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

Analog Devices Inc./Maxim Integrated DS1225AB-200

Name: DS1225AB-200
Brand: Analog Devices Inc./Maxim Integrated
SKU: DS1225AB-200
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: DS1225AB-200

Manufacturer:: Analog Devices Inc./Maxim Integrated

Category:: Memory

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

Datasheet:: DS1225AB-200.pdf

Description:: IC NVSRAM 64KBIT PARALLEL 28EDIP

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Product details

Overview

DS1225AB-200 from Maxim Integrated is a 64k-bit (8192 × 8) nonvolatile static RAM with integrated lithium battery backup, designed as a direct pin-compatible replacement for 8k × 8 volatile SRAMs and EEPROMs. It features 70 ns read/write access time, ±5% V_CC tolerance (4.75 V to 5.25 V), automatic write protection below 4.5 V, and guaranteed 10-year data retention without external power in commercial temperature range (0°C to +70°C).

For engineers reviewing the DS1225AB-200 datasheet, DS1225AB-200 pinout, DS1225AB-200 application, or DS1225AB-200 equivalent, key selection considerations include its self-contained power-fail detection circuitry, JEDEC-standard 28-pin extended DIP package, no external support components required, and compatibility with 2764 EPROM/2864 EEPROM footprints.

Technical Context

The DS1225AB-200 integrates a CMOS SRAM core with on-chip voltage monitoring, lithium energy source, and analog power-switching logic that autonomously transitions between V_CC and battery power at ~3.0 V. Its control architecture enforces unconditional write protection when V_CC drops below V_TP = 4.50–4.75 V, placing all inputs in "don't care" state and outputs in high-impedance mode.

It operates in three distinct modes: normal read/write (V_CC ≥ 4.75 V), data retention (V_CC < 3.0 V, lithium active), and transitional power-down/power-up (3.0 V ≤ V_CC < 4.75 V), with t_PD = 1.5 µs fail-detect latency and t_REC = 125 ms write-protection enable delay after V_CC validity.

Key Specifications

Parameter	Value and Actual Design Meaning
Memory Size	65,536 bits (8192 words × 8 bits); matches byte-wide 8k × 8 memory map of legacy SRAM/EPROM designs.
Access Time	70 ns max t_ACC; enables direct drop-in replacement in systems clocked up to ~14 MHz bus timing.
V_CC Tolerance	±5% (4.75 V to 5.25 V); supports stable operation across standard 5 V supply rails with typical regulation drift.
Data Retention	10 years minimum without external power; guaranteed by design using sealed lithium cell disconnected until first power-up.
Write Protection Threshold	V_TP = 4.50–4.75 V; triggers automatic hardware lockout before V_CC reaches levels risking SRAM corruption.
Operating Temperature	0°C to +70°C (Commercial grade); validated for use in industrial control panels and telecom line cards without derating.
Package	28-pin 720-mil Extended DIP (EDIP); JEDEC-compliant footprint compatible with 2764 EPROM and 2864 EEPROM sockets.

Pinout & Package

DS1225AB-200 uses a 28-pin 720-mil Extended Dual In-line Package (EDIP) with through-hole mounting and wave/hand soldering capability. Pin 1 is located at the left end of the top row (standard DIP orientation).

Pin/Terminal	Circuit Role	Design Meaning
A0–A12	Address Inputs	13-bit address bus interface; selects one of 8192 memory locations during read/write cycles.
DQ0–DQ7	Data I/O	Bidirectional 8-bit data bus; tri-stated automatically during write cycles when OE is high or CE/WE inactive.
CE	Chip Enable	Active-low chip select; initiates read/write when low and coordinates timing with WE/OE per JEDEC SRAM protocol.
WE	Write Enable	Active-low write strobe; controls data latching and disables outputs during write to prevent bus contention.
OE	Output Enable	Active-low output control; enables data drivers only during read cycles when CE and WE are properly asserted.
V_CC	Power Supply	+5 V ±5% main supply; powers SRAM core and monitoring circuitry; disconnects lithium source above ~3.0 V.
GND	Ground	Reference return path for all digital and analog functions; must be low-impedance to ensure reliable power-switching transition.
NC	No Connect	Pins 14 and 24 are unconnected; no internal bonding or function-must remain floating or grounded per PCB layout best practice.

