SHT45 — i2c address & wiring
High-precision temperature and humidity from Sensirion.
Key facts
SHT45 at a glance
| i2c address | 0x44 fixed address |
|---|---|
| Logic voltage | 3.3–5 V |
| Type | sensor |
| Part | Sensirion SHT45 |
| Ships with | Qwiic, STEMMA QT |
| Datasheet | Sensirion SHT45 — manufacturer documentation ↗ |
The chip
What the Sensirion SHT45 actually is
High-accuracy digital temperature and humidity sensor featuring fully calibrated measurements, excellent long-term stability, fast response time and low power consumption for precision environmental monitoring.
Wiring
How to connect the SHT45
The SHT45 talks i2c at address 0x44. It runs at 3.3–5 V, so match your host's logic level — if your host is 5 V and a board on the bus is 3.3 V-only, add a level shifter. Use the compatibility checker to confirm the exact cable for your setup.
The address is fixed, so two SHT45s can't share a bus directly — the address-conflict guide covers the workarounds (multiplexer, second bus).
Wiring is the usual four: power, ground, SDA and SCL, plus pull-up resistors — almost always already fitted on the breakout. Nothing showing up? Run an i2c scan first; if the bus is silent, the 7-step checklist finds it faster than guessing.
Ecosystems
Plug-together options for the SHT45
SHT45 breakouts ship with Qwiic and STEMMA QT — keyed 4-pin cables carrying power, ground, SDA and SCL, so there's nothing to solder and nothing to wire backwards. Chain it to the next board and keep going.
Running a mixed bench? Those ecosystems interoperate more than their marketing suggests — see every connector pairing for the cable or adapter you need, or the standards overview for how they compare.
Alternatives
Other environmental boards
Watch the bus
Boards that clash with the SHT45
These want an address the SHT45 also answers (0x44), so they can't share a bus with it untouched. If one is address-selectable, strap it elsewhere; if not, the conflict guide covers the multiplexer and second-bus routes, and the collision roundup explains why a scan won't warn you.
Get one
Questions
SHT45 i2c FAQ
What is the SHT45's i2c address?
The SHT45 sits at a fixed address of 0x44. It can't be changed, so two of them can't share one bus without a multiplexer or a second bus.
What voltage does the SHT45 run at?
3.3–5 V logic. That range covers both 3.3 V and 5 V hosts, so it drops onto a Pi, ESP32 or Arduino without a level shifter.
Can I use two SHT45s on one i2c bus?
Not directly — every SHT45 answers to 0x44, so two on one bus would collide. Use a TCA9548A multiplexer to give each its own channel, or put the second one on a separate bus.
Does the SHT45 work with Qwiic and STEMMA QT?
Yes — SHT45 breakouts ship with Qwiic / STEMMA QT, so it plugs straight in with no soldering. Mixing ecosystems? The compatibility checker gives you the exact cable or adapter.