Top 10 Real Time Clocks ICs

Today, electronic products can keep to time, even when they must have been powered off for many hours. Ever wondered why your laptop or even your smartphone keeps to time and activates the alarms, even when you must have turned it off the previous day? It happens because the devices use a Real Time Clock (RTC), which is embedded in it in the form of an Integrated Circuit (IC).

Different manufacturers have produced several variants of the RTC, with each offering a wide range of functions. If you are keen on maintaining an accurate time in your device, it is time you invested in Real Time Clocks (RTCs).

How does a Real Time Clock Work?

A Real Time Clock (RTC) works by measuring the “passage of time,” especially in an electronic device. To help make this work, the clock is optimized into an Integrated Circuit (IC), thus, making it easy to integrate or add to the target devices.

Does a Real Time Clock Work when the Device is out of Power?

Yes, it does and that is one of the most outstanding features. The ability to keep to time, even when the device is off or out of power is possible because of the backup power sources.

Typically, a Real Time Clock (RTC) uses a supercapacitor or auxiliary batteries. This is common in newer electronic devices. The older variants of these devices use lithium or a single battery. The latter is common in specific consumer-grade motherboards, and in that instance, the Real Time Clock would be reset when the battery is removed.

Where Can I Use Real Time Clocks (RTCs)?

If you are keen on maintaining accurate timing on an electronic device even after the main power source is off, it is time you invested in a Real Time Clock.

But what type of devices or use cases does it support? The most common applications are:

• Embedded systems
• Radios
• Personal computers
• Servers

Choosing a Real Time Clock (RTC): The Top Options to Choose from

We have narrowed down on the numbers of Real Time Clocks (RTCs) in the market and picked some of the best.

Here are the ten (10) handpicked RTCs you may want to buy today:

1. S-35390A-J8T1G

ABLIC Inc. manufacturers the S-35390A-J8T1G Real Time Clock (RTC). The company focused on creating a flexible timing device that is not only embeddable on electronic devices, but which can also fast-track the functions of the target device.

Here are some of the amazing features of the S-35390A-J8T1G Real Time Clock (RTC):

Auto Calendar Operations

One of the core features is the ability to “project” the calendar to the future. This is because of the Automatic Leap Year Calculation Function, which can update the device’s calendar up to year 2099.

Lengthy Battery Life

Besides the flexible timing, the S-35390A-J8T1G also extends the battery life – which is one of the features of a Real Time Clock (RTC), by the way.

How it does this is by its 0.25 µA. This aids the clock’s lower current (power) consumption, extends the battery life, which helping in providing power supply to a wide range of other power supply needs.

Flag Generator

There are moments when a Real Time Clock (RTC) begins to lag, especially in the area of power supply and detecting changes in the circuit’s frequency.

The S-35390A-J8T1G RTC solves that with the built-in flag generator, which helps to determine when the circuit’s frequency begins to deviate. The flag generator also helps to detect low voltage on the circuit board.

Frequency Deviation Correction Function

When the circuit’s frequency begins to deviate, it is probably because of the malfunctioning of the crystal oscillator.

Rather than allow that to linger and cause more damages to the device’s timing, the S-35390A-J8T1G uses a built-in correction function. The function combines with the temperature sensor to find the best possible high-precise clock function and which wouldn’t be affected by the ambient temperature range.

2. RV-8263-C7-32.768KHZ-20PPM-TA-QC

A Real Time Clock (RTC) deserves to be kept safe too and that is what the RV-8263-C7-32.768KHZ-20PPM-TA-QC is all about. It protects the timing device with a vacuum, which in turn, hermetically seals the ceramic package with a metal lid.

The technology used in manufacturing the RV-8263-C7-32.768KHZ-20PPM-TA-QC is also impressive. It combines the XTAL with the CMOS technology.

Stop Detection and Lower Power Consumption

RV-8263-C7-32.768KHZ-20PPM-TA-QC detects when the oscillator begins to malfunction or stops entirely. The early detection helps the RTC to switch to a feasible timing management interface, pending when the crystal oscillator is back to its normal function.

