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. 778-1484
Mfr. Part No.DS3231MZ+
BrandMaxim
MYR32.07
Each
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. 165-9743
Mfr. Part No.DS3231MZ+
BrandMaxim
MYR23.89
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. 146-1117
Mfr. Part No.DS12C887+
BrandMaxim
MYR37.18
Each (In a Tube of 14)
units
Alarm Binary, DW:DM:M:Y Binary, HH:MM:SS 113B Multiplexed Through Hole EDIP 24 34.04 x 18.29 x 9.4mm 34.04mm 18.29mm 9.4mm 5.5 V +70 °C
RS Stock No. 139-600
Mfr. Part No.DS12C887+
BrandMaxim
MYR41.15
Each
units
Alarm Binary, DW:DM:M:Y Binary, HH:MM:SS 113B Multiplexed Through Hole EDIP 24 34.04 x 18.29 x 9.4mm 34.04mm 18.29mm 9.4mm 5.5 V +70 °C
RS Stock No. 540-2704
Mfr. Part No.DS1302+
BrandMaxim
MYR15.51
Each
units
Alarm, Battery Backup, Calendar DW:DM:M:Y HH:MM:SS 31B Serial Through Hole PDIP 8 9.91 x 7.87 x 4.45mm 9.91mm 7.87mm 4.45mm 5.5 V +70 °C
RS Stock No. 165-9065
Mfr. Part No.DS1302+
BrandMaxim
MYR11.70
Each (In a Tube of 50)
units
Alarm, Battery Backup, Calendar DW:DM:M:Y HH:MM:SS 31B Serial Through Hole PDIP 8 9.91 x 7.87 x 4.45mm 9.91mm 7.87mm 4.45mm 5.5 V +70 °C
RS Stock No. 124-2362
Mfr. Part No.PCF8563T/5,518
BrandNXP
MYR2.147
Each (On a Reel of 2500)
units
Calendar, Clock YY:MM:DD:dd HH:MM:SS - Serial-2 Wire, Serial-I2C Surface Mount SOIC 8 5 x 4 x 1.45mm 5mm 4mm 1.45mm 5.5 V +85 °C
RS Stock No. 923-7614
Mfr. Part No.DS1307N+
BrandMaxim
MYR11.90
Each (In a Tube of 50)
units
Clock DM:M:DW:Y SS:MM:HH 56B Serial-I2C Through Hole PDIP 8 9.91 x 7.87 x 4.45mm 9.91mm 7.87mm 4.45mm 5.5 V +85 °C
RS Stock No. 865-2208
Mfr. Part No.PCF8563T/5,518
BrandNXP
MYR3.063
Each (In a Pack of 10)
units
Calendar, Clock YY:MM:DD:dd HH:MM:SS - Serial-2 Wire, Serial-I2C Surface Mount SOIC 8 5 x 4 x 1.45mm 5mm 4mm 1.45mm 5.5 V +85 °C
RS Stock No. 786-0745
Mfr. Part No.DS1307N+
BrandMaxim
MYR16.69
Each (In a Pack of 2)
units
Clock DM:M:DW:Y SS:MM:HH 56B Serial-I2C Through Hole PDIP 8 9.91 x 7.87 x 4.45mm 9.91mm 7.87mm 4.45mm 5.5 V +85 °C
RS Stock No. 146-0203
Mfr. Part No.MCP7940M-I/P
BrandMicrochip
MYR3.105
Each (In a Tube of 60)
units
Alarm, Calendar DW:DM:M:Y HH:MM:SS 64B Serial-I2C Through Hole PDIP 8 10.16 x 7.11 x 4.95mm 10.16mm 7.11mm 4.95mm 5.5 V +85 °C
RS Stock No. 540-4772
Mfr. Part No.DS1307Z+
BrandMaxim
MYR15.30
Each
units
Alarm, Battery Backup, Calendar, Power Fail DW:DM:M:Y 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. 920-9001
Mfr. Part No.M48T35Y-70PC1
MYR85.248
Each (In a Tube of 12)
units
Battery Backup, Calendar, Chip Deselect, Switch Over, Write Protection DW:DM:M:Y HH:MM:SS 32768B 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. 774-7403
Mfr. Part No.MCP7940M-I/P
BrandMicrochip
MYR3.516
Each (In a Bag of 10)
units
Alarm, Calendar DW:DM:M:Y HH:MM:SS 64B Serial-I2C Through Hole PDIP 8 10.16 x 7.11 x 4.95mm 10.16mm 7.11mm 4.95mm 5.5 V +85 °C
RS Stock No. 923-7490
Mfr. Part No.DS1307Z+T&R
BrandMaxim
MYR10.215
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. 761-9759
Mfr. Part No.DS1307Z+T&R
BrandMaxim
MYR13.50
Each
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. 624-8466
Mfr. Part No.M48T35Y-70PC1
MYR99.55
Each
units
Battery Backup, Calendar, Chip Deselect, Switch Over, Write Protection DW:DM:M:Y HH:MM:SS 32768B 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. 496-874
Mfr. Part No.CDP68HC68T1EZ
BrandIntersil
MYR46.63
Each
units
Alarm, Battery Backup, Calendar, Watchdog Timer DW:DM:M:Y HH:MM:SS 32B Serial-SPI Through Hole PDIP 16 19.68 x 7.11 x 4.95mm 19.68mm 7.11mm 4.95mm 6 V +85 °C
RS Stock No. 169-8278
Mfr. Part No.CDP68HC68T1EZ
BrandIntersil
MYR41.106
Each (In a Tube of 25)
units
Alarm, Battery Backup, Calendar, Watchdog Timer DW:DM:M:Y HH:MM:SS 32B Serial-SPI Through Hole PDIP 16 19.68 x 7.11 x 4.95mm 19.68mm 7.11mm 4.95mm 6 V +85 °C
RS Stock No. 169-8316
Mfr. Part No.DS1307Z+
BrandMaxim
MYR10.84
Each (In a Tube of 100)
units
Alarm, Battery Backup, Calendar, Power Fail DW:DM:M:Y 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
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