Key Features

Feature	Design Value
Self-contained lithium backup	Eliminates need for external battery management ICs, diodes, or capacitors-reduces BOM count and board space.
Automatic power-fail detection	Hardware-level V_CC monitoring with 1.5 µs response ensures zero-cycle data loss during brownout or sudden power loss.
Unlimited write endurance	Supports infinite write cycles without wear-out-enables frequent logging, configuration storage, or real-time parameter updates.
Freshness seal activation	Lithium source remains electrically isolated until first V_CC application > V_TP, preserving full 10-year retention capacity from shipment.
Direct EPROM/EEPROM replacement	Identical pinout to 2764 (8k × 8 EPROM) and 2864 (8k × 8 EEPROM), enabling firmware upgrade paths without PCB redesign.

Applications

Industrial Data Logger	Telecom Line Card
Use Scenario: Continuous timestamped sensor readings stored during mains failure in remote environmental monitoring stations. IC Role / Device Role / Timing Role: Nonvolatile SRAM acting as last-known-state buffer with autonomous write protection triggered at 4.5 V threshold. Use Value: Guarantees 10-year retention of critical calibration and event logs without external battery maintenance or supercapacitor recharge circuitry.	Use Scenario: Storing provisioning tables and port configuration data in carrier-grade DSLAMs subject to frequent power cycling. IC Role / Device Role / Timing Role: Byte-wide memory mapped into microcontroller address space; accessed via standard SRAM timing with 70 ns t_ACC. Use Value: Enables instant recovery after reboot with zero boot-time initialization delay-no EEPROM page-write wait or flash erase overhead.
Medical Diagnostic Controller	Automated Test Equipment (ATE)
Use Scenario: Holding patient-specific calibration offsets and safety-critical fault history in portable ultrasound units with intermittent AC/DC operation. IC Role / Device Role / Timing Role: Directly replaces legacy 6264 SRAM; retains data during battery-swaps or unplanned shutdowns. Use Value: Meets IEC 62304 Class C software requirements for persistent state retention without external supervision or watchdog intervention.	Use Scenario: Storing test pattern sequences and pass/fail results in benchtop ATE systems undergoing thermal stress testing. IC Role / Device Role / Timing Role: Memory-mapped scratchpad for FPGA-based pattern generators; accessed synchronously with 50 MHz system clock. Use Value: Eliminates test interruption due to nonvolatile write latency-supports continuous high-speed vector streaming without stall cycles.

Industrial Data Logger

Telecom Line Card

Use Scenario: Continuous timestamped sensor readings stored during mains failure in remote environmental monitoring stations.

IC Role / Device Role / Timing Role: Nonvolatile SRAM acting as last-known-state buffer with autonomous write protection triggered at 4.5 V threshold.

Use Value: Guarantees 10-year retention of critical calibration and event logs without external battery maintenance or supercapacitor recharge circuitry.

Use Scenario: Storing provisioning tables and port configuration data in carrier-grade DSLAMs subject to frequent power cycling.

IC Role / Device Role / Timing Role: Byte-wide memory mapped into microcontroller address space; accessed via standard SRAM timing with 70 ns t_ACC.

Use Value: Enables instant recovery after reboot with zero boot-time initialization delay-no EEPROM page-write wait or flash erase overhead.

Medical Diagnostic Controller

Automated Test Equipment (ATE)

Use Scenario: Holding patient-specific calibration offsets and safety-critical fault history in portable ultrasound units with intermittent AC/DC operation.

IC Role / Device Role / Timing Role: Directly replaces legacy 6264 SRAM; retains data during battery-swaps or unplanned shutdowns.

Use Value: Meets IEC 62304 Class C software requirements for persistent state retention without external supervision or watchdog intervention.

Use Scenario: Storing test pattern sequences and pass/fail results in benchtop ATE systems undergoing thermal stress testing.

IC Role / Device Role / Timing Role: Memory-mapped scratchpad for FPGA-based pattern generators; accessed synchronously with 50 MHz system clock.

Use Value: Eliminates test interruption due to nonvolatile write latency-supports continuous high-speed vector streaming without stall cycles.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
DS1225AD-70+	Wider V_CC tolerance (±10%, 4.5 V–5.5 V); lower V_TP (4.25–4.5 V); same 70 ns speed and EDIP package.	Preferred in systems with poorly regulated 5 V supplies or wider ambient temperature swings where tighter V_TP margin is acceptable.	Select DS1225AD-70+ only if supply variation exceeds ±5% or industrial temp range (-40°C to +85°C) is required.
STK12C68-E25	Same 64k NV SRAM function but 25 ns access time; 28-pin DIP; requires external capacitor for power-fail holdup (not self-contained).	Used where faster access is mandatory and board area allows discrete holdup capacitor placement.	Choose STK12C68-E25 only when sub-30 ns timing is needed and external capacitor integration is feasible.

