CS3301-ISZR

Overview

The CS3301-ISZR is a low-noise, chopper-stabilized CMOS differential input and output amplifier with programmable gain. It features selectable gains of x1 through x64 via binary-weighted pin settings. The device supports multiplexed inputs (INA, INB, or internal 800Ω termination) and provides rough/fine charge outputs optimized for connecting to delta-sigma modulators like the CS5371/72. It operates from single (+5V/0V) or dual (±2.5V) analog supplies and a 3.3V to 5V digital supply. Key electrical specifications include an input voltage noise density of 8.5 nV/√Hz (0.1 Hz to 2 kHz), typical THD of -118 dB, and input bias current of 500 pA.

Feature Summary

• Chopper-stabilized architecture providing low noise and minimal distortion for precision analog signals between DC and 2 kHz.
• Multiplexed differential inputs allowing selection between sensor channels INA/INB or an internal 800Ω termination for noise testing.
• Separate rough and fine charge differential outputs designed to simplify connections to delta-sigma modulator inputs.
• Configurable power modes including normal operation, low-power consumption, and power-down states controlled by dedicated pins.

Applications

• Signal acquisition systems utilizing CS5371/72 delta-sigma modulators and CS5376A digital filters.
• Amplification of low-impedance differential sensors such as geophones and hydrophones.
• Low-frequency measurement instruments requiring high dynamic range and flat noise performance down to 0.1 Hz.

Procurement Notes

Verify component authenticity and datasheet revision status prior to integration. Confirm that the specific ISZR suffix corresponds to the lead-free 24-pin SSOP package in reel format. Ensure supply sequencing adheres to absolute maximum ratings to prevent latch-up conditions. Validate that the industrial temperature range (-40°C to +85°C) meets system environmental requirements.

Selection Notes

Select this component when designing systems requiring low-noise amplification of differential signals up to 2 kHz. It is specifically suited for applications interfacing directly with Cirrus Logic delta-sigma modulators due to its rough and fine charge outputs. Consider the low-power mode if energy efficiency is critical, noting the trade-off in noise performance. Ensure the design accommodates the required bipolar or unipolar analog supply configurations.

Part Context

The CS3301 belongs to a family of precision amplifiers designed for earth physics and seismic data acquisition. It is often paired with the CS3302 hydrophone amplifier variant. The device integrates anti-alias filtering resistors at the output, reducing external component count. It serves as a front-end conditioning stage before analog-to-digital conversion in high-resolution instrumentation.

FAQ

How is the master clock configured for the CS3301?

The CLK pin can be driven by an external clock source for synchronous operation. Alternatively, connecting the CLK pin to DGND enables the internal oscillator, which generates a master clock at approximately 2 MHz.

What is the purpose of the separate rough and fine charge outputs?

The outputs are separated into rough and fine charge signals to facilitate easy connection to the inputs of delta-sigma modulators like the CS5371/72. This configuration simplifies the creation of input anti-alias filters using only two differential capacitors.