Real Time Clocks

This Product Selection Guide contains information to help select products in the Real Time Clocks category on

Real Time Clocks (RTCs) provide time and/or date information in almost any electronic device which needs to keep accurate time. The clock types are binary counter, clock/calendar/supervisor, elapsed time counter, phantom time chip, portable system controller, temperature recorder, time event recorder, and timer clock peripheral. They contain memory sizes ranging from 2 B to 2 MB and have interface options of I2C, Parallel, Serial, SPI, 1-Wire, 2-Wire, 3-Wire, and 4-Wire.


DigiKey Programmable: For verified products, DigiKey can program/flash your compiled code or configuration variables prior to shipping. For unverified products, please inquire with

Type: Indicates the operational mode(s) of a featured amplifier IC, which has categorical significance for performance traits such as electrical efficiency.

Features: These are different capabilities or properties of the device such as alarm, battery switch, or unique ID.

Memory Size: The amount of memory available on chip for program storage.

Time Format: Indicates the format in which time data is retrieved from a device.

Date Format: Indicates the format/encoding of date information provided by the device.

Interface: Indication of which interface(s) or protocol(s) are used by the device to communicate with other components in the system.

Voltage - Supply: Typically represented by a range, this indicates the low and high voltage limits which one can expect standard operation. Voltages outside this range may damage the device and other system components.

Voltage - Supply, Battery: The recommended battery operating voltage range specified for a device’s internal logic functions; may differ from the supply required to power a device’s interface and I/O functions.

Current - Timekeeping (Max): Supply current required for maintenance of the device’s time keeping function.

Operating Temperature: Recommended operating temperature, typically given in a range or as a maximum. Exceeding these temperatures may affect performance or damage the device and other system components.

Mounting Type: Indicates how the device is attached.

Package / Case: Indicates the type of protective case used on an electronic component to allow easy handling, installation, and protection. This selection was determined to be the closest industry standard applicable to the suppliers device packaging. Typically it is best to check the actual dimensions from the datasheet rather than depend on this terminology when designing your circuit.

Supplier Device Package: This is what the manufacturer calls the package of this device. They are manufacturer specific. It is typically best to use the actual dimensions from the datasheets rather than to go by this terminology when designing your circuit.


8-TSSOP, 8-MSOP Leap Year, Trickle-Charger

MFR PART # DS1340U-33+T&R
MANUFACTURER Analog Devices Inc./Maxim Integrated

Real Time Clock (RTC) Board

MFR PART # 3296
DIGI-KEY PART # 1528-1788-ND
MANUFACTURER Adafruit Industries LLC


Timing Solutions - Product Overview
Using the Peripheral Management Unit–Part 4: A PMU Program
Cymbet EVAL 06 EnerChip RTC Backup Demo

Enhance Battery Life in Wearables Through Efficient Timekeeping During Idle States

Product Training Modules
DS1307 Real Time Clocks
Real Time Clock (RTC)
Real Time Clocks
Low Power Real-Time Clocks
Accurate Real Time Clock Series
32.768KHz Timing Solutions
Low Power, High ESR Real-Time Clocks

Real Time Clock

If you have any general questions on the specifications for selecting Real Time Clocks, please reply using the button below. If you have questions on specific Real Time Clocks please post those questions in the Integrated Circuits (ICs) category.