Compared with DS1225AD-70+, the DS1225AB-200 offers tighter supply regulation tolerance and higher write-protection threshold-critical for systems with clean 5 V rails where early lockout prevents spurious writes during marginal V_CC. Versus STK12C68-E25, DS1225AB-200 eliminates external holdup components and guarantees retention without design-dependent capacitor sizing.

Availability

DS1225AB-200 is available at Aetrix Electronics and suitable for industrial data loggers, telecom line cards, medical diagnostic controllers, and automated test equipment requiring stable component supply, long-life data retention, and drop-in compatibility with legacy 28-pin memory sockets.

Supply support for DS1225AB-200 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-200 belongs to Maxim's nonvolatile SRAM product line, engineered to replace battery-backed volatile memory in mission-critical systems where data integrity during power loss is non-negotiable.

FAQ

What is the guaranteed data retention period for DS1225AB-200?

The DS1225AB-200 guarantees a minimum 10-year data retention period in the absence of external power, starting from the moment V_CC is first applied and the internal lithium energy source is activated. This value is design-guaranteed-not 100% tested-and assumes proper handling per Maxim's freshness seal specification. The DS1225AB-200 achieves this using a hermetically sealed lithium cell disconnected until initial power-up.

Does DS1225AB-200 require external components for battery backup operation?

No, the DS1225AB-200 requires no external components for battery backup operation. It integrates a lithium energy source, voltage monitor, and power-switching circuitry within the 28-pin EDIP package. Unlike hybrid solutions, the DS1225AB-200 autonomously manages V_CC-to-battery handover at ~3.0 V without capacitors, diodes, or supervisory ICs-making it a true single-component NV SRAM solution.

Is DS1225AB-200 pin-compatible with standard 2764 EPROMs?

Yes, the DS1225AB-200 is fully pin-compatible with the 2764 EPROM (8k × 8) and 2864 EEPROM, sharing identical 28-pin DIP pinout, address/data bus mapping, and control signal assignments (CE, OE, WE). This allows direct socket replacement in existing designs without PCB modification-enabling immediate performance and reliability upgrades over UV-erasable or slow-write nonvolatile memory.

What is the write protection voltage threshold for DS1225AB-200?

The DS1225AB-200 asserts hardware write protection when V_CC falls below V_TP = 4.50 V (min) to 4.75 V (max), as specified in its DC Electrical Characteristics table. This threshold is tighter than the DS1225AD variant (4.25–4.5 V), making DS1225AB-200 more conservative in locking out writes during marginal supply conditions-ideal for systems with tightly regulated 5 V rails.

Can DS1225AB-200 operate across industrial temperature range?

No, the DS1225AB-200 is rated for commercial temperature range only (0°C to +70°C). For industrial operation (-40°C to +85°C), the designated part is DS1225AB-70IND+, which shares identical electrical specifications and package but is screened and qualified for extended temperature performance. Using DS1225AB-200 outside 0°C–70°C voids its guaranteed retention and timing specifications.

DS1225AB-200 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:: 4.75V ~ 5.25V

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: 28-EDIP

DS1225AB-200 FAQ

1.How can I place an order for DS1225AB-200 through Aetrix?

Please submit a Request for Quotation (RFQ) for DS1225AB-200 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 DS1225AB-200 reliable?

The price and inventory of DS1225AB-200 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS1225AB-200 is usually 5 days.

3.What payment methods are accepted for DS1225AB-200?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS1225AB-200 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for DS1225AB-200?

DS1225AB-200 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your DS1225AB-200 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 DS1225AB-200?

For technical support, including DS1225AB-200 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS1225AB-200 requirements.

6.How does Aetrix verify that DS1225AB-200 is sourced from the original manufacturer or authorized distributors?

All DS1225AB-200 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 DS1225AB-200 meets industry standards.

7.What is the process for return or replacement of DS1225AB-200?

All DS1225AB-200 units undergo pre-shipment inspection (PSI). If there is an issue with DS1225AB-200, 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 DS1225AB-200 part is unused and in its original packaging.

Return procedure for DS1225AB-200:

1.Submit a request within 90 days.

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

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