Real Time Clock – Mouser Ireland

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Real Time Clocks for Thermostats

Real Time Clocks (RTCs) are IC devices that keep track of time. A typical RTC can provide the time of day as well as the date via a serial bus such as I2C or SPI

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Image	Part #	Mfr.	Description	Datasheet	Availability	Pricing (EUR) Filter the results in the table by unit price based on your quantity.	Qty.	RTC Bus Interface	Date Format	Time Format	Package/Case	Battery Backup Switching	Supply Voltage - Min	Supply Voltage - Max	Minimum Operating Temperature	Maximum Operating Temperature	Series	Mounting Style	Packaging
Real Time Clock I C Serial Real-Time Clock DS1339U-3+ Analog Devices / Maxim Integrated 1: €5.71 1,309In Stock	Mfr. Part No. DS1339U-3+ Mouser Part No 700-DS1339U-3	Analog Devices / Maxim Integrated	Real Time Clock I C Serial Real-Time Clock Learn More about Analog Devices / Maxim Integrated maxim hvac solutions	Datasheet	1,309In Stock	€5.71 €4.38 €4.02 €3.67 View €3.50 €3.39 €3.35	Min.: 1 Mult.: 1 Max.: 1,047	Serial 2-Wire, I2C	YY-MM-DD-dd	HH:MM:SS:hh (12 hr, 24 hr)	uSOP-8	Backup Switching	2.7 V	3.3 V	- 40 C	+ 85 C	DS1339U	SMD/SMT	Tube
Real Time Clock I2C GP RTCC 64B SRAM MCP7940N-I/MS Microchip Technology 1: €0.774 2,055In Stock	Mfr. Part No. MCP7940N-I/MS Mouser Part No 579-MCP7940N-I/MS	Microchip Technology	Real Time Clock I2C GP RTCC 64B SRAM Learn More about Microchip Technology microchip mcp7940n calendar	Datasheet	2,055In Stock	€0.774 €0.715	Min.: 1 Mult.: 1	Serial 2-Wire, I2C	YY-MM-DD-dd	HH:MM:SS:hh (12 hr, 24 hr)	MSOP-8	Backup Switching	1.8 V	5.5 V	- 40 C	+ 85 C		SMD/SMT	Tube
Real Time Clock I2C GP RTCC 1Kb EE 64B SRAM ID MCP79410-I/MS Microchip Technology 1: €0.929 1,492In Stock	Mfr. Part No. MCP79410-I/MS Mouser Part No 579-MCP79410-I/MS	Microchip Technology	Real Time Clock I2C GP RTCC 1Kb EE 64B SRAM ID Learn More about Microchip Technology microchip mcp794xx calendars	Datasheet	1,492In Stock	€0.929 €0.869 €0.861	Min.: 1 Mult.: 1	I2C	YY-MM-DD-dd	HH:MM:SS:hh (12 hr, 24 hr)	MSOP-8	Backup Switching	1.8 V	5.5 V	- 40 C	+ 85 C		SMD/SMT	Tube
Real Time Clock 128 NVRAM Serial RTC 3.0 to 3.6 Vcc M41ST87WSS6F STMicroelectronics 1: €6.68 361In Stock 1,350On Order	Mfr. Part No. M41ST87WSS6F Mouser Part No 511-M41ST87WSS6F	STMicroelectronics	Real Time Clock 128 NVRAM Serial RTC 3.0 to 3.6 Vcc	Datasheet	361In Stock 1,350On Order	Cut Tape €6.68 €5.16 €4.77 €4.36 Reel €3.74 View €4.09 €3.56 MouseReel Available	Min.: 1 Mult.: 1 : 1,350	Serial 2-Wire, I2C	YY-MM-DD-dd	HH:MM:SS:hh (12 hr, 24 hr)	SSOP-20	Backup Switching	2.7 V	3.6 V	- 40 C	+ 85 C	M41ST87W	SMD/SMT	Reel, Cut Tape, MouseReel
Real Time Clock I2C GP RTCC 64B SRAM MCP7940N-I/ST Microchip Technology 1: €0.774 100In Stock 500Expected 26/10/2026	Mfr. Part No. MCP7940N-I/ST Mouser Part No 579-MCP7940N-I/ST	Microchip Technology	Real Time Clock I2C GP RTCC 64B SRAM Learn More about Microchip Technology microchip mcp7940n calendar	Datasheet	100In Stock 500Expected 26/10/2026	€0.774 €0.715	Min.: 1 Mult.: 1	Serial 2-Wire, I2C	YY-MM-DD-dd	HH:MM:SS:hh (12 hr, 24 hr)	TSSOP-8	Backup Switching	1.8 V	5.5 V	- 40 C	+ 85 C		SMD/SMT	Tube
Real Time Clock I2C GP RTCC 1Kb EE 64B SRAM ID MCP79410-I/ST Microchip Technology 1: €0.929 934In Stock	Mfr. Part No. MCP79410-I/ST Mouser Part No 579-MCP79410-I/ST	Microchip Technology	Real Time Clock I2C GP RTCC 1Kb EE 64B SRAM ID Learn More about Microchip Technology microchip mcp794xx calendars	Datasheet	934In Stock	€0.929 €0.869 €0.861	Min.: 1 Mult.: 1	I2C	YY-MM-DD-dd	HH:MM:SS:hh (12 hr, 24 hr)	TSSOP-8	Backup Switching	1.8 V	5.5 V	- 40 C	+ 85 C		SMD/SMT	Tube
