cs5520-bp Cirrus Logic, Inc., cs5520-bp Datasheet - Page 10

• Manufacturer Part Number: cs5520-bp
• Description: 16/20-bit Bridge Transducer A/d Converters
• Manufacturer: Cirrus Logic, Inc.

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GENERAL DESCRIPTION
The CS5516 and CS5520 are monolithic CMOS
A/D converters which include an instrumentation
amplifier input, an on-chip programmable gain
amplifier, and a DAC for offset trimming.
While the devices are optimized for ratiometric
measurement of Wheatstone bridge applications,
they can be used for general purpose low-level
signal measurement.
Each of the devices includes a two-channel dif-
ferential delta-sigma modulator (the signal
measurement input and the reference input are
digitized independently before a digital output
word is computed), a calibration microcontroller,
a two-channel digital filter, a programmable in-
strumentation amplifier block, a 4-bit DAC for
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Unused logic inputs
must be connected
to DGND or VD+
Figure 1. System Connection Diagram: AC Excitation Mode Using External Excitation
Excitation
Analog
Supply
Analog
Supply
Supply
+5V
Bridge
-5V
1 F
-
Excitation Supply
Synch. Signals
0.1 F
0.1 F
+
1 F
1 F
12
11
10
2
1
9
6
7
5
8
MDRV-
MDRV+
BX1
BX2
VREF+
VREF-
AIN+
AIN-
AGND1
AGND2
coarse offset trimming, circuitry for generation
and demodulation of AC (actually switched DC)
bridge excitation, and a serial port. The CS5516
outputs 16-bit words; the CS5520 outputs 20-bit
words.
The CS5516/20 devices can measure either
unipolar or bipolar signals. Self-calibration is
utilized to maximize performance of the meas-
urement system.
capabilities of the CS5516/20, it is helpful to ex-
amine some of the error sources in bridge
measurement systems.
VA+
VA-
4
3
CS5516
CS5520
10
10
SMODE
VD+
VD-
DGND
DRDY
XOUT
SCLK
21
SOD
20
RST
XIN
SID
CS
1 F
23
22
16
18
17
24
15
13
14
19
To better understand the
0.1 F
CS5516, CS5520
0.1 F
Interface
Optional
Control
Source
Serial
Clock
Logic
Data
1 F
DS74F2
DS74F1