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0755-82798135Real Time Clocks
Real Time Clock (RTC) ICs are timing components used to maintain accurate time and calendar information in electronic systems, even when the main power is turned off. They are widely used in embedded systems, industrial control, consumer electronics, communication equipment, medical devices, automotive electronics, IoT products, meters and data logging applications.
This category includes real time clock ICs, battery-backed RTCs, low-power RTCs, I2C RTCs, SPI RTCs, calendar clock ICs and related clock/timing components. These devices are commonly selected based on timekeeping accuracy, backup power support, interface type, alarm functions, operating voltage, current consumption, package type and application requirements.
TomatoElec supplies original Real Time Clock RTC ICs from recognized semiconductor manufacturers such as Microchip, NXP, STMicroelectronics, Renesas, Texas Instruments, Analog Devices, onsemi, Infineon and other major brands. As an in-stock electronic components supplier and independent distributor, TomatoElec provides inventory support, original component sourcing and BOM sourcing services for global customers.
| Photo | Mfr. Part # | Availability | Price | Quantity | Datasheet | Series | Package/Case | Packaging | Product Status | Programmable | Type | Features | Memory Size | Time Format | Date Format | Interface | Voltage - Supply | Voltage - Supply, Battery | Current - Timekeeping (Max) | Operating Temperature | Mounting Type | Grade | Qualification | Supplier Device Package |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
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PCF2123BS/1,512IC RTC CLK/CALENDAR SPI 16HVQFN |
0 | - |
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Datasheet |
- | 16-VFQFN Exposed Pad | Tube | Discontinued at Digi-Key | Not Verified | Clock/Calendar | Alarm, Leap Year, Square Wave Output, Watchdog Timer | - | HH:MM:SS (12/24 hr) | YY-MM-DD-dd | SPI | 1.6V ~ 5.5V | - | 0.33µA ~ 0.38µA @ 2V ~ 5V | -40°C ~ 85°C | Surface Mount | - | - | 16-HVQFN (3x3) |
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PCF2129AT/1,518IC RTC CLOCK/CALENDAR I2C 20SO |
0 | - |
|
Datasheet |
- | 20-SOIC (0.295", 7.50mm Width) | Tape & Reel (TR) | Obsolete | Not Verified | Clock/Calendar | Alarm, Leap Year, Square Wave Output, TCXO/Crystal, Watchdog Timer | - | HH:MM:SS (12/24 hr) | YY-MM-DD-dd | I2C, 2-Wire Serial | 1.8V ~ 4.2V | 1.8V ~ 4.2V | 1.5µA @ 3.3V | -40°C ~ 85°C | Surface Mount | - | - | 20-SO |
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PCF2127AT/1,518IC RTC CLOCK/CALENDAR I2C 20SO |
0 | - |
|
Datasheet |
- | 20-SOIC (0.295", 7.50mm Width) | Tape & Reel (TR) | Obsolete | Not Verified | Clock/Calendar | Alarm, Leap Year, Square Wave Output, SRAM, TCXO/Crystal, Watchdog Timer | 512B | HH:MM:SS (12/24 hr) | YY-MM-DD-dd | I2C, 2-Wire Serial | 1.8V ~ 4.2V | 1.8V ~ 4.2V | 1.5µA @ 3.3V | -40°C ~ 85°C | Surface Mount | - | - | 20-SO |
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PCF8564ACX9/1,005IC RTC CLOCK/CALENDAR I2C DIE |
0 | - |
|
Datasheet |