Real Time Clock Parallel RTC A 595-B Q4802LYPWR A 595-BQ A 595-BQ4802LYPWR BQ4802LYPW Texas Instruments 1: €8.26 50In Stock End of Life	Mfr. Part No. BQ4802LYPW Mouser Part No 595-BQ4802LYPW End of Life	Texas Instruments	Real Time Clock Parallel RTC A 595-B Q4802LYPWR A 595-BQ A 595-BQ4802LYPWR	Datasheet	50In Stock	€8.26 €6.68 €5.67 €5.37 View €5.22 €5.13 €5.04 Quote	Min.: 1 Mult.: 1	Parallel	YY-MM-DD-dd	HH:MM:SS (24 hr)	TSSOP-28	Backup Switching	2.7 V	3.6 V	0 C	+ 70 C	BQ4802LY	SMD/SMT	Tube
Real Time Clock I C RTC with 56-Byte NV RAM DS1338U-33+ Analog Devices / Maxim Integrated 1: €5.36 460In Stock	Mfr. Part No. DS1338U-33+ Mouser Part No 700-DS1338U-33	Analog Devices / Maxim Integrated	Real Time Clock I C RTC with 56-Byte NV RAM	Datasheet	460In Stock	€5.36 €4.38 €3.72 €3.67	Min.: 1 Mult.: 1 Max.: 208	I2C	YY-MM-DD-dd	HH:MM:SS:hh (12 hr, 24 hr)	uSOP-8	Backup Switching	3 V	5.5 V	- 40 C	+ 85 C	DS1338U	SMD/SMT	Tube
Real Time Clock I C Serial Real-Time Clock DS1339U-33+ Analog Devices / Maxim Integrated 1: €6.05 818In Stock	Mfr. Part No. DS1339U-33+ Mouser Part No 700-DS1339U-33	Analog Devices / Maxim Integrated	Real Time Clock I C Serial Real-Time Clock Learn More about Analog Devices / Maxim Integrated maxim hvac solutions	Datasheet	818In Stock	€6.05 €4.64 €3.94 €3.90 View €3.71 €3.59	Min.: 1 Mult.: 1 Max.: 646	Serial 2-Wire, I2C	YY-MM-DD-dd	HH:MM:SS:hh (12 hr, 24 hr)	uSOP-8	Backup Switching	2.97 V	5.5 V	- 40 C	+ 85 C	DS1339U	SMD/SMT	Tube
Real Time Clock RTC IC with 400 kHz I2C interface in TSSOP8 package. PCF8563TS/5,118 NXP Semiconductors 1: €1.51 1,341In Stock 15,000On Order	Mfr. Part No. PCF8563TS/5,118 Mouser Part No 771-PCF8563TS/5118	NXP Semiconductors	Real Time Clock RTC IC with 400 kHz I2C interface in TSSOP8 package.	Datasheet	1,341In Stock 15,000On Order On Order Ship Dates Mfr. No: PCF8563TS/5,118 Stock: 1,341 Can Dispatch Immediately On Order: 7,500 Expected 16/11/2026 7,500 Expected 25/01/2027 Factory Lead Time: 27 Weeks	Cut Tape €1.51 €1.10 €1.01 €0.894 View Reel €0.735 €0.838 €0.806 €0.786 €0.735 MouseReel Available	Min.: 1 Mult.: 1 : 2,500	I2C	YY-MM-DD-dd	HH:MM:SS (24 hr)	TSSOP-8	No Backup Switching	1 V	5.5 V	- 40 C	+ 85 C	PCF8563	SMD/SMT	Reel, Cut Tape, MouseReel
Real Time Clock I C Serial Real-Time Clock DS1337U+ Analog Devices / Maxim Integrated 1: €4.32 396In Stock	Mfr. Part No. DS1337U+ Mouser Part No 700-DS1337U	Analog Devices / Maxim Integrated	Real Time Clock I C Serial Real-Time Clock Learn More about Analog Devices / Maxim Integrated maxim ds1337 rtc	Datasheet	396In Stock	€4.32 €3.26 €2.98 €2.69 €2.55	Min.: 1 Mult.: 1 Max.: 321	I2C	YY-MM-DD-dd	HH:MM:SS:hh (12 hr, 24 hr)	uSOP-8	No Backup Switching	1.8 V	5.5 V	- 40 C	+ 85 C	DS1337U	SMD/SMT	Tube
Real Time Clock I C RTC with Trickle Charger DS1340U-33+ Analog Devices / Maxim Integrated 1: €5.71 119In Stock	Mfr. Part No. DS1340U-33+ Mouser Part No 700-DS1340U-33	Analog Devices / Maxim Integrated	Real Time Clock I C RTC with Trickle Charger Learn More about Analog Devices / Maxim Integrated maximds1343	Datasheet	119In Stock	€5.71 €4.38 €4.01	Min.: 1 Mult.: 1 Max.: 95	I2C	YY-MM-DD-dd	HH:MM:SS (24 hr)	uSOP-8	Backup Switching	2.97 V	5.5 V	- 40 C	+ 85 C	DS1340U	SMD/SMT	Tube

Real Time Clocks for Thermostats

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