CDB5376 Cirrus Logic Inc, CDB5376 Datasheet - Page 19

• Manufacturer Part Number: CDB5376
• Description: EVALUATION BOARD FOR CS5376
• Manufacturer: Cirrus Logic Inc

Specifications of CDB5376

• Main Purpose: Seismic Evaluation System
• Embedded: Yes, MCU, 8-Bit
• Utilized Ic / Part: CS3301A, CS3302A, CS4373A, CS5372A, CS5376A
• Primary Attributes: Quad Digital Filter
• Secondary Attributes: Graphical User Interface, SPI™ & USB Interfaces
• Processor To Be Evaluated: CS330x, CS4373A, CS537x
• Interface Type: USB
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Contains lead / RoHS non-compliant
• Other names: 598-1778

2.2.2
The CS3301A/02A amplifiers act as a low-noise gain stage for internal or external differential analog sig-
nals.
2.2.2.1
By default, channels 1 and 2 of CDB5376 use the CS3301A geophone amplifier while channels 3 and 4
use the CS3302A hydrophone amplifier. The CS3301A amplifier is chopper stabilized and connects pin
13 to a clock source (ACLK) to run the chopper circuitry synchronous to the modulator analog sampling
clock. The CS3302A device is not chopper stabilized (with 1/f noise typically buried below the low-fre-
quency ocean noise) to achieve very high input impedance. To minimize leakage from high-impedance
sensors connected to the CS3302A amplifier, pin 13 produces a GUARD signal output to actively drive a
sensor cable shield with the common mode voltage of the sensor signal.
Comparing the CS3301A and CS3302A amplifiers, the functionality of pin 13 (ACLK input vs. GUARD out-
put) is the only external difference. CDB5376 can be converted to use any combination of CS3301A and
CS3302A amplifiers by replacing the amplifier device and properly setting the pin 13 jumper (J42, J242,
J342, J442). By default these jumpers are not populated and have shorting traces between pins on the
back side of the PCB. Converting between amplifier types requires carefully cutting the default short and
installing a jumper.
Common amplifier configurations for CDB5376 include 3x or 4x CS3301A amplifiers for land applications,
4x CS3302A amplifiers for marine streamer applications, and 3x CS3301A amplifiers plus 1x CS3302A
amplifier for seabed reservoir monitoring applications. Replacement amplifiers can be requested as sam-
ples from your local Cirrus Logic sales representative.
2.2.2.2
The analog outputs of the CS3301A/02A differential amplifiers are split into rough-charge and fine-charge
signals for input to the CS5372A ∆Σ modulators. The amplifier outputs include integrated series resistors
to create the anti-alias RC filters required to limit the modulator input signal bandwidth.
Analog signal traces out of the CS3301A/02A amplifiers and into the CS5372A modulators are 4-wire
INR+ / INF+ / INF- / INR- quad groups, and are routed with INF+ and INF- as a traditional differential pair
and INR+ and INR- as guard traces outside the respective INF+ and INF- traces.
DS612DB3
Analog Signals
INA
INB
OUTR, OUTF
GUARD
Digital Signals
MUX[0..1]
GAIN[0..2]
PWDN
CLK
Differential Amplifiers
ACLK Input vs. GUARD Output
Rough-Fine Outputs - OUTR, OUTF
Description
Sensor analog input
Test DAC analog input
Analog rough / fine outputs
CS3302A guard output (jumper selection)
Description
Input mux selection
Gain range selection
Power down mode enable
CS3301A clock input (jumper selection)
CDB5376
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