Cirrus Logic CS3302A - Manual (Page 10)

CS3302A
CS3302A
DS765PP1
10 DS765PP1
2. GENERAL DESCRIPTION
The CS3302A is a high-impedance, low-noise
CMOS differential input, differential output ampli-
fier 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 performance of this amplifier makes it ideal
for low-frequency, high-dynamic-range applica-
tions requiring low distortion and minimal power
consumption. It is optimized for use in acquisition
systems designed around the CS5371A/72A sin-
gle/dual
∆Σ modulators and the CS5376A quad
digital filter or the CS5373A
∆Σ modulator and
CS5378 digital filter. Figure 3 shows the system-
level architecture of a 4-channel acquisition system
using four CS3302A, two CS5372A, one
CS4373A, and one CS5376A.
Figure 4 shows the
system architecture of a single channel acquisition
system using a CS3302A, CS5373A, and CS5378.
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
CS5371A/72A/73A inputs. Each differential output
∆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. System Architecture