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Home > Products > Integrated Circuits (ICs) > Memory > Memory

Analog Devices Inc./Maxim Integrated DS1249Y-85#

Name: DS1249Y-85#
Brand: Analog Devices Inc./Maxim Integrated
SKU: DS1249Y-85#
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: DS1249Y-85#

Manufacturer:: Analog Devices Inc./Maxim Integrated

Category:: Memory

Package:: 32-DIP Module (0.600", 15.24mm)

Datasheet:: DS1249Y-85#.pdf

Description:: IC NVSRAM 2MBIT PARALLEL 32EDIP

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Product details

Overview

DS1249Y-85# from Maxim Integrated is a 2048k (2,097,152-bit) nonvolatile static RAM organized as 262,144 × 8, featuring lithium-backed data retention, 70 ns read/write access time, ±10% V_CC operation (4.5V–5.5V), and industrial temperature support (–40°C to +85°C). It autonomously enables battery backup below ~3.0V and protects data during power loss in embedded systems requiring persistent memory without external support circuitry.

For engineers reviewing the DS1249Y-85# datasheet, DS1249Y-85# pinout, DS1249Y-85# application, or DS1249Y-85# equivalent, key selection criteria include guaranteed 10-year data retention without power, unlimited write cycles, JEDEC-standard 32-pin extended DIP package, V_TP = 4.25V–4.5V write-protection threshold, and compatibility with standard SRAM bus timing.

Technical Context

The DS1249Y-85# integrates on-die lithium battery and voltage-monitoring circuitry that triggers automatic write protection and seamless switchover to battery power when V_CC falls below 4.25V (V_TP) and disconnects the battery until first power application. Its full CMOS interface supports standard microprocessor bus protocols with CE/OE/WE control logic and no external components required for NV operation.

It operates across –40°C to +85°C with ±10% V_CC tolerance (4.5V–5.5V), delivers t_ACC = 70 ns and t_WC = 70 ns, and maintains high-impedance outputs during power transition events per t_PD = 1.5 µs fail-detect latency and t_REC = 125 ms recovery after V_CC restoration.

Key Specifications

Parameter	Value and Actual Design Meaning
Memory Size	2,097,152-bit (262,144 × 8) - provides byte-addressable nonvolatile storage compatible with 8-bit data buses.
Access Time	70 ns - ensures compatibility with legacy microprocessors and controllers running at ≤14 MHz bus speeds.
V_CC Range	4.5V to 5.5V (±10%) - supports wide-input power rails without regulation, reducing BOM count in industrial designs.
Data Retention	10 years without power - enabled by sealed lithium cell and automatic switchover at ~3.0V, eliminating need for external backup capacitors or batteries.
Write Protection Threshold	V_TP = 4.25V–4.5V - initiates unconditional write lock before V_CC drops to levels risking SRAM corruption.
Operating Temperature	–40°C to +85°C - qualified for industrial environments including factory automation, metering, and transportation control systems.
Package	32-pin 740-mil extended DIP - enables through-hole mounting and direct replacement of legacy SRAMs in existing PCB layouts.

Pinout & Package

DS1249Y-85# uses a JEDEC-standard 32-pin extended dual in-line package (EDIP), 740 mil width, with lead finish compliant with RoHS exemptions. Pin 1 is marked with a notch or dot; pins are numbered counter-clockwise from top-left corner.

Pin/Terminal	Circuit Role	Design Meaning
A0–A17	Address Inputs	18-bit address bus supporting full 262,144-word addressing; TTL-compatible inputs with VIH ≥ 2.2V.
DQ0–DQ7	Data I/O	Bi-directional 8-bit data bus; high-impedance when CE or OE inactive; drives 1 TTL load.
CE	Chip Enable	Active-low chip select; must be low for read/write; controls internal power state and write-enable arbitration.
WE	Write Enable	Active-low write strobe; falling edge initiates write cycle; output drivers disabled if OE active during write.
OE	Output Enable	Active-low output control; enables data drivers only during reads; high during writes prevents bus contention.
V_CC	Power Supply	+5V supply input; monitored continuously for voltage decay; powers RAM core and control logic.
GND	Ground	Reference return path for all signals and internal circuitry; requires low-impedance connection.
NC	No Connect	Pin 16 is unconnected internally; must remain floating or tied to GND per layout best practices.

Key Features

Feature	Design Value
Lithium energy source with freshness seal	Battery remains electrically disconnected until first V_CC application > V_TP, preserving full 10-year capacity and eliminating shelf-life degradation.
Automatic power-fail detection and switchover	On-chip comparator triggers battery backup within 1.5 µs when V_CC drops below ~3.0V, preventing data loss during brownouts.
Unlimited write cycles	No endurance limit on SRAM core - eliminates wear-leveling firmware and enables frequent configuration or log updates.
Full ±10% V_CC operation	Operates reliably from 4.5V to 5.5V without external regulators, simplifying power design in noisy or variable-supply environments.
Industrial temperature qualification	Guaranteed functionality and timing compliance over –40°C to +85°C, validated per JEDEC JESD22-A108.

