CS5374 Datasheet, PDF (1/44 Pages) Cirrus Logic – Dual High-performance Amplifier & ΔΣ Modulator

CS5374
Dual High-performance Amplifier & ΔΣ Modulator
Features
 High Input Impedance Differential Amplifier
• Ultra-low input bias: < 1 pA
• Max signal amplitude: 5 Vpp differential
 Fourth Order Delta-Sigma (ΔΣ) Modulator
• Signal Bandwidth: DC to 2 kHz
• Common mode rejection: 110 dB CMRR
 Differential Analog Input, Digital ΔΣ Output
• Multiplexed inputs: INA, INB, 800Ω termination
• Selectable Gain: 1x, 2x, 4x, 8x, 16x, 32x, 64x
 Excellent Amplifier Noise Performance
• 1.5 μVpp between 0.1 Hz and 10 Hz
• 11 nV / √Hz from 200 Hz to 2 kHz
 High Modulator Dynamic Range
• 126 dB SNR @ 215 Hz BW (2 ms sampling)
• 123 dB SNR @ 430 Hz BW (1 ms sampling)
 Low Total Harmonic Distortion
• –118 dB THD typical (0.000126%)
• –108 dB THD maximum (0.0004%)
 Low Power Consumption
• Normal operation: 6.5 mA per channel
• Power down: 20 μA per channel max
 Dual Power Supply Configuration
• VA+ = +2.5 V; VA– = –2.5 V; VD = +3.3 V
Description
The CS5374 combines two marine seismic analog mea-
surement channels into one 7 mm x 7 mm QFN
package. Each measurement channel consists of a high
input impedance programmable gain differential amplifi-
er that buffers analog signals into a high-performance,
fourth-order ΔΣ modulator. The low-noise ΔΣ modulator
converts the analog signal into a one-bit serial bit stream
suitable for the CS5376A digital filter.
Each amplifier has two sets of external inputs, INA and
INB, to simplify system design as inputs from a hydro-
phone sensor or the CS4373A test DAC. An internal
800Ω termination can also be selected for noise tests.
Gain settings are binary weighted (1x, 2x, 4x, 8x, 16x,
32x, 64x) and match the CS4373A test DAC output at-
tenuation settings for full-scale testing at all gain ranges.
Both the input multiplexer and gain are set by registers
accessed through a standard SPI™ port.
Each fourth-order ΔΣ modulator has very high dynamic
range combined with low total harmonic distortion and
low power consumption. It converts differential analog
signals from the amplifier to an oversampled ΔΣ serial bit
stream which is decimated by the CS5376A digital filter
to a 24-bit output at the final output word rate.
ORDERING INFORMATION
See page 43.
GUARD1
INA1+
+
INB1+
-
MUX1
-
INA1-
INB1-
+
VA+
VA-
INA2+
+
INB2+
-
OUT1+ OUT1- INR1- INF1- INF1+INR1+
VA- VA+
Reset, Clock,
and
Synchronization
RST
MCLK
MSYNC
CS5374
4^th Order
Modulator
4^th Order
Modulator
MDATA1
MFLAG1
VD
GND
MDATA2
MFLAG2
MUX2
-
INA2-
INB2-
+
GUARD2
SPI^TM Serial
Interface
SDO
SDI
SCLK
CS
OUT2+ OUT2- INR2- INF2- INF2+INR2+
VREF+ VREF-
Preliminary Product Information
http://www.cirrus.com
This document contains information for a new product.
Cirrus Logic reserves the right to modify this product without notice.
Copyright  Cirrus Logic, Inc. 2009
(All Rights Reserved)
APR '09
DS862PP1