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

Analog Devices Inc./Maxim Integrated DS1225AD-70IND

Name: DS1225AD-70IND
Brand: Analog Devices Inc./Maxim Integrated
SKU: DS1225AD-70IND
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: DS1225AD-70IND

Manufacturer:: Analog Devices Inc./Maxim Integrated

Category:: Memory

Package:: 28-DIP Module (0.600", 15.24mm)

Datasheet:: DS1225AD-70IND.pdf

Description:: IC NVSRAM 64KBIT PARALLEL 28EDIP

Quantity:: RFQ Add To RFQ list

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Product details

Overview

DS1225AD-70IND from Maxim Integrated is a 64k-bit (8k × 8) nonvolatile static RAM with integrated lithium battery backup, 70 ns read/write access time, ±10% V_CC tolerance (4.5V–5.5V), and industrial temperature operation (–40°C to +85°C). It replaces volatile SRAMs and EEPROMs in embedded controllers requiring persistent data retention without external support circuitry.

For engineers reviewing the DS1225AD-70IND datasheet, DS1225AD-70IND pinout, DS1225AD-70IND application, or DS1225AD-70IND equivalent, key selection considerations include its automatic power-fail write protection, unlimited write cycles, JEDEC-standard 28-pin DIP package, and guaranteed 10-year data retention in battery-backup mode.

Technical Context

The DS1225AD-70IND integrates a self-contained lithium energy source and voltage-monitoring circuitry that triggers unconditional write protection when V_CC drops below 4.25 V, then switches to battery power below ~3.0 V. Its control logic ensures high-impedance outputs and "don't care" inputs during power transition.

It operates as a drop-in replacement for 2764 EPROM and 2864 EEPROM pinouts while delivering SRAM-speed random access. Read and write timing is fully specified at 70 ns under V_CC = 5 V ±10%, with t_OE = 35 ns and t_CO = 70 ns, supporting direct microprocessor interfacing without wait states.

Key Specifications

Parameter	Value and Actual Design Meaning
Memory Size	65,536 bits (8,192 × 8), byte-wide parallel interface compatible with legacy 8k×8 memory systems
Access Time	70 ns max - enables direct connection to 14 MHz bus systems without wait-state insertion
V_CC Range	4.5 V to 5.5 V (±10%) - supports wide-input industrial power rails without regulation
Data Retention	10 years minimum without external power - guaranteed by internal lithium cell and sealed freshness design
Operating Temp	–40°C to +85°C - qualified for industrial control, avionics, and metering environments
Write Cycles	Unlimited - eliminates wear-out concerns in logging, configuration, or real-time clock backup applications
Package	28-pin 720-mil extended DIP - JEDEC-standard footprint, wave-solder compatible, no PCB redesign needed

Pinout & Package

DS1225AD-70IND uses a JEDEC-standard 28-pin encapsulated DIP (720-mil width) with through-hole mounting. The package includes internal lithium battery, voltage monitor, and power-switching circuitry - all integrated into the same footprint as legacy 28-pin memory devices.

Pin/Terminal	Circuit Role	Design Meaning
A0–A12	Address Inputs	13-bit address bus for selecting one of 8,192 bytes; TTL-compatible, no pull-ups required
DQ0–DQ7	Data I/O	Bidirectional 8-bit data bus; high-impedance when CE/OE inactive or during power transition
CE	Chip Enable	Active-low chip select; initiates read/write when low with WE/OE conditions satisfied
WE	Write Enable	Active-low write strobe; controls data latching and disables outputs during write if OE is active
OE	Output Enable	Active-low output enable; used only in read mode; must be high during writes to avoid contention
V_CC	Power Supply	+5 V supply input; monitored continuously; triggers battery switchover at ~3.0 V
GND	Ground	Reference return path for all signals and internal battery circuitry
NC	No Connect	Pins 14 and 24 are unconnected; no internal bonding or function

Key Features

Feature	Design Value
Automatic Power-Fail Protection	Hardware-monitored V_CC triggers immediate write disable and battery activation - no firmware or external supervisor IC required
Freshness Seal	Lithium cell electrically disconnected until first V_CC application > V_TP, preserving full 10-year retention capacity from shipment
Direct EPROM/EEPROM Replacement	Pinout matches 2764 EPROM and 2864 EEPROM - allows upgrade to nonvolatile SRAM without layout change
Wide V_CC Tolerance	Operates across 4.5 V–5.5 V - accommodates unregulated 5 V rails common in industrial power supplies
Zero External Support Circuitry	No capacitors, diodes, or regulators needed - simplifies BOM and reduces board area vs. discrete NV-SRAM + battery solutions

