STMicroelectronics M48Z35AV-10MH1E

Overview

M48Z35AV-10MH1E from STMicroelectronics is a 256 Kbit (32 K × 8) battery-backed zero-power SRAM with integrated power-fail detection, write protection, and BOK (Battery OK) flag monitoring. It operates at 3.0–3.6 V, provides 100 ns read/write cycle time, and retains data for ≥10 years on internal lithium cell during VCC loss-used in industrial real-time clocks, metering registers, and configuration memory where data persistence across power cycles is critical.

For engineers reviewing the M48Z35AV-10MH1E datasheet, M48Z35AV-10MH1E pinout, M48Z35AV-10MH1E application, or M48Z35AV-10MH1E equivalent, key selection criteria include VPFD window (2.7–3.0 V), battery switchover voltage (VPFD − 100 mV), BOK flag behavior, SOIC-28 + SNAPHAT® mechanical integration, and JEDEC 32K×8 pin compatibility.

Technical Context

The M48Z35AV-10MH1E integrates a 32 K × 8 SRAM array, voltage-sense circuitry, battery switch, and BOK flag logic on a single die. Its power-fail detection triggers automatic write protection when VCC falls within the 2.7–3.0 V VPFD window, then switches to internal lithium cell at VSO = VPFD − 100 mV.

It supports standard TTL/CMOS-compatible control timing (E, G, W), delivers 100 ns access in both read and write modes, and maintains high-impedance I/O during battery backup. The SOH28 package enables post-reflow SNAPHAT® top-mounting to avoid thermal damage to the lithium cell.

Key Specifications

Pinout & Package

SOH28 (28-pin SOIC) package with gold-plated contacts at both ends for direct mating with SNAPHAT® battery housing (M4Z28-BR00SH1). Designed for post-reflow top-mounting to prevent lithium cell thermal damage.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar battery-backed SRAM applications.

Compared with DS1248-100+, the M48Z35AV-10MH1E enables 3.3 V compatibility and SOIC-based surface-mount assembly; versus M48Z35AY-100MH1E, it shifts VPFD downward to match 3.3 V rail collapse profiles-critical for accurate fail-safe write locking in modern low-voltage systems.

Availability

M48Z35AV-10MH1E is available at Aetrix Electronics and suitable for industrial energy metering, real-time clock backup, and medical device configuration requiring stable component supply, long-term lifecycle support, and traceable battery-backed memory sourcing.

Supply support for M48Z35AV-10MH1E includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader specializing in microcontrollers, power management, and analog/mixed-signal ICs for industrial, automotive, and consumer applications.

The M48Z35AV-10MH1E belongs to ST's ZEROPOWER® SRAM product line, engineered specifically for fail-safe, battery-backed data retention in mission-critical infrastructure where power integrity cannot be assumed.

FAQ

What is the purpose of the BOK (Battery OK) flag?

The BOK flag is a hardware status bit set on power-up if the internal lithium cell voltage falls below ~2.5 V. When asserted, it blocks the first attempted write to prevent data corruption from insufficient backup power. The flag clears automatically after that write completes, restoring normal operation-enabling firmware to detect and log low-battery conditions before data integrity is compromised.

Can M48Z35AV-10MH1E operate without the SNAPHAT® battery housing?

No-the SOH28 package requires the SNAPHAT® top (e.g., M4Z28-BR00SH1) to provide the lithium cell and mechanical interlock. The SOIC contains only the silicon die and control circuitry; battery functionality is physically external. Operation without SNAPHAT® results in no data retention during VCC loss and disables BOK flag functionality.

How does the VPFD window affect system-level brownout response?

The 2.7–3.0 V VPFD window defines the precise voltage band where the device initiates automatic write protection and high-impedance I/O. This ensures data integrity during slow VCC decay (e.g., capacitor discharge), but requires system designers to ensure VCC fall time exceeds 300 µs (tF) to guarantee timely deselection-otherwise, transient noise may cause false triggering or delayed lockout.

Is M48Z35AV-10MH1E pin-compatible with standard 32K×8 SRAMs like the 62256?

Yes-it is JEDEC-standard pin- and function-compatible with 32 K × 8 SRAMs including the 62256, supporting identical address (A0–A14), data (DQ0–DQ7), and control (E, G, W, VCC, VSS) pinouts. No PCB changes are needed for drop-in replacement, though firmware must account for BOK flag checking and VPFD-triggered write protection behavior.