Analog Devices AD4170-4 Product Info

The AD4170-4 is a DC to 50 kHz input bandwidth, low noise, high speed, completely integrated analog front end for high precision measurement applications. The AD4170-4 offers output data rates from 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 configured to have four differential inputs or eight single-ended or pseudodifferential inputs. The on-chip low noise gain stage ensures that signals of 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 external differential references, which can be internally buffered. Other key integrated features include the following:

• Programmable gain amplifier (PGA). Due to the programmable gain (0.5 to 128), the PGA allows direct interfacing to transducers with low output amplitudes such as resistive bridges, thermocouples, and resistance temperature detectors (RTDs).
• The PGA has a wide common-mode input range, giving designers greater margin for widely varying input common modes.
• Low drift, well matched precision current sources. Excitation current sources can be used to excite 2-, 3-, and 4-wire RTDs or bridge type sensors. Excitation current output options include 10 μA, 50 μA, 100 μA, 250 μA, 500 μA, 1 mA, and 1.5 mA. The currents can also be added if higher currents are needed. The currents are made up of two pairs with the pairs optimized for matching and drift matching.
• The low-side power switch (PDSW) can be used to power down bridge sensors between conversions.
• Voltage bias for thermocouples (the VBIAS source sets the common-mode voltage of a channel to (AVDD + AVSS)/2.
• The smart sequencer allows the conver