LM75 I2C Temperature Sensor ICs and Breakout Modules

LM75-family digital temperature sensors: IC or ready-to-wire board?

Explore LM75/LM75A-family I²C temperature-monitoring chips and small development modules for electronic enclosures, embedded boards and controller projects. This collection contains bare SOP/SOIC-8 and VSSOP-8 device listings, CJMCU-75-style breakout boards, Arduino-oriented temperature modules and two TFT display shields with an onboard LM75. It also includes mixed-chip menus and products whose model merely contains “LM75” as unrelated text. Select the actual product option before treating it as a temperature sensor; a headline listing multiple part numbers is not a package containing all of them.

What the sensor actually measures

An LM75-family IC senses its local die temperature and makes a digital reading available over an I²C-compatible two-wire interface. Many versions provide programmable temperature thresholds or an overtemperature output, useful for supervisory alerts. That does not make the device a calibrated remote-probe thermometer, humidity sensor or direct mains thermostat. The chip measures its own thermal environment: PCB copper, nearby regulators, airflow, enclosure heating and mounting method influence the temperature you read. Compare the full manufacturer part number, supply, temperature span, accuracy band, output polarity, resolution, conversion timing and register behavior in that part's datasheet; LM75, LM75A, LM75B, LM75CIM3/CIM5, LM75AD, LM75AIMX and LM75BIM-3 are not automatically identical in all specifications.

A “high precision,” “high speed,” “-55°C to +125°C” or “9 bit” phrase on one listing applies only where substantiated for the selected component and conditions. Temperature range and accuracy are different quantities; resolution is the size of a digital step, not a guarantee of system accuracy. Avoid assigning a semiconductor's extreme rating to an entire breakout, display shield, connector or installation. For an enclosure-monitoring design, validate the temperature of the component you care about rather than assuming a distant board-mounted sensor has the same reading.

Choose package and assembly level

• Bare LM75-class chips: listings present LM75CIM3, LM75CIM5, LM75AD, LM75AIMX/NOPB, LM75AIMMX/AIMM and LM75BIM-3 among various SOP-8, SOIC-8 and VSSOP-8 offers. Selected quantities include one, two, three, five, ten, twenty and fifty pieces depending on the listing. Confirm the complete suffix and actual selected package: eight terminals do not guarantee the same land pattern, body width, pin orientation or supply range. A bare IC needs a suitable PCB, decoupling and an I²C host.
• Breakout modules: CJMCU-75 and LM75/LM75A/LM75B module pages sell one-, two-, three-, five-, ten- or twenty-piece choices in different listings. The assembled board may bring out supply, ground, SDA and SCL, and potentially address or alert connections. Check its installed chip, labeling, operating voltage, pull-ups, connector/header condition and size in the individual product. The title “development board” does not confirm a host MCU, USB connection, battery or calibration certificate is included.
• Display assemblies: a 2.2-inch or 2.4-inch TFT touchscreen shield for a Mega2560-style host is listed with an onboard LM75 and stylus. That is a complete display accessory with an integrated sensor, not a standalone loose LM75 IC; check board pin mapping, display/touch drivers, power demands and available I²C connections. Similar screen dimensions do not establish software or physical interchangeability.

Planning the I²C interface

Check host supply and logic voltage first. SDA and SCL are shared bus signals; their pull-ups must terminate at a voltage acceptable to both the selected sensor and the host. A breakout can already carry pull-ups, so stacking modules may change the effective resistance. Verify supply decoupling, common reference, cable length and electrical noise; “high-speed I2C” in a listing is not proof of reliable operation over an arbitrarily long harness. If the system mixes 5 V Arduino-style boards and 3.3 V microcontrollers, inspect the actual pull-up rails and level-translation requirements before connecting signals.

Some module descriptions reference a seven-bit address pattern of 1001xxx, indicating selectable address bits on a particular implementation. Confirm the selected device's address-pin strapping and the board's solder bridges or fixed wiring before relying on that range. Shared I²C addresses can conflict with other peripherals even if the connectors fit. An I²C scan identifies responding addresses, but it does not prove which sensor suffix is installed or validate its register semantics. Host software should read the correct temperature-register format and handle sign, bit alignment, conversion interval, threshold registers and error states for the exact chip.

For thermal alarms, determine whether the selected device provides a comparator or interrupt-style output and how its threshold, hysteresis, polarity and reset behavior are configured. A programmable alert is not a substitute for a properly engineered independent overtemperature cutoff where damage or injury is possible. Test the assembly through realistic startup, bus failure, sensor disconnection and enclosure heat conditions instead of relying solely on a nominal room-temperature reading.

Model-name traps in this collection

Several mixed menus offer LM75CIM3 or LM75AD only as one choice among unrelated parts. One lists DF005S, EUP3482A, PT6983A-D, D5E160AJ and LA4708N; another combines LM75CIM3 with LM10CN, IR1167A, TLC2262CP, S8036 and ACT50DH. Additional menus contain LD7552BPS, AD797BRZ, THS7314DR, IRF7307PBF and CAT7106CA, or 42665AGA, LF441CM and LN6. These alternatives have different functions and packages. Selecting a non-LM75 option will not supply an I²C temperature IC simply because LM75 appears elsewhere in the title.

Other pages offer LM74CIM5, LM75CIM5 and LM77CIM-3 as separate digital temperature IC choices, or LM358DT, LM393DR, LM4558S, LM4875M and LM75BIM-3 in one mixed SOP-8 listing. LM74 and LM77 require their own data sheets; an op amp, comparator or audio amplifier is not an LM75. A related LM35DZ/LM61CIZ/LM134Z/LM135Z/LM334Z/LM335Z TO-92 menu offers analog-output, reference or other semiconductor choices, not a shared I²C interface. The selected LM35DZ or LM335Z does not work with an LM75 I²C driver. Product titles combining LM78L05ACM, LM78L12ACM, LM741CM, LM7322MA, LM7171AIM or LM6172IM similarly require choosing the actual model and quantity.

A “LM75-10C...” 75 W AC-DC enclosed switching-power-supply page is particularly different: its LM75-like model prefix denotes a power supply, not a local digital thermometer. Listings for TPS51275 power-management chips, LM3940/LM2940/LM2937 regulators, LM321 amplifiers and YD7120/YD7127 parts likewise should not be treated as temperature-sensor alternatives. They remain visible in the collection, but their presence does not broaden the LM75 sensor's capabilities or imply that one order includes both types of hardware.

Selection and evaluation checklist

1. Choose the actual selected model: distinguish LM75A/LM75B/LM75AD/LM75CIM3/CIM5 and other suffixes, not just the LM75 search word in the product title.
2. Confirm delivery level: loose surface-mount IC, breakout module, integrated TFT shield, or another unrelated component. Check quantity and pin/header assembly in the option.
3. Match the datasheet: package footprint, pinout, supply, I²C address, conversion format, accuracy interval, threshold behavior and alert output may vary between versions.
4. Match host and bus: validate pull-ups and logic levels, address conflicts, board wiring and firmware before integrating with Arduino, ESP32 or another controller.
5. Validate thermal performance: measure near the actual target under installed airflow and heat load; use appropriate calibration and independent safeguards when temperature controls equipment.

For a reliable purchase, let the selected suffix, variant and delivered board determine your design. The word “LM75” alone is not a specification, an authenticity certificate or a promise that every listed device measures temperature.