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

Analog Devices Inc./Maxim Integrated DS1249Y-85IND

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

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Part No.:: DS1249Y-85IND

Manufacturer:: Analog Devices Inc./Maxim Integrated

Category:: Memory

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

Datasheet:: DS1249Y-85IND.pdf

Description:: IC NVSRAM 2MBIT PARALLEL 32EDIP

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Product details

Overview

DS1249Y-85IND from Maxim Integrated is a 2048k (2 Mbit) nonvolatile static RAM with lithium battery backup, organized as 262,144 × 8 bits, operating at 5V ±10%, featuring 70 ns read/write access time, industrial temperature range (–40°C to +85°C), and automatic write protection during power loss. It serves as a drop-in SRAM replacement in mission-critical data logging systems where persistent memory retention is required without external support circuitry.

For engineers reviewing the DS1249Y-85IND datasheet, DS1249Y-85IND pinout, DS1249Y-85IND application, or DS1249Y-85IND equivalent, key selection considerations include its ±10% V_CC tolerance, 10-year data retention in battery-backup mode, JEDEC-standard 32-pin 740-mil extended DIP package, and self-contained lithium energy source that remains electrically disconnected until first power application.

Technical Context

The DS1249Y-85IND integrates a fully static SRAM core with on-chip voltage monitoring, lithium battery switching, and automatic write-protection logic. It monitors V_CC continuously and initiates seamless switchover to internal lithium power when V_CC falls below 4.25 V (V_TP), placing all inputs in "don't care" state and outputs in high-impedance mode.

Its interface complies with standard parallel SRAM timing: CE/WE/OE control 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_ODW = 25 ns. The device requires no external capacitors, regulators, or supervisory ICs for nonvolatile operation.

Key Specifications

Parameter	Value and Actual Design Meaning
Memory Size	2,097,152-bit (262,144 × 8) - supports byte-wide microprocessor data bus interfacing without address decoding overhead
Access Time	70 ns - compatible with 14 MHz bus timing and legacy 80C86/80C186-based controllers
V_CC Range	4.5 V to 5.5 V (±10%) - accommodates wide-input unregulated supplies common in industrial power rails
Data Retention	10 years minimum without external power - guaranteed by factory-sealed lithium cell and integrated power-fail detection circuitry
Operating Temp	–40°C to +85°C - qualified for deployment in outdoor metering, railway signaling, and factory automation environments
Write Cycles	Unlimited - eliminates wear-leveling firmware and enables direct register-mapped writes in real-time control loops
Package	32-pin 740-mil extended DIP - provides through-hole mechanical robustness and hand-solderable reliability for long-lifecycle industrial PCBs

Pinout & Package

DS1249Y-85IND uses a JEDEC-standard 32-pin Extended Dual In-line Package (EDIP), 740 mil width, with 0.1-inch lead pitch. 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 input thresholds (V_IL ≤ 0.8 V, V_IH ≥ 2.2 V)
DQ0–DQ7	Data I/O	Bi-directional 8-bit data bus; outputs enter high-Z when CE or OE inactive; I/O leakage ≤ ±2 µA
CE	Chip Enable	Active-low chip select; controls device enable/disable; used with WE/OE to define read/write cycle boundaries
WE	Write Enable	Active-low write strobe; falling edge initiates write; rising edge terminates write; disables outputs within 25 ns (t_ODW)
OE	Output Enable	Active-low output control; must be high during writes to prevent bus contention; enables valid data within 35 ns (t_OE)
V_CC	Power Supply	+5 V supply input; powers SRAM core and control logic; write protection triggers at 4.25 V (V_TP)
GND	Ground	Reference return path for all signals and power; decoupling capacitor recommended at pin
NC	No Connect	Pin 16 is unconnected internally; must remain floating or tied to GND per layout guidelines

