Analog Devices Inc. ADA4350 AFE with ADC Driver

Analog Devices ADA4350 Analog Front End (AFE) with ADC driver is designed to interface directly with current mode sensors in voltage input applications that require the designer to select between very precise gain levels to maximize the dynamic range or whose output has a current proportional to the sensed parameter. ADA4350 integrates a FET input amplifier, a gain switching network, and an ADC driver into a single IC. Designers can control all functions via a serial peripheral interface (SPI) or parallel control logic.

ADA4350's switching network allows the designer to select up to six different externally configurable feedback networks. Using external components for the feedback network, the designer can more easily match the system to the required photodetector or sensor capacitance. The design of the switches minimizes error sources so that they add virtually no error in the signal path. Designers can use the output driver in either single-ended or a differential mode. With its low-noise performance at low frequencies of 90nV/√Hz at 10Hz and broadband noise of 5nV/√Hz at 100kHz, the ADA4350 is an excellent choice for a wide range of photodetectors, high output impedance voltage sensors, and precision data acquisition systems.

Features

Low noise, low input bias current FET input amplifier
- Very low input bias current: ±0.25pA typical at 25°C
- Low input voltage noise
  - 92nV/√Hz typical at 10Hz at 5V
  - 5nV/√Hz typical at 100kHz at ±5V
Gain bandwidth product: 175MHz
Input capacitance
- 3pF typical, differential mode
- 2pF typical, common-mode
Integrated gain switching
- Sampling and feedback switch off leakage: ±0.5pA typical
- Worst-case tON/tOFF times: 105ns typical/65ns typical

Integrated analog-to-digital converter (ADC) driver
- Differential mode and single-ended mode
- Adjustable output common-mode voltage
- −5V to +3.8V typical for ±5V supply
- Wide output voltage swing: ±4.8V minimum for ±5V supply
Linear output current: 18mA rms typical for ±5V supply
SPI or parallel switch control of all functions
Wide operating range: 3.3V to 12V
Quiescent current: 8.5mA typical (±5V full system)