Applications

Industrial Data Logger	Energy Meter Firmware Storage
Use Scenario: Continuous recording of sensor readings and event timestamps in remote utility meters with intermittent or unreliable mains power. IC Role / Device Role / Timing Role: Nonvolatile SRAM providing instant-access scratchpad memory and secure firmware parameter storage during brownouts. Use Value: Eliminates need for EEPROM wear-leveling or flash programming delays; retains critical calibration and billing data for ≥10 years without backup power management firmware.	Use Scenario: Storing tariff tables, consumption history, and tamper logs in ANSI C12.22-compliant smart meters operating across –40°C to +85°C ambient. IC Role / Device Role / Timing Role: Pin-compatible 8k×8 memory replacing obsolete 2864 EEPROMs while enabling real-time write updates without erase cycles. Use Value: Supports sub-second firmware updates and secure log writes under fluctuating 5 V supply; meets UL E99151 recognition for safety-critical metering.
Avionics Flight Recorder Buffer	PLC Configuration Backup
Use Scenario: Capturing high-frequency aircraft telemetry (attitude, engine parameters) during transient power loss or emergency shutdown. IC Role / Device Role / Timing Role: High-speed (70 ns) nonvolatile buffer ensuring zero-data-loss capture during rapid V_CC collapse. Use Value: Guarantees deterministic write-protection activation within 1.5 µs of V_CC failure (t_PD), preserving last valid flight state before power interruption.	Use Scenario: Preserving ladder logic runtime variables, I/O mapping, and alarm thresholds in DIN-rail mounted programmable logic controllers exposed to factory EMI and thermal cycling. IC Role / Device Role / Timing Role: Industrial-grade NV SRAM serving as volatile configuration store with automatic fail-safe persistence. Use Value: Enables hot-restart capability after power cycle; withstands 85°C ambient and repeated thermal shock without data corruption or retention degradation.

Industrial Data Logger

Energy Meter Firmware Storage

Use Scenario: Continuous recording of sensor readings and event timestamps in remote utility meters with intermittent or unreliable mains power.

IC Role / Device Role / Timing Role: Nonvolatile SRAM providing instant-access scratchpad memory and secure firmware parameter storage during brownouts.

Use Value: Eliminates need for EEPROM wear-leveling or flash programming delays; retains critical calibration and billing data for ≥10 years without backup power management firmware.

Use Scenario: Storing tariff tables, consumption history, and tamper logs in ANSI C12.22-compliant smart meters operating across –40°C to +85°C ambient.

IC Role / Device Role / Timing Role: Pin-compatible 8k×8 memory replacing obsolete 2864 EEPROMs while enabling real-time write updates without erase cycles.

Use Value: Supports sub-second firmware updates and secure log writes under fluctuating 5 V supply; meets UL E99151 recognition for safety-critical metering.

Avionics Flight Recorder Buffer

PLC Configuration Backup

Use Scenario: Capturing high-frequency aircraft telemetry (attitude, engine parameters) during transient power loss or emergency shutdown.

IC Role / Device Role / Timing Role: High-speed (70 ns) nonvolatile buffer ensuring zero-data-loss capture during rapid V_CC collapse.

Use Value: Guarantees deterministic write-protection activation within 1.5 µs of V_CC failure (t_PD), preserving last valid flight state before power interruption.

Use Scenario: Preserving ladder logic runtime variables, I/O mapping, and alarm thresholds in DIN-rail mounted programmable logic controllers exposed to factory EMI and thermal cycling.

IC Role / Device Role / Timing Role: Industrial-grade NV SRAM serving as volatile configuration store with automatic fail-safe persistence.

Use Value: Enables hot-restart capability after power cycle; withstands 85°C ambient and repeated thermal shock without data corruption or retention degradation.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
DS1225Y-70IND+	Same 64k NV-SRAM architecture but with extended temperature range (–40°C to +125°C) and higher ICC01 (100 mA)	Targeted at automotive under-hood and military applications exceeding +85°C ambient	Select DS1225Y-70IND+ only if operation above +85°C is required; otherwise DS1225AD-70IND offers lower power and cost
STK12C68-A70I	64k NV-SRAM with 70 ns access, but uses external capacitor-based backup and lacks integrated lithium cell	Requires external 0.1 F supercapacitor and charging circuit; shorter retention (~5 years) and higher system complexity	Choose STK12C68-A70I only if lithium-free compliance (e.g., RoHS Pb-free + battery exemption) is mandatory; DS1225AD-70IND provides simpler, longer-retention solution

Compared with DS1225Y-70IND+ and STK12C68-A70I, the DS1225AD-70IND delivers optimal balance of industrial temperature support, integrated lithium reliability, and low-system-cost implementation - making it the preferred choice for fixed-temperature industrial and metering designs where +85°C suffices and battery integration is acceptable.

