CS3302

10

2.

GENERAL DESCRIPTION

The CS3302 is a high impedance low-noise CMOS

differential input, differential output amplifier for

precision analog signals between DC and 2 kHz. It

has multiplexed inputs, rough/fine charge outputs,

and programmable gains of x1, x2, x4, x8, x16,

x32, and x64.

The amplifier’s performance makes it ideal for

low-frequency, high dynamic range applications

requiring low distortion and minimal power con-

sumption. It’s optimized for use in acquisition sys-

tems designed around the CS5371/72 single/dual

∆Σ modulators and the CS5376A quad digital fil-

ter.

Figure 3 shows the system level architecture

of a 4-channel acquisition system using four

CS3302, two CS5372, and one CS5376A.

2.1

Analog Signals

2.1.1

Analog Inputs

The amplifier analog inputs are designed for high

impedance differential sensors. Input multiplexing

simplifies system connections by providing sepa-

rate inputs for a sensor and test DAC (INA, INB) as

well as an internal termination for noise tests. The

MUX0, MUX1 digital pins determine which multi-

plexed input is connected to the amplifier.

2.1.2

Analog Outputs

The amplifier analog outputs are separated into

rough charge / fine charge signals to easily connect

to the CS5371/72 inputs. Each output also includes

a series resistor, requiring only two differential ca-

pacitors to create the CS5371/72 input anti-alias

filter.

Differential

Sensor

Differential

Sensor

Differential

Sensor

Differential

Sensor

∆Σ

Modulator

CS5371/72

∆Σ

Modulator

CS5371/72

Digital Filter

CS5376

Test

DAC

µController

or

Configuration

EEPROM

System

Telemetry

CS89712

EP7312

CS8900A

AMP

M

U

X

CS3302

AMP

M

U

X

CS3302

AMP

M

U

X

CS3302

AMP

M

U

X

CS3302

CS4373

Figure 3. System Architecture

CS5376A