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

Analog Devices Inc./Maxim Integrated DS1225AD-200IND

Name: DS1225AD-200IND
Brand: Analog Devices Inc./Maxim Integrated
SKU: DS1225AD-200IND
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: DS1225AD-200IND

Manufacturer:: Analog Devices Inc./Maxim Integrated

Category:: Memory

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

Datasheet:: DS1225AD-200IND.pdf

Description:: IC NVSRAM 64KBIT PARALLEL 28EDIP

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Product details

Overview

DS1225AD-200IND from Maxim Integrated is a 64k-bit (8k × 8) nonvolatile static RAM with integrated lithium battery backup, JEDEC-standard 28-pin extended DIP package, 70 ns read/write access time, ±10% V_CC tolerance (4.5V–5.5V), and industrial temperature rating (–40°C to +85°C). It replaces volatile SRAMs or EEPROMs in embedded data-logging systems requiring guaranteed 10-year data retention without external power.

For engineers reviewing the DS1225AD-200IND datasheet, DS1225AD-200IND pinout, DS1225AD-200IND application, or DS1225AD-200IND equivalent, key selection criteria include automatic write protection during V_CC decay, unlimited write cycles, no support circuitry required, and direct compatibility with 2764 EPROM/2864 EEPROM footprints in legacy industrial controllers.

Technical Context

The DS1225AD-200IND implements a self-contained power-fail detection and switchover architecture: internal circuitry continuously monitors V_CC, triggers unconditional write protection when voltage drops below 4.25 V (V_TP), and connects the lithium cell to RAM when V_CC falls below ~3.0 V. During power-up, the lithium source disconnects automatically above ~3.0 V.

It operates as a byte-wide parallel memory with full static timing-no clocks or refresh required-and supports standard microprocessor bus protocols via CE, WE, and OE controls. Its 13 address lines (A0–A12) and 8 bidirectional data lines (DQ0–DQ7) match industry-standard 8k×8 memory interfaces without address decoding logic.

Key Specifications

Parameter	Value and Actual Design Meaning
Memory Size	65,536 bits (8,192 × 8), directly substitutable for 8k×8 SRAM/EPROM/EEPROM
Access Time	70 ns-guarantees compatibility with 14 MHz Z80, 8086, and 68000-based systems
V_CC Range	4.5 V to 5.5 V (±10%)-supports wide-tolerance industrial power rails without regulation
Data Retention	10 years minimum without external power-enabled by sealed lithium cell and automatic power switchover
Write Protection Threshold	V_TP = 4.25 V to 4.5 V-prevents corruption during brown-out before full power loss
Operating Temperature	–40°C to +85°C (IND grade)-qualified for uncontrolled industrial enclosures and outdoor telemetry units
Package	28-pin 720-mil extended DIP-mechanically and electrically compatible with socketed legacy designs

Pinout & Package

DS1225AD-200IND uses a JEDEC-standard 28-pin Extended Dual In-line Package (EDIP), 720 mil width, with through-hole mounting and wave/hand-soldering capability. Pin 1 is marked with a notch or dot; NC pins are internally unused and must remain unconnected.

Pin/Terminal	Circuit Role	Design Meaning
A0–A12	Address Inputs	13-bit binary address bus-selects one of 8,192 bytes; TTL-compatible inputs
DQ0–DQ7	Data I/O	Bidirectional 8-bit data bus-high-impedance when CE or OE inactive
CE	Chip Enable	Active-low chip select-must be low for read/write; enables internal logic and memory array
WE	Write Enable	Active-low write strobe-controls data latching; disables outputs when asserted during reads
OE	Output Enable	Active-low output control-gates data drivers; high during writes to prevent bus contention
V_CC	Power Supply	+5 V supply (4.5–5.5 V)-powers logic and RAM; triggers lithium activation on first power-up
GND	Ground	Reference return path-must be low-impedance; shared with system ground plane
NC	No Connect	Pins 14 and 24-internally unconnected; must float or tie to GND per layout best practice

