64 Kbit SPI EEPROM rated for 150°C — the extended-temperature variant
The Microchip 25LC640A-H/SN is a 64 Kbit serial EEPROM organized as 8K x 8 bits, accessed via an SPI bus at clock frequencies up to 5 MHz. This makes the -H/SN variant the appropriate choice when the memory must survive or operate in high-temperature environments such as engine compartments, downhole instrumentation, or sealed enclosures near heat sources.
Supply voltage and bus compatibility
A firmware engineer bringing up the SPI bus should confirm the master's clock polarity and phase (SPI mode 0,0 or 1,1 per the standard 25LC640 datasheet) and that the 5 MHz clock rate does not exceed the master's timing budget. The write cycle time is 6 ms per word or page, which sets the upper bound on sustained write throughput in a data-logging or configuration-storage application.
Package and footprint for board integration
The PCB layout engineer can use the same footprint and decoupling capacitor placement (a 0.1 µF ceramic near the supply pin is typical). The shipping form is Tube, which is relevant for automated pick-and-place feeder setup but does not affect the electrical design.
Lifecycle and sourcing posture
It is ROHS3 compliant.