Datasheet SHT20 (Sensirion) - 6

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3 Interface Specification 4 Electrical Characteristics
Pin Name Comment
4.1 Absolute Maximum Ratings
1 SDA Serial Data, bidirectional The electrical characteristics of SHT2x are defined in 2 VSS Ground 4 3 Table 1. The absolute maximum ratings as given in Table 5 VDD Supply Voltage 3 are stress ratings only and give additional information. 5 2 Functional operation of the device at these conditions is 6 SCL Serial Clock, bidirectional 6 1 not implied. Exposure to absolute maximum rating 3,4 NC Not Connected conditions for extended periods may affect the sensor
Table 2
SHT2x pin assignment, NC remain floating (top view) reliability (e.g. hot carrier degradation, oxide breakdown). Parameter min max Units
3.1 Power Pins (VDD, VSS)
VDD to VSS -0.3 5 V The supply voltage of SHT2x must be in the range of 2.1 – 3.6 V, recommended supply voltage is 3.0 V. Power Digital I/O Pins (SDA, SCL) -0.3 VDD + 0.3 V to VSS supply pins Supply Voltage (VDD) and Ground (VSS) must be decoupled with a 100 nF capacitor, that shall be placed Input Current on any Pin -100 100 mA as close to the sensor as possible – see Figure 11.
Table 3
Electrical absolute maximum ratings
3.2 Serial clock (SCL)
ESD immunity is qualified according to JEDEC JESD22- SCL is used to synchronize the communication between A114 method (Human Body Model at 4 kV), JEDEC microcontroller (MCU) and the sensor. Since the interface JESD22-A115 method (Machine Model 200 V) and consists of fully static logic there is no minimum SCL ESDA ESD-STM5.3.1-1999 and AEC-Q100-011 (Charged frequency. Device Model, 750 V corner pins, 500 V other pins). Latch- up immunity is provided at a force current of 100mA with
3.3 Serial SDA (SDA)
Tamb = 125°C according to JEDEC JESD78. For exposure The SDA pin is used to transfer data in and out of the beyond named limits the sensor needs additional sensor. For sending a command to the sensor, SDA is protection circuit. valid on the rising edge of SCL and must remain stable while SCL is high. After the falling edge of SCL the SDA
4.2 Input / Output Characteristics
value may be changed. For safe communication SDA shall The electrical characteristics such as power consumption, be valid tSU and tHD before the rising and after the falling low- and high-level input and output voltages depend on edge of SCL, respectively – see Figure
12
. For reading the supply voltage. For proper communication with the data from the sensor, SDA is valid tVD after SCL has gone sensor it is essential to make sure that signal design is low and remains valid until the next falling edge of SCL. strictly within the limits given in Table
4
& 5 and Figure
12
. VDD Parameter Conditions min typ max Units Output Low VDD = 3.0 V,
MCU (master)
RP RP Voltage, VOL -4 mA < IOL < 0 mA 0 - 0.4 V SCL IN SCL C = Output Sink SCL OUT - - -4 mA 1
SHT2x
0 Current, IOL 0
(slave
) n SDA IN SDA F Input Low 0 - 30% V SDA OUT Voltage, VIL VDD GND Input High 70% - VDD V Voltage, VIH VDD
Figure 11
Typical application circuit, including pull-up resistors Input Current VDD = 3.6 V, R VIN = 0 V to 3.6 V - - ±1 uA P and decoupling of VDD and VSS by a capacitor.
Table 4
DC characteristics of digital input/output pads. VDD = To avoid signal contention the micro-controller unit (MCU) 2.1 V to 3.6 V, T = -40°C to 125°C, unless otherwise noted. must only drive SDA and SCL low. External pull-up resistors (e.g. 10 kΩ), are required to pull the signal high. For the choice of resistor size please take bus capacity requirements into account (compare Table 5). It should be noted that pull-up resistors may be included in I/O circuits of MCUs. See Table
4
and Table
5
for detailed I/O characteristic of the sensor. www.sensirion.com Version 5 – October 2022 6/14