LTC2325-16 PIN FUNCTIONSPINS THAT ARE THE SAME FOR ALL DIGITAL I/O MODESREFOUT1 (Pin 22): Reference Buffer 1 Output. An onboard AIN4+, AIN4– (Pins 2, 1): Analog Differential Input Pins. buffer nominally outputs 4.096V to this pin. This pin is Full-scale range (AIN4+ – AIN4–) is ±REFOUT4 voltage. referred to GND and should be decoupled closely to the These pins can be driven from V pin with a 10µF (X5R, 0805 size) ceramic capacitor. The DD to GND. internal buffer driving this pin may be disabled by ground- GND (Pins 3, 7, 12, 18, 26, 32, 38, 46, 49): Ground. ing the REFBUFEN pin. If the buffer is disabled, an external These pins and exposed pad (Pin 53) must be tied directly reference may drive this pin in the range of 1.25V to 5V. to a solid ground plane. SDR / DDR (Pin 23): Double Data Rate Input. Controls the AIN3+, AIN3– (Pins 5, 4): Analog Differential Input Pins. frequency of SCK and CLKOUT. Tie to GND for the falling Full-scale range (AIN3+ – AIN3–) is ±REFOUT3 voltage. edge of SCK to shift each serial data output (Single Data These pins can be driven from VDD to GND. Rate, SDR). Tie to OVDD to shift serial data output on each REFOUT3 (Pin 6): Reference Buffer 3 Output. An onboard edge of SCK (Double Data Rate, DDR). CLKOUT will be a buffer nominally outputs 4.096V to this pin. This pin is delayed version of SCK for both pin states. referred to GND and should be decoupled closely to the CNV (Pin 24): Convert Input. This pin, when high, defines pin with a 10µF (X5R, 0805 size) ceramic capacitor. The the acquisition phase. When this pin is driven low, the internal buffer driving this pin may be disabled by ground- conversion phase is initiated and output data is clocked ing the REFBUFEN pin. If the buffer is disabled, an external out. This input must be driven at OVDD levels with a low reference may drive this pin in the range of 1.25V to 5V. jitter pulse. This pin is unaffected by the CMOS/LVDS pin. REF (Pin 8): Common 4.096V reference output. Decouple CMOS/LVDS (Pin 25): I/O Mode Select. Ground this pin to GND with a 1μF low ESR ceramic capacitor. May be to enable CMOS mode, tie to OVDD to enable LVDS mode. overdriven with a single external reference to establish a Float this pin to enable low power LVDS mode. common reference for ADC cores 1 through 4. OVDD (Pins 31, 37): I/O Interface Digital Power. The range REFOUT2 (Pin 9): Reference Buffer 2 Output. An onboard of OVDD is 1.71V to 2.63V. This supply is nominally set buffer nominally outputs 4.096V to this pin. This pin is to the same supply as the host interface (CMOS: 1.8V or referred to GND and should be decoupled closely to the 2.5V, LVDS: 2.5V). Bypass OVDD to GND (Pins 32 and 38) pin with a 10µF (X5R, 0805 size) ceramic capacitor. The with 0.1µF capacitors. internal buffer driving this pin may be disabled by ground- ing the REFBUFEN pin. If the buffer is disabled, an external REFBUFEN (Pin 43): Reference Buffer Output Enable. Tie reference may drive this pin in the range of 1.25V to 5V. to VDD when using the internal reference. Tie to ground to disable the internal REFOUT1–4 buffers for use with AIN2+, AIN2– (Pins 11, 10): Analog Differential Input Pins. external voltage references. This pin has a 500k internal Full-scale range (AIN2+ – AIN2–) is ±REFOUT2 voltage. pull-up to VDD. These pins can be driven from VDD to GND. REFOUT4 (Pin 45): Reference Buffer 4 Output. An onboard AIN1+, AIN1– (Pins 14, 13): Analog Differential Input Pins. buffer nominally outputs 4.096V to this pin. This pin is Full-scale range (AIN1+ – AIN1–) is ±REFOUT1 voltage. referred to GND and should be decoupled closely to the These pins can be driven from VDD to GND. pin with a 10µF (X5R, 0805 size) ceramic capacitor. The V internal buffer driving this pin may be disabled by ground- DD (Pins 15, 21, 44, 52): Power Supply. Bypass VDD to GND with a 10µF ceramic capacitor and a 0.1µF ceramic ing the REFBUFEN pin. If the buffer is disabled, an external capacitor close to the part. The V reference may drive this pin in the range of 1.25V to 5V. DD pins should be shorted together and driven from the same supply. Exposed Pad (Pin 53): Ground. Solder this pad to ground. 232516fa 10 For more information www.linear.com/LTC2325-16 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Electrical Characteristics Converter Characteristics Digital Inputs And Digital Outputs Power Requirements ADC Timing Characteristics Typical Performance Characteristics Pin Functions Functional Block Diagram Timing Diagram Applications Information Package Description Typical Application Related Parts