CS3302 Datasheet, PDF (10/15 Pages) Cirrus Logic – HIGH Z PROGRAMMABLE GAIN DIFFERENTIAL AMPLIFIER

CS3302
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
CS3302
M
U
AMP
X
CS3302
M
U
AMP
X
CS5371/72
∆Σ
Modulator
CS3302
M
U
AMP
X
CS3302
M
U
AMP
X
CS5371/72
∆Σ
Modulator
CCSS55337766A
Digital Filter
CS4373
Test
DAC
CS89712
EP7312
µController
or
Configuration
EEPROM
CS8900A
System
Telemetry
Figure 3. System Architecture
10