LX2448

The effective resolution (or ENOB - Effective Number Of Bits) of the LX2448 depends on PGA gain and output data rate: At PGA=1, 10SPS: ENOB ~ 21-22 bits (noise ~ 1.5μV RMS). At PGA=128, 10SPS: ENOB ~ 19-20 bits (noise ~ 40nV RMS). The effective resolution is always less than the 24-bit resolution due to noise. To calculate for your application: Determine the input-referred noise from datasheet (depends on PGA and ODR). Calculate the RMS noise in volts. Divide the full-scale range by noise to get SNR. Convert SNR to bits: ENOB = (SNR - 1.76) / 6.02. Example: PGA=128, ±39mV range, 40nV noise: SNR = 20×log(39mV/40nV) ≈ 120dB, ENOB ≈ (120-1.76)/6.02 ≈ 19.6 bits. The LX2448 provides excellent effective resolution for precision measurement applications.

Effective resolution depends on PGA and ODR. Contact our FAE team for noise analysis.

Selecting the optimal PGA gain for the LX2448 involves matching the sensor output to the ADC input range: The LX2448 has a ±2.048V input range at PGA=1. With PGA gain G, the effective input range becomes ±2.048V/G. For example: PGA=1: ±2.048V range, suitable for large signals. PGA=32: ±64mV range, good for bridge sensors. PGA=128: ±16mV range, ideal for thermocouples. Selection guidelines: Calculate your sensor's maximum output voltage. Choose the highest PGA gain that accommodates this voltage with 20% headroom. Higher PGA reduces noise but limits input range. Consider startup transients and fault conditions. Example for load cell: 2mV/V sensitivity, 5V excitation = 10mV full scale. Use PGA=128 (±16mV range) for best noise performance. The PGA can be changed dynamically if different measurement ranges are needed.

Match PGA gain to sensor output for optimal noise performance. Contact our FAE team for PGA selection.

Minimizing noise in LX2448 measurements requires attention to multiple aspects: Hardware design: Use clean, low-noise power supplies (LDO recommended). Add proper decoupling capacitors (0.1μF + 10μF) near the ADC. Keep analog input traces short and shielded if possible. Use differential inputs to reject common-mode noise. Implement proper grounding (star ground or ground plane). Software techniques: Use lower output data rates (more averaging = lower noise). Enable digital filter for additional noise reduction. Take multiple samples and average. Use appropriate PGA gain to maximize signal utilization. System considerations: Minimize digital switching near analog inputs. Keep ADC away from switching power supplies. Use external RC filters on inputs if needed. Consider temperature effects on noise. The LX2448's noise scales with √(ODR) - halving the data rate reduces noise by √2 (~30%).

Optimize PCB layout, use lower ODR, and proper filtering. Contact our FAE team for noise optimization.

The LX2448 supports both internal and external reference options: Internal reference: Convenient, no external components. 2.048V nominal output. 10-20ppm/°C drift (varies by grade). Suitable for many applications. External reference: Better accuracy and drift performance. Can use 2.5V, 3.0V, 4.096V, or 5V references. Recommended for high-precision applications. Selection considerations: For 0.1% accuracy or better: Use external precision reference. For wide temperature range: External reference with low drift (<5ppm/°C). For battery-powered apps: Internal reference saves power. Recommended external references: LX432 (2.5V, 3ppm/°C). LX4040 (4.096V, 5ppm/°C). Connect external reference to REFP/REFN pins. Bypass with 0.1μF capacitor close to pins. The reference voltage determines the ADC full-scale range and directly affects measurement accuracy.

Use internal for convenience, external for higher precision. Contact our FAE team for reference selection.

Interfacing the LX2448 with Arduino is straightforward using SPI: Hardware connections: VDD to 3.3V or 5V (LX2448 accepts 2.7V-5.25V). GND to Arduino GND. SCLK to Arduino SCK (pin 13 on Uno). DIN to Arduino MOSI (pin 11). DOUT to Arduino MISO (pin 12). CS to Arduino pin 10 (any digital pin). DRDY to Arduino pin 2 (for interrupt, optional). Software: Use Arduino SPI library. Set SPI mode to MODE1 (CPOL=0, CPHA=1). Set clock speed to 1-2MHz (can go higher if needed). Send command bytes to configure ADC. Read conversion results. Basic read sequence: Pull CS low. Send RDATA command (0x01). Read 3 bytes (24-bit result). Pull CS high. Example libraries: Lingxing IC provides Arduino library. Community libraries available on GitHub. The LX2448 works well with Arduino for prototyping and low-speed data acquisition applications.

Use SPI interface with MODE1. Contact our FAE team for Arduino example code.

The LX2448 conversion latency depends on the output data rate (ODR) setting: The LX2448 uses a sigma-delta architecture with digital filtering. Latency is primarily determined by the filter settling time. Typical latency values: 10 SPS: ~300-400ms latency (50/60Hz rejection). 80 SPS: ~40-50ms latency. 480 SPS: ~6-8ms latency. The latency is approximately 3-4 conversion cycles for full settling. Why latency matters: Control loops need low latency for stability. Data acquisition may need synchronized sampling. Real-time applications require predictable timing. Reducing latency: Use higher ODR settings. Accept higher noise for lower latency. Use single-cycle conversion mode if available. Note that lower latency (higher ODR) results in higher noise. For most measurement applications, the latency is not critical. For control applications, consider using the LX1632 SAR ADC instead.

Latency 300ms at 10SPS, 6ms at 480SPS. Contact our FAE team for latency-critical applications.