Part: Si7021-A20-GM1 — 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 precision sensing over a wide range and low power consumption.

Operating Conditions:

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

Absolute Maximum Ratings:

• Max supply voltage: 4.2 V
• Max junction/storage temperature: 150 °C

Key Specs:

• RH accuracy: ±3 %RH (max), 0-80% RH, at 30 °C
• Temperature accuracy: ±0.4 °C (max), -10 to 85 °C
• Active current (RH conversion): 150 μA (typ)
• Standby current: 60 nA (typ) at -40 to +85 °C
• I2C SCL frequency: 400 kHz (max)
• RH conversion time (12-bit): 10 ms (typ)
• Temperature conversion time (14-bit): 7 ms (typ)
• RH hysteresis: ±1 %RH (typ)
• Temperature long term stability: 0.01 °C/Yr (typ)

Features:

• Precision Relative Humidity Sensor
• High Accuracy Temperature Sensor
• Wide operating voltage (1.9 to 3.6 V)
• 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-6
• 3x3 mm DFN-6 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

SI7021-A20-GM1 Pinout

Package: 3×3 mm DFN-6

Notes

• Pins 3 and 4 (DNC) must be soldered to PCB pads for mechanical stability but are not electrically connected to the device. They may be left floating or tied to VDD, but must NOT be tied to GND.
• The thermal paddle (TGND) is critical for accurate temperature measurement and should be soldered to a dedicated floating pad on the PCB.
• SDA and SCL are open-drain I²C interface pins; external pull-up resistors are typically required.

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 16. 3x3 6-pin DFN Package Diagram Dimensions

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