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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 64kbit (8k × 8) nonvolatile static RAM with integrated lithium battery backup, JEDEC-standard 28-pin extended DIP package, 70 ns read/write access time, ±5% V_CC tolerance (4.75–5.25 V), and industrial-grade data retention of ≥10 years without power. It replaces volatile SRAMs and EEPROMs in real-time clock, configuration storage, and firmware parameter retention applications.

For engineers reviewing the DS1225AB-200+ datasheet, DS1225AB-200+ pinout, DS1225AB-200+ application, or DS1225AB-200+ equivalent, key selection criteria include write-protection voltage threshold (4.50–4.75 V), automatic power-fail detection and switch-over timing (t_PD = 1.5 µs), and compatibility with 2764 EPROM/2864 EEPROM footprints.

Technical Context

The DS1225AB-200+ integrates a self-contained lithium energy source and analog voltage-monitoring circuitry that continuously tracks V_CC; when supply drops below 4.5 V (V_TP), it unconditionally enables write protection and switches to battery power within 1.5 µs. Its CMOS architecture supports unlimited write cycles and requires no external support circuitry for microprocessor interfacing.

It operates as a drop-in replacement for 8k × 8 SRAMs with identical address (A0–A12), data (DQ0–DQ7), and control (CE, WE, OE) pin assignments. The device maintains high-impedance outputs during power transition and guarantees data integrity across full commercial (0°C to +70°C) or industrial (–40°C to +85°C) temperature ranges.

Key Specifications

Parameter	Value and Actual Design Meaning
Memory Size	65,536 bits (8,192 words × 8 bits); matches standard 8k × 8 SRAM footprint and addressing
Access Time	70 ns t_ACC; ensures compatibility with 14 MHz bus systems without wait states
V_CC Tolerance	±5% (4.75 V to 5.25 V); tighter regulation than DS1225AD, reducing need for precision regulators
Write Protection Threshold	V_TP = 4.50–4.75 V; triggers automatic battery switchover before data corruption occurs
Data Retention	≥10 years without external power; guaranteed by design using sealed lithium cell disconnected until first power-up
Operating Temperature	Commercial grade: 0°C to +70°C; IND variant available for –40°C to +85°C environments
Package	28-pin 720-mil extended DIP (EDIP); JEDEC-compliant, wave-solderable, RoHS-compliant (+ suffix)

Pinout & Package

DS1225AB-200+ uses a 28-pin extended dual in-line package (EDIP), 720 mil width, with through-hole mounting and wave-solder compatibility. Pin 1 is top-left corner, pin 28 bottom-right, with NC pins at positions 14 and 25.

Pin/Terminal	Circuit Role	Design Meaning
A0–A12	Address Inputs	13-bit address bus supporting full 8k-word decoding; compatible with Z80, 8086, and 68K families
DQ0–DQ7	Bidirectional Data I/O	8-bit parallel data path; high-impedance during write cycles when OE is inactive
CE	Chip Enable	Active-low chip select; must be stable before address setup; controls device activation and power-down entry
WE	Write Enable	Active-low write strobe; determines write start/stop timing with CE; disables outputs 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	+5 V ±5%; powers logic and RAM array; disconnects lithium source during normal operation
GND	Ground Reference	Signal and power return; required for valid logic thresholds and battery-switching reference
NC	No Connect	Pins 14 and 25 are unconnected internally; must remain floating or grounded per layout guidelines

Key Features

Feature	Design Value
Automatic Power-Fail Detection	Monitors V_CC continuously; initiates write protection and battery switchover within 1.5 µs of V_TP breach
Lithium Freshness Seal	Lithium cell electrically isolated until first V_CC application > V_TP, preserving full 10-year retention capacity
Unlimited Write Cycles	No endurance limit on SRAM core; eliminates wear-leveling firmware overhead required for EEPROM/Flash
Direct EPROM/EEPROM Replacement	Pinout matches 2764 EPROM and 2864 EEPROM; enables legacy system upgrades without PCB redesign
Low-Power CMOS Operation	Standby current ≤5 mA (ICCS2); reduces thermal load and extends battery life in backup mode

Applications

Real-Time Clock (RTC) Backup	Firmware Configuration Storage
Use Scenario: Maintaining RTC registers and calendar data during AC power loss in industrial controllers. IC Role / Device Role / Timing Role: Nonvolatile SRAM providing zero-latency, byte-addressable storage for timekeeping registers. Use Value: Eliminates need for separate RTC IC with battery and NVRAM; retains accuracy across 10+ year deployments without maintenance.	Use Scenario: Storing calibration coefficients, network settings, and user preferences in medical diagnostic equipment. IC Role / Device Role / Timing Role: Parameter memory holding critical configuration data between power cycles. Use Value: Guarantees instant restoration of operational state after unexpected shutdown; avoids factory recalibration.
Industrial PLC Data Logging	Legacy System Memory Upgrade
Use Scenario: Capturing sensor event timestamps and fault logs in programmable logic controllers operating in harsh environments. IC Role / Device Role / Timing Role: High-reliability buffer memory retaining last-known operational state during brownouts. Use Value: Enables deterministic recovery and root-cause analysis via preserved log history, even after extended power loss.	Use Scenario: Replacing aging 2764 EPROMs in vintage test instrumentation where firmware updates are infrequent but critical. IC Role / Device Role / Timing Role: Drop-in nonvolatile memory with identical pinout and faster 70 ns access vs. EPROM's 250+ ns erase/write latency. Use Value: Delivers immediate read performance improvement and eliminates UV eraser dependency while maintaining board compatibility.