- | Die | Bulk | Obsolete | Not Verified | Clock/Calendar | Alarm, Leap Year, Square Wave Output, Watchdog Timer | - | HH:MM:SS (24 hr) | YY-MM-DD-dd | I2C, 2-Wire Serial | 1V ~ 5.5V | - | 0.6µA ~ 0.75µA @ 2V ~ 5V | -40°C ~ 85°C | Surface Mount | - | - | Die |
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RX-4801JE:UBIC RTC CLK/CALENDAR SPI 20VSOJ |
0 | - |
|
Datasheet |
- | 20-LSSOJ (0.213", 5.40mm Width) | Bulk | Obsolete | Not Verified | Clock/Calendar | Alarm, Leap Year | 16B | HH:MM:SS (24 hr) | YY-MM-DD-dd | SPI | 1.6V ~ 5.5V | - | 2.1µA ~ 3.4µA @ 3V ~ 5V | -40°C ~ 85°C | Surface Mount | - | - | 20-VSOJ |
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PCF8523TS/1,112IC RTC CLK/CALENDAR I2C 14TSSOP |
0 | - |
|
Datasheet |
- | 14-TSSOP (0.173", 4.40mm Width) | Tube | Obsolete | Not Verified | Clock/Calendar | Alarm, Leap Year, Watchdog Timer | - | HH:MM:SS (12/24 hr) | YY-MM-DD-dd | I2C, 2-Wire Serial | 1.6V ~ 5.5V | 1.8V ~ 5.5V | 0.5µA @ 2V ~ 5V | -40°C ~ 85°C | Surface Mount | - | - | 14-TSSOP |
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ISL12027AIB27Z-TIC RTC CLK/CALENDAR I2C 8SOIC |
0 | - |
|
Datasheet |
- | 8-SOIC (0.154", 3.90mm Width) | Tape & Reel (TR) | Obsolete | Not Verified | Clock/Calendar | Alarm, Leap Year, Supervisor, Watchdog Timer | - | HH:MM:SS (12/24 hr) | YY-MM-DD-dd | I2C, 2-Wire Serial | 2.7V ~ 5.5V | 1.8V ~ 5.5V | 10µA ~ 20µA @ 2.7V ~ 5.5V | -40°C ~ 85°C | Surface Mount | - | - | 8-SOIC |
|
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ISL12027AIV27Z-TIC RTC CLK/CALENDAR I2C 8TSSOP |
0 | - |
|
Datasheet |
- | 8-TSSOP (0.173", 4.40mm Width) | Tape & Reel (TR) | Obsolete | Not Verified | Clock/Calendar | Alarm, Leap Year, Supervisor, Watchdog Timer | - | HH:MM:SS (12/24 hr) | YY-MM-DD-dd | I2C, 2-Wire Serial | 2.7V ~ 5.5V | 1.8V ~ 5.5V | 10µA ~ 20µA @ 2.7V ~ 5.5V | -40°C ~ 85°C | Surface Mount | - | - | 8-TSSOP |
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ISL12028AIB27Z-TIC RTC CLK/CALENDAR I2C 14SOIC |
0 | - |
|
Datasheet |
- | 14-SOIC (0.154", 3.90mm Width) | Tape & Reel (TR) | Obsolete | Not Verified | Clock/Calendar | Alarm, Leap Year, Supervisor, Watchdog Timer | - | HH:MM:SS (12/24 hr) | YY-MM-DD-dd | I2C, 2-Wire Serial | 2.7V ~ 5.5V | 1.8V ~ 5.5V | 10µA ~ 20µA @ 2.7V ~ 5.5V | -40°C ~ 85°C | Surface Mount | - | - | 14-SOIC |
|
ISL12028AIV27Z-TIC RTC CLK/CALENDAR I2C 14TSSOP |
0 | - |
|
Datasheet |
- | 14-TSSOP (0.173", 4.40mm Width) | Tape & Reel (TR) | Obsolete | Not Verified | Clock/Calendar | Alarm, Leap Year, Supervisor, Watchdog Timer | - | HH:MM:SS (12/24 hr) | YY-MM-DD-dd | I2C, 2-Wire Serial | 2.7V ~ 5.5V | 1.8V ~ 5.5V | 10µA ~ 20µA @ 2.7V ~ 5.5V | -40°C ~ 85°C | Surface Mount | - | - | 14-TSSOP |
|
ISL12029AIB27Z-TIC RTC CLK/CALENDAR I2C 14SOIC |
0 | - |
|
Datasheet |
- | 14-SOIC (0.154", 3.90mm Width) | Tape & Reel (TR) | Obsolete | Not Verified | Clock/Calendar | Alarm, Leap Year, Supervisor, Watchdog Timer | - | HH:MM:SS (12/24 hr) | YY-MM-DD-dd | I2C, 2-Wire Serial | 2.7V ~ 5.5V | 1.8V ~ 5.5V | 10µA ~ 20µA @ 2.7V ~ 5.5V | -40°C ~ 85°C | Surface Mount | - | - | 14-SOIC |
|
ISL12029AIV27Z-TIC RTC CLK/CALENDAR I2C 14TSSOP |
0 | - |
|
Datasheet |
