DS1302N+

DS1302N+ is a Real-Time Clock (RTC) chip derived from Maxim’s DS1302. It keeps calendar time and provides a small amount of battery-backed RAM for data logging. It uses a simple 3-wire serial interface (CE, IO, SCLK), not I2C, and requires an external 32.768 kHz crystal for the timebase.
Key features:
- Timekeeping: seconds, minutes, hours, day, date, month, year, day-of-week; leap-year aware
- 31 bytes of NV RAM for user data
- Programmable square-wave output (1 Hz to 32 kHz)
- Trickling charger to charge a backup battery or supercapacitor
- Power: 2.0–5.5 V main supply with VBAT backup
- Suitable for battery-backed operation when main power is off
Typical use:
- Time stamping, alarms, data logging in microcontroller projects where power can fail
Pros/cons:
- Pros: cheap, simple interface, no I2C bridge needed
- Cons: less accurate than high-end RTCs (e.g., DS3231); requires external crystal and battery backup
Note: DS1302N+ names appear on many modules; functionally similar to DS1302.

Direct drop-in equivalents for DS1302N+ do not exist because of its unique 3‑wire interface and trickle-charge feature. Closest are other parts in the DS1302 family (DS1302/DS1302N). For alternatives, consider I2C RTCs such as DS3231, DS1307, MCP7940N, or RV-3029-C3, but you’ll need software/board changes to accommodate the different protocol.

Here are the DS1302N+ features (concise):
- Real-time clock/calendar: seconds, minutes, hours (12/24h), day, date, month, year with leap-year handling.
- 32.768 kHz crystal oscillator input for accurate timekeeping (external crystal required).
- Battery-backed operation with VBAT and on-chip trickle-charge circuit for backup battery.
- 31 bytes of battery-backed RAM for user data storage.
- Three-wire serial interface: CE, I/O, SCLK (no I2C/SPI protocol; simple MCU interfacing).
- Programmable SQW/OUT pin for a square-wave/interrupt signal at selectable frequencies.
- Wide supply range: 2.0 V to 5.5 V; suitable for low-power/industrial environments.
- Small 8-pin package (DIP8/SOIC8).
- Optional use with a backup battery when main power is off; timekeeping continues.
Note: DS1302N+ is typically used with an external crystal and battery backup for continuous timekeeping.

Pin count: 8 pins (DIP8/SOIC8).
Functions:
- Real‑time clock with 32 kHz crystal input (X1, X2) for timekeeping.
- 3‑wire serial interface: CE (chip enable), IO (bidirectional data), SCLK (clock) to read/write time registers and RAM.
- Time registers: seconds, minutes, hours, day, date, month, year (including leap year handling).
- Battery backup: VBAT pin to maintain timekeeping when VCC is off.
- Main power: VCC and GND.
- On‑chip battery‑backed RAM: typically 31 bytes of SRAM accessible via the same interface.

The DS1302N+ is manufactured by Dallas Semiconductor (the DS1302 line). Dallas Semiconductor is a semiconductor company that designs and manufactures integrated circuits; the DS1302 became part of Maxim Integrated after the acquisition of Dallas, and Maxim is now under Analog Devices.

DS1302N+ is used wherever a low-power, battery-backed real-time clock with time-stamping is needed. Common applications:
- Real-time clock with battery backup for embedded systems
- Data logging and event time-stamping
- Digital clocks, alarm clocks, and timers
- IoT/Home automation: scheduling and time synchronization
- Metering, security, and access-control timekeeping
- Medical device time base
- Automotive dashboards and trip logging
- Industrial automation and remote monitoring
- Portable/wearable devices requiring accurate timekeeping

DS1302N+ is an 8-pin device, available in DIP-8 and SOIC-8 (DIP or SOP) package variants.