Analog Devices Inc./Maxim Integrated DS1249AB-70

Overview

DS1249AB-70 from Maxim Integrated is a 2048k (2,097,152-bit) nonvolatile static RAM organized as 262,144 × 8, featuring 70 ns read/write access time, ±5% V_CC tolerance (4.75–5.25 V), and industrial temperature support (–40°C to +85°C). It integrates a lithium energy source and automatic power-fail write protection for data retention in battery-backup mode, used in mission-critical memory logging and configuration storage.

For engineers reviewing the DS1249AB-70 datasheet, DS1249AB-70 pinout, DS1249AB-70 application, or DS1249AB-70 equivalent, key selection considerations include guaranteed 10-year data retention without external power, unlimited write cycles, JEDEC-standard 32-pin 740-mil extended DIP package, and automatic V_CC monitoring that triggers seamless lithium switchover below ~3.0 V.

Technical Context

The DS1249AB-70 implements a self-contained NV SRAM architecture with integrated lithium battery and analog voltage-monitoring circuitry. It continuously monitors V_CC, enabling write protection when voltage drops below 4.50 V (V_TP) and switching to battery power below ~3.0 V - all without external components.

Its interface follows standard asynchronous SRAM timing: CE/WE/OE control logic enables read cycles (CE&OE low, WE high) and write cycles (CE&WE low), with t_ACC = 70 ns, t_WC = 70 ns, and t_OE = 35 ns. Address inputs A0–A17 and bidirectional DQ0–DQ7 support full 8-bit parallel access with no wait states.

Key Specifications

Pinout & Package

DS1249AB-70 uses a JEDEC-standard 32-pin Extended Dual In-line Package (EDIP), 740 mil width, with 0.1" lead pitch. Pin 1 is marked by notch or dot; pins are arranged in two rows of 16, with A0–A17, 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 STK12C68-70 and DS1248-70, the DS1249AB-70 uniquely delivers 2048k density with fully integrated lithium and autonomous power-fail response - reducing design risk, PCB area, and qualification effort for new industrial and medical platforms.

Availability

DS1249AB-70 is available at Aetrix Electronics and suitable for industrial PLCs, medical diagnostic devices, avionics data recorders, and smart energy meters requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant through-hole packaging.

Supply support for DS1249AB-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, medical, and communications applications.

The DS1249AB-70 belongs to Maxim's nonvolatile SRAM product line, engineered for systems demanding zero-data-loss memory retention during unpredictable power interruptions - especially in safety-critical and unattended operation environments.

FAQ

What is the guaranteed data retention period for DS1249AB-70 when external power is removed?

The DS1249AB-70 guarantees a minimum of 10 years of data retention in the absence of external power, based on accumulated time after first V_CC application. This is achieved using an integrated lithium energy source that remains sealed until initial power-up, preserving full capacity. The DS1249AB-70 specification defines this retention under industrial temperature conditions (–40°C to +85°C) and is assured by component selection and process control - not measured per unit during production.

Does DS1249AB-70 require external circuitry to manage battery backup or power-fail detection?

No, the DS1249AB-70 requires no external circuitry for battery backup or power-fail detection. It contains fully integrated lithium energy source switching and analog voltage monitoring that automatically enables write protection when V_CC falls below 4.50 V and connects the lithium cell when V_CC drops below ~3.0 V. The DS1249AB-70 handles all transitions autonomously, eliminating the need for external supervisors, diodes, or capacitors.

What is the difference between DS1249AB-70 and DS1249Y-70?

The DS1249AB-70 operates over a tighter V_CC range (4.75–5.25 V, ±5%) and triggers write protection at 4.50–4.75 V, while the DS1249Y-70 supports wider tolerance (4.5–5.5 V, ±10%) and protects at 4.25–4.5 V. Both share identical 70 ns speed, 2048k density, and industrial temperature option (IND suffix), but the DS1249AB-70 is optimized for systems with well-regulated 5 V supplies.

Can DS1249AB-70 be used as a drop-in replacement for standard 256K × 8 SRAMs?

The DS1249AB-70 is pin-compatible with industry-standard 256K × 8 SRAMs in the 32-pin EDIP package and uses identical CE/WE/OE control protocol and address/data timing. However, its integrated lithium and automatic write protection mean it behaves differently during power loss - making it functionally superior but requiring verification that the host system does not assert conflicting control signals during V_CC decay. The DS1249AB-70 retains full SRAM read/write compatibility under normal operation.

Is DS1249AB-70 RoHS compliant and what is its lead-free status?

Yes, DS1249AB-70IND# is RoHS-compliant and carries the "#" suffix indicating exemption-permitted lead content per EU RoHS Directive Annex III. It meets JEDEC J-STD-020 moisture sensitivity level (MSL) requirements and is qualified for wave and hand soldering (lead temperature ≤260°C for 10 seconds). The DS1249AB-70 is manufactured and tested to RoHS specifications, with full traceability documentation available upon request.