CS3302_07 Datasheet, PDF (10/16 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 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 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, one CS4373A, 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.
Geophone
or
Hydrophone
Sensor
Geophone
or
Hydrophone
Sensor
Geophone
or
Hydrophone
Sensor
Geophone
or
Hydrophone
Sensor
10
CS3301
M
CS3302
U
AM P
X
CS5371
CS5372
∆Σ
M odulator
CS3301
M
CS3302
U
AM P
X
CS3301
M
CS3302
U
AM P
X
CS5371
CS5372
∆Σ
CS3301
M odulator
M
CS3302
U
AM P
X
Switch
SMwUitXch
MUX
CS5376A
Digital Filter
CS4373A
Test
DAC
Figure 3. System Architecture
System Telemetry
µController
or
Configuration
EEPROM
C o m m u n icatio n
Interface
DS596F3