Datasheet LTC2496 (Analog Devices) - 8

LTC2496
pin FuncTions GND (Pins 1, 3, 4, 5, 6, 31, 32, 33):
Ground. Multiple
SDI (Pin 34):
Serial Data Input. This pin is used to select ground pins internally connected for optimum ground cur- the input channel. The serial data input is applied under rent flow and VCC decoupling. Connect each one of these control of the serial clock (SCK) during the data output pins to a common ground plane through a low impedance operation. The first conversion following a new input is connection. All 8 pins must be connected to ground for valid. proper operation.
fO (Pin 35):
Frequency Control Pin. Digital input that
NC (Pin 2):
No Connection, this pin can be left floating controls the internal conversion clock rate. When fO is or tied to GND. connected to VCC or GND, the converter uses its internal
COM (Pin 7):
The common negative input (IN–) for all oscillator running at 307.2kHz. The conversion clock may single-ended multiplexer configurations. The voltage on also be overridden by driving the fO pin with an external CH0 to CH15 and COM pins can have any value between clock in order to change the output rate and the digital GND – 0.3V to V filter rejection null. CC + 0.3V. Within these limits, the two selected inputs (IN+ and IN–) provide a bipolar input range
CS (Pin 36):
Active LOW Chip Select. A LOW on this pin (VIN = IN+ – IN–) from –0.5 • VREF to 0.5 • VREF. Outside enables the digital input/output and wakes up the ADC. this input range, the converter produces unique over-range Following each conversion, the ADC automatically enters and under-range output codes. the Sleep mode and remains in this low power state as
CH0 to CH15 (Pins 8 to 23):
Analog Inputs. May be pro- long as CS is HIGH. A LOW-to-HIGH transition on CS grammed for single-ended or differential mode. during the Data Output aborts the data transfer and starts a new conversion.
MUXOUTP (Pin 24):
Positive Multiplexer Output. Used to drive an external buffer/amplifier or can be shorted
SDO (Pin 37):
Three-State Digital Output. During the data directly to ADCINP. output period, this pin is used as the serial data output. When the chip select pin is HIGH, the SDO pin is in a high
ADCINP (Pin 25):
Positive ADC Input. Tie to the output of impedance state. During the conversion and sleep periods, a buffer/amplifier driven by MUXOUTP or short directly this pin is used as the conversion status output. When to MUXOUTP. the conversion is in progress this pin is HIGH; once the
ADCINN (Pin 26):
Negative ADC Input. Tie to the output conversion is complete SDO goes low. The conversion of a buffer/amplifier driven by MUXOUTN or short directly status is monitored by pulling CS LOW. to MUXOUTN.
SCK (Pin 38):
Bidirectional, Digital I/O, Clock Pin. In Internal
MUXOUTN (Pin 27):
Negative Multiplexer Output. Used Serial Clock Operation mode, SCK is generated internally to drive an external buffer/amplifier or can be shorted and is seen as an output on the SCK pin. In External Serial directly to ADCINN. Clock Operation mode, the digital I/O clock is externally applied to the SCK pin. The Serial Clock operation mode
VCC (Pin 28):
Positive Supply Voltage. Bypass to GND with is determined by the logic level applied to the SCK pin at a 10µF tantalum capacitor in parallel with a 0.1µF ceramic power up and during the most recent falling edge of CS. capacitor as close to the part as possible.
GND (Exposed Pad Pin 39):
Ground. This pin is ground
REF+ (Pin 29), REF– (Pin 30):
Differential Reference Input. and must be soldered to the PCB ground plane. For pro- The voltage on these pins can have any value between totyping purposes, this pin may remain floating. GND and VCC as long as the reference positive input, REF+, remains more positive than the negative reference input, REF–, by at least 0.1V. The differential voltage (REF = REF+ – REF–) sets the full-scale range for all input channels. 2496fc 8 For more information www.linear.com/LTC2496 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Converter Characteristics Analog Input and Reference Digital Inputs and Digital Outputs Power Requirements Typical Performance Characteristics Pin Functions Functional Block Diagram Test Circuits Timing Diagrams Applications Information Package Description Revision History Typical Application Related Parts