CS5532-BS Cirrus Logic Inc, CS5532-BS Datasheet - Page 45

• Manufacturer Part Number: CS5532-BS
• Description: IC, ADC, 24BIT, 3.84KSPS, SSOP-20
• Manufacturer: Cirrus Logic Inc

Specifications of CS5532-BS

• Resolution (bits): 24bit
• Sampling Rate: 3.84kSPS
• Input Channel Type: Differential
• Data Interface: 3-Wire, Serial
• Supply Current: 13mA
• Digital Ic Case Style: SSOP
• No. Of Pins: 20
• Rohs Compliant: No

2.12. Getting Started
This A/D converter has several features. From a
software programmer’s prospective, what should
be done first? To begin, a 4.9152 MHz or 4.096
MHz crystal takes approximately 20 ms to start. To
accommodate for this, it is recommended that a
software delay of approximately 20 ms start the
processor’s ADC initialization code. Next, since
the CS5531/32/33/34 do not provide a power-on-
reset function, the user must first initialize the ADC
to a known state. This is accomplished by resetting
the ADC’s serial port with the Serial Port Initializa-
tion sequence. This sequence resets the serial port
to the command mode and is accomplished by
transmitting 15 SYNC1 command bytes (0xFF
hexadecimal), followed by one SYNC0 command
(0xFE hexadecimal). Once the serial port of the
ADC is in the command mode, the user must reset
all the internal logic by performing a system reset
sequence (see 2.3.2 System Reset Sequence). The
next action is to initialize the voltage reference
mode. The voltage reference select (VRS) bit in the
configuration register must be set based upon the
magnitude of the reference voltage between the
VREF+ and the VREF- pins.
After this, the channel-setup registers (CSRs) should
be initialized, as these registers determine how cali-
brations and conversions will be performed. Once
the CSRs are initialized, the user has three options in
calibrating the ADC: 1) don’t calibrate and use the
default settings; 2) perform self or system calibra-
DS289PP5
tions; or 3) upload previously saved calibration re-
sults to the offset and gain registers. At this point,
the ADC is ready to perform conversions.
2.13. PCB Layout
For optimal performance, the CS5531/32/33/34
should be placed entirely over an analog ground
plane. All grounded pins on the ADC, including the
DGND pin, should be connected to the analog
ground plane that runs beneath the chip. In a split-
plane system, place the analog-digital plane split
immediately adjacent to the digital portion of the
chip.
Note:
See the CDB5531/32/33/34 data sheet for
suggested layout details and Applications
Note 18 for more detailed layout guidelines.
Before layout, please call for our Free
Schematic Review Service.
CS5531/32/33/34
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