cs5378 Cirrus Logic, Inc., cs5378 Datasheet - Page 18

• Manufacturer Part Number: cs5378
• Description: Low-power Single-channel Decimation Filter
• Manufacturer: Cirrus Logic, Inc.

3. SYSTEM DESIGN WITH CS5378
Figure 9 illustrates a simplified block diagram of
the CS5378 in a single channel measurement sys-
tem.
A differential sensor is connected through the
CS3301/02 differential amplifiers to the CS5371
∆Σ modulator, where analog to digital conversion
occurs. The modulator’s 1-bit output connects to
the CS5378 MDATA input, where the oversam-
pled ∆Σ data is decimated and filtered to 24-bit out-
put samples at a programmed output rate. These
output samples are buffered into an 8-deep data
FIFO and then passed to the system telemetry.
System self tests are performed by connecting the
CS5378 test bit stream (TBS) generator to the
CS4373 test DAC. Analog tests drive differential
signals from the CS4373 test DAC into the multi-
plexed inputs of the CS3301/02 amplifiers or di-
rectly to the differential sensor. Digital loopback
tests internally connect the TBS digital output di-
rectly to the CS5378 modulator input.
DS639F1
Hydrophone
Geophone
Sensor
or
M
U
X
Figure 9. Single-Channel System Block Diagram
AMP
CS3301
CS3302
Modulator
CS5371
Test DAC
CS4373
∆Σ
∆Σ
3.1 Power Supplies
The system shown in Figure 9 typically operates
from a
3.3 V digital power supply. The CS5378 logic core
can be powered from 2.5 V to minimize power con-
sumption, if required.
3.2 Reset Control
System reset is required only for the CS5378 de-
vice, and is a standard active low signal that can be
generated by a power supply monitor or microcon-
troller. Other system devices default to a power-
down state when the CS5378 is reset.
3.3 PLL and Clock Generation
A PLL is included on the CS5378 to generate an in-
ternal
1.024 MHz, 2.048 MHz, or 4.096 MHz standard
clock or manchester encoded input. Clock inputs
for other system devices are driven by clock out-
puts from the CS5378.
±
2.5 V or a 5 V analog power supply and a
32.768 MHz
CS5378
Digital Filter
w/ PLL
master
System
Telemetry
Communication
Configuration
µController
clock
EEPROM
Interface
or
CS5378
from
18
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