What accuracy and measurement ranges does FHTC3 specify?

The performance table lists typical accuracy of ±3.0 %RH and ±0.3 °C, a humidity range of 0 to 100 %RH, and a temperature range of -45 to +130 °C.

What is the FHTC3 I²C address?

FHTC3 uses the fixed 7-bit I²C address 0x70 and supports bus clock rates up to 1 MHz.

How is FHTC3 measurement data checked?

Each two-byte measurement value is followed by a CRC-8 byte using polynomial 0x31 and initialization value 0xFF.

What package and order code are specified?

The product is supplied in a 2 mm × 2 mm DFN6 package. The listed tape-and-reel order code is FHTC3-TR with a standard packing quantity of 2,000.

FHTC3 Temperature & Humidity Sensor

NYFEA FHTC3 integrates calibrated relative-humidity and temperature sensing, CRC-protected digital output and an I²C interface in a reflow-solderable 2 mm × 2 mm DFN6 package. Normal and low-power measurement commands support battery-powered and space-constrained designs.

Product scope: the supplied performance table specifies 0 to 100 %RH and -45 °C to +130 °C. A description paragraph states an upper limit of +135 °C; this page uses +130 °C because that value is repeated in the performance and absolute-maximum tables.

Download FHTC3 Datasheet View I²C Commands

This engineering selection page summarizes the supplied datasheet. Use the controlled specification for final limits, timing, assembly and production release.

NYFEA FHTC3 digital temperature and humidity sensor in a six-pad DFN package, shown at a 45-degree angle — FHTC3 in the 2 mm × 2 mm DFN6 package. The product marking and NYFEA brand are shown on separate lines around the sensing aperture.

±3.0 %RHTypical relative-humidity accuracy across a 0 to 100 %RH specified range.

±0.3 °CTypical temperature accuracy across a -45 °C to +130 °C specified range.

I²C · 0x70Fixed 7-bit address, clock stretching and bus operation up to 1 MHz.

1.6 V to 5.5 VUltra-low-power operation in a 2 mm × 2 mm × 0.75 mm DFN6 package.

Product Overview and Selection Scope

FHTC3 is a factory-calibrated digital sensor for simultaneous temperature and relative-humidity measurement. Its low standby current, two measurement-power modes and small leadless package suit compact connected products.

Humidity measurement: 0 to 100 %RH range with typical ±3.0 %RH accuracy.
Temperature measurement: -45 °C to +130 °C specified range with typical ±0.3 °C accuracy.
Fine digital output: 0.01 %RH and 0.01 °C resolution entries in the performance table.
Low power: 0.2 µA typical sleep current and 1 µA typical average current at one low-power measurement per second.
Digital interface: I²C Normal, Fast and Fast Mode Plus operation with clock stretching.
Wide supply: 1.6 V to 5.5 V operating supply range.
Compact assembly: DFN6, 2 mm × 2 mm × 0.75 mm, reflow solderable and MSL1.
Production ready: factory calibrated; tape-and-reel ordering with a dustproof breathable film.

System-level validationPackaged-sensor accuracy does not include enclosure gradients, self-heating, condensation, contamination, airflow, thermal coupling, assembly stress, calibration policy or system EMC. Validate the complete design under its real operating conditions.

Humidity and Temperature Performance

Relative-humidity parameter	Minimum	Typical	Maximum	Unit / condition
Measurement range	0	-	100	%RH
Accuracy	-	±3.0	See performance curve	%RH at 25 °C
Resolution	-	0.01	-	%RH
Hysteresis	-	±1.0	-	%RH
Response time, t63	-	8	-	s
Long-term drift	-	<0.5	-	%RH/year

Temperature performance

Temperature parameter	Minimum	Typical	Maximum	Unit / condition
Measurement range	-45	-	+130	°C
Accuracy	-	±0.3	See performance curve	°C
Resolution	-	0.01	-	°C
Hysteresis	-	±1.0	-	°C
Response time, t63	-	<5–30	-	s, as printed in source
Long-term drift	-	<0.02	-	°C/year

FHTC3 relative humidity accuracy, temperature accuracy and humidity response curves — Humidity accuracy, temperature accuracy and humidity response curves reproduced from the supplied datasheet. Typical curves are descriptive and do not replace guaranteed table limits.