Real-Time Clock (RTC) Backup

Firmware Configuration Storage

Use Scenario: Maintaining RTC registers and calendar data during AC power loss in industrial controllers.

IC Role / Device Role / Timing Role: Nonvolatile SRAM providing zero-latency, byte-addressable storage for timekeeping registers.

Use Value: Eliminates need for separate RTC IC with battery and NVRAM; retains accuracy across 10+ year deployments without maintenance.

Use Scenario: Storing calibration coefficients, network settings, and user preferences in medical diagnostic equipment.

IC Role / Device Role / Timing Role: Parameter memory holding critical configuration data between power cycles.

Use Value: Guarantees instant restoration of operational state after unexpected shutdown; avoids factory recalibration.

Industrial PLC Data Logging

Legacy System Memory Upgrade

Use Scenario: Capturing sensor event timestamps and fault logs in programmable logic controllers operating in harsh environments.

IC Role / Device Role / Timing Role: High-reliability buffer memory retaining last-known operational state during brownouts.

Use Value: Enables deterministic recovery and root-cause analysis via preserved log history, even after extended power loss.

Use Scenario: Replacing aging 2764 EPROMs in vintage test instrumentation where firmware updates are infrequent but critical.

IC Role / Device Role / Timing Role: Drop-in nonvolatile memory with identical pinout and faster 70 ns access vs. EPROM's 250+ ns erase/write latency.

Use Value: Delivers immediate read performance improvement and eliminates UV eraser dependency while maintaining board compatibility.

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%, 4.5–5.5 V); lower V_TP (4.25–4.5 V); same speed, package, and retention	Better suited for systems with less-regulated 5 V rails or wider input voltage variation	Select DS1225AD-70+ when supply stability is marginal; DS1225AB-200+ preferred for tightly regulated 5 V designs
STK12C68-70I	Same 8k × 8 organization and 70 ns speed; uses capacitor-based backup (not lithium); shorter retention (~5 years)	Lower cost, no battery handling restrictions, but requires external capacitor and charging circuit	Choose STK12C68-70I for cost-sensitive, short-lifecycle products where 10-year retention is not mandatory

Compared with DS1225AD-70+, DS1225AB-200+ offers tighter V_CC regulation and higher write-protection threshold-critical for noise-immune operation in clean power domains-while STK12C68-70I trades long-term reliability for simpler BOM and no battery compliance constraints.

Availability

DS1225AB-200+ is available at Aetrix Electronics and suitable for real-time clock backup, firmware configuration storage, and industrial PLC data logging requiring stable component supply, long-life data retention, and RoHS-compliant through-hole packaging.

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, designed specifically to replace volatile memory and legacy EPROM/EEPROM in systems demanding guaranteed data retention during unpredictable power loss.

FAQ

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

The DS1225AB-200+ guarantees ≥10 years of data retention in the absence of external power, based on its sealed lithium energy source and internal power-fail detection circuitry. This retention period begins after first application of V_CC and accumulates only during battery-backed operation-not during powered operation. The DS1225AB-200+ achieves this without external capacitors or charging circuits, making it ideal for maintenance-free deployments in inaccessible locations.

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

No, the DS1225AB-200+ requires no external support components for battery backup operation. Its integrated lithium cell and analog monitoring circuitry handle all power switchover, write protection, and voltage threshold detection autonomously. Unlike capacitor-backed NV SRAMs, the DS1225AB-200+ does not need external charging resistors, diodes, or timing capacitors-reducing BOM count and simplifying layout while ensuring consistent 10-year retention.

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

Yes, DS1225AB-200+ is pin-compatible with 2764 EPROMs and 2864 EEPROMs, sharing identical 28-pin DIP pinout, address/data/control signal mapping, and JEDEC-standard footprint. This allows direct substitution in legacy designs without PCB modification. The DS1225AB-200+ also matches timing parameters such as t_ACC (70 ns), enabling faster read access than typical 2764 devices (250–450 ns), with no change to existing microprocessor interface logic.

What is the write protection voltage threshold (V_TP) for DS1225AB-200+?

The DS1225AB-200+ has a write protection voltage threshold (V_TP) of 4.50–4.75 V, meaning it automatically disables writes and initiates battery switchover when V_CC falls within this range. This tighter threshold compared to the DS1225AD variant (4.25–4.5 V) provides earlier intervention against marginal supply conditions, preventing partial writes and ensuring data integrity in systems with well-regulated 5 V supplies.

Can DS1225AB-200+ operate across industrial temperature ranges?

The DS1225AB-200+ is specified for commercial temperature range (0°C to +70°C). For industrial operation (–40°C to +85°C), the correct variant is DS1225AB-70IND+, which shares identical electrical specifications, pinout, and retention performance-but undergoes extended temperature screening. Using DS1225AB-200+ outside its rated range may compromise data retention, timing margins, and long-term reliability.

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:: Active

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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