STMicroelectronics M48Z35Y-70MH6E

Overview

M48Z35Y-70MH6E from STMicroelectronics is a 256 Kbit (32 K × 8) non-volatile zero-power SRAM with integrated lithium battery, power-fail detection circuitry, and automatic write protection. It operates across 4.5–5.5 V, features 70 ns read/write cycle time, VPFD window of 4.2–4.5 V, and delivers ≥11 years data retention in battery backup mode. It serves as drop-in replacement for JEDEC-standard 32K×8 SRAMs in real-time clock and configuration memory applications.

For engineers reviewing the M48Z35Y-70MH6E datasheet, M48Z35Y-70MH6E pinout, M48Z35Y-70MH6E application, or M48Z35Y-70MH6E equivalent, key selection criteria include battery-backed data retention duration, VPFD voltage threshold compatibility, SOIC package + SNAPHAT® top integration, and power-fail write-protection timing behavior under VCC droop conditions.

Technical Context

The M48Z35Y integrates a 32 K × 8 SRAM array, voltage-sense comparator, battery switchover logic, and write-protect control on a single die. Its power-fail detection triggers at VPFD (4.2–4.5 V), forcing chip deselect and high-Z outputs before VCC falls below VSO (3.0 V), at which point the internal lithium cell powers the memory.

It supports standard asynchronous SRAM timing: tAVQV = 70 ns, tELQV = 70 ns, tGLQV = 35 ns (CL = 100 pF), and maintains identical read/write cycle times. The device enters battery backup mode autonomously without external control signals, and resumes normal operation only after VCC exceeds VPFD(max) and trec (40–200 ms) elapses.

Key Specifications

Pinout & Package

The M48Z35Y-70MH6E is supplied in a 28-pin SOIC (SOH28) package, designed for surface-mount assembly and subsequent mating with the M4Z28-BR00SH1 SNAPHAT® battery housing. The SOIC provides dual-row gold-plated contacts enabling mechanical and electrical stacking without solder reflow exposure to the battery.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar non-volatile SRAM applications.

Compared with M48Z35Y-70MH6E, DS1248 offers identical core functionality but lacks the integrated SOIC+SNAPHAT® mechanical solution and requires manual battery integration, while no valid second alternative meets the exact specification set - making M48Z35Y-70MH6E uniquely suited for space-constrained, surface-mount battery-backed SRAM designs.

Availability

M48Z35Y-70MH6E is available at Aetrix Electronics and suitable for real-time clock memory, industrial PLC configuration storage, medical event logging, and point-of-sale transaction buffering requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for M48Z35Y-70MH6E 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 headquartered in Geneva, Switzerland, designing and manufacturing microcontrollers, power management ICs, sensors, and memory solutions for industrial, automotive, and consumer markets.

The M48Z35Y belongs to ST's ZEROPOWER® SRAM product line, engineered specifically for applications demanding autonomous, maintenance-free, long-duration data retention during power loss - targeting embedded systems where reliability, board space, and assembly simplicity are critical.

FAQ

What is the battery chemistry and capacity used in M48Z35Y-70MH6E?

The M48Z35Y-70MH6E integrates a non-rechargeable lithium carbon monofluoride (LiCFₓ) button cell rated at 48 mAh. This chemistry provides stable voltage output, ultra-low self-discharge (<1% per year), and guaranteed ≥11 years data retention at 25 °C with VCC = 0 V. The battery is fully encapsulated within the SNAPHAT® housing and not user-replaceable.

Can M48Z35Y-70MH6E operate without the SNAPHAT® top installed?

No - the SOH28 package alone contains only the silicon die and interconnects; it lacks the battery and switchover circuitry housed exclusively in the M4Z28-BR00SH1 SNAPHAT® top. Operation without the SNAPHAT® top results in functional SRAM behavior only while VCC is applied; no data retention capability exists without the attached battery module.

How does the VPFD window differ between M48Z35 and M48Z35Y variants?

The M48Z35 specifies VPFD = 4.5–4.75 V (min 4.5 V, max 4.75 V), optimized for 5 V ±5% supplies. The M48Z35Y lowers the window to 4.2–4.5 V (min 4.2 V, max 4.5 V), enabling earlier write protection activation in systems with looser 5 V tolerance or higher VCC droop rates - critical for robustness in noisy industrial environments.

Is the M48Z35Y-70MH6E compatible with lead-free reflow processes?

Yes - the SOH28 package is qualified for lead-free reflow with a peak temperature of 260 °C (time above 255 °C ≤ 30 seconds). However, the SNAPHAT® top must be installed *after* reflow; mounting it prior to soldering would expose the lithium battery to destructive thermal stress. ST explicitly prohibits wave soldering of the SOH28 package.