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Copyright
Cirrus Logic, Inc. 2000
(All Rights Reserved)
P.O. Box 17847, Austin, Texas 78760
(512) 445 7222 FAX: (512) 445 7581
http://www.cirrus.com
CS5521/22/23/24/28
16-Bit or 24-Bit, 2/4/8-Channel ADCs with PGIA
Features
l Low Input Current (100 pA), Chopper
Stabilized Instrumentation Amplifier
l Scalable Input Span (Bipolar/Unipolar)
- 2.5V VREF: 25 mV, 55 mV, 100 mV, 1 V, 2.5 V,
5V
- External: 10 V, 100 V
l Wide V
REF
Input Range (+1 to +5 V)
l Fourth Order Delta-Sigma A/D Converter
l Easy to Use Three-wire Serial Interface Port
- Programmable/Auto Channel Sequencer with
Conversion Data FIFO
- Accessible Calibration Registers per Channel
- Compatible with SPI
TM
and Microwire
TM
l System and Self-Calibration
l Eight Selectable Word Rates
- Up to 617 Hz (XIN = 200 kHz)
- Single Conversion Settling
- 50/60 Hz ±3 Hz Simultaneous Rejection
l Single +5 V Power Supply Operation
- Charge Pump Drive for Negative Supply
- +3 to +5 V Digital Supply Operation
l Low Power Consumption: 5.5 mW
General Description
The CS5521/22/23/24/28 are highly integrated ∆Σ Ana-
log-to-Digital Converters (ADCs) which use charge-
balance techniques to achieve 16-bit (CS5521/23) and
24-bit (CS5522/24/28) performance. The ADCs
come as
either two-channel (CS5521/22), four-channel
(CS5523/24), or eight-channel (CS5528) devices, and
include a low input current, chopper-stabilized instru-
mentation amplifier. To permit selectable input spans of
25 mV, 55 mV, 100 mV, 1 V, 2.5 V, and 5 V, the ADCs
include a PGA (programmable gain amplifier). To ac-
commodate ground-based thermocouple applications,
the devices include a Charge Pump Drive which pro-
vides a negative bias voltage to the on-chip amplifiers.
These devices also include a fourth order ∆Σ modulator
followed by a digital filter
which provides eight selectable
output word rates
. The digital filters are designed to settle
to full accuracy within one conversion cycle and when
operated at word rates below 30 Hz, they reject both 50
and 60 Hz interference.
These single supply products are ideal solutions for
measuring isolated and non-isolated, low-level signals in
process control applications.
ORDERING INFORMATION
See page 51.
Programmable
Gain
VA+ AGND VREF+ VREF- VD+DGND
XIN XOUT
SDO
SDI
NBV
Latch
Differential
Digital Filter
Calibration
Register
Control
Register
Output
Register
4th Order
∆Σ
Modulator
Calibration
Memory
Calibration
µ
C
Clock
Gen.
SCLK
CS
MUX
AIN2+
+
X20
X1
X1
X1
CS5524
Shown
AIN2-
AIN1+
AIN1-
AIN4+
AIN4-
AIN3+
AIN3-
A0 A1
CPD
Data
FIFO
MAY ‘00
DS317F2
