M95256-W M95256-R M95256-DF Datasheet 256-Kbit serial SPI bus EEPROM with high-speed clock Features Compatible with the serial peripheral interface (SPI) bus SO8N Memory array 256-Kbit (32 Kbytes) of EEPROM (150 mil width) Page size: 64 bytes Additional write lockable page (Identification page) Write time Byte Write within 5 ms Page Write within 5 ms TSSOP8 Write protect (169 mil width) quarter array half array whole memory array High-speed clock: 20 MHz Single supply voltage: UFDFPN8 (DFN8) 2.5 V to 5.5 V for M95256-W (2 x 3 mm) 1.8 V to 5.5 V for M95256-R 1.7 V to 5.5 V for M95256-DF Operating temperature range: from -40 C up to +85 C WLSCP8 Enhanced ESD protection (1.289 x 1.376 mm) More than 4 million Write cycles Product status link More than 200-year data retention Packages M95256-DF SO8N (ECOPACK2) M95256-R TSSOP8 (ECOPACK2) M95256-W UFDFPN8 (ECOPACK2) WLCSP8 (ECOPACK2) DS4712 - Rev 22 - September 2021 www.st.com For further information contact your local STMicroelectronics sales office.M95256-W M95256-R M95256-DF Description 1 Description The M95256 devices are electrically erasable programmable memories (EEPROMs) organized as 32768 x 8 bits, accessed through the SPI bus. The M95256-W can operate with a supply voltage from 2.5 V to 5.5 V, the M95256-R can operate with a supply voltage from 1.8 V to 5.5 V and the M95256-DF can operate with a supply voltage from 1.7 V to 5.5 V, over an ambient temperature range of -40 C / +85 C. The M95256-DF, -DR or -DW (hereinafter referred to as M95256-Dx) offer an additional page, named the Identification page (64 bytes). The Identification page can be used to store sensitive application parameters that can be (later) permanently locked in read-only mode. Figure 1. Logic diagram V CC D C S M95xxx Q W HOLD VSS The SPI bus signals are C, D and Q, as shown in Figure 1 and Table 1. The device is selected when Chip select (S) is driven low. Communications with the device can be interrupted when the HOLD is driven low. Table 1. Signal names Signal name Function Direction C Serial clock Input D Serial data input Input Q Serial data output Output S Chip select Input W Write protect Input HOLD Hold Input V Supply voltage - CC V Ground - SS DS4712 - Rev 22 page 2/51