On the other hand, the RV-8263-C7-32.768KHZ-20PPM-TA-QC Real Time Clock (RTC) reduces power consumption via the 190 nA @ 3-volt rating.

Multi-Timing Functions

RV-8263-C7-32.768KHZ-20PPM-TA-QC offers both the alarm and timer functions. In terms of the date format, it uses the YY-MM-DD-dd format. For the time format, it uses the HH:MM:SS, which equals the 12/24-hour format.

RV-8263-C7-32.768KHZ-20PPM-TA-QC also provides the timing features in the following combinations:

• Year
• Month
• Date
• Weekday
• Hours
• Minutes
• Seconds

It also has an automatic leap year calculation, starting from the year 2000 to the year 2099.

Applications

RV-8263-C7-32.768KHZ-20PPM-TA-QC is typically used in providing real time solutions to applications in the following markets:

• Metering
• Portable devices
• Internet of Things (IoTs) devices
• Wearables
• Industrial
• Healthcare

RV-8263-C7-32.768KHZ-20PPM-TA-QC also meets the automotive qualifications, as per the AEC-Q200 rating. Therefore, it can also be used to provide real time clocking solutions to automotive devices.

3. AB0805-T3

Abracon LLC produces the AB0805-T3 Real Time Clock (RTC). It is a solution for electronic product manufacturers looking to provide real time clocking solutions to their devices.

Worthy of mentioning is that the AB0805-T3, like most of the semiconductor devices from the same manufacturer, is based on the SPOT technology. The Subthreshold Power Optimized Technology (SPOT) combines with the CMOS technology to deliver a significant reduction in the power consumption. Typically, you should expect the RTC to consume about 14 nA at most.

It Uses a Variety of Advanced Timekeeping Feature

If you are looking for a Real Time Clock (RTC) that keeps time using different metrics, it has got to be the AB0805-T3. This RTC’s timekeeping capabilities range from a watchdog timer using a hardware reset feature; an integrated power optimized RC oscillator and an automatic calibration of the RC oscillator to crystal oscillator.

The other advanced timekeeping functions are:

• 256 bytes of general-purpose Random Access Memory (RAM)
• Advanced RC calibration up to ± 16 ppm.

AB0805-T3 Supports Multiple Counters

From seconds to hours, the AB0805-T3 counts them all. The supported counters include:

• Hundredths
• Seconds
• Century
• Minutes
• Hours
• Weekdays
• Dates
• Years
• Months

Minimum Power Consumption

Like the other Real Time Clocks (RTCs) out there, the AB0805-T3 ensures that power consumption is minimal. In that case, it uses the on-chip oscillators to provide both the full RTC functions, minimize power consumption, while backing up the battery.

4. MAX31341BEWC+T

Maxim Integrated’s MAX31341BEWC+T Real Time Clock (RTC) provides both low-current and real-time clocking solutions with a I²C interface.

It is a clock and calendar type of Real Time Clock (RTC), designed to extend the battery life, while providing the nanoamperes timekeeping current.

Here are some of the remarkable attributes of the MAX31341BEWC+T Real Time Clock (RTC):

Flexible Configuration

Configuring or optimizing a Real Time Clock (RTC) is a major factor in its functionality. That is why the MAX31341BEWC+T leads with its flexible configuration, extending from the programmable square-wave output for the clock monitoring, the Schmitt trigger input to trigger interrupt and the one analog input with an adjustable threshold to trigger interrupt.

Maximum Real Time Clock (RTC) Protection

MAX31341BEWC+T provides the best protective features that a Real Time Clock (RTC) can have.

These features include a lockup-free operation with bus timeout, an operating voltage range of up to 3.6 volts and an automatic switchover. The switchover works as a battery backup terminal. It also serves as a supercapacitor, helping to keep the target device active (in terms of timing), especially it is out of power.

MAX31341BEWC+T Maximizes and Conserves Power

In addition to using the best power usage as possible, MAX31341BEWC+T also saves some in the process. The power-reduction metrics include a trickle charger, which aids in the boosting of the rechargeable battery of the external, supercapacitor.

Multiple Applications

MAX31341BEWC+T comes in handy when providing flexible real time clocking solutions to specific applications.