Recommended normal conditionsThe datasheet recommends 5 °C to 60 °C and 20 %RH to 80 %RH for normal operating conditions. Extended exposure outside that region can cause a temporary humidity offset.

Electrical Characteristics and Interface Timing

Unless otherwise stated, the electrical entries below apply at 25 °C and VDD = 3.3 V.

Parameter	Minimum	Typical	Maximum	Unit / condition
Supply voltage, VDD	1.6	3.3	5.5	V
Power-on reset threshold, VPOR	1.3	1.4	1.5	V
Idle current	-	45	80	µA
Sleep current	-	0.2	0.3	µA
Measurement current, normal mode	-	500	860	µA
Measurement current, low-power mode	-	320	620	µA
Average current, normal mode	-	3	-	µA at 1 measurement/s
Average current, low-power mode	-	1	-	µA at 1 measurement/s
Input LOW, VIL	-	-	0.4 × VDD	V
Input HIGH, VIH	0.7 × VDD	-	-	V
Output LOW, VOL	-	-	0.2 × VDD	V at 3 mA sink

System timing

Operation	Typical	Maximum	Unit
Power-up time	180	500	µs
Soft-reset time	180	500	µs
Measurement duration, normal mode	10	11	ms
Measurement duration, low-power mode	1.5	2	ms

FHTC3 I²C bus timing diagram and timing parameter table — I²C timing diagram and Normal/Fast Mode Plus limits reproduced from the supplied datasheet. Maximum bus frequency is 100 kHz in the normal timing column and 1 MHz in the high-speed column.

Absolute maximum ratings

Stress	Limit
Supply voltage	-0.3 V to +6 V
Operating and storage temperature	-45 °C to +130 °C
ESD, human-body model	-4 kV to +4 kV
ESD, charged-device model	-500 V to +500 V
Latch-up current at 125 °C	±100 mA

Pin Assignment and Application Circuit

FHTC3 DFN6 top view and pin assignment — DFN6 pin assignment. Pins 2 and 5 are not used; the center pad is grounded.

FHTC3 application circuit with I²C pullups and 100 nanofarad decoupling capacitor — Reference connection with I²C pullups and a 100 nF supply-decoupling capacitor.

Pin	Name	Function	Design guidance
1	VDD	Supply voltage	Place a 100 nF decoupling capacitor close to the sensor.
2	NC	No use	Leave unconnected as directed by the controlled datasheet.
3	SCL	I²C serial clock	Use an external pullup sized for supply voltage, capacitance and required timing.
4	SDA	I²C serial data	Use an external pullup and route away from noise sources.
5	NC	No use	Leave unconnected as directed by the controlled datasheet.
6	GND	Ground	Provide a low-impedance return.
Center pad	GND	Exposed pad	Solder to ground; the datasheet identifies this as necessary for mechanical-stress control.

Assembly-sensitive sensorThe sensing opening, center pad, solder profile, PCB stress and airflow path can affect the finished assembly. Keep flux, coating and cleaning residue away from the sensing aperture.

I²C Interface and Measurement Flow

FHTC3 uses the fixed 7-bit I²C address 0x70. It supports Normal, Fast and Fast Mode Plus operation up to 1 MHz and can hold SCL LOW with clock stretching while a measurement is in progress.

FHTC3 wake, measurement, read and sleep transaction flow — Recommended transaction sequence: wake the device, send one measurement command, read CRC-protected data, then return it to sleep.

Wake first: send command 0x3517 before measurement or register access.
Select order: command options return temperature first or relative humidity first.
Select power mode: normal mode takes about 10 ms; low-power mode takes about 1.5 ms typically.
Clock stretching: when enabled, the device can acknowledge a read and hold SCL LOW until data is ready.
Polling without stretching: an attempted read typically receives NACK while conversion is still running.
Sleep after use: send 0xB098 to minimize average current.