Key Features

Feature	Design Value
Automatic Power-Fail Switchover	Seamless transition to lithium backup at ~3.0 V without software intervention or external supervision
Freshness Seal	Lithium cell electrically disconnected until first V_CC application-ensures full 10-year retention capacity
Unlimited Write Cycles	No endurance limit-enables real-time logging, configuration storage, and firmware patching in field-deployed units
Direct EPROM/EEPROM Replacement	Pins match 2764 (EPROM) and 2864 (EEPROM)-allows drop-in upgrade without PCB redesign
Wide V_CC Tolerance	±10% operation (4.5–5.5 V)-eliminates need for precision regulators in cost-sensitive industrial hardware

Applications

Industrial Data Logger	Legacy PLC Memory Module
Use Scenario: Standalone environmental sensor node recording temperature, pressure, and humidity every 5 seconds into nonvolatile memory during mains failure. IC Role / Device Role / Timing Role: Primary data buffer and retention store-holds up to 8,192 timestamped samples without refresh or external controller involvement. Use Value: Guarantees 10-year data integrity after power loss; eliminates need for external battery management or supercapacitor charging circuits.	Use Scenario: Retrofit memory upgrade for 1980s-era programmable logic controller replacing failing 2764 EPROM with writable, field-programmable storage. IC Role / Device Role / Timing Role: Drop-in replacement for read-only program memory-accepts same address/data/control signals but enables runtime firmware updates. Use Value: Enables in-field reprogramming without removing the module; retains ladder logic during power cycling and brown-outs.
Medical Device Configuration Store	Avionics Black Box Recorder
Use Scenario: Storing calibration coefficients, user preferences, and fault history in portable ultrasound equipment subject to frequent battery swaps and thermal cycling. IC Role / Device Role / Timing Role: Nonvolatile parameter register-retains settings across 10,000+ power cycles and –40°C to +85°C ambient swings. Use Value: Meets IEC 62304 Class B software requirements for persistent configuration; avoids EEPROM wear-out failures.	Use Scenario: Crash-protected flight data recorder capturing critical avionics bus messages during emergency descent where primary power may collapse abruptly. IC Role / Device Role / Timing Role: Last-resort memory buffer-captures final 8k bytes of ARINC 429 or MIL-STD-1553 traffic before total power loss. Use Value: Activates lithium backup within 1.5 µs of V_CC decay (t_PD), ensuring zero data loss during catastrophic power events.

Industrial Data Logger

Legacy PLC Memory Module

Use Scenario: Standalone environmental sensor node recording temperature, pressure, and humidity every 5 seconds into nonvolatile memory during mains failure.

IC Role / Device Role / Timing Role: Primary data buffer and retention store-holds up to 8,192 timestamped samples without refresh or external controller involvement.

Use Value: Guarantees 10-year data integrity after power loss; eliminates need for external battery management or supercapacitor charging circuits.

Use Scenario: Retrofit memory upgrade for 1980s-era programmable logic controller replacing failing 2764 EPROM with writable, field-programmable storage.

IC Role / Device Role / Timing Role: Drop-in replacement for read-only program memory-accepts same address/data/control signals but enables runtime firmware updates.

Use Value: Enables in-field reprogramming without removing the module; retains ladder logic during power cycling and brown-outs.

Medical Device Configuration Store

Avionics Black Box Recorder

Use Scenario: Storing calibration coefficients, user preferences, and fault history in portable ultrasound equipment subject to frequent battery swaps and thermal cycling.

IC Role / Device Role / Timing Role: Nonvolatile parameter register-retains settings across 10,000+ power cycles and –40°C to +85°C ambient swings.

Use Value: Meets IEC 62304 Class B software requirements for persistent configuration; avoids EEPROM wear-out failures.

Use Scenario: Crash-protected flight data recorder capturing critical avionics bus messages during emergency descent where primary power may collapse abruptly.

IC Role / Device Role / Timing Role: Last-resort memory buffer-captures final 8k bytes of ARINC 429 or MIL-STD-1553 traffic before total power loss.

Use Value: Activates lithium backup within 1.5 µs of V_CC decay (t_PD), ensuring zero data loss during catastrophic power events.

