SHT31

Part: SHT3x-DIS from Sensirion

Type: Humidity and Temperature Sensor

Description: The SHT3x-DIS is a fully calibrated, linearized, and temperature compensated digital humidity and temperature sensor with a wide 2.15–5.5 V supply voltage range, I2C interface up to 1 MHz, and available in a tiny 8-Pin DFN package.

Operating Conditions:

• Supply voltage: 2.15–5.5 V
• Operating temperature: -40 to 125 °C
• I2C communication speed: 0 to 1000 kHz
• Humidity specified range: 0 to 100 %RH
• Temperature specified range: -40 to 125 °C

Absolute Maximum Ratings:

• Max supply voltage: 6 V
• Max junction/storage temperature: 150 °C

Key Specs:

• SHT35 Humidity Accuracy: ±1.5 %RH (Typ.)
• SHT35 Temperature Accuracy: ±0.1 °C (Typ., 20°C to 60°C)
• Humidity Resolution: 0.01 %RH (Typ.)
• Temperature Resolution: 0.01 °C (Typ.)
• Idle Supply Current: 0.2 μA (Typ., at 25°C, single shot mode)
• Measuring Supply Current: 1500 μA (Max)
• Heater Power: 3.6 to 33 mW
• Measurement Duration (High repeatability): 12.5 ms (Typ.)

Features:

• Fully calibrated, linearized, and temperature compensated digital output
• I2C Interface with communication speeds up to 1 MHz
• Two user selectable I2C addresses (0x44, 0x45)
• Very fast start-up and measurement time
• Tiny 8-Pin DFN package (2.5 x 2.5 mm footprint, 0.9 mm height)
• Enhanced signal processing
• CRC checksum protection for data and commands

Package:

• 8-Pin DFN (2.5 x 2.5 mm footprint, 0.9 mm height)

The SHT3x-DIS comes in a 8-pin DFN package - see Table 7.

Table 7 SHT3x-DIS pin assignment (transparent top view). Dashed lines are only visible if viewed from below. The die pad is internally connected to VSS.

Table 3 Electrical specifications, typical values are valid for T=25°C, min. & max. values for T=-40°C … 125°C

Stress levels beyond those listed in Table 6 may cause permanent damage to the device or affect the reliability of the sensor. These are stress ratings only and functional operation of the device at these conditions is not guaranteed. Ratings are only tested each at a time.

Table 6 Minimum and maximum ratings; voltages may only be applied for short time periods.

9 According to ANSI/ESDA/JEDEC JS-001-2014; AEC-Q100-002.

10 According to ANSI/ESD S5.3.1-2009; AEC-Q100-011.

The sensor shows best performance when operated within recommended normal temperature and humidity range of 5 °C - 60 °C and 20 %RH - 80 %RH, respectively. Long-term exposure to conditions outside normal range, especially at high humidity, may temporarily offset the RH signal (e.g. +3%RH after 60h kept at >80%RH). After returning into the normal temperature and humidity range the sensor will slowly come back to calibration state by itself. Prolonged exposure to extreme conditions may accelerate ageing. To ensure stable operation of the humidity sensor, the conditions described in the document 'SHTxx Assembly of SMD Packages', section 'Storage and Handling Instructions' regarding exposure to volatile organic compounds have to be met. Please note as well that this does apply not only to transportation and manufacturing, but also to operation of the SHT3x-DIS.

Figure 15 shows the land pattern. The land pattern is understood to be the open metal areas on the PCB, onto which the DFN pads are soldered.

The solder mask is understood to be the insulating layer on top of the PCB covering the copper traces. It is recommended to design the solder pads as a NonSolder Mask Defined (NSMD) type. For NSMD pads, the solder mask opening should provide a 60 μm to 75 μm design clearance between any copper pad and solder mask. As the pad pitch is only 0.5 mm we recommend to have one solder mask opening for all 4 I/O pads on one side.

For solder paste printing it is recommended to use a laser-cut, stainless steel stencil with electro-polished trapezoidal walls and with 0.1 or 0.125 mm stencil thickness. The length of the stencil apertures for the I/O pads should be the same as the PCB pads. However, the position of the stencil apertures should have an offset of 0.1 mm away from the center of the package. The die pad aperture should cover about 70 - 90 % of the die pad area -thus it should have a size of about 0.9 mm x 1.6 mm.

For information on the soldering process and further recommendation on the assembly process please consult the Application Note HT_AN_SHTxx_Assembly_of_SMD_Packages , which can be found on the Sensirion webpage.