Applications

Industrial Data Logger	Medical Device Configuration Storage
Use Scenario: Continuous recording of sensor readings in remote field equipment powered by intermittent solar or battery sources. IC Role / Device Role / Timing Role: Nonvolatile SRAM storing real-time operational parameters and last-known valid state during power interruptions. Use Value: Guarantees 10-year data integrity without supercapacitors or external battery management, reducing system size and certification burden.	Use Scenario: Storing calibrated settings, user preferences, and fault history in portable diagnostic instruments subject to frequent power cycling. IC Role / Device Role / Timing Role: Byte-accessible, pin-compatible SRAM replacing EEPROM for faster configuration writes and zero-write-delay updates. Use Value: Enables unlimited rewrites of calibration tables without wear-out concerns, while maintaining data across sterilization cycles and transport-induced power loss.
Factory Automation PLC Memory	Smart Meter Firmware Parameter Storage
Use Scenario: Retaining ladder logic variables and I/O state snapshots in programmable logic controllers deployed in harsh manufacturing environments. IC Role / Device Role / Timing Role: Industrial-grade NV SRAM interfacing directly to 8-bit microcontroller buses with deterministic 70 ns timing. Use Value: Eliminates need for external backup power supervision ICs and supports operation down to –40°C ambient without derating.	Use Scenario: Holding tariff schedules, billing registers, and tamper-event logs in ANSI C12.22-compliant electricity meters with long field life requirements. IC Role / Device Role / Timing Role: Self-contained nonvolatile memory with autonomous write protection triggered at 4.25V, meeting ANSI/IEEE C37.118.2 voltage-fail thresholds. Use Value: Ensures regulatory-compliant data retention during grid sags and outages, verified to 10 years without periodic refresh or maintenance.

Industrial Data Logger

Medical Device Configuration Storage

Use Scenario: Continuous recording of sensor readings in remote field equipment powered by intermittent solar or battery sources.

IC Role / Device Role / Timing Role: Nonvolatile SRAM storing real-time operational parameters and last-known valid state during power interruptions.

Use Value: Guarantees 10-year data integrity without supercapacitors or external battery management, reducing system size and certification burden.

Use Scenario: Storing calibrated settings, user preferences, and fault history in portable diagnostic instruments subject to frequent power cycling.

IC Role / Device Role / Timing Role: Byte-accessible, pin-compatible SRAM replacing EEPROM for faster configuration writes and zero-write-delay updates.

Use Value: Enables unlimited rewrites of calibration tables without wear-out concerns, while maintaining data across sterilization cycles and transport-induced power loss.

Factory Automation PLC Memory

Smart Meter Firmware Parameter Storage

Use Scenario: Retaining ladder logic variables and I/O state snapshots in programmable logic controllers deployed in harsh manufacturing environments.

IC Role / Device Role / Timing Role: Industrial-grade NV SRAM interfacing directly to 8-bit microcontroller buses with deterministic 70 ns timing.

Use Value: Eliminates need for external backup power supervision ICs and supports operation down to –40°C ambient without derating.

Use Scenario: Holding tariff schedules, billing registers, and tamper-event logs in ANSI C12.22-compliant electricity meters with long field life requirements.

IC Role / Device Role / Timing Role: Self-contained nonvolatile memory with autonomous write protection triggered at 4.25V, meeting ANSI/IEEE C37.118.2 voltage-fail thresholds.

Use Value: Ensures regulatory-compliant data retention during grid sags and outages, verified to 10 years without periodic refresh or maintenance.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
DS1249AB-70IND#	±5% V_CC tolerance (4.75V–5.25V); higher V_TP = 4.50V–4.75V; identical package and speed.	Requires tighter-regulated 5V supply; better suited for systems with stable regulated rails and stricter voltage-margin requirements.	Select DS1249AB-70IND# when V_CC regulation is precise and write-protection margin above 4.5V is preferred.
STK12C68-E25I	Same 2048k size and 32-pin DIP; 25 ns access time; lithium-backed; but rated only for –40°C to +70°C (not +85°C).	Lacks full industrial +85°C rating; lower t_ACC enables faster bus timing but reduces thermal margin in enclosed enclosures.	Choose STK12C68-E25I only if ambient temperature stays ≤+70°C and sub-70 ns timing is critical for host controller compatibility.

