Real-time clock (RTC) ICs provide continuous timekeeping for a wide range of embedded systems, from industrial control equipment and smart meters to IoT devices. The DS1302ZN from Analog Devices (formerly Dallas Semiconductor/Maxim Integrated) has long been used in these applications due to its established architecture and reliable performance.
However, supply chain uncertainty and the need for greater sourcing flexibility are leading engineers and purchasing teams to evaluate compatible RTC solutions.
YXC D1302F is a trickle-charge timekeeping chip designed to be compatible with the DS1302ZN in pin configuration, register functions, and serial communication. This compatibility allows engineers to evaluate the D1302F for existing or new designs while minimizing PCB and firmware changes.
Pin, Register, and Interface Compatibility with DS1302ZNWhen evaluating an RTC IC, engineers typically need to confirm whether the device can fit the existing PCB, support the current firmware, and communicate with the system MCU. The D1302F is designed to simplify this evaluation through pin, register, and interface compatibility.
The D1302F uses an SOP-8 package with the same pin arrangement as the DS1302ZN. This pin compatibility allows it to fit into an existing PCB design without changing the board layout, subject to final application verification.
The D1302F provides compatible clock/calendar registers, control registers, and RAM address mapping based on the DS1302 architecture. Existing firmware may therefore be reused with minimal software changes, depending on the application and implementation details.
Compatible 3-Wire Serial InterfaceThe D1302F communicates through a 3-wire serial interface using RST, I/O, and SCLK signals. Its interface compatibility supports connection with commonly used MCUs such as STM32, GD32, and ESP32, making it suitable for a broad range of embedded designs.
In addition to its compatibility features, the D1302F provides the timekeeping and power-management functions required in embedded applications.
The D1302F tracks seconds, minutes, hours, day, date, month, and year, with leap-year compensation up to 2100. Calendar adjustment is handled automatically, including months with different numbers of days.
Both 12-hour and 24-hour time formats are supported, including AM/PM indication in 12-hour mode.
The device integrates 31 × 8 bytes of static RAM that can be used by the system to store device parameters and other small amounts of data.
The D1302F supports dual power supplies, with automatic switching between the primary supply (VCC2) and backup supply (VCC1). This enables continuous timekeeping when the main system power is unavailable.
Its trickle-charge function can also be used with supported rechargeable backup batteries or supercapacitors, depending on the system design.
Burst mode enables sequential access to clock/calendar registers or RAM, reducing the number of individual communication operations required when transferring multiple bytes.
Power consumption is especially important in portable devices, smart meters, IoT terminals, and other systems that rely on backup batteries for long-term timekeeping.
The D1302F maintains a current consumption of less than 300 nA at 2.0 V, while standby current with the oscillator stopped can be as low as 100 nA.
With an operating voltage range of 2.0 V to 5.5 V, the device can be integrated into both 3.3 V and 5 V embedded systems. Its low current consumption helps extend backup operation when a small battery is used to maintain RTC functionality.
Embedded equipment is often required to operate under changing environmental conditions.
The D1302F supports an industrial operating temperature range of -40°C to +85°C, making it suitable for outdoor equipment, industrial control systems, smart meters, and other applications where temperature conditions may be more demanding than in standard consumer electronics.
The D1302F can be used in embedded systems that require continuous clock and calendar functions, including:
Selecting an RTC IC for an existing or new design involves more than comparing basic timekeeping functions. Engineers also need to consider pin compatibility, register compatibility, serial interface compatibility, power consumption, operating conditions, and long-term sourcing.
The D1302F is designed to address these requirements with:
For new embedded designs or existing systems requiring a DS1302ZN-compatible RTC solution, the D1302F provides a practical option while helping reduce PCB and firmware modification requirements.
For D1302F specifications, compatibility information, samples, or technical support, contact YXC to discuss your application requirements.
YXC provides frequency control and timing solutions for industrial, communications, automotive, medical, and consumer applications.