Measurement readout

The device returns two bytes for the first selected quantity, one CRC byte, two bytes for the second quantity and a second CRC byte. The host acknowledges each byte it wants to continue reading and can terminate the transaction with NACK.

Measurement and System Commands

Measurement command matrix

Power mode	Clock stretching	First value	Command
Normal	Enabled	Temperature	0x7CA2
Normal	Enabled	Relative humidity	0x5C24
Normal	Disabled	Temperature	0x7866
Normal	Disabled	Relative humidity	0x58E0
Low power	Enabled	Temperature	0x6458
Low power	Enabled	Relative humidity	0x44DE
Low power	Disabled	Temperature	0x609C
Low power	Disabled	Relative humidity	0x401A

System commands

Function	Command	Use	Engineering note
Wake	0x3517	Exit sleep before communicating.	Allow the specified wake timing before the next operation.
Sleep	0xB098	Enter the lowest-current state.	Use after readout where duty-cycled operation is required.
Soft reset	0x805D	Reset the addressed device state.	Typical execution time is 180 µs; maximum is 500 µs.
General-call reset	Address 0x00, data 0x06	Reset all compatible devices that accept I²C general call.	Confirm other slaves on the bus before using this command.
Read ID	0xEFC8	Read the 16-bit device ID and CRC.	Check the returned CRC before accepting the identity.

CRC Verification and Raw-Data Conversion

Every 16-bit humidity, temperature or ID word is followed by a CRC-8 byte. Calculate the CRC over the two preceding data bytes and reject or retry data when the result does not match.

CRC-8 polynomial: 0x31 (x⁸ + x⁵ + x⁴ + 1)
Initialization: 0xFF · Reflect input/output: false · Check value: CRC(0xBEEF) = 0x92

Conversion formulas

Relative humidity: RH (%RH) = 100 × S_RH / 2¹⁶
Temperature: T (°C) = -45 + 175 × S_T / 2¹⁶

S_RH and S_T are unsigned 16-bit raw values assembled most-significant byte first from the I²C response.

DFN6 Package, Land Pattern and Ordering

FHTC3 DFN6 package drawing and dimensions — DFN6 package views and dimensional table. Use the controlled drawing to create the production CAD library.

FHTC3 recommended PCB land pattern and tape-and-reel drawing — Recommended land pattern and tape-and-reel information reproduced from the supplied datasheet.

Dimension	Minimum	Nominal	Maximum	Unit
Body width, D	1.90	2.00	2.10	mm
Body length, E	1.90	2.00	2.10	mm
Overall height, A	0.70	0.75	0.80	mm
Lead pitch, e	0.50 basic			mm
Lead width, b	0.20	0.25	0.30	mm
Lead length, L	0.30	0.35	0.40	mm
Sensing aperture, ØS	0.80 basic			mm
Inner aperture, ØS1	0.70 basic			mm

Ordering information

Order code	Device	Package	Standard packing quantity	Packing
FHTC3-TR	FHTC3	DFN6, 2 mm × 2 mm	2,000	Tape and reel, dustproof breathable film

The package is identified as moisture-sensitivity level MSL1. Follow the controlled reflow, stencil, land-pattern and handling requirements for production.

Quality, Storage and Chemical Handling

Qualification basisThe datasheet states qualification based on JESD47.

Material declarationsThe source states RoHS, REACH and halogen compliance and absence of Pb, Cd and Hg.

Storage guidanceRecommended storage is 10 °C to 50 °C and 20 %RH to 65 %RH, with a stated one-year storage period.