Compared with DS1249AB-70IND#, DS1249Y-85# trades tighter V_CC tolerance for wider supply flexibility and lower V_TP, while STK12C68-E25I offers faster access but sacrifices the +85°C operating ceiling essential for sealed industrial housings.

Availability

DS1249Y-85# is available at Aetrix Electronics and suitable for industrial data loggers, medical device configuration storage, and factory automation PLC memory requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant through-hole packaging.

Supply support for DS1249Y-85# 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 U.S.-based semiconductor company specializing in precision analog, mixed-signal, and high-reliability power management solutions.

The DS1249 family was designed specifically for mission-critical nonvolatile memory applications where data persistence, autonomous power fail response, and industrial temperature resilience are mandatory - not merely desirable.

FAQ

What is the guaranteed data retention period for DS1249Y-85# without external power?

The DS1249Y-85# guarantees 10 years of data retention in the absence of external power, based on built-in lithium cell capacity, hermetic sealing, and process-controlled aging characteristics. This specification applies from the moment V_CC is first applied and accumulates only during actual power-off periods - not shelf time prior to first use. The DS1249Y-85# achieves this without requiring external capacitors or battery management circuitry.

Does DS1249Y-85# require external circuitry to enable nonvolatile operation?

No, the DS1249Y-85# requires no external components for nonvolatile operation. Its integrated lithium energy source, voltage monitor, and power-switching circuitry automatically manage backup activation, write protection, and data retention. The DS1249Y-85# connects directly to a standard 8-bit microprocessor bus using only CE, OE, WE, address, and data lines - no glue logic, supervisors, or charge pumps needed.

What is the write-protection trigger voltage (V_TP) for DS1249Y-85#?

The DS1249Y-85# asserts unconditional write protection when V_CC falls within the range of 4.25V to 4.5V (V_TP). This threshold is factory-trimmed and specified under DC electrical characteristics. Below this level, all inputs become "don't care," outputs go high-impedance, and the lithium source engages to maintain RAM contents - ensuring data integrity even during gradual brownouts.

Is DS1249Y-85# compatible with standard 32-pin DIP sockets used for conventional SRAMs?

Yes, the DS1249Y-85# uses a JEDEC-standard 32-pin extended DIP (740-mil width) footprint identical to legacy volatile SRAMs like the HM62256 or IS61LV25616. Pinout matches industry-standard parallel SRAM interfaces - A0–A17, DQ0–DQ7, CE, OE, WE, V_CC, GND - enabling drop-in replacement in existing designs without PCB modification.

How does DS1249Y-85# behave during power-up and power-down transitions?

During power-down, the DS1249Y-85# detects V_CC decay within 1.5 µs (t_PD) and switches to lithium backup when V_CC reaches ~3.0V. During power-up, it reconnects V_CC to the RAM core and isolates the battery once V_CC exceeds ~3.0V, resuming full operation after V_CC stabilizes above 4.5V. The DS1249Y-85# enforces t_REC = 125 ms recovery before accepting new commands to ensure internal state consistency.

DS1249Y-85# Specifications

Product attributes: Attribute value

Manufacturer:: Analog Devices Inc./Maxim Integrated

Series:: -

Package/Case:: 32-DIP Module (0.600", 15.24mm)

Packaging:: Tube

Product Status:: Obsolete

Programmable:: Not Verified

Memory Type:: Non-Volatile

Memory Format:: NVSRAM

Technology:: NVSRAM (Non-Volatile SRAM)

Memory Size:: 2Mbit

Memory Organization:: 256K x 8

Memory Interface:: Parallel

Clock Frequency:: -

Write Cycle Time - Word, Page:: 85ns

Access Time:: 85 ns

Voltage - Supply:: 4.5V ~ 5.5V

Operating Temperature:: 0°C ~ 70°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: 32-EDIP

DS1249Y-85# FAQ

1.How can I place an order for DS1249Y-85# through Aetrix?

Please submit a Request for Quotation (RFQ) for DS1249Y-85# on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for DS1249Y-85# reliable?

The price and inventory of DS1249Y-85# are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS1249Y-85# is usually 5 days.

3.What payment methods are accepted for DS1249Y-85#?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS1249Y-85# transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for DS1249Y-85#?

DS1249Y-85# orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your DS1249Y-85# order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for DS1249Y-85#?

For technical support, including DS1249Y-85# datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS1249Y-85# requirements.

6.How does Aetrix verify that DS1249Y-85# is sourced from the original manufacturer or authorized distributors?

All DS1249Y-85# products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that DS1249Y-85# meets industry standards.

7.What is the process for return or replacement of DS1249Y-85#?

All DS1249Y-85# units undergo pre-shipment inspection (PSI). If there is an issue with DS1249Y-85#, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The DS1249Y-85# part is unused and in its original packaging.

Return procedure for DS1249Y-85#:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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