Si7021

Part: Si7021-A10 — Silicon Labs

Type: I2C Humidity and Temperature Sensor

Description: The Si7021 is a monolithic CMOS IC integrating humidity and temperature sensor elements, an analog-to-digital converter, signal processing, calibration data, and an I2C Interface, offering ±3% RH (max) accuracy from 0-80% RH and ±0.4 °C (max) accuracy from -10 to 85 °C.

Operating Conditions:

• Supply voltage: 1.9–3.6 V
• Operating temperature: -40 to +125 °C (I and Y grade), -40 to +85 °C (G grade)
• Operating humidity range: 0 to 100% RH (non-condensing)

Absolute Maximum Ratings:

• Max supply voltage: 4.2 V
• Max junction/storage temperature: 150 °C
• Max ambient temperature under bias: 125 °C

Key Specs:

• RH accuracy: ±3% RH (max), 0-80% RH
• Temperature accuracy: ±0.4 °C (max), -10 to 85 °C
• Active current (RH conversion): 150 μA (typ)
• Active current (Temperature conversion): 90 μA (typ)
• Standby current: 60 nA (typ), -40 to +85 °C
• RH conversion time (12-bit): 10 ms (typ)
• Temperature conversion time (14-bit): 7 ms (typ)
• I2C SCLK frequency: 400 kHz (max)

Features:

• Precision Relative Humidity Sensor
• High Accuracy Temperature Sensor
• Low Power Consumption
• Factory-calibrated
• I2C Interface
• Integrated on-chip heater
• Excellent long term stability
• Optional factory-installed cover

Applications:

• HVAC/R
• Thermostats/humidistats
• Respiratory therapy
• White goods
• Indoor weather stations
• Micro-environments/data centers
• Automotive climate control and defogging
• Asset and goods tracking
• Mobile phones and tablets

Package:

• 3x3 mm DFN
• 3x3 mm 6-pin DFN with Protective Cover

• Precision Relative Humidity Sensor
• ± 3% RH (max), 0-80% RH
• High Accuracy Temperature Sensor ±0.4 °C (max), -10 to 85 °C
• 0 to 100% RH operating range
• Up to -40 to +125 °C operating range
• Wide operating voltage (1.9 to 3.6 V)
• Low Power Consumption
• 150 μA active current
• 60 nA standby current

• HVAC/R
• Thermostats/humidistats
• Respiratory therapy
• White goods
• Indoor weather stations

Unless otherwise specified, all min/max specifications apply over the recommended operating conditions.

Table 1. Recommended Operating Conditions

1. Absolute maximum ratings are stress ratings only, operation at or beyond these conditions is not implied and may shorten the life of the device or alter its performance.

2. Special handling considerations apply; see application note, 'AN607: Si70xx Humidity Sensor Designer's Guide'.

The primary function of the Si7021 is to measure relative humidity and temperature. Figure 4 demonstrates the typical application circuit to achieve these functions.

Figure 4. Typical Application Circuit for Relative Humidity and Temperature Measurement

Figure 4. Typical Application Circuit for Relative Humidity and Temperature Measurement

Figure 10. 3x3 6-pin DFN

Table 14. 3x3 6-pin DFN Package Diagram Dimensions

1. All dimensions shown are in millimeters (mm).
2. Dimensioning and Tolerancing per ANSI Y14.5M-1994.