SPI RTC with 96B NVSRAM and trickle-charger
The DS1305+ is a full-featured SPI real-time clock that tracks time in HH:MM:SS (12/24 hr) and date in YY-MM-DD-dd format, with an integrated 96-byte NVSRAM for storing calibration or configuration data without an external EEPROM. It runs from a single 2V to 5.5V supply and draws 25.3µA to 81µA in timekeeping (depending on supply voltage) — low enough for battery-backed designs where the main rail drops out and the RTC must keep running on a coin cell.
Package and integration fit
Housed in a 16-pin DIP (0.300" body width, 7.62mm pitch) with through-hole mounting — the DS1305+ is a direct drop-in for breadboard prototyping or legacy through-hole PCB layouts that need a SPI RTC without migrating to a surface-mount package. The 16-PDIP footprint is standard, so the DS1305+ mates with a 16-pin DIP socket or solders into plated through-holes on a 0.100" pitch grid.
Built-in features that reduce external BOM
The battery-backup supply input (Vbatin) accepts 2V to 5.5V, matching the main supply range, so the same coin-cell chemistry works for both the RTC core and the NVSRAM retention.