Real Time Clocks

What is a Real Time Clock?
A Real Time Clock (RTC) is a computer clock which is usually in the form of an integrated circuit. They have been designed to keep track of time, in real time - hence the product name. A Real Time Clock is usually an integral part of the computer motherboard. More often than not, a RTC will also include a calendar and an alarm

How do Real Time Clocks work?
The memory on the clocks system stores system descriptions and set up values such as "Current Time Value". The information that is held in the RTC is read with a microprocessor, commonly over a serial interface which facilitate the performance of the software functions that are time dependant. They are designed to run on an ultra-low power consumption, often run on a lithium battery source or normal power. This power source allows them to continue running and generating real time when a system is down. The newer models of RTC use super-capacitors as a source of power that can be recharged and soldered to the board.
Some Real Time Clocks feature synchronisation to an external signal, such as a compensated power line frequency. It allows the device to provide an accurate result without having an on-board temperature compensation scheme.

RTC Time Values
• Year
• Month
• Date
• Hours
• Minutes
• Seconds

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Description Price Functions Date Format Time Format User RAM Bus Type Mounting Type Package Type Pin Count Dimensions Length Width Height Maximum Operating Supply Voltage Maximum Operating Temperature
RS Stock No. 797-9607
Mfr. Part No.DS17887-5+
SGD30.02
Each
units
Alarm, Calendar YY:MM:DD HH:MM:SS 114B Multiplexed Through Hole EDIP 24 38.1 x 18.29 x 10.67mm 38.1mm 18.29mm 10.67mm 5.5 V +70 °C
RS Stock No. 920-9004
Mfr. Part No.M48T58-70PC1
SGD26.82
Each (In a Tube of 12)
units
Battery Backup, Calendar, Chip Deselect, Switch Over, Write Protection DW:DM:M:Y HH:MM:SS 8192B Parallel Through Hole PCDIP 28 39.88 x 18.34 x 8.89mm 39.88mm 18.34mm 8.89mm 5.5 V +70 °C
RS Stock No. 889-5121
Mfr. Part No.MCP79410-I/SN
BrandMicrochip
SGD1.19
Each (In a Tube of 100)
units
Battery Backup, Calendar, Clock, NV Timekeeping SRAM DW:DM:M:Y HH:MM:SS 64B Serial-I2C Surface Mount SOIC 8 4.9 x 3.9 x 1.25mm 4.9mm 3.9mm 1.25mm 5.5 V +85 °C
RS Stock No. 761-3896
Mfr. Part No.DS1337S+T&R
SGD4.222
Each (In a Pack of 5)
units
Calendar YY:MM:DD HH:MM:SS - Serial-I2C Surface Mount SOIC 8 5 x 4 x 1.5mm 5mm 4mm 1.5mm 5.5 V +85 °C
RS Stock No. 732-7535
Mfr. Part No.DS2417P+
SGD3.85
Each
units
Battery Backup, Calendar, ROM Binary Binary - Serial Surface Mount TSOC 6 4 x 3.89 x 1.5mm 4mm 3.89mm 1.5mm 5.5 V +85 °C
RS Stock No. 189-8414
Mfr. Part No.DS1306EN+
SGD9.25
Each (In a Pack of 2)
units
Battery Backup, Calendar, NV RAM DW:DM:M:Y HH:MM:SS 96B Serial-SPI Surface Mount TSSOP 20 6.6 x 4.5 x 0.95mm 6.6mm 4.5mm 0.95mm 5.5 V +85 °C
RS Stock No. 168-8043
