legendsemi

LHA9955

The LHA9955 is a 32‑bit, low‑power, analog‑to‑digital converter (ADC), with a programmable gain amplifier (PGA) and a finite impulse response (FIR) filter. The ADC is designed for the demanding needs of seismology equipment requiring low‑noise precision digitization and extended battery run time. The low‑noise PGA allows direct connection of geophones and transformer‑coupled hydrophones without the need of an external amplifier. The ADC incorporates a high‑resolution, delta‑sigma (ΔΣ) modulator and a FIR filter with programmable phase response. The high‑pass filter removes dc and low‑frequency content from the signal. Clock frequency error is compensated by the sample rate converter with 7‑ppb resolution. Choice of power modes optimize dynamic range verses power consumption. Power consumption is further reduced by PGA bypass operation. The ADC is available in a compact 5‑mm × 5‑mm VQFN package and is fully specified over the ‑40℃ to +125℃ ambient temperature range.
LHA9955

产品特性

• Selectable resolution‑power modes:

  - 135.4dB SNR at 500sps, 9.8mW, PGA 2.5V range

  - 129.7dB SNR at 500sps, 3.3mW, PGA 2.5V range

  - 140dB SNR at 500sps, 5.6mW, Buffer 5V range

• Flexible digital filter:

  - Selectable SINC + FIR + IIR

  - Linear or minimum phase

  - High‑pass filter

• THD: -125 dB

• CMRR: 140dB

• Data rates: 50 SPS to 8000 SPS

• Programmable gains: 1 to 64

• PGA bypass option, low input current

• SYNC input

• Clock error compensation

• Two‑channel multiplexer

• Offset and gain calibration

• General‑purpose digital I/Os

• Analog supply operation: 5 V, 3.3 V, or ±2.5 V

• Reference voltage options: 5 V, 4.096 V, or 2.5 V

• Option to support 4.096V/5V input range

应用场景

• Energy exploration

• Passive seismic monitoring

• Earth sciences and geology

• Precision instrumentation