Cirrus Logic CS5534-BS - Manual

Copyright © Cirrus Logic, Inc. 2008
(All Rights Reserved)
http://www.cirrus.com
CS5532/34-BS
24-bit
∆Σ
ADCs with Ultra-low-noise PGIA
Features
‰ Chopper-stabilized PGIA (Programmable
Gain Instrumentation Amplifier, 1x to 64x)
– 6 nV/
√Hz @ 0.1 Hz (No 1/f noise) at 64x
– 1200 pA Input Current with Gains >1
‰ Delta-sigma Analog-to-digital Converter
– Linearity Error: 0.0007% FS
– Noise-free Resolution: Up to 23 bits
‰ Two- or Four-channel Differential MUX
‰ Scalable Input Span via Calibration
– ±5 mV to differential ±2.5V
‰ Scalable V
REF
Input: Up to Analog Supply
‰ Simple Three-wire Serial Interface
– SPI™ and Microwire™ Compatible
– Schmitt Trigger on Serial Clock (SCLK)
‰ R/W Calibration Registers Per Channel
‰ Selectable Word Rates: 6.25 to 3,840 Sps
‰ Selectable 50 or 60 Hz Rejection
‰ Power Supply Configurations
– VA+ = +5 V; VA- = 0 V; VD+ = +3 V to +5 V
– VA+ = +2.5 V; VA- = -2.5 V; VD+ = +3 V to +5 V
– VA+ = +3 V; VA- = -3 V; VD+ = +3 V
General Description
The CS5532/34 are highly integrated
∆Σ Analog-to-Digi-
tal Converters (ADCs) which use charge-balance
techniques to achieve 24-bit performance. The ADCs
are optimized for measuring low-level unipolar or bipolar
signals in weigh scale, process control, scientific, and
medical applications.
To accommodate these applications, the ADCs come as
either two-channel (CS5532) or four-channel (CS5534)
devices and include a very low-noise, chopper-stabilized
instrumentation amplifier (6 nV/
√Hz @ 0.1 Hz) with se-
lectable gains of 1Ч, 2Ч, 4Ч, 8Ч, 16Ч, 32Ч, and 64×.
These ADCs also include a fourth-order
∆Σ modulator
followed by a digital filter which provides twenty selectable
output word rates of 6.25, 7.5, 12.5, 15, 25, 30, 50, 60, 100,
120, 200, 240, 400, 480, 800, 960, 1600, 1920, 3200, and
3840 Sps (MCLK = 4.9152 MHz).
To ease communication between the ADCs and a micro-
controller, the converters include a simple three-wire se-
rial interface which is SPI™ and Microwire™ compatible
with a Schmitt-trigger input on the serial clock (SCLK).
High dynamic range, programmable output rates, and
flexible power supply options makes these ADCs ideal
solutions for weigh scale and process control
applications.
ORDERING INFORMATION
See page 47
VA+ C1 C2 VREF+ VREF- VD+
DIFFERENTIAL
4 TH ORDER ∆Σ
MODULATOR
PGIA
1,2,4,8,16
PROGRAMMABLE
SINC FIR FILTER
MUX
(CS5534
SHOWN)
AIN1+
AIN1-
AIN2+
AIN2-
AIN3+
AIN3-
AIN4+
AIN4-
SERIAL
INTERFACE
LATCH
CLOCK
GENERATOR CALIBRATION
SRAM/CONTROL
LOGIC
DGND
CS
SDI
SDO
SCLK
OSC2 OSC1 A1 A0/GUARD VA-
32,64
OCT ‘08
DS755F3