Availability

DS1225AD-70IND is available at Aetrix Electronics and suitable for industrial data loggers, smart energy meters, avionics recorders, and PLC configuration backup systems requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant sourcing.

Supply support for DS1225AD-70IND 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, communications, and computing applications.

The DS1225AB/AD product line was designed to deliver plug-in nonvolatile memory replacement for legacy 28-pin memory sockets - eliminating external backup components while guaranteeing decade-long data integrity in harsh environments.

FAQ

What is the guaranteed data retention period for DS1225AD-70IND?

The DS1225AD-70IND guarantees a minimum 10-year data retention period in the absence of external power, measured from the time V_CC is first applied by the user. This is enabled by its sealed lithium energy source and internal power-switching circuitry, and is validated by design - not 100% tested per unit.

Does DS1225AD-70IND require external components for battery backup operation?

No, the DS1225AD-70IND requires no external components for battery backup operation. Its integrated lithium cell, voltage monitor, and power-switching circuitry are fully contained within the 28-pin DIP package. No capacitors, diodes, regulators, or charge controllers are needed for functional nonvolatile operation.

How does DS1225AD-70IND handle power failure during a write cycle?

During a power failure, the DS1225AD-70IND detects V_CC decay via internal monitoring and activates write protection within 1.5 µs (t_PD). All inputs become "don't care," outputs go high-impedance, and the lithium source powers the SRAM array - preventing partial writes or data corruption even mid-cycle.

Is DS1225AD-70IND pin-compatible with standard 2764 EPROMs?

Yes, the DS1225AD-70IND is pin-compatible with the 2764 EPROM and 2864 EEPROM. Its 28-pin DIP footprint, address/data/control signal mapping (A0–A12, DQ0–DQ7, CE, OE, WE), and timing behavior allow direct socket replacement without PCB modification or firmware changes.

What is the minimum V_CC level at which DS1225AD-70IND enters write-protected battery-backup mode?

The DS1225AD-70IND enters write-protected battery-backup mode when V_CC falls below 4.25 V (V_TP min). At approximately 3.0 V, the internal power switch connects the lithium cell to retain data. Full functional operation resumes only after V_CC exceeds 4.5 V.

DS1225AD-70IND Specifications

Product attributes: Attribute value

Manufacturer:: Analog Devices Inc./Maxim Integrated

Series:: -

Package/Case:: 28-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:: 64Kbit

Memory Organization:: 8K x 8

Memory Interface:: Parallel

Clock Frequency:: -

Write Cycle Time - Word, Page:: 70ns

Access Time:: 70 ns

Voltage - Supply:: 4.5V ~ 5.5V

Operating Temperature:: -40°C ~ 85°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: 28-EDIP

DS1225AD-70IND FAQ

1.How can I place an order for DS1225AD-70IND through Aetrix?

Please submit a Request for Quotation (RFQ) for DS1225AD-70IND 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 DS1225AD-70IND reliable?

The price and inventory of DS1225AD-70IND are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS1225AD-70IND is usually 5 days.

3.What payment methods are accepted for DS1225AD-70IND?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS1225AD-70IND transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for DS1225AD-70IND?

DS1225AD-70IND orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your DS1225AD-70IND 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 DS1225AD-70IND?

For technical support, including DS1225AD-70IND datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS1225AD-70IND requirements.

6.How does Aetrix verify that DS1225AD-70IND is sourced from the original manufacturer or authorized distributors?

All DS1225AD-70IND 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 DS1225AD-70IND meets industry standards.

7.What is the process for return or replacement of DS1225AD-70IND?

All DS1225AD-70IND units undergo pre-shipment inspection (PSI). If there is an issue with DS1225AD-70IND, 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 DS1225AD-70IND part is unused and in its original packaging.

Return procedure for DS1225AD-70IND:

1.Submit a request within 90 days.

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

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