Keep the film intact: do not tear or contaminate the dustproof breathable film over the sensing aperture.
Avoid volatile chemicals: the source specifically lists substances including acetone, methyl ethyl ketone, isopropanol, ethanol and toluene.
Avoid aggressive media: bases above pH 9, hydrogen peroxide, ammonia and corrosive gases can damage or shift the sensor.
Control coating processes: prevent conformal coating, adhesive, flux and cleaning agents from reaching the sensing surface.
Recover from extreme humidity: prolonged high-humidity exposure can create a temporary offset; use the source conditioning guidance.
Protect against condensation: liquid water and residue can block diffusion and change response time or accuracy.

Compliance statusThe declarations above reproduce supplier claims in the supplied datasheet and are not independent certifications. Obtain current material declarations and qualification reports for the exact orderable part before release.

Application Areas

The supplied datasheet identifies consumer electronics, cold-chain transportation, smart homes, smart agriculture, communication equipment and photovoltaic energy storage.

Consumer electronics icon showing a smartphone and earbuds

Consumer ElectronicsCompact environmental sensing for connected and battery-powered devices.

Cold-chain transportation icon showing a refrigerated truck

Cold-Chain TransportHumidity and temperature logging after placement and response-time validation.

Smart home icon showing a connected house and thermometer

Smart HomeRoom monitoring, comfort control and connected appliance sensing.

Smart agriculture icon showing a greenhouse and wireless sensor

Smart AgricultureGreenhouse and growing-environment monitoring with contamination protection.

Communication equipment icon showing a radio tower

Communication EquipmentEnvironmental monitoring inside cabinets, radios and network infrastructure.

Photovoltaic energy storage icon showing a solar panel and battery

PV Energy StorageCabinet and enclosure monitoring after thermal-gradient and EMC testing.

Application qualificationThe application list does not establish automotive, medical, functional-safety, food-contact or other regulated-use qualification. Confirm sealing, calibration, diagnostics and compliance for the finished product.

FHTC3 Engineering FAQs

What humidity and temperature accuracy does FHTC3 specify?

The performance table lists typical accuracy of ±3.0 %RH and ±0.3 °C. Review the performance curves and complete operating conditions when setting a system error budget.

What measurement ranges should be used in a design?

Use 0 to 100 %RH and -45 °C to +130 °C. Although one description paragraph states +135 °C, both the performance and absolute-maximum tables state +130 °C.

What are the supply and I²C limits?

The supply range is 1.6 V to 5.5 V. The fixed 7-bit address is 0x70, and the interface supports I²C operation up to 1 MHz under the corresponding timing limits.

How low is the operating current?

Typical sleep current is 0.2 µA. At one measurement per second, the datasheet lists typical average current of 3 µA in normal mode and 1 µA in low-power mode.

How long does a measurement take?

The system-timing table lists 10 ms typical and 11 ms maximum in normal mode, or 1.5 ms typical and 2 ms maximum in low-power mode.

How are humidity and temperature read?

Wake the device, send the required measurement command, wait or use clock stretching, then read two data bytes plus CRC for each quantity. Send the sleep command after readout for minimum power.

How should the host verify data?

Calculate CRC-8 with polynomial 0x31 and initialization 0xFF over each two-byte word. The supplied check example gives CRC(0xBEEF) = 0x92.

Does the exposed center pad need to be connected?

Yes. The pin-assignment section identifies the center pad as grounded and instructs that it be soldered to ground for mechanical-stress control.

What package and ordering code are specified?

FHTC3 is supplied in a 2 mm × 2 mm × 0.75 mm DFN6 package. The listed tape-and-reel ordering code is FHTC3-TR, with a standard packing quantity of 2,000.

What materials must be kept away from the sensor?

Keep solvents, volatile organic compounds, high-pH bases, hydrogen peroxide, ammonia, corrosive gases, conformal coating, adhesive and cleaning residue away from the sensing aperture.

Technical source and design authority

This page summarizes the supplied “FHTC3_datasheet .pdf” for component evaluation and engineering reference. It does not replace the complete controlled datasheet. Confirm the current revision, guaranteed performance, interface timing, command sequence, package tolerances, reflow process, chemical compatibility and qualification requirements before production release.

Download FHTC3 Datasheet Contact NYFEA for Product Support