AD4170-4中文资料24-Bit, DC to 50 kHz Input Bandwidth, Multichannel, Low Noise Precision Sigma-Delta ADC with PGA数据手册ADI规格书

描述 Description

The AD4170-4 is a DC to 50 kHz input bandwidth, low noise, highspeed, completely integrated analog front end for high precisionmeasurement applications. The AD4170-4 offers output data ratesfrom 7.6 SPS up to 500 kSPS. The device contains a low noise,24-bit Σ-Δ analog-to-digital converter (ADC), and can be configuredto have four differential inputs or eight single-ended or pseudodifferentialinputs. The on-chip low noise gain stage ensures that signalsof small amplitude can be interfaced directly to the AD4170-4.
The AD4170-4 offers the highest degree of signal chain integration.The device contains an internal reference and accepts two externaldifferential references, which can be internally buffered. Other keyintegrated features include the following:
Programmable gain amplifier (PGA). Due to the programmablegain (0.5 to 128), the PGA allows direct interfacing to transducerswith low output amplitudes such as resistive bridges, thermocouples,and resistance temperature detectors (RTDs). The PGA has a wide common-mode input range, giving designersgreater margin for widely varying input common modes. Low drift, well matched precision current sources. Excitationcurrent sources can be used to excite 2-, 3-, and 4-wire RTDsor bridge type sensors. Excitation current output options include10 μA, 50 μA, 100 μA, 250 μA, 500 μA, 1 mA, and 1.5 mA. Thecurrents can also be added if higher currents are needed. Thecurrents are made up of two pairs with the pairs optimized formatching and drift matching. The low-side power switch (PDSW) can be used to power downbridge sensors between conversions. Voltage bias for thermocouples (the VBIAS source sets thecommon-mode voltage of a channel to (AVDD + AVSS)/2. The smart sequencer allows the conversion of each enabledpreconfigured channel in a predetermined order, allowing a mixof transducer, system checks, and diagnostic measurements tobe interleaved. The sequencer eliminates the need for repetitiveserial interface communication with the device to change configuration.Sixteen channels can be configured in the sequence.Each of these channels selects from eight user-defined ADCsetups that allow selection of gain, filter type, output data rate,buffering, and reference source.
The AD4170-4 also has extensive diagnostic functionality integratedas part of its comprehensive feature set. These diagnosticsinclude a cyclic redundancy check (CRC), signal chain checks, andserial interface checks, which lead to a more robust solution.
The device also offers a multitude of digital filter options, ensuringthat the user has the highest degree of flexibility. The devicecontains a finite impulse response (FIR) filter which offers lowpass-band ripple for analog inputs from DC up to 50 kHz, quickroll-off and excellent stop-band rejection. Also available in thisdevice is a programmable FIR filter that can accept up to 72 usercoefficients. The part contains sinc filters which allow faster settlingin multiplexed applications. In addition, the AD4170-4 offers multipleoptions for simultaneous 50 Hz and 60 Hz rejection.
The AD4170-4 also has overvoltage/undervoltage tolerance. If achannel has a signal which is slightly beyond AVDD or AVSS,adjacent channels can continue to function and convert correctly.The embedded features, diagnostics, and intelligence minimizethe component count when designing a signal chain, resulting inreduced board space needs, reduced design cycle times, and costsavings.
The device operates with a single analog power supply from 4.75 Vto 5.25 V or a bipolar +2.5 V power supply. The digital supply has arange of 1.7 V to 5.25 V. The device is specified for a temperaturerange of −40°C to +105°C. The AD4170-4 is housed in a 32-leadLFCSP package.
APPLICATIONS

Industrial process control: PLC/DCS modules Temperature and pressure measurement High accuracy medical and scientific instrumentation ChromatographySeismic and energy exploration Electrical test and measurementAcoustic analysis Instrumentation Weigh scale

特性 Features

Precision AC and DC performance
Noise RTI 5.5 nV/√Hz (gain = 128)
INL: ±0.5 ppm of FSR
SNR 110 dB typical (VREF = 4.096 V, gain = 1 precharge, sinc5 filter)
THD: −120 dB typical
Crosspoint multiplexed analog inputs
4 differential/8 pseudodifferential inputs
Overvoltage/undervoltage tolerant on inactive analog inputs
Channel scan data rate of 71.4 kSPS/channel (14 μs settling)
Ultra-low noise integrated PGA, gains of 0.5 to 128
Output data rate: 7.6 SPS to 500 kSPS
Flexible digital filters
Low ripple FIR: ±0.005 dB maximum pass-band ripple
User programmable FIR filter options
Low latency sinc filters
Simultaneous 50 Hz/60 Hz rejection
Band gap reference with 5 ppm/°C drift typical
Internal oscillator and temperature sensor
Analog power supply: 4.75 V to 5.25 V or ±2.5 V
Digital power supply: 1.7 V to 5.25 V
Matched programmable excitation current sources
Low-side power switches
AC excitation
On-chip bias voltage generator
4 general-purpose inputs/outputs
Internal and system calibration
Sensor burnout detection
Diagnostic functions
Per channel configuration
Flexible channel sequencer
3- or 4-wire serial interface
Schmitt trigger on SCLK
SPI, QSPI, MICROWIRE, and DSP compatible
TDM compatible interface for data streaming
Performance temperature range: −40°C to +105°C
Functional temperature range: −40°C to +125°C
32-lead 4 mm × 6 mm LFCSP