CS5374
Dual High-performance Amplifier and ΔΣ Modulator
Overview
| Description | Resolution (bits) | Dynamic Range (dB) | THD (dB) | Power Consumption Per Channel (mW) | Signal Range (V) | Package |
|---|
| Dual Hydrophone Amplifier and ADC |
24 |
124 |
-118 |
32.5 |
5 Vp-p diff |
48 QFN |
Description
The CS5374 combines two marine seismic analog measurement channels into one 7 mm x 7 mm QFN package. Each measurement channel consists of a high input impedance programmable gain differential amplifier 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 hydrophone 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 attenuation 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.
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
Diagram
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