ADA4858-3 Op Amp Single-Supply Biased Non-Inverting Amplifier

Application

This circuit shows the ADA4858-3 used as a 5 V single-supply non-inverting amplifier. The input and feedback network are biased around a 2.5 V reference so a small AC signal can swing inside the single supply range.

Design Context

VCC supplies 5 V and VREF supplies the 2.5 V mid-supply bias. RF and RG are both 1K, giving an ideal non-inverting gain of 2 V/V around VREF. Vin is a small sine source centered near VREF, and RL provides a 1K output load to ground.

Expected Behavior

Vin should swing around the 2.5 V reference. Vout should follow the input with roughly twice the AC amplitude while remaining inside the 0 V to 5 V supply rails.

Key Values

• Supply: VCC = 5 V, GND = 0 V.
• Bias reference: VREF = 2.5 V.
• Input: 50 mV sine source with a 2.55 V DC offset.
• Feedback: RF = 1K and RG = 1K for an ideal gain of 2 around VREF.
• Load: RL = 1K to ground.

Suggested Experiments

• Change the input offset and verify the output remains inside the 0 V to 5 V rails.
• Change RF or RG to adjust the closed-loop gain around VREF.
• Change RL to compare how output loading affects Vout.

Featured Component

The ADA4858-3 is the featured single-supply op amp. Its non-inverting input, inverting feedback node, 5 V supply, ground pin, and output are wired in a practical biased amplifier configuration.