DP8570AVX vs DP8570AVX/NOPB

Part Number	DP8570AVX	DP8570AVX/NOPB
Category	Clock/Timing - Real Time Clocks	Clock/Timing - Real Time Clocks
Manufacturer	Texas Instruments	National Semiconductor
Description	IC RTC TCP PAR 28-PLCC	DP8570A TIMER CONTROL PERIPHERAL
Package	Tape & Reel (TR)	Bulk
Series	-	-
Type	Timer Clock Peripheral (TCP)	Timer Clock Peripheral (TCP)
Features	Alarm, Leap Year	Alarm, Leap Year
Time Format	HH:MM:SS:hh (12/24 hr)	HH:MM:SS:hh (12/24 hr)
Date Format	YY-MM-DD-dd	YY-MM-DD-dd
Interface	Parallel	Parallel
Voltage - Supply	4.5V ~ 5.5V	4.5V ~ 5.5V
Current - Timekeeping (Max)	1µA @ 5V	1µA @ 5V
Operating Temperature	-40°C ~ 85°C	-40°C ~ 85°C
Mounting Type	Surface Mount	Surface Mount
Package / Case	28-LCC (J-Lead)	28-LCC (J-Lead)
Supplier Device Package	28-PLCC (11.51x11.51)	28-PLCC (11.51x11.51)
Memory Size	44B	44B
Voltage - Supply, Battery	2.2V ~ 5.1V	2.2V ~ 5.1V

1. How does a real-time clock work?

RTC is usually driven by a low-power oscillator (such as a quartz crystal oscillator) and powered by an independent power source (such as a battery), which can continuously time even when the main power supply is off.
2. How accurate is the real-time clock?

The accuracy of RTC usually depends on the clock source used (such as a crystal oscillator), and most RTC accuracies range from a few seconds to a few minutes per month. For higher precision, a temperature compensated crystal oscillator (TCXO) can be used.
3. How often do RTC batteries need to be replaced?

The battery life of RTC can usually last for several years, depending on the type of battery used, the power consumption of RTC, and the ambient temperature. Generally speaking, button batteries can last for 5-10 years under normal conditions.
4. Can real-time clocks be used to set timers or alarms?

Yes, many RTC chips have built-in alarm functions that can trigger interrupts at set times to perform specific tasks or wake up the system.