DS1302 RTC Clock DIP

The DS1302 is a real-time clock (RTC) IC with a serial interface, widely used for keeping accurate time and date information in embedded systems. This RTC module includes features like a trickle-charge capability to recharge a connected backup battery, allowing it to maintain timekeeping even when main power is lost. The DS1302 can keep track of seconds, minutes, hours, day, date, month, and year, with automatic leap-year compensation for years divisible by 4.

Key Specifications for DS1302

General Specifications

1. Type: Real-time clock (RTC) with calendar function
2. Interface: Serial (SPI-like interface, with three-wire communication: RST, SCLK, I/O)
3. Package: Commonly available in DIP-8 and SOIC-8 packages for easy integration
4. Battery Backup: Built-in trickle charger for battery backup to maintain the clock during power outages

Timekeeping Functions

1. Timekeeping: Tracks seconds, minutes, hours, day of the week, date, month, and year
2. Clock Format: 12-hour (AM/PM) or 24-hour format
3. Leap Year Compensation: Automatically adjusts for leap years up to 2100

Electrical Characteristics

1. Operating Voltage (V_CC): 2.0 V to 5.5 V
2. Backup Battery Voltage (V_BAT): Typically 2.0 V to 3.5 V
3. Current Consumption:
4. Timekeeping Mode: ~300 nA (at 2.0 V with battery backup)
5. Active Mode: ~1.2 mA (at 5 V)

Trickle-Charge Feature

1. Battery Backup Charging: Configurable trickle-charge circuit that can recharge a backup battery or supercapacitor
2. Selectable Diodes and Resistors: Allows customization of charge current based on battery type or capacitor

Communication Interface

1. 3-Wire Serial Interface: Uses RST (reset), SCLK (serial clock), and I/O (data input/output) pins for communication
2. Clock Speed: Supports clock frequencies up to 2 MHz for serial communication
3. Bidirectional Data Line: Uses a single I/O line for both input and output

Pin Configuration (DIP-8/SOIC-8)

1. V_CC: Primary power supply (2.0–5.5 V)
2. GND: Ground
3. SCLK: Serial clock input
4. I/O: Data input/output (for reading and writing to registers)
5. RST: Active-high reset or chip select for serial communication
6. V_BAT: Battery backup input (optional, for trickle charge)
7. NC: No connection
8. NC: No connection

Key Features

1. Battery Backup: Maintains timekeeping when main power is disconnected, ideal for systems with intermittent power
2. Low Power Consumption: Efficient timekeeping mode extends battery life in backup mode
3. Simple Interface: Easy to integrate using only three communication pins, saving I/O resources in embedded designs
4. Reliable Timekeeping: Automatically adjusts for months with fewer than 31 days and for leap years

Applications

1. Embedded Systems and Microcontrollers: Keeps track of time in microcontroller-based applications
2. Data Logging: Adds timestamp data to sensor measurements and other logged data
3. Clocks and Timers: Used in electronic clocks, alarm systems, and interval timing applications
4. Power-Sensitive Devices: Ideal for devices that need accurate timekeeping with minimal power consumption

The DS1302 is a versatile and low-power RTC solution, well-suited for designs requiring accurate time tracking with backup capabilities and minimal component requirements.