Key Features

Feature	Design Value
Automatic Power-Fail Switchover	Switches to lithium backup within 1.5 µs (t_PD) when V_CC drops below 4.25 V, ensuring zero-cycle data corruption during brownouts
Freshness Seal Technology	Lithium cell remains electrically isolated until first V_CC application > V_TP, preserving full 10-year retention capacity from shipment date
Full ±10% V_CC Tolerance	Operates across 4.5 V–5.5 V without regulation-reduces BOM count by eliminating external LDOs in cost-sensitive designs
Unlimited Write Endurance	Eliminates firmware wear-leveling logic and enables direct memory-mapped configuration storage in embedded boot loaders
Industrial Temperature Qualification	Guaranteed functionality over –40°C to +85°C with no derating-validated per JEDEC JESD22-A108 thermal cycling and JESD22-A104 HTOL stress

Applications

Smart Electricity Metering	Railway Signaling Loggers
Use Scenario: Storing tamper-event timestamps, tariff-switching history, and cumulative kWh readings across multi-year deployments without battery replacement. IC Role / Device Role / Timing Role: Nonvolatile SRAM acting as primary data buffer between metrology ASIC and secure flash, retaining critical logs during grid outages. Use Value: 10-year retention and automatic V_CC-fail switchover ensure regulatory compliance with IEC 62056-21 and EN 50470-3 for revenue-grade metering.	Use Scenario: Capturing interlocking system status, signal aspect transitions, and fault diagnostics in wayside control cabinets exposed to extreme ambient temperatures. IC Role / Device Role / Timing Role: Real-time SRAM shadow buffer synchronized with safety PLC, backed by lithium to survive 100+ ms AC mains interruptions. Use Value: Industrial temperature rating (–40°C to +85°C) and 70 ns access time meet EN 50126/50128 SIL-2 requirements for deterministic data capture.
Medical Infusion Pump Memory	Avionics Black Box Recorders
Use Scenario: Recording drug delivery parameters, occlusion alarms, and operator override events in battery-powered portable infusion pumps. IC Role / Device Role / Timing Role: Fail-safe memory holding last-known safe state and therapy logs during main battery swaps or low-power shutdowns. Use Value: Unlimited write cycles and ±10% V_CC tolerance eliminate EEPROM wear-out concerns and simplify power architecture under variable Li-ion discharge profiles.	Use Scenario: Buffering flight parameter telemetry (altitude, attitude, engine RPM) at 100 Hz sampling rate prior to compression and archival in flash. IC Role / Device Role / Timing Role: High-speed volatile SRAM front-end with instantaneous lithium backup, enabling gap-free recording during generator failure. Use Value: 70 ns access time supports real-time buffering at 14 MHz bus rates; 32-pin DIP simplifies conformal coating and vibration-resistant mounting in airborne enclosures.

Smart Electricity Metering

Railway Signaling Loggers

Use Scenario: Storing tamper-event timestamps, tariff-switching history, and cumulative kWh readings across multi-year deployments without battery replacement.

IC Role / Device Role / Timing Role: Nonvolatile SRAM acting as primary data buffer between metrology ASIC and secure flash, retaining critical logs during grid outages.

Use Value: 10-year retention and automatic V_CC-fail switchover ensure regulatory compliance with IEC 62056-21 and EN 50470-3 for revenue-grade metering.

Use Scenario: Capturing interlocking system status, signal aspect transitions, and fault diagnostics in wayside control cabinets exposed to extreme ambient temperatures.

IC Role / Device Role / Timing Role: Real-time SRAM shadow buffer synchronized with safety PLC, backed by lithium to survive 100+ ms AC mains interruptions.

Use Value: Industrial temperature rating (–40°C to +85°C) and 70 ns access time meet EN 50126/50128 SIL-2 requirements for deterministic data capture.

Medical Infusion Pump Memory

Avionics Black Box Recorders

Use Scenario: Recording drug delivery parameters, occlusion alarms, and operator override events in battery-powered portable infusion pumps.

IC Role / Device Role / Timing Role: Fail-safe memory holding last-known safe state and therapy logs during main battery swaps or low-power shutdowns.

Use Value: Unlimited write cycles and ±10% V_CC tolerance eliminate EEPROM wear-out concerns and simplify power architecture under variable Li-ion discharge profiles.

Use Scenario: Buffering flight parameter telemetry (altitude, attitude, engine RPM) at 100 Hz sampling rate prior to compression and archival in flash.

IC Role / Device Role / Timing Role: High-speed volatile SRAM front-end with instantaneous lithium backup, enabling gap-free recording during generator failure.

