The AD7701 is a 16-bit ADC which uses a sigma-delta conver-sion technique. The analog input is continuously sampled by an analog modulator whose mean output duty cycle is proportional to the input signal. The modulator output is processed by an on-chip digital filter with a six-pole Gaussian response, which updates the output data register with 16-bit binary words at word rates up to 4 kHz. The sampling rate, filter corner fre-
quency and output word rate are set by a master clock input that may be supplied externally, or by a crystal-controlled on- chip clock oscillator.
The inherent linearity of the ADC is excellent, and endpoint accuracy is ensured by self-calibration of zero and full scale which may be initiated at any time. The self-calibration scheme can also be extended to null system offset and gain errors in the input channel.
The output data is accessed through a flexible serial port, which has an asynchronous mode compatible with UARTs and two synchronous modes suitable for interfacing to shift registers or the serial ports of industry-standard microcontrollers. CMOS construction insures low power dissipation, and a power down mode reduces the idle power consumption to only 10 W.
|
|
Monolithic 16-Bit ADC0.0015% Linearity ErrorOn-Chip Self-Calibration CircuitryProgrammable Low-Pass Filter0.1 Hz to 10 Hz Corner Frequency0 V to +2.5 V or 2.5 V Analog Input Range4 kSPS Output Data RateFlexible Serial InterfaceUltralow PowerAPPLICATIONSIndustrial Process ControlWeigh ScalesPortable InstrumentationRemote Data Acquisition
|
DVDD to AGND . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . 0.3 V to +6 V
DVDD to AVDD . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . 0.3 V to +0.3 V
DVSS to AGND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +0.3 V to 6 V
AVDD to AGND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . 0.3 V to +6 V
AVSS to AGND . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . +0.3 V to 6 V
AGND to DGND . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . 0.3 V to +0.3 V
Digital Input Voltage to DGND . . .. . . . . . . . . . . . . . . . . . . . 0.3 V to DVDD +0.3 V
Analog Input
Voltage to AGND . . . . .. . . . .. . . . .. . . . .. . . . .. . . . ..AVSS 0.3 V to AVDD + 0.3 V
Input Current to Any Pin Except Supplies2 . . . . . . . . .. . . . . . . . . . .. . . . ±10 mA
Operating Temperature Range
Commercial Plastic (A, B Versions) . . . . . . . . . .. . . . .. . . . .. . . . . 40°C to +85°C
Industrial Cerdip (A, B Versions) . . . . . . .. . . . .. . . . .. . . . .. . . . . 40°C to +85°C
Extended Cerdip (S, T Versions) . . . . . . . . . . .. . . . . .. . . . .. . . .55°C to +125°C
Storage Temperature Range . . . . . . . . . . . . . . .. . . . .. . . . .. .. 65°C to +150°C
Lead Temperature (Soldering, 10 secs) . . . . . .. . . . .. . . . . . . . . . . . . . . . +300°C
Power Dissipation (Any Package) to +75°C . . . .. . . . .. . . . . . . . . . . . . . 450 mW
Derates above +75°C by . . . . . . . . . . . . . . . . . . . . . . . .. . . . .. . . . . . . 10
Post a Buying Lead
Required Field 
