
NXP Semiconductors
S9KEAZ128AMLH is an MCU alternate only with PCB and firmware redesign.
ATMEGA2560-16AU is a 100-TQFP AVR MCU. No reviewed candidate is pin-compatible from the supplied evidence.
Voltage and peripherals need checks.
Kept MCUs are not 100-TQFP.
ARM candidates are not AVR.
Lifecycle data is mixed.
No direct pin-compatible replacement is supported by the provided candidate data.
Use an ATmega2560 family pinout match if required; supplied ARM MCUs need redesign.
Pinout, package and firmware incompatibility.

NXP Semiconductors
S9KEAZ128AMLH is an MCU alternate only with PCB and firmware redesign.
| Feature / factor | ATMEGA2560-16AU | S9KEAZ128AMLH | S9KEAZ128AMLK | Alt 3 | Compatibility / risk |
|---|---|---|---|---|---|
| Package | 100-TQFP | LQFP-64 | LQFP-80 | LQFP-64 / LQFP-80 — PCB change likely; S9KEAZ128AMLK: PCB change likely | |
| Pinout | 100 pins | 64 pins | 80 pins | 64 pins / 80 pins — not pin compatible; S9KEAZ128AMLK: not pin compatible | |
| Application | 8-bit AVR MCU | 32-bit Cortex-M0+ MCU | 32-bit Cortex-M0+ MCU | 32-bit Cortex-M0+ MCU — firmware port needed; S9KEAZ128AMLK: firmware port needed | |
| Voltage | 4.5 V listed | 2.7 V to 5.5 V | missing | 2.7 V to 5.5 V / missing — range includes 4.5 V; S9KEAZ128AMLK: not in key attrs | |
| Temperature | missing | AEC-Q100 | +125°C max | AEC-Q100 / +125°C max — target temp absent; S9KEAZ128AMLK: target temp absent |
From the supplied list, only S9KEAZ128 parts are MCU alternatives, but both need redesign.