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Analog Devices Inc./Maxim Integrated DS1225AB-70IND+
- Part No.:
- DS1225AB-70IND+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Memory
- Package:
- 28-DIP Module (0.600", 15.24mm)
- Datasheet:
-
DS1225AB-70IND+.pdf
- Description:
- IC NVSRAM 64KBIT PARALLEL 28EDIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,257
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Product details
Overview
DS1225AB-70IND+ from Maxim Integrated is a 64k-bit (8192 × 8) nonvolatile static RAM with lithium-backed data retention, 70 ns read/write access time, ±5% VCC tolerance (4.75–5.25 V), and industrial temperature operation (–40°C to +85°C). It replaces volatile SRAMs and EEPROMs in battery-free memory backup applications such as real-time clock registers and configuration storage.
For engineers reviewing the DS1225AB-70IND+ datasheet, DS1225AB-70IND+ pinout, DS1225AB-70IND+ application, or DS1225AB-70IND+ equivalent, key selection criteria include guaranteed 10-year data retention without external power, automatic write protection during VCC failure, JEDEC-standard 28-pin DIP compatibility, and direct substitution for 2764 EPROM/2864 EEPROM footprints.
Technical Context
The DS1225AB-70IND+ integrates self-contained lithium energy source and voltage-monitoring circuitry that triggers seamless switchover to battery backup when VCC drops below 4.5 V (VTP). Its control logic unconditionally enables write protection and places all I/Os in high-impedance state before VCC falls below ~3.0 V.
It operates as a fully static, byte-wide parallel memory with standard SRAM timing: CE/OE/WE-controlled read/write cycles, no refresh required, and full compatibility with microprocessor bus protocols. The device matches the pinout and timing of 28-pin 8k×8 memories while adding nonvolatility without external support components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 65,536 bits (8192 words × 8 bits); supports direct replacement of 8k×8 SRAM/EPROM/EEPROM |
| Access Time | 70 ns max tACC; ensures compatibility with 14 MHz Z80, 8086, and 68000-based systems |
| VCC Range | 4.75 V to 5.25 V (±5%); stable operation across industrial-grade power rails |
| Data Retention | ≥10 years without external power; enabled by sealed lithium cell activated only on first power-up |
| Operating Temp | –40°C to +85°C (IND grade); qualified for industrial control, metering, and telecom infrastructure |
| Write Cycles | Unlimited; no wear-out mechanism unlike EEPROM or Flash |
| Package | 28-pin 720-mil extended DIP (EDIP); JEDEC MS-011AC compliant, wave-solderable |
Pinout & Package
DS1225AB-70IND+ uses a 28-pin 720-mil extended dual in-line package (EDIP), RoHS-compliant (indicated by '+' suffix), with through-hole mounting and wave-solder process compatibility.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A12 | Address Inputs | 13-bit address bus interface; selects one of 8192 memory locations |
| DQ0–DQ7 | Data Input/Output | Bi-directional 8-bit data bus; TTL-compatible, high-impedance when disabled |
| CE | Chip Enable | Active-low chip select; disables internal circuitry and reduces ICCS2 standby current to ≤5 mA |
| WE | Write Enable | Active-low write strobe; controls data latching and output disable during writes (tODW = 25 ns) |
| OE | Output Enable | Active-low output enable; isolates DQ bus when high to prevent contention |
| VCC | Power Supply | +5 V ±5% main supply; powers logic and RAM array until switchover to lithium backup |
| GND | Ground | Reference return path for all signals and power domains |
| NC | No Connect | Pins 14 and 24 are unconnected; must remain floating per design |
Key Features
| Feature | Design Value |
|---|---|
| Automatic Power-Fail Detection | Monitors VCC continuously; initiates write protection and lithium switchover within 1.5 µs of VTP breach |
| Freshness Seal | Lithium cell electrically disconnected until first VCC application > VTP, preserving full 10-year capacity |
| Direct EPROM/EEPROM Replacement | Pinout and timing match 2764 EPROM and 2864 EEPROM; no PCB redesign needed |
| Zero External Support Circuitry | No external capacitors, diodes, or controllers required for nonvolatile operation or power-fail response |
| Industrial Temperature Qualification | Guaranteed functionality and data retention over –40°C to +85°C ambient, per ordering code IND |
Applications
| Industrial Programmable Logic Controllers (PLCs) | Smart Electricity Meters |
|---|---|
Use Scenario: Storing calibration coefficients, firmware patch flags, and event logs during mains power interruption. IC Role / Device Role / Timing Role: Nonvolatile SRAM providing immediate, byte-accessible memory backup without