The supported applications or devices include portable audio device, Point-of-Sale (POS) systems, portable instruments and wearables. It also provides real time clocking to telematics.

Space Conservation

It is common to find Real Time Clocks (RTCs) made into an Integrated Circuit (IC) – and that is for one reason. The reason, most times, is to help save space on the circuit board, especially if more components are to be added.

MAX31341BEWC+T’s space-saving design includes a 3mm x 3mm, 10-pin TDFN; integrated load capacitors for the crystal oscillator and a 12-Bump WLP with a 0.5mm pitch.

5. RV-4162-C7-32.768KHZ-20PPM-TA-QC

Manufactured by Micro Crystal AG, RV-4162-C7-32.768KHZ-20PPM-TA-QC is a Real Time Clock (RTC) module with an I²C-bus interface. It also uses a combination of the Surface Mount Technology (SMT), XTAL and the CMOS circuit.

The major characteristics are:

• 400 kHz I²-C bus interface.
• Up to 85-degree Celsius operating temperature.
• RoHS-compliant
• As low as 350 nA @ 3 volts for the power consumption.
• Up to 1 Hertz (Hz) of clock output frequencies.
• It uses a ±20 ppm @ 25-degree Celsius timing accuracy.
• Supports both the watchdog and alarm functions.

6. ISL1208IB8Z-TK

Renesas Electronics America Inc. manufactures the ISL1208IB8Z-TK Real Time Clock (RTC). It is a type of RTC, designed to provide low-power clock timing solutions, track time as it clocks and indicates when power falls.

These are some of the additional features of the ISL1208IB8Z-TK Real Time Clock:

Variety of Package Options

ISL1208IB8Z-TK supports several packages or designs, including the low package variants. The examples of the package variants are:

• 8 Ld TDFN Package
• 8 Ld MSOP and SOIC Packages

Real Time Tracker

Depending on the optimization of the timer, the Real Time Clock (RTC) may not effectively track all the parameters.

The ISL1208IB8Z-TK RTC tracks most of the parameters, via a separate register, which tracks the following:

• Seconds
• Hours
• Minutes

It also has a dedicated calendar register that tracks the days of the week, the dates, months and years.

The calendar register uses an automatic leap year correction, and can be forwarded up to the year 2099.

Typical Applications

The major use cases or applications of the ISL1208IB8Z-TK Real Time Clock (RTC) include:

• Point-of-Sale (POS) equipment
• Utility meters
• Pagers
• HVAC equipment
• Computer products
• Modems
• Office automation equipment, including faxes and copiers.
• Television sets
• Video components
• Fixed Broadband Wireless Equipment

7. M41T0M6F

From the stables of STMicroelectronics is M41T0M6F, a Serial Real Time Clock (RTC) with 2-bus wiring architecture, built-in 32.768 kHz oscillator and an external crystal-controlled oscillator.

It also features the following:

• Binary Coded Decimal (BCD) clock and calendar register formats.
• Up to 85-degree Celsius of operating temperature.
• It provides counters covering century, minutes, seconds, dates, days, hours and years.
• It requires a special software programmable output.

Excellent Oscillator Performance

As you know, the (crystal) oscillator plays a major role in the clocking performance of a Real Time Clock (RTC). To ensure that the oscillator is functioning maximally, the M41T0M6F has been equipped with an oscillator stop detection feature. The feature helps to monitor the clock operations and detect or find out when the oscillator stops working.

The oscillator performance is also bolstered by the 32 kHz crystal oscillator integrating load capacitance of up to 12.5pF. This capacitance helps to provide an exceptional oscillator stability, while increasing the resistance operations of the crystal series.

Final Words

A Real Time Clock (RTC), such as the ones on this list, helps to regulate the clocking performance of any device it is attached to. You want to be sure that the RTC fits into the description of the target device, balances the operating temperature range perfectly and consistently monitors the crystal oscillator to be sure of its constant performance.

If you are looking to buy a Real Time Clock (RTC) anytime soon, some of the factors you want to pay attention to are the estimated (battery) backup time, the backup operating voltage and the low-power usage.