Analog Devices Inc./Maxim Integrated DS1245W-150

Overview

DS1245W-150 from Maxim Integrated is a 3.3V, 1024k-bit (131,072 × 8) nonvolatile static RAM with lithium backup, 100ns read/write access time, automatic power-loss data protection, and JEDEC-standard 32-pin DIP packaging. It replaces volatile SRAM, EEPROM, or Flash in systems requiring persistent memory without external support circuitry-e.g., industrial PLCs retaining configuration during brownouts.

For engineers reviewing the DS1245W-150 datasheet, DS1245W-150 pinout, DS1245W-150 application, or DS1245W-150 equivalent, key selection criteria include guaranteed 10-year data retention at 25°C, write-protection activation at ≤2.9V VCC, 3.0–3.6V operating supply range, and compatibility with standard 32-pin bytewide DIP sockets used for legacy 128k×8 SRAM upgrades.

Technical Context

The DS1245W-150 integrates SRAM, lithium battery, and voltage-monitoring control logic into a monolithic 32-pin EDIP package. Its power-switching circuit autonomously connects the lithium source when VCC drops below 2.9V and disconnects it upon power-up above 2.5V-enabling seamless transition to battery-backed retention mode without host intervention.

It operates as a drop-in replacement for standard 128k×8 SRAMs using identical address/data/control timing: CE/OE/WE dual-gated read cycles, WE/CE-synchronized writes, and high-impedance outputs during deselection. The device requires no external capacitors, regulators, or write-protection logic-only a stable 3.3V ±0.3V supply and standard parallel bus interface.

Key Specifications

Pinout & Package

DS1245W-150 uses a JEDEC-standard 32-pin Extended Dual In-line Package (EDIP), 740-mil width, wave-solderable only. The package integrates SRAM, lithium battery, and power-fail detection circuitry in one hermetically sealed unit.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar nonvolatile SRAM applications.

Compared with STK12C68-5 and DS1248W-100, the DS1245W-150 uniquely delivers 3.3V compatibility, integrated lithium backup, and JEDEC 32-pin DIP packaging in a single monolithic unit-making it the only option for direct socket replacement of legacy 128k×8 SRAMs in commercial-temperature 3.3V systems.

Availability

DS1245W-150 is available at Aetrix Electronics and suitable for industrial data loggers, medical device configuration storage, and telecom base station control memory requiring stable component supply, long-term data integrity, and legacy SRAM upgrade paths.

Supply support for DS1245W-150 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

Maxim Integrated (now part of Analog Devices) is a semiconductor company specializing in analog, mixed-signal, and power-management ICs for industrial, communications, and computing applications.

The DS1245W-150 belongs to Maxim's nonvolatile SRAM product line, designed specifically to eliminate external backup components and simplify migration from volatile memory in mission-critical embedded systems.

FAQ

What is the guaranteed data retention period for DS1245W-150 under normal conditions?

The DS1245W-150 guarantees ≥10 years of data retention at +25°C in the absence of external power. This specification assumes the lithium energy source is activated on first power-up (>3.0V) and accounts for cumulative time spent in battery-backup mode. Retention time decreases at elevated temperatures per Arrhenius modeling, but the DS1245W-150 maintains functional integrity across its commercial temperature range (0°C to +70°C).

Does DS1245W-150 require external components for nonvolatile operation?

No, the DS1245W-150 requires no external capacitors, regulators, or control logic for nonvolatile operation. Its monolithic 32-pin EDIP package integrates the 1024k-bit SRAM, lithium battery, and voltage-monitoring circuitry. The internal freshness seal ensures full battery capacity until first VCC application, and automatic switching activates backup power when VCC drops below 2.9V-making DS1245W-150 a true single-component solution.

Can DS1245W-150 be used as a direct replacement for standard 128k×8 SRAMs?

Yes, DS1245W-150 is engineered as a pin- and function-compatible replacement for 128k×8 volatile SRAMs using the JEDEC-standard 32-pin DIP footprint. Its address (A0–A16), data (DQ0–DQ7), and control (CE/OE/WE/VCC/GND) signals match industry-standard timing and electrical characteristics-including 100ns access time and TTL-compatible I/O-enabling drop-in upgrades without PCB or firmware changes.

What happens to DS1245W-150 outputs during power failure?

During VCC decay below ~2.9V, the DS1245W-150 automatically disables all outputs, placing them in high-impedance state, and locks write functionality. Address, data, and control inputs become "don't care," preventing bus contention or unintended writes. This behavior is hardware-enforced by the internal power-fail detector-no software or external circuitry is needed to ensure safe shutdown, making DS1245W-150 ideal for fail-safe memory applications.

Is DS1245W-150 RoHS-compliant and lead-free?

Yes, DS1245W-150 is RoHS-compliant and lead-free, indicated by the "+" suffix in its ordering code (e.g., DS1245W-150+). It meets EU Directive 2011/65/EU requirements and is manufactured using lead-free solderable terminations. The device is rated for wave soldering only (not reflow), consistent with its 32-pin EDIP package construction and internal lithium cell safety constraints.