CS1238

The CS1238 integrated temperature sensor provides ±2°C accuracy over the -40°C to +85°C operating range. For many applications, this accuracy is sufficient for temperature compensation algorithms. The temperature sensor output is available through a dedicated register and can be read independently of the ADC conversion. The sensor has a resolution of 0.03125°C (1/32°C per LSB). For applications requiring higher temperature accuracy, an external precision temperature sensor can be used, but for most weighing scale and sensor compensation applications, the internal sensor provides adequate accuracy. The temperature update rate is typically every 100ms, which is sufficient for tracking environmental changes.

Use internal sensor for compensation; add external sensor if ±2°C accuracy is insufficient.

Using the CS1238 temperature sensor for load cell compensation involves several steps: 1) Read the temperature sensor value periodically (e.g., every second); 2) Characterize your load cell's temperature coefficient by measuring output at different temperatures; 3) Calculate compensation factor based on temperature deviation from calibration point; 4) Apply compensation to ADC readings using: Compensated_Value = Raw_Value × (1 + TC × (T - T0)), where TC is temperature coefficient, T is current temperature, T0 is calibration temperature. Typical load cells have temperature coefficients of 10-20ppm/°C for zero and span. The CS1238's ±2°C accuracy provides sufficient temperature information for effective compensation. For best results, calibrate the system at a known temperature (e.g., 25°C) and store calibration coefficients in non-volatile memory.

Characterize load cell TC, implement compensation algorithm, calibrate at known temperature.

The CS1238 power consumption depends on operating mode and data rate: Active conversion mode: 0.9mA typical at 5V, 10SPS; 1.2mA typical at 5V, 640SPS; Power-down mode: <1µA typical. Power consumption scales with data rate - lower rates consume less power. The temperature sensor adds approximately 50µA when active. For battery-powered applications, use the lowest data rate that meets your application requirements and utilize power-down mode between conversions. The I2C interface remains active in standby mode, allowing the host to wake the device for conversions. At 10SPS with periodic temperature readings, average current can be kept below 200µA, enabling multi-year operation on coin cell batteries.

Use lowest required data rate and power-down mode for battery applications.

Yes, the CS1238 temperature sensor and ADC can operate independently. The temperature conversion and analog-to-digital conversion are separate processes with independent control: Temperature sensor can be read without performing an ADC conversion; ADC can convert analog input without updating temperature reading; Both can be configured for automatic periodic updates. This flexibility allows you to: Read temperature more frequently than ADC conversions for fast environmental tracking; Perform ADC conversions without temperature overhead for fastest response; Coordinate both readings for synchronized measurements. The temperature reading is available through register 0x04-0x05, while ADC results are in registers 0x00-0x02. Both use the same I2C interface but are controlled by different configuration bits. This independence is valuable for optimizing power consumption and measurement timing in your application.

Configure independent update rates for temperature and ADC based on application requirements.

The CS1238 is available in TSSOP-16 package (5.0mm × 4.4mm body, 0.65mm pitch). This package provides: 16 pins for power, analog input, reference, I2C interface, and control signals; Compact size suitable for space-constrained designs; Industry-standard footprint compatible with automated assembly; Good thermal performance for industrial temperature range. The pinout includes: AVDD/DVDD power supplies; AIN+/- differential analog input; VREF reference input; SDA/SCL I2C interface; DRDY data ready output; ADDR address select; GND ground. The TSSOP-16 package is widely supported by PCB assembly houses and is suitable for both prototype and high-volume production. For detailed mechanical dimensions and recommended PCB footprint, refer to the CS1238 datasheet.

TSSOP-16 package suitable for most applications; verify PCB layout against datasheet.