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Four small green circuit boards with gold pins and black chips

WaveShare

WaveShare RTC Clock Module High Precision 4 Pcs

SKU CH-M9DR-ZAK4B

High-precision RTC module with leap-year compensation to 2100, ±0.432 s/day accuracy, 1 Hz and 32.768 kHz outputs, 3.3 V/5 V compatible, operating from -40 °C to +85 °C, four pieces

  • CPU TypeOther
  • Complete calendar with leap-year support until 2100
  • ±5 ppm timing accuracy equals ±0.432 seconds per day
  • Low power draw with 1 Hz and 32.768 kHz outputs
  • Works on 3.3 V and 5 V logic levels
  • Industrial temperature range from -40 °C to +85 °C

What this product is and who it is for

The WaveShare RTC Clock Module provides a complete clock calendar with seconds, minutes, hours, day, date, month and year timing valid until 2100 including leap year compensation. It delivers timing accuracy kept at ±5ppm (±0.432 sec per day) via a ±3 digital temperature sensor. The module suits Raspberry Pi projects and other embedded systems that require persistent, precise timekeeping without a network connection.

Thermals, noise and power draw in normal use

The module operates with low power consumption and offers both 1 Hz and 32.768 kHz output frequencies. It is adapted for 3.3 V and 5 V systems and functions across a -40 °C to +85 °C temperature range. As a passive semiconductor component it produces no audible noise and adds negligible thermal load to the host board.

What this replaces or upgrades

This module replaces reliance on software-based system clocks or network time protocols that fail when the device is offline or powered down. The upgrade is worth it for data-logging, scheduling or timestamping tasks that need accurate time immediately at boot. It does not suit designs that require an integrated backup battery or a different communication bus than the one this module exposes.

Highlights

  • Complete calendar with leap-year support until 2100
  • ±5 ppm timing accuracy equals ±0.432 seconds per day
  • Low power draw with 1 Hz and 32.768 kHz outputs
  • Works on 3.3 V and 5 V logic levels
  • Industrial temperature range from -40 °C to +85 °C

Specifications

CPU TypeOther

Questions about this item

How do I wire the module to a Raspberry Pi GPIO header for 3.3 V operation?

Connect VCC to 3.3 V, GND to ground, and SDA/SCL to the I²C pins; the module works directly at 3.3 V without level shifting.

When must the onboard backup cell be replaced?

The coin cell keeps time during power loss; replace it when the clock drifts or loses the date after mains-off periods.

What timing drift appears first during continuous operation at 85 °C?

Accuracy is held to ±5 ppm (±0.432 sec/day) across the full -40 °C to +85 °C range, so daily drift remains the limiting factor.

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