M41T81 / DS1338 → RV-8564
Cross-reference / replacement · STMicroelectronics · Maxim/ADI → Micro Crystal
- Interface:
- I²C (up to 400 kHz)
- Oscillator:
- Integrated 32.768 kHz
- Compatibility:
- PCF8563 register-compatible
- Timekeeping Current:
- ~250 nA @ 3V
Compatibility & sourcing notes
The M41T81 and DS1338 use a Dallas/ST register map at I²C address 0x68, whereas the RV-8564 (PCF8563-style map, address 0x51) has an entirely different address and register layout — so both the bus address and the timekeeping driver must change. A functional design-in replacement, not pin- or register-compatible. The RV-8564’s clock+SRAM feature set maps most naturally to these basic RTCs.
A functional alternative requiring design-in: pinout and driver may differ — re-validate with the corresponding development resources before production.
Frequently asked questions
Can RV-8564 replace the M41T81 / DS1338? ▾
The M41T81 and DS1338 use a Dallas/ST register map at I²C address 0x68, whereas the RV-8564 (PCF8563-style map, address 0x51) has an entirely different address and register layout — so both the bus address and the timekeeping driver must change. A functional design-in replacement, not pin- or register-compatible. The RV-8564’s clock+SRAM feature set maps most naturally to these basic RTCs.
What should I check when replacing the M41T81 / DS1338? ▾
A functional alternative requiring design-in: pinout and driver may differ — re-validate with the corresponding development resources before production.
Is the RV-8564 in stock, and can I get a quote? ▾
JLink Technology is an authorized distributor and supplies RV-8564 with stock, pricing, and lead time. Click "Request a Quote" with your quantity and we reply within one business day.