- | 14-TSSOP (0.173", 4.40mm Width) | Tape & Reel (TR) | Obsolete | Not Verified | Clock/Calendar | Alarm, Leap Year, Supervisor, Watchdog Timer | - | HH:MM:SS (12/24 hr) | YY-MM-DD-dd | I2C, 2-Wire Serial | 2.7V ~ 5.5V | 1.8V ~ 5.5V | 10µA ~ 20µA @ 2.7V ~ 5.5V | -40°C ~ 85°C | Surface Mount | - | - | 14-TSSOP |
|
ISL12027AIB27ZIC RTC CLK/CALENDAR I2C 8SOIC |
0 | - |
|
Datasheet |
- | 8-SOIC (0.154", 3.90mm Width) | Tube | Obsolete | Not Verified | Clock/Calendar | Alarm, Leap Year, Supervisor, Watchdog Timer | - | HH:MM:SS (12/24 hr) | YY-MM-DD-dd | I2C, 2-Wire Serial | 2.7V ~ 5.5V | 1.8V ~ 5.5V | 10µA ~ 20µA @ 2.7V ~ 5.5V | -40°C ~ 85°C | Surface Mount | - | - | 8-SOIC |
|
|
ISL12027AIV27ZIC RTC CLK/CALENDAR I2C 8TSSOP |
0 | - |
|
Datasheet |
- | 8-TSSOP (0.173", 4.40mm Width) | Tube | Obsolete | Not Verified | Clock/Calendar | Alarm, Leap Year, Supervisor, Watchdog Timer | - | HH:MM:SS (12/24 hr) | YY-MM-DD-dd | I2C, 2-Wire Serial | 2.7V ~ 5.5V | 1.8V ~ 5.5V | 10µA ~ 20µA @ 2.7V ~ 5.5V | -40°C ~ 85°C | Surface Mount | - | - | 8-TSSOP |
|
ISL12028AIB27ZIC RTC CLK/CALENDAR I2C 14SOIC |
0 | - |
|
Datasheet |
- | 14-SOIC (0.154", 3.90mm Width) | Tube | Obsolete | Not Verified | Clock/Calendar | Alarm, Leap Year, Supervisor, Watchdog Timer | - | HH:MM:SS (12/24 hr) | YY-MM-DD-dd | I2C, 2-Wire Serial | 2.7V ~ 5.5V | 1.8V ~ 5.5V | 10µA ~ 20µA @ 2.7V ~ 5.5V | -40°C ~ 85°C | Surface Mount | - | - | 14-SOIC |
|
ISL12028AIV27ZIC RTC CLK/CALENDAR I2C 14TSSOP |
0 | - |
|
Datasheet |
- | 14-TSSOP (0.173", 4.40mm Width) | Tube | Obsolete | Not Verified | Clock/Calendar | Alarm, Leap Year, Supervisor, Watchdog Timer | - | HH:MM:SS (12/24 hr) | YY-MM-DD-dd | I2C, 2-Wire Serial | 2.7V ~ 5.5V | 1.8V ~ 5.5V | 10µA ~ 20µA @ 2.7V ~ 5.5V | -40°C ~ 85°C | Surface Mount | - | - | 14-TSSOP |
|
ISL12029AIB27ZIC RTC CLK/CALENDAR I2C 14SOIC |
0 | - |
|
Datasheet |
- | 14-SOIC (0.154", 3.90mm Width) | Tube | Obsolete | Not Verified | Clock/Calendar | Alarm, Leap Year, Supervisor, Watchdog Timer | - | HH:MM:SS (12/24 hr) | YY-MM-DD-dd | I2C, 2-Wire Serial | 2.7V ~ 5.5V | 1.8V ~ 5.5V | 10µA ~ 20µA @ 2.7V ~ 5.5V | -40°C ~ 85°C | Surface Mount | - | - | 14-SOIC |
|
ISL12029AIV27ZIC RTC CLK/CALENDAR I2C 14TSSOP |
0 | - |
|
Datasheet |
- | 14-TSSOP (0.173", 4.40mm Width) | Tube | Obsolete | Not Verified | Clock/Calendar | Alarm, Leap Year, Supervisor, Watchdog Timer | - | HH:MM:SS (12/24 hr) | YY-MM-DD-dd | I2C, 2-Wire Serial | 2.7V ~ 5.5V | 1.8V ~ 5.5V | 10µA ~ 20µA @ 2.7V ~ 5.5V | -40°C ~ 85°C | Surface Mount | - | - | 14-TSSOP |
|
RTC-7301DG:B ROHSIC RTC CLK/CALENDAR PAR 18DIP |
0 | - |
|
Datasheet |
- | 18-DIP (0.300", 7.62mm) | Tube | Obsolete | Not Verified | Clock/Calendar | Alarm, Leap Year | - | HH:MM:SS (24 hr) | YY-MM-DD-dd | Parallel | 2.4V ~ 5.5V | - | 1µA ~ 2µA @ 3V ~ 5V | -40°C ~ 85°C | Through Hole | - | - | 18-DIP |
|
|
RX-8581JE:B3 I2C-BUSIC RTC CLK/CALENDAR I2C 20VSOJ |
0 | - |
|
Datasheet |
RX-8581JE | 20-LSSOJ (0.213", 5.40mm Width) | Tape & Reel (TR) | Obsolete | Not Verified | Clock/Calendar | Alarm, Leap Year | - | HH:MM:SS (24 hr) | YY-MM-DD-dd | I2C, 2-Wire Serial | 1.8V ~ 5.5V | - | 0.8µA ~ 1.2µA @ 3V ~ 5V | -40°C ~ 85°C | Surface Mount | - | - | 20-VSOJ |

