that controls
COM (Pin 7):
The Common Negative Input (IN–) for All the internal conversion clock rate. When fO is connected Single-Ended Multiplexer Configurations. The voltage to GND, the converter uses its internal oscillator running on CH0-CH3 and COM pins can have any value between at 307.2kHz. The conversion clock may also be overrid- GND – 0.3V to VCC + 0.3V. Within these limits, the two den by driving the fO pin with an external clock in order to selected inputs (IN+ and IN– ) provide a bipolar input change the output rate and the digital filter rejection null. range (VIN = IN+ – IN– ) from –0.5 • VREF to 0.5 • VREF.
CA0, CA1 (Pins 2, 3):
Chip Address Control Pins. These Outside this input range, the converter produces unique pins are configured as a three-state (LOW, HIGH, Floating) over-range and under-range output codes. address control bits for the device’s I2C address.
CH0 to CH3 (Pin 8-Pin 11):
Analog Inputs. May be pro-
SCL (Pin 4):
Serial Clock Pin of the I2C Interface. The grammed for single-ended or differential mode. LTC2489 can only act as a slave and the SCL pin only
VCC (Pin 12):
Positive Supply Voltage. Bypass to GND with accepts an external serial clock. Data is shifted into the a 10µF tantalum capacitor in parallel with a 0.1µF ceramic SDA pin on the rising edges of the SCL clock and output capacitor as close to the part as possible. through the SDA pin on the falling edges of the SCL clock.
REF+, REF– (Pin 13, Pin 14):
Differential Reference Input.
SDA (Pin 5):
Bidirectional Serial Data Line of the I2C Inter- The voltage on these pins can have any value between face. In the transmitter mode (Read), the conversion result GND and VCC as long as the reference positive input, REF+, is output through the SDA pin, while in the receiver mode remains more positive than the negative reference input, (Write), the device channel select bits are input through the REF–, by at least 0.1V. The differential voltage (VREF = REF+ SDA pin. The pin is high impedance during the data input – REF–) sets the full-scale range for all input channels. mode and is an open drain output (requires an appropri-
Exposed Pad (Pin 15):
Ground. This pin is ground and ate pull-up device to VCC) during the data output mode. must be soldered to the PCB ground plane. For prototyping
GND (Pin 6):
Ground. Connect this pin to a common ground purposes, this pin may remain floating. plane through a low impedance connection. 2489fb 8 For more information www.linear.com/LTC2489 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Converter Characteristics Analog Input and Reference I2C Inputs and Digital Outputs Power Requirements Digital Inputs and Digital Outputs I2C Timing Characteristics Typical Performance Characteristics Pin Functions Functional Block Diagram Applications Information Package Description Revision History Typical Application Related Parts