Mfr. Part No.M41ST87WSS6F
SGD5.263
Each (On a Reel of 1350)
units
Calendar D:D:M:Y:C HH:MM:SS:HSS 128B Serial Surface Mount SSOP 20 7.5 x 5.6 x 1.85mm 7.5mm 5.6mm 1.85mm 3.6 V +85 °C
New
RS Stock No. 190-4740
Mfr. Part No.DS1374U-18+
SGD4.91
Each (In a Tube of 50)
units
Binary Counter, Real Time Clock, Trickle Charger - - - Serial-I2C Surface Mount μSOP 10 3.16 x 3.12 x 0.95mm 3.16mm 3.12mm 0.95mm 1.89 V +85 °C
RS Stock No. 714-0855
Mfr. Part No.M41T00SM6F
SGD3.98
Each
units
- DW:DM:M:Y HH:MM:SS 8B Serial-2 Wire, Serial-I2C Surface Mount SOIC 8 5 x 4 x 1.25mm 5mm 4mm 1.25mm 5.5 V +85 °C
RS Stock No. 190-4730
Mfr. Part No.DS1315-5+
SGD23.214
Each (In a Tube of 25)
units
Real Time Clock, SRAM D:DM:M:Y - - - Through Hole PDIP 16 19.43 x 7.87 x 4.45mm 19.43mm 7.87mm 4.45mm 5.5 V +70 °C
RS Stock No. 171-1648
Mfr. Part No.RV-8523-C3-TA-020
SGD9.078
Each (On a Tape of 100)
units
Alarm, Interrupt, Timer - - - Serial-I2C Surface Mount SON 10 - 3.7mm 3.7mm 2.5mm 5.5 V +85 °C
RS Stock No. 177-0305
Mfr. Part No.MCP7940N-E/SN
BrandMicrochip
SGD1.243
Each (In a Tube of 100)
units
- D:M:Y, DW HH:MM:SS - Serial-I2C Surface Mount SOIC 8 4.9 x 3.9 x 1.5mm 4.9mm 3.9mm 1.5mm 5.5 V +125 °C
RS Stock No. 642-3106
Mfr. Part No.CDP68HC68T1MZ
SGD17.11
Each
units
Alarm, Battery Backup, Calendar, Watchdog Timer DW:DM:M:Y HH:MM:SS 32B Serial-SPI Surface Mount SOIC W 20 13 x 7.6 x 2.35mm 13mm 7.6mm 2.35mm 6 V +85 °C
RS Stock No. 189-7249
Mfr. Part No.DS3231MZ+
SGD9.834
Each (In a Tube of 100)
units
Battery Backup, Calendar Binary HH:MM:SS - Serial-I2C Surface Mount SOIC 8 5 x 4 x 1.5mm 5mm 4mm 1.5mm 5.5 V +85 °C
RS Stock No. 189-7214
Mfr. Part No.DS1307Z+T&R
SGD2.68
Each (On a Reel of 2500)
units
Battery Backup, Calendar, NV RAM YY:MM:DD HH:MM:SS 56B Serial-I2C Surface Mount SOIC 8 5 x 4 x 1.5mm 5mm 4mm 1.5mm 5.5 V +70 °C
RS Stock No. 169-8137
Mfr. Part No.Q41454351000111
BrandEPSON
SGD4.765
Each (On a Reel of 250)
units
Calendar, Timer - - - Serial Surface Mount SOP 14 5 x 10.1 x 3.2mm 5mm 10.1mm 3.2mm 5.5 V +85 °C
RS Stock No. 667-6224
Mfr. Part No.Q42724231000711
BrandEPSON
SGD10.24
Each
units
Calendar DW:DM:M:Y HH:MM:SS - Parallel Surface Mount SOP 24 16.3 x 7.9 x 2.8mm 16.3mm 7.9mm 2.8mm 5.5 V +85 °C
RS Stock No. 169-8223
Mfr. Part No.X1B000301000212
BrandEPSON
SGD9.48
Each (On a Reel of 250)
units
Clock - SS:MM - Serial-I2C Surface Mount - 10 3.2 x 2.5 x 1mm 3.2mm 2.5mm 1mm 5.5 V +85 °C
RS Stock No. 813-5769
Mfr. Part No.RV-3029-C3-TA-QC-Opt.A
SGD11.77
Each
units
Alarm, Battery Backup, Calendar, Clock, Timer D:W:M:LY HH:MM:SS 8B Serial-2 Wire, Serial-I2C Surface Mount SON 10 3.7 x 2.5 x 0.9mm 3.7mm 2.5mm 0.9mm 5.5 V +85 °C
RS Stock No. 190-4749
Mfr. Part No.DS3231S#T&R
SGD7.331
Each (On a Reel of 1000)
units
Real Time Clock DM:M:DW:Y SS:MM:HH - Serial-I2C Surface Mount SO 16 10.5 x 7.6 x 2.35mm 10.5mm 7.6mm 2.35mm 5.5 V +70 °C
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