Datasheet LTC1747 (Analog Devices) - 9
| Manufacturer | Analog Devices |
| Description | 12-Bit, 80Msps Low Noise ADC |
| Pages / Page | 20 / 9 — PI FU CTIO S. SENSE (Pin 1):. MSBINV (Pin 22):. ENC (Pin 23):. VCM (Pin … |
| File Format / Size | PDF / 504 Kb |
| Document Language | English |
PI FU CTIO S. SENSE (Pin 1):. MSBINV (Pin 22):. ENC (Pin 23):. VCM (Pin 2):. ENC (Pin 24):
Model Line for this Datasheet
Text Version of Document
LTC1747
U U U PI FU CTIO S SENSE (Pin 1):
Reference Sense Pin. Ground selects ±1V.
MSBINV (Pin 22):
MSB Inversion Control. Low inverts VDD selects ±1.6V. Greater than 1V and less than 1.6V the MSB, 2’s complement output format. High does not applied to the SENSE pin selects an input range of ±VSENSE, invert the MSB, offset binary output format. ±1.6V is the largest valid input range.
ENC (Pin 23):
Encode Input. The input sample starts on the
VCM (Pin 2):
2.35V Output and Input Common Mode Bias. positive edge. Bypass to ground with 4.7µF ceramic chip capacitor.
ENC (Pin 24):
Encode Complement Input. Conversion
GND (Pins 3, 6, 9, 12, 13, 16, 19, 21, 36, 37):
ADC Power starts on the negative edge. Bypass to ground with 0.1µF Ground. ceramic for single-ended ENCODE signal.
A + IN (Pin 4):
Positive Differential Analog Input.
OE (Pin 25):
Output Enable. Low enables outputs. Logic
A –
high makes outputs Hi-Z. OE should not exceed the
IN (Pin 5):
Negative Differential Analog Input. voltage on 0V
V
DD.
DD (Pins 7, 8, 17, 18, 20):
5V Supply. Bypass to AGND with 1µF ceramic chip capacitors.
CLKOUT (Pin 26):
Data Valid Output. Latch data on the rising edge of CLKOUT.
REFLB (Pin 10):
ADC Low Reference. Bypass to Pin 11 with 0.1µF ceramic chip capacitor. Do not connect to
OGND (Pins 27, 38, 47):
Output Driver Ground. Pin␣ 14.
NC (Pins 28, 29):
Do not connect these pins.
REFHA (Pin 11):
ADC High Reference. Bypass to Pin 10 with
D0-D1 (Pins 30 to 31):
Digital Outputs. 0.1µF ceramic chip capacitor, to Pin 14 with a 4.7µF ceramic
OVDD (Pins 32, 43):
Positive Supply for the Output Driv- capacitor and to ground with 1µF ceramic capacitor. ers. Bypass to ground with 0.1µF ceramic chip capacitor.
REFLA (Pin 14):
ADC Low Reference. Bypass to Pin 15 with
D2-D4 (Pins 33 to 35):
Digital Outputs. 0.1µF ceramic chip capacitor, to Pin 11 with a 4.7µF ce-
D5-D8 (Pins 39 to 42):
Digital Outputs. ramic capacitor and to ground with 1µF ceramic capacitor.
D9-D11 (Pins 44 to 46):
Digital Outputs.
REFHB (Pin 15):
ADC High Reference. Bypass to Pin 14 with 0.1µF ceramic chip capacitor. Do not connect to
OF (Pin 48):
Over/Under Flow Output. High when an over Pin␣ 11. or under flow has occurred. 1747fa 9
U U U PI FU CTIO S SENSE (Pin 1):
Reference Sense Pin. Ground selects ±1V.
MSBINV (Pin 22):
MSB Inversion Control. Low inverts VDD selects ±1.6V. Greater than 1V and less than 1.6V the MSB, 2’s complement output format. High does not applied to the SENSE pin selects an input range of ±VSENSE, invert the MSB, offset binary output format. ±1.6V is the largest valid input range.
ENC (Pin 23):
Encode Input. The input sample starts on the
VCM (Pin 2):
2.35V Output and Input Common Mode Bias. positive edge. Bypass to ground with 4.7µF ceramic chip capacitor.
ENC (Pin 24):
Encode Complement Input. Conversion
GND (Pins 3, 6, 9, 12, 13, 16, 19, 21, 36, 37):
ADC Power starts on the negative edge. Bypass to ground with 0.1µF Ground. ceramic for single-ended ENCODE signal.
A + IN (Pin 4):
Positive Differential Analog Input.
OE (Pin 25):
Output Enable. Low enables outputs. Logic
A –
high makes outputs Hi-Z. OE should not exceed the
IN (Pin 5):
Negative Differential Analog Input. voltage on 0V
V
DD.
DD (Pins 7, 8, 17, 18, 20):
5V Supply. Bypass to AGND with 1µF ceramic chip capacitors.
CLKOUT (Pin 26):
Data Valid Output. Latch data on the rising edge of CLKOUT.
REFLB (Pin 10):
ADC Low Reference. Bypass to Pin 11 with 0.1µF ceramic chip capacitor. Do not connect to
OGND (Pins 27, 38, 47):
Output Driver Ground. Pin␣ 14.
NC (Pins 28, 29):
Do not connect these pins.
REFHA (Pin 11):
ADC High Reference. Bypass to Pin 10 with
D0-D1 (Pins 30 to 31):
Digital Outputs. 0.1µF ceramic chip capacitor, to Pin 14 with a 4.7µF ceramic
OVDD (Pins 32, 43):
Positive Supply for the Output Driv- capacitor and to ground with 1µF ceramic capacitor. ers. Bypass to ground with 0.1µF ceramic chip capacitor.
REFLA (Pin 14):
ADC Low Reference. Bypass to Pin 15 with
D2-D4 (Pins 33 to 35):
Digital Outputs. 0.1µF ceramic chip capacitor, to Pin 11 with a 4.7µF ce-
D5-D8 (Pins 39 to 42):
Digital Outputs. ramic capacitor and to ground with 1µF ceramic capacitor.
D9-D11 (Pins 44 to 46):
Digital Outputs.
REFHB (Pin 15):
ADC High Reference. Bypass to Pin 14 with 0.1µF ceramic chip capacitor. Do not connect to
OF (Pin 48):
Over/Under Flow Output. High when an over Pin␣ 11. or under flow has occurred. 1747fa 9
