AD7195 ADC IC Chip

AD7195（4.8 kHz, Ultralow Noise, 24-Bit,Sigma-Delta ADC with PGA and AC Excitation）

Introduction

The AD7195 is a low noise, complete analog front end for high precision measurement applications.The AD7195 contains a low noise, 24-bit sigma-delta (Σ-Δ) analog-to-digital converter (ADC). It also features an on-chip low noise gain stage, allowing signals of small amplitude to be interfaced directly to the ADC. Additionally, the AD7195 includes AC excitation, which is utilized to remove DC-induced offsets from bridge sensors.

The device allows configuration for two differential inputs or four pseudo-differential inputs. The on-chip channel sequencer enables several channels, with the AD7195 sequentially converting on each enabled channel.This simplifies communication with the part. The on-chip 4.92 MHz clock can be used as the clock source to the ADC or, alternatively, an external clock or crystal can be used. The output data rate from the part can be varied from 4.7 Hz to 4.8 kHz. .

The device has two digital filter options. The choice of filter affects the rms noise/noise-free resolution at the programmed output data rate, the settling time, and the 50 Hz/60 Hz rejection. The AD7195 includes a zero latency feature for applications that require all conversions to be settled.

The part operates with a 5 V analog power supply and a digital power supply from 2.7V to 5.25V. It consumes a current of 6 mA. It is housed in a 32-lead LFCSP package.

Feature

• AC or DC sensor excitation
• RMS noise: 8.5 nV at 4.7 Hz (gain = 128)
• 16 noise-free bits at 2.4 kHz (gain = 128)
• Up to 22.5 noise-free bits (gain = 1)
• Offset drift: 5 nV/°C
• Gain drift: 1 ppm/°C
• Specified drift over time
• 2 differential/4 pseudo differential input channels
• Automatic channel sequencer
• Programmable gain (1 to 128)
• Output data rate: 4.7 Hz to 4.8 kHz
• Internal or external clock
• Simultaneous 50 Hz/60 Hz rejection
• Power supply
  -AVDD: 4.75 V to 5.25 V
  -DVDD: 2.7V to 5.25 V
• Current: 6 mA
• Temperature range: -40°C to +105°C .
• Package: 32-lead LFCSP

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