Analog Devices Inc./Maxim Integrated DS1250AB-70

Overview

DS1250AB-70 from Maxim Integrated is a 4,194,304-bit (512k × 8) nonvolatile static RAM with integrated lithium backup, JEDEC-standard 32-pin DIP package, 70 ns access time, ±5% V_CC tolerance (4.75–5.25 V), and industrial temperature rating (-40°C to +85°C). It replaces volatile SRAM in battery-backed data logging systems requiring guaranteed 10-year data retention without external support circuitry.

For engineers reviewing the DS1250AB-70 datasheet, DS1250AB-70 pinout, DS1250AB-70 application, or DS1250AB-70 equivalent, key selection criteria include write-protection voltage threshold (4.50–4.75 V), standby current (50–150 µA at CE = V_CC−0.5 V), and compatibility with standard 32-pin byte-wide memory sockets in legacy industrial controllers.

Technical Context

The DS1250AB-70 implements autonomous power-fail detection and lithium switchover: when V_CC drops below 4.5 V, it unconditionally enables write protection and transitions all outputs to high-impedance within 1.5 µs. Its internal control circuitry monitors V_CC continuously and disconnects the lithium source until first power-up, preserving full battery capacity.

It operates as a drop-in replacement for 512k × 8 volatile SRAMs using standard asynchronous parallel bus timing - supporting independent CE/OE/WE control, t_ACC = 70 ns, t_WC = 70 ns, and no external write-cycle management. The device requires no initialization sequence and supports unlimited write cycles with no wear leveling.

Key Specifications

Pinout & Package

DS1250AB-70 uses a JEDEC-standard 32-pin Extended DIP (740-mil) package with through-hole mounting. Pin 1 is marked with a notch or dot; pins are arranged in two rows of 16, with A0–A18, DQ0–DQ7, CE, WE, OE, V_CC, GND, and NC terminals.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS1250Y-70IND+, the DS1250AB-70IND+ offers tighter V_CC regulation tolerance and higher write-protection voltage - improving noise immunity in stable power environments. Against STK12C68-70I, DS1250AB-70IND+ delivers true plug-and-play nonvolatility with no external components or layout dependencies.

Availability

DS1250AB-70 is available at Aetrix Electronics and suitable for smart meter data logging, industrial PLC configuration storage, and medical device event history requiring stable component supply, long-lifecycle availability, and RoHS-compliant packaging.

Supply support for DS1250AB-70 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 precision analog, mixed-signal, and power management ICs for industrial, automotive, and communications applications.

The DS1250AB-70 belongs to Maxim's nonvolatile SRAM product line, designed specifically to eliminate external backup circuitry while delivering guaranteed 10-year data retention in mission-critical industrial and instrumentation systems.

FAQ

What is the guaranteed data retention period for the DS1250AB-70?

The DS1250AB-70 guarantees a minimum 10-year data retention period in the absence of external power, measured from the time V_CC is first applied. This is achieved via an integrated lithium energy source and freshness seal technology that preserves full battery capacity until initial power-up. The DS1250AB-70 meets this specification under industrial temperature conditions (-40°C to +85°C) without requiring external support components.

Does the DS1250AB-70 require external circuitry for battery backup operation?

No, the DS1250AB-70 does not require any external circuitry for battery backup operation. It integrates a lithium energy source, power-fail detection circuitry, and automatic switchover logic into a single JEDEC-standard 32-pin DIP package. The DS1250AB-70 manages all backup functions autonomously - including write protection activation, lithium connection/disconnection, and high-impedance output control - eliminating the need for diodes, capacitors, or supervisory ICs.

What is the difference between DS1250AB-70 and DS1250Y-70?

The DS1250AB-70 and DS1250Y-70 share identical memory size, timing (70 ns), pinout, and industrial temperature rating, but differ in V_CC tolerance and write-protection voltage. The DS1250AB-70 operates over 4.75–5.25 V (±5%) with write protection triggered at 4.50–4.75 V, while the DS1250Y-70 supports 4.5–5.5 V (±10%) and protects at 4.25–4.5 V. Both are valid for DS1250AB-70IND+ and DS1250Y-70IND+ variants.

Can the DS1250AB-70 be used as a direct replacement for standard 512k × 8 SRAMs?

Yes, the DS1250AB-70 is designed as a direct pin-compatible replacement for standard 512k × 8 volatile SRAMs in JEDEC 32-pin DIP sockets. Its address (A0–A18), data (DQ0–DQ7), and control (CE, WE, OE) signals match industry-standard timing and voltage levels. No PCB changes, firmware modifications, or external components are needed to integrate the DS1250AB-70 into existing designs originally using volatile SRAM.

What is the purpose of the "Freshness Seal" feature in the DS1250AB-70?

The Freshness Seal feature in the DS1250AB-70 electrically disconnects the internal lithium energy source until the first application of V_CC >4.25 V, preserving full battery capacity and ensuring the full 10-year data retention specification is met from installation. This prevents shelf-life degradation and guarantees optimal performance at deployment. The DS1250AB-70 activates the lithium source automatically on initial power-up - no user intervention or configuration is required.