DS1307N

DS1307N is a small, low‑power real‑time clock (RTC) IC with I2C interface. It keeps track of time (seconds to year) using a 32.768 kHz crystal and can run on main power or backup power when VCC is off.
Key features
- I2C interface (SDA, SCL); default 7‑bit address 0x68
- Clock/calendar registers (BCD) plus leap‑year handling
- 56 bytes of battery‑backed RAM for data logging
- 1 Hz square‑wave output (SQW/OUT) for timing signals
- Battery backup with VBAT pin; supports a trickle-charge circuit to back up the RTC from VCC
- External 32.768 kHz crystal (X1, X2) required
- VCC typically 4.5–5.5 V; VBAT usually around 3 V for a coin cell or supercap
Applications
- Timekeeping in microcontrollers, data loggers, digital clocks, event timestamps
Pros/cons
- Pros: cheap, simple, widely supported
- Cons: less accurate/temperature‑drifted compared to DS3231; requires an external crystal and careful power design

Common equivalents (I2C RTCs) to the DS1307N include:
- DS3231 (Maxim) – high-accuracy I2C RTC with VBAT
- MCP7940N (Microchip) – 8-pin I2C RTC with 56-byte RAM and backup battery
- PCF8563 (NXP) – I2C RTC with RAM and extended features
- ISL1208/ISL1200 (Renesas/Intersil) – I2C RTCs with RAM and alarms
Note: pinouts, voltage, and accuracy differ; check datasheets for a true drop-in replacement.

DS1307N is an I2C real-time clock with battery-backed RAM. Key features:
- I2C serial interface (7-bit address 0x68; 8-bit write/read: 0xD0/0xD1)
- Timekeeping registers: seconds, minutes, hours, day, date, month, year (BCD)
- 32.768 kHz crystal/ oscillator input for accurate timebase
- 56 bytes of battery-backed RAM for user data
- Automatic power-fail switchover to VBAT so time and RAM are preserved
- Trickle-charge circuit to charge a backup battery or supercap (requires external diode/resistor network)
- Programmable SQW/OUT output with selectable frequencies: 1 Hz, 4.096 kHz, 8.192 kHz, 32.768 kHz, or disabled
- Low power operation in battery mode
- Available in 8-pin package (DS1307N)

- Pin count: 8 pins (DIP-8/SO-8).
- Function: Real-Time Clock/calendar with I2C interface. Uses a 32.768 kHz crystal (pins X1/X2) for timekeeping, provides battery backup via VBAT, includes 56 bytes of NV RAM, and a programmable SQW/OUT square‑wave output. Main power at VCC with GND reference; I2C lines are SDA and SCL. I2C address is fixed (0x68 7‑bit).

- Manufacturer: Maxim Integrated (originally Dallas Semiconductor).
- Company type: A semiconductor company that designs and manufactures integrated circuits (ICs); it became part of Analog Devices in 2021.

DS1307N is a low-power I2C real-time clock with a 32.768 kHz crystal, battery-backed RAM (56 bytes), alarms, timer, and a 1 Hz square-wave output. It keeps calendar/time when main power is off via a trickle-charge circuit.
Applications:
- Embedded systems needing accurate timekeeping
- Data loggers and sensor networks with timestamps
- Digital clocks, alarm clocks, timers
- Portable/consumer electronics and wearables, IoT devices
- Industrial/automotive time‑stamping and scheduling
- POS, access control, inventory systems
- Remote monitoring and smart metering

DS1307N comes in an 8-pin DIP (DIP-8) through-hole package (plastic DIP).