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. 732-7309
Mfr. Part No.DS12887A+
$16.26
Each
units
Alarm, Calendar Binary, DW:DM:M:Y Binary, HH:MM:SS 114B 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. 624-8466
Mfr. Part No.M48T35Y-70PC1
$35.11
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. 920-9001
Mfr. Part No.M48T35Y-70PC1
$39.677
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. 865-2208
Mfr. Part No.PCF8563T/5,518
BrandNXP
$1.061
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. 686-5030
Mfr. Part No.M48T58Y-70PC1
$29.30
Each
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. 920-8991
Mfr. Part No.M48T58Y-70PC1
$21.98
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. 124-2362
Mfr. Part No.PCF8563T/5,518
BrandNXP
$1.236
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. 761-7627
Mfr. Part No.MCP7940M-I/SN
BrandMicrochip
$0.98
Each (In a Pack of 5)
units
Calendar, NV 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. 761-9711
Mfr. Part No.DS1339U-33+T&R
$5.19
Each
units
Battery Backup, Calendar YY:MM:DD HH:MM:SS - Serial-I2C Surface Mount μSOP 8 3.1 x 3.1 x 0.95mm 3.1mm 3.1mm 0.95mm 5.5 V +85 °C
RS Stock No. 912-6943
Mfr. Part No.MCP7940M-I/SN
BrandMicrochip
$0.865
Each (In a Tube of 100)
units
Calendar, NV 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. 923-7472
Mfr. Part No.DS1339U-33+T&R
$2.542
Each (On a Reel of 3000)
units
Battery Backup, Calendar YY:MM:DD HH:MM:SS - Serial-I2C Surface Mount μSOP 8 3.1 x 3.1 x 0.95mm 3.1mm 3.1mm 0.95mm 5.5 V +85 °C
RS Stock No. 511-103
Mfr. Part No.PCF8563TS/4,118
BrandNXP
$2.652
Each (In a Pack of 5)
units
Alarm, Battery Backup, Calendar, Watchdog Timer DW:DM:M:Y HH:MM:SS - Serial-I2C Surface Mount TSSOP 8 3.1 x 3.1 x 0.95mm 3.1mm 3.1mm 0.95mm 5.5 V +85 °C
RS Stock No. 714-7298
Mfr. Part No.M48T18-100PC1
$32.63
Each
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. 919-6337
Mfr. Part No.M48T18-100PC1
$24.85
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. 166-1602
Mfr. Part No.PCF8563TS/4,118
BrandNXP
$2.564
Each (On a Reel of 2500)
units
Alarm, Battery Backup, Calendar, Watchdog Timer DW:DM:M:Y HH:MM:SS - Serial-I2C Surface Mount TSSOP 8 3.1 x 3.1 x 0.95mm 3.1mm 3.1mm 0.95mm 5.5 V +85 °C
RS Stock No. 825-1076
Mfr. Part No.MCP79510-I/MS
BrandMicrochip
$1.918
Each (In a Pack of 5)
units
Calendar DW:M:Y:LY HH:MM:SS:HSS 64B Serial-SPI Surface Mount MSOP 10 3 x 3 x 0.95mm 3mm 3mm 0.95mm 3.6 V +85 °C
RS Stock No. 798-5258
Mfr. Part No.MCP7940N-I/SN
BrandMicrochip
$1.188
Each (In a Pack of 10)
units
Battery Backup, Calendar DW:DM:M:Y HH:MM:SS 64B Serial-I2C Surface Mount SOIC 8 4.9 x 3.9 x 1.5mm 4.9mm 3.9mm 1.5mm 5.5 V +85 °C
RS Stock No. 912-2774
Mfr. Part No.MCP7940N-I/SN
BrandMicrochip
$1.10
Each (In a Tube of 100)
units
Battery Backup, Calendar DW:DM:M:Y HH:MM:SS 64B Serial-I2C Surface Mount SOIC 8 4.9 x 3.9 x 1.5mm 4.9mm 3.9mm 1.5mm 5.5 V +85 °C
RS Stock No. 165-2099
Mfr. Part No.MCP79510-I/MS
BrandMicrochip
$1.93
Each (In a Tube of 100)
units
Calendar DW:M:Y:LY HH:MM:SS:HSS 64B Serial-SPI Surface Mount MSOP 10 3 x 3 x 0.95mm 3mm 3mm 0.95mm 3.6 V +85 °C
RS Stock No. 166-0314
Mfr. Part No.PCA8565TS/1,118
BrandNXP
$1.23
Each (On a Reel of 2500)
units
Alarm, Calendar, Interrupt, Timer DW:DM:M:Y HH:MM:SS - Serial-I2C Surface Mount TSSOP 8 3.1 x 3.1 x 0.95mm 3.1mm 3.1mm 0.95mm 5.5 V +125 °C
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