Component comparison · Last verified 2026-07-27
DS3231S# and DS3232S# are accurate I2C RTCs with integrated crystal and temperature compensation. DS3231S# uses a 16-pin wide SO package and does not provide general-purpose user SRAM. DS3232S# uses a 20-pin wide SO package and adds 236 bytes of battery-backed SRAM. Choose by memory, footprint and pin requirements rather than treating them as direct substitutes.
DS3231S# vs DS3232S# specifications
| Specification | DS3231S# | DS3232S# |
|---|---|---|
| Serial interface | I2C up to 400 kHz | I2C up to 400 kHz |
| Timekeeping accuracy | ±2 ppm from 0°C to +40°C | ±2 ppm from 0°C to +40°C |
| Timebase | Integrated crystal and TCXO | Integrated crystal and TCXO |
| Battery-backed user SRAM | None | 236 bytes |
| Package / case | 16-pin wide SOIC, 300 mil | 20-pin wide SOIC, 300 mil |
| Pin count | 16 | 20 |
| Operating temperature grade | Commercial, 0°C to +70°C | Commercial, 0°C to +70°C |
| Time-of-day alarms | Two | Two |
| Programmable square-wave output | Supported | Supported |
| Battery backup | Supported | Supported |
Key differences
DS3232S# adds battery-backed user SRAM
DS3232S# includes 236 bytes of battery-backed SRAM for application data that must survive a main-power interruption. DS3231S# maintains time and RTC state but does not expose comparable general-purpose user SRAM.
The package and pin count are different
DS3231S# uses a 16-pin, 300-mil SO package, while DS3232S# uses a 20-pin, 300-mil SO package. The larger package and additional pins prevent a footprint-level substitution.
Their core timing functions are closely aligned
Both use a 400 kHz I2C interface, integrated temperature-compensated crystal timing, two alarms, square-wave output and battery-backed timekeeping. The decision is therefore driven mainly by SRAM and hardware layout requirements.
Can these parts be interchanged?
DS3231S# and DS3232S# are not drop-in replacements because the package, pin count and available user memory differ. Their I2C timing functions, alarm capability and temperature-compensated crystal architecture are closely related, but a migration still requires a new footprint and pinout review. Verify supply and backup limits, address and register behavior, reset and clock outputs, SRAM use, firmware, package drawing and the complete commercial or industrial orderable suffix.
- Electrical ratings and operating conditions
- Package dimensions, footprint and pinout
- Interface, timing and firmware behavior
- Temperature and qualification grade
- Lifecycle status and current documentation revision
DS3231S# vs DS3232S# FAQ
What is the main difference between DS3231S# and DS3232S#?
DS3232S# adds 236 bytes of battery-backed user SRAM and uses a 20-pin wide SO package. DS3231S# has no comparable user SRAM and uses a 16-pin wide SO package.
Do DS3231S# and DS3232S# have the same RTC accuracy?
Both families specify ±2 ppm from 0°C to +40°C and integrate the crystal with temperature compensation. Confirm the required limit across the complete application temperature range.
Can DS3232S# replace DS3231S# without changing the PCB?
No. DS3232S# has 20 pins and DS3231S# has 16 pins, so their footprints and pin assignments differ even though both packages are 300-mil-wide SO styles.
When is DS3232S# preferable to DS3231S#?
DS3232S# is preferable when the design needs battery-backed application SRAM in addition to accurate RTC functions. DS3231S# is the smaller choice when that SRAM is unnecessary.
Do both devices support alarms and battery-backed timekeeping?
Yes. Both provide two time-of-day alarms, programmable square-wave output and battery-backed timekeeping. The SRAM, package and pin differences still require separate hardware and firmware verification.
Sources and verification
- Analog Devices DS3231 product page
- Analog Devices DS3231 datasheet
- Analog Devices DS3232 product page
- Analog Devices DS3232 datasheet
This comparison supports preliminary selection and sourcing review. Similar specifications do not establish drop-in compatibility. Confirm the complete orderable code and current manufacturer documentation before design release or purchase.
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