Datasheet LTC2498 (Analog Devices) - 10

LTC2498
typical perForMance characteristics PSRR vs Frequency at VCC PSRR vs Frequency at VCC (2x Speed Mode) (2x Speed Mode)
0 0 VCC = 4.1V DC ±1.4V VCC = 4.1V DC ±0.7V REF+ = 2.5V –20 REF+ = 2.5V REF– = GND –20 REF– = GND IN+ = GND IN+ = GND –40 IN– = GND –40 IN– = GND fO = GND fO = GND –60 TA = 25°C –60 TA = 25°C –80 –80 RREJECTION (dB) REJECTION (dB) –100 –100 –120 –120 –140 –140 0 20 40 60 80 100 120 140 160 180 200 220 30600 30650 30700 30750 30800 FREQUENCY AT VCC (Hz) FREQUENCY AT VCC (Hz) 2498 G37 2498 G38
pin Functions GND (Pins 1, 3, 4, 5, 6, 31, 32, 33):
Ground. Multiple
ADCINP (Pin 25):
Positive ADC Input. Tie to the output ground pins internally connected for optimum ground cur- of a buffer/amplifier driven by MUXOUTP or tie directly rent flow and VCC decoupling. Connect each one of these to MUXOUTP. pins to a common ground plane through a low impedance
ADCINN (Pin 26):
Negative ADC Input. Tie to the output connection. All eight pins must be connected to ground of a buffer/amplifier driven by MUXOUTN or tie directly for proper operation. to MUXOUTN.
NC (Pin 2):
No Connection. This pin can be left floating
MUXOUTN (Pin 27):
Negative Multiplexer Output. Used or tied to GND. to drive an external buffer/amplifier or can be shorted
COM (Pin 7):
The Common Negative Input (IN–) for All directly to ADCINN. Single-Ended Multiplexer Configurations. The voltage on
V
CH0 to CH15 and COM pins can have any value between
CC (Pin 28):
Positive Supply Voltage. Bypass to GND with a 10µF tantalum capacitor in parallel with a 0.1µF ceramic GND – 0.3V to VCC + 0.3V. Within these limits, the two capacitor as close to the part as possible. selected inputs (IN+ and IN–) provide a bipolar input range (VIN = IN+ – IN–) from –0.5 • VREF to 0.5 • VREF. Outside
REF+ (Pin 29), REF– (Pin 30):
Differential Reference Input. this input range, the converter produces unique over-range The voltage on these pins can have any value between and under-range output codes. GND and VCC as long as the reference positive input, REF+, remains more positive than the negative reference input,
CH0 to CH15 (Pins 8 to 23):
Analog Inputs. May be pro- REF–, by at least 0.1V. The differential voltage (REF = REF+ grammed for single-ended or differential mode. – REF–) sets the full-scale range for all input channels.
MUXOUTP (Pin 24):
Positive Multiplexer Output. Used When performing an on-chip temperature measurement, to drive an external buffer/amplifier or can be shorted the minimum value of REF = 2V. directly to ADCINP. 2498fg 10 For more information www.linear.com/LTC2498 Document Outline Features Description Applications Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics (Normal Speed) Electrical Characteristics (2x Speed) Converter Characteristics Analog Input and Reference Digital Inputs and Digital Outputs Power Requirements Digital Inputs and Digital Outputs Typical Performance Characteristics Pin Functions Functional Block Diagram Test Circuits Timing Diagrams Applications Information Package Description Revision History Related Parts