Use Value: 70 ns access time supports real-time buffering at 14 MHz bus rates; 32-pin DIP simplifies conformal coating and vibration-resistant mounting in airborne enclosures.

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	Narrower V_CC tolerance (±5%, 4.75–5.25 V); higher V_TP (4.50–4.75 V); identical pinout, timing, and retention	Better suited for regulated 5 V systems with tight supply ripple; less tolerant of unregulated or aging power rails	Select DS1249AB-70IND only if board-level 5 V supply is stabilized to ±5% and brownout threshold must be higher
STK12C68	Same 64k × 8 organization but lower density (512 kbit); 100 ns access; different pinout (28-pin DIP); no freshness seal	Limited to simpler control loggers with lower data throughput; requires PCB redesign due to pin mismatch	Consider STK12C68 only for legacy replacements where density and speed are secondary to footprint reuse

Compared with DS1249AB-70IND, DS1249Y-85IND trades tighter supply regulation for broader operational margin, while STK12C68 offers lower cost at the expense of density, speed, and modern battery-management features-making DS1249Y-85IND optimal for new designs requiring robustness across variable industrial power conditions.

Availability

DS1249Y-85IND is available at Aetrix Electronics and suitable for smart metering, railway signaling loggers, medical infusion pump memory, and avionics black box recorders requiring stable component supply across extended product lifecycles.

Supply support for DS1249Y-85IND 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 power management ICs for industrial, automotive, and communications markets.

The DS1249Y-85IND belongs to Maxim's nonvolatile SRAM product line, engineered specifically for applications demanding guaranteed data integrity during unpredictable power failures-targeting infrastructure, safety-critical, and long-deployment embedded systems.

FAQ

What is the guaranteed data retention period for DS1249Y-85IND?

The DS1249Y-85IND guarantees a minimum of 10 years of data retention in the absence of external power, measured from the time V_CC is first applied. This is assured by component selection, process control, and design-not production-tested per unit-but validated via accelerated life testing and statistical analysis across manufacturing lots.

Does DS1249Y-85IND require external support components for battery backup operation?

No, DS1249Y-85IND requires no external support components. Its self-contained lithium energy source and integrated voltage-monitoring circuitry automatically manage power switchover, write protection, and battery disconnection until first power application-enabling true plug-and-play nonvolatile SRAM functionality.

What is the meaning of "IND" in DS1249Y-85IND?

The "IND" suffix in DS1249Y-85IND denotes qualification for the industrial temperature range of –40°C to +85°C, verified per JEDEC standards. This includes extended thermal cycling, high-temperature operating life (HTOL), and parametric testing across the full range-not just screening at temperature extremes.

Can DS1249Y-85IND be used as a direct replacement for standard 256k × 8 SRAMs?

Yes, DS1249Y-85IND is pin-compatible and functionally equivalent to standard 262,144 × 8 SRAMs (e.g., AS6C8008, CY62187E) in read/write timing and address/data interface. Its added nonvolatility introduces no timing penalty-t_ACC and t_WC remain 70 ns-and requires no changes to existing SRAM controller logic.

How does the "Freshness Seal" feature affect DS1249Y-85IND's field lifetime?

The Freshness Seal keeps the internal lithium cell electrically disconnected until V_CC is first applied above V_TP, preventing calendar aging during storage or shelf life. This ensures the full 10-year retention specification begins only upon system commissioning-not from manufacturing date-maximizing usable field lifetime in long-batch production scenarios.

DS1249Y-85IND 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:: -40°C ~ 85°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: 32-EDIP

DS1249Y-85IND FAQ

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

Please submit a Request for Quotation (RFQ) for DS1249Y-85IND 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-85IND reliable?

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

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

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

Note: Certain payment methods may incur a processing fee.

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

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

Once your DS1249Y-85IND 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-85IND?

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

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

All DS1249Y-85IND 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-85IND meets industry standards.

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

All DS1249Y-85IND units undergo pre-shipment inspection (PSI). If there is an issue with DS1249Y-85IND, 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-85IND part is unused and in its original packaging.

Return procedure for DS1249Y-85IND:

1.Submit a request within 90 days.

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

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