DS1302Z Trickle-Charge Timekeeping IC SOP-8

DS1302Z Trickle-Charge Timekeeping IC SOP-8 is a powerful Real-Time Clock (RTC) chip designed to maintain precise track of time—seconds, minutes, hours, day of the month, month, day of the week, and year—with automatic compensation for leap years. What truly sets the DS1302Z apart is its built-in trickle-charge circuit, which allows it to charge an external lithium-ion battery or supercapacitor, ensuring the clock continues running for years even when the main power is disconnected. This feature eliminates the need for manual battery replacement in many applications, significantly improving device longevity and reliability. Its simple 3-wire serial interface easily connects with any microcontroller, making it a favorite for engineers building data loggers, industrial controls, and battery-backed consumer devices that require accurate, long-term timekeeping.

Key Features:

• Full Real-Time Clock: Tracks all time data, from seconds through to the year, and handles leap-year correction up to 2100.
• Trickle-Charge Circuit: The integrated charging circuit allows the use of rechargeable backup batteries or supercapacitors, providing indefinite power backup.
• Simple 3-Wire Interface: Communicates with a microcontroller using just three signals: RST (Reset), I/O (Data Line), and SCLK (Serial Clock).
• Ultra Low Power Consumption: Consumes minimal power in backup mode, ensuring the battery lasts for a prolonged period.
• RAM Storage: Includes 31 bytes of static RAM for storing temporary or configuration data that needs to be retained during power loss.
• Dual Power Supplies: Operates using both a main power supply (VCC1) and a dedicated backup supply (VCC2).

Technical Specifications:

• Operating Voltage (Main): 2.0 V to 5.5 V
• Backup Voltage: 1.5 V to 5.5 V
• Timekeeping Accuracy: $\pm$ 20 ppm at $25^{\circ}\text{C}$ (using a standard 32.768 kHz crystal)
• Interface: 3-Wire Serial (SPI compatible)
• RAM Capacity: 31 Bytes Static RAM
• Time Base: External 32.768 kHz Crystal
• Package: SOP-8 (Surface Mount)

Mechanical Specifications:

• Mounting: Surface Mount Device (SMD).
• Material: Molded plastic package.
• Pin Plating: Tin-Lead or Lead-Free plating.

Dimensions (SOP-8):

• Body Length: ~4.9 mm
• Body Width: ~3.9 mm
• Pitch (Pin Spacing): 1.27 mm (0.05 in)

Pinout and Wiring:

• VCC1: Main Power Supply (2.0V to 5.5V).
• VCC2: Backup Power Supply (Battery/Capacitor).
• GND: Ground connection.
• CLK (SCLK): Serial Clock Input. Connect to the microcontroller’s SCK pin.
• DAT (I/O): Data Input/Output. Connect to a digital I/O pin on the microcontroller.
• RST (CE): Reset/Chip Enable. Connect to a digital I/O pin on the microcontroller.
• 32.768 kHz X1/X2: Connect these pins across an external 32.768 kHz crystal and required loading capacitors.
• Wiring Note: Connect the three data pins (CLK, DAT, RST) to dedicated digital I/O pins. Connect VCC2 to your rechargeable backup source, and connect VCC1 to your system’s main power.

Datasheet Reference:

• Download Datasheet

Commonly Used in:

• Energy Monitoring: Logging usage data with precise timestamps.
• Industrial Control Panels: Providing reliable timing for automation schedules and event logging.
• Consumer Electronics: Powering battery-backed clocks and scheduling features in appliances.

Applications:

• Data Loggers: Stamping collected sensor data with exact time and date for analysis.
• Digital Clocks and Timers: Building stand-alone clocks, countdown timers, and alarms.
• Battery-Backed Memory: Utilizing the 31 bytes of RAM to store critical system settings that must persist through power cycles.

Equivalent Models:

• DS1307: A popular I²C (2-wire) RTC module, often used in Arduino projects, which requires a non-rechargeable battery.
• PCF8563: A low-power CMOS RTC that uses an I²C bus and is known for its high accuracy.

Package Includes:

• 1 x DS1302Z Trickle-Charge Timekeeping IC SOP-8