The LTD2284 is a 32-bit resolution, high-performance, analog-to-digital converter (ADC). It provides high resolution and low power operation modes to offer a trade-off between power consumption and SNR performance. It consists of a two-channel multiplexer, a low-noise programmable gain amplifier (PGA), a 4th-order delta-sigma (Δ-Σ) modulator and a programmable digital filter combination. It is SPI-compatible.

The two-channel differential-input multiplexer allows multiple configurations including two differential inputs and internal self-test modes.

The PGA has high input impedance and low noise, capable of small-signal applications.

Chopper stabilization is incorporated to minimize the offset, offset drifts, and 1/f noise.

The fourth-order, inherently stable modulator provides outstanding noise and linearity performance. The modulator output is filtered and decimated by the on-chip digital filter to yield the ADC conversion result.

The digital filter provides data rates from 250 to 4000 SPS. Combinations of on-chip sinc filter,finite-impulse response (FIR) filter and high-pass filter (HPF) provides options for higher resolution or higher data rate. Gain and offset scale registers support system calibration.

The synchronization function allows external event triggering for ADC conversion as well as multiple LTD2284 together when applied synchronized pulses. The power-down input puts the ADC into power-down mode to minimize power and resets the register settings. SPI compatibility allows parallel ADCs sharing a common serial bus.

The LTD2284 is available in a compact 24-lead, 5 mm × 4 mm QFN package, and is fully specified from -40℃ to +85℃, with a maximum operating temperature range of -50℃ to+125℃.

• Selectable Operating Modes

• Low-Power Mode:

  – 12 mW (PGA = 1, 2, 4 and 8)

  – 128 dB SNR (250 SPS, PGA = 1)

• High-Resolution Mode:

  – 18 mW (PGA = 1, 2, 4 and 8)

  – 130 dB SNR (250 SPS, PGA = 1)

• THD: –120 dB

• CMRR: 110 dB

• Two-Channel Differential Multiplexer

• Low Noise Programmable Gain Amplifier

• Inherently-Stable 4th-order Δ-Σ Modulator

• Fast Responding Overrange Detector

• Flexible Digital Filter:

  – Sinc + FIR + IIR (Selectable)

  – Linear or Minimum Phase Optionn

  – Programmable High-Pass Filtern

• Offset and Gain Calibration

• Synchronization function

• SPI compatibility

• Analog Supply: 5 V or ±2.5V

• Digital Supply: 1.8 V to 3.3 V

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