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 8k×8 organization and IND temp grade, but uses older "Y" suffix indicating prior revision; identical AC/DC specs and pinout	No functional difference-used interchangeably in legacy production where DS1225AD-200IND is unavailable	Select DS1225Y-70IND+ only if DS1225AD-200IND is out of stock; verify latest wafer lot qualification status with distributor
STK12C68-AW50I	64k-bit NV SRAM with 50 ns access time, same 28-pin DIP, but requires external capacitor for power-fail hold-up and lacks freshness seal	Higher speed but increased BOM count and reduced long-term reliability due to external capacitor aging	Prefer DS1225AD-200IND for new designs requiring guaranteed 10-year retention and zero-support-component implementation

Compared with DS1225Y-70IND+, DS1225AD-200IND offers identical functionality with updated process qualification; compared with STK12C68-AW50I, DS1225AD-200IND delivers superior reliability through integrated lithium management and eliminates capacitor-dependent retention margins.

Availability

DS1225AD-200IND is available at Aetrix Electronics and suitable for industrial data loggers, legacy PLC retrofits, medical device configuration stores, and avionics black box recorders requiring stable component supply across extended product lifecycles.

Supply support for DS1225AD-200IND 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 high-reliability analog, mixed-signal, and nonvolatile memory solutions for industrial, medical, and aerospace applications.

The DS1225AB/AD family was designed specifically to replace aging EPROM and EEPROM modules in mission-critical systems where data integrity during power interruption is non-negotiable-prioritizing retention guarantee, pin compatibility, and zero-support-component integration.

FAQ

What is the guaranteed data retention period for DS1225AD-200IND?

The DS1225AD-200IND 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 enabled by its sealed lithium energy source and automatic power switchover circuitry, which activates only when V_CC drops below ~3.0 V. The specification is design-guaranteed and not 100% tested per unit.

Does DS1225AD-200IND require external support components for battery backup operation?

No, DS1225AD-200IND requires no external capacitors, diodes, or supervisory ICs. Its integrated lithium cell, power-fail detector, and switchover logic are fully self-contained. The "freshness seal" ensures the battery remains disconnected until first power application, preserving full capacity for the rated 10-year retention period.

Is DS1225AD-200IND pin-compatible with standard 2764 EPROMs and 2864 EEPROMs?

Yes, DS1225AD-200IND uses the exact same 28-pin DIP pinout as the 2764 EPROM and 2864 EEPROM, including identical address (A0–A12), data (DQ0–DQ7), and control (CE, OE, WE) signal assignments. This allows direct socket replacement in legacy designs without PCB modification or firmware changes.

What is the write protection voltage threshold for DS1225AD-200IND?

The DS1225AD-200IND asserts unconditional write protection when V_CC falls below its specified write protection voltage (V_TP) of 4.25 V (min) to 4.5 V (max). This prevents data corruption during brown-out conditions and precedes full lithium switchover at ~3.0 V, providing two-stage power-loss defense.

Can DS1225AD-200IND operate across the full industrial temperature range without derating?

Yes, DS1225AD-200IND is fully specified and qualified for continuous operation from –40°C to +85°C. All DC and AC electrical characteristics-including 70 ns access time, standby current (≤10 mA), and input leakage (±1.0 µA)-are guaranteed across this range, making it suitable for uncontrolled industrial environments and outdoor deployments.

DS1225AD-200IND 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:: 200ns

Access Time:: 200 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-200IND FAQ

1.How can I place an order for DS1225AD-200IND through Aetrix?

Please submit a Request for Quotation (RFQ) for DS1225AD-200IND 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-200IND reliable?

The price and inventory of DS1225AD-200IND are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS1225AD-200IND is usually 5 days.

3.What payment methods are accepted for DS1225AD-200IND?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS1225AD-200IND transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for DS1225AD-200IND?

DS1225AD-200IND orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your DS1225AD-200IND 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-200IND?

For technical support, including DS1225AD-200IND datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS1225AD-200IND requirements.

6.How does Aetrix verify that DS1225AD-200IND is sourced from the original manufacturer or authorized distributors?

All DS1225AD-200IND 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-200IND meets industry standards.

7.What is the process for return or replacement of DS1225AD-200IND?

All DS1225AD-200IND units undergo pre-shipment inspection (PSI). If there is an issue with DS1225AD-200IND, 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-200IND part is unused and in its original packaging.

Return procedure for DS1225AD-200IND:

1.Submit a request within 90 days.

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

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