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Cirrus Logic CS5526 User Manual

Features, General description, Delta-sigma a/d converter

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Copyright

© Cirrus Logic, Inc. 2005

(All Rights Reserved)

http://www.cirrus.com

CS5525
CS5526

16-bit/20-bit, Multi-range ADC with 4-bit Latch

Features

z

Delta-sigma A/D Converter

- Linearity Error: 0.0015%FS
- Noise-free Resolution: 18-bits

z

Bipolar/Unipolar Input Ranges

- 25 mV, 55 mV, 100 mV, 1 V, 2.5 V and 5 V

z

Chopper Stabilized Instrumentation Amplifier

z

On-chip Charge Pump Drive Circuitry

z

4-bit Output Latch

z

Simple three-wire serial interface

- SPI™ and Microwire™ Compatible
- Schmitt Trigger on Serial Clock (SCLK)

z

Programmable Output Word Rates

- 3.76 Sps to 202 Sps (XIN = 32.768 kHz)
- 11.47 Sps to 616 Sps (XIN = 100 kHz)

z

Output Settles in One Conversion Cycle

z

Simultaneous 50/60 Hz Noise Rejection

z

System and Self-calibration with
Read/Write Registers

z

Single +5 V Analog Supply
+3.0 V or +5 V Digital Supply

z

Low-power Mode Consumption: 4.9 mW

- 1.8 mW in 1 V, 2.5 V, and 5 V Input Ranges

General Description

The 16-bit CS5525 and the 20-bit CS5526 are highly in-
tegrated

∆Σ A/D converters which include an

instrumentation amplifier, a PGA (programmable gain
amplifier), eight digital filters, and self and system cali-
bration circuitry.

The converters are designed to provide their own nega-
tive supply which enables their on-chip instrumentation
amplifiers to measure bipolar ground-referenced signals

≤±100 mV. By directly supplying NBV with -2.5 V and
with VA+ at 5 V,

±

2.5 V signals (with respect to ground)

can be measured.

The digital filters provide programmable output update
rates between 3.76 Sps to 202 Sps (XIN = 32.768 kHz).
Output word rates can be increased by approximately 3X
by using XIN = 100 kHz. Each filter is designed to settle
to full accuracy for its output update rate in one conver-
sion cycle. The filters with word rates of 15 Sps or less
(XIN = 32.768 kHz) reject both 50 and 60 Hz (

±

3 Hz) line

interference simultaneously.

Low power, single conversion settling time, programma-
ble output rates, and the ability to handle negative input
signals make these single supply products ideal solu-
tions for isolated and non-isolated applications.

ORDERING INFORMATION

See

page 29

.

AIN+

AIN-

+

-

X20

Programmable

Gain

VA+

AGND

VREF+

VREF-

VD+

DGND

XIN XOUT

SDO

SDI

NBV

A0

A1

A2

A3

Latch

Differential

Digital Filter

Calibration

Register

Control

Register

Output

Register

4th Order

Delta-Sigma

Modulator

Calibration

Memory

Calibration

µ

C

Clock

Gen.

SCLK

CS

CPD

AUG ‘05

DS202F5

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