LTC2158-14 TYPICAL PERFORMANCE CHARACTERISTICSLTC2158-14: IOVDD vs Sample Rate,LTC2158-14: IVDD vs Sample Rate,15MHz Sine Wave Input, –1dBFS15MHz Sine Wave Input, –1dBFSLTC2158-14: Frequency Response 80 360 –0.5 LVDS CURRENT 3.5mA 340 –1.0 70 –1.5 320 60 –2.0 (mA) (mA) 300 –2.5 50 I VDD I OVDD LVDS CURRENT –3.0 280 1.75mA 40 INPUT AMPLITUDE (dBFS) –3.5 260 –4.0 30 240 –4.5 0 50 100 150 200 250 300 0 62 124 186 248 310 100 1000 SAMPLE RATE (Msps) SAMPLE RATE (Msps) INPUT FREQUENCY (MHz) 215814 G18 215814 G19 215814 G20 PIN FUNCTIONS V–DD (Pins 1, 2, 15, 16, 17, 64): 1.8V Analog Power Supply. AINB (Pin 12): Negative Differential Analog Input for Bypass to ground with 0.1µF ceramic capacitors. Pins 1, Channel B. 2, 64 can share a bypass capacitor. Pins 15, 16, 17 can A + (Pin 13): Positive Differential Analog Input for share a bypass capacitor. INB Channel B. GND (Pins 3, 6, 9, 11, 14, 18, 21, 58, Exposed PadENC+ (Pin 19): Encode Input. Conversion starts on the Pin 65): ADC Power Ground. The exposed pad must be rising edge. soldered to the PCB ground. ENC– (Pin 20): Encode Complement Input. Conversion A +INA (Pin 4): Positive Differential Analog Input for starts on the falling edge. Channel A. OGND (Pins 33, 48): Output Driver Ground. A –INA (Pin 5): Negative Differential Analog Input for Channel A. OVDD (Pins 32, 49): 1.8V Output Driver Supply. Bypass each pin to ground with separate 0.1µF ceramic capacitors. SENSE (Pin 7): Reference Programming Pin. Connecting SENSE to VDD selects the internal reference and a ±0.66V SDO (Pin 59): Serial Interface Data Output. In serial pro- input range. The same input voltage range can be achieved gramming mode, (PAR/SER = 0V), SDO is the optional serial by applying an external 1.25V reference to SENSE. interface data output. Data on SDO is read back from the mode control registers and can be latched on the falling VREF (Pin 8): Reference Voltage Output. Bypass to ground edge of SCK. SDO is an open-drain N-channel MOSFET with a 2.2µF ceramic capacitor. Nominally 1.25V. output that requires an external 2k pull-up resistor from VCM (Pin 10): Common Mode Bias Output; nominally equal 1.8V to 3.3V. If readback from the mode control registers to 0.435 • VDD. VCM should be used to bias the common is not needed, the pull-up resistor is not necessary and mode of the analog inputs. Bypass to ground with a 0.1µF SDO can be left unconnected. ceramic capacitor. 215814fa 8 For more information www.linear.com/LTC2158-14 Document Outline Features Description Applications Typical Application Absolute Maximum Ratings Pin Configuration Order Information Converter Characteristics Analog Input Dynamic Accuracy Internal Reference Characteristics Power Requirements Digital Inputs And Outputs Timing Characteristics Typical Performance Characteristics Pin Functions Functional Block Diagram Timing Diagrams Applications Information Typical Applications Package Description Related Parts
