Cirrus Logic CS3301A - Manual (Page 9)

CS3301A
DS757F1 9
2. GENERAL DESCRIPTION
The CS3301A is a low-noise chopper-stabilized
CMOS differential input, differential output ampli-
fier for precision analog signals between DC and
2 kHz. It has multiplexed inputs, rough / fine out-
puts 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 CS5371A/72A
single/dual
∆Σ modulators and the CS5376A quad
digital filter or the CS5373A
∆Σ modulator and
CS5378 digital filter.
Figure 3 on page 9 shows the system architecture of
a 4-channel acquisition system using four
CS3301A, two CS5372A, one CS4373A, and one
CS5376A.
Figure 4 on page 10 shows the system
architecture of a single channel acquisition system
using a CS3301A, CS5373A, and CS5378.
2.1 Analog Signals
2.1.1 Analog Inputs
The amplifier analog inputs are designed for differ-
ential sensors. Input multiplexing simplifies sys-
tem connections by providing separate inputs for a
sensor and test DAC (INA, INB) as well as an in-
ternal termination for noise tests. The MUX0,
MUX1 digital pins determine which multiplexed
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 CS5371A/72A/73A modulator inputs. Each
differential output requires two series resistors and
a differential capacitor to create the modulator anti-
alias RC filter.
∆Σ
Modulator
∆Σ
Modulator
Digital Filter
AMP
AMP
AMP
AMP
Geophone
or
Hydrophone
Sensor
Geophone
or
Hydrophone
Sensor
Geophone
or
Hydrophone
Sensor
Geophone
or
Hydrophone
Sensor
M
U
X
M
U
X
M
U
X
M
U
X
Test
DAC
µController
or
Configuration
EEPROM
Communication
Interface
CS3301A
CS3302A
CS5371A
CS5371A
CS5376A
CS4373A
System Telemetry
CS3301A
CS3302A
CS3301A
CS3302A
CS3301A
CS3302A
CS5372A
CS5372A
Switch
MUX
Switch
MUX
Figure 3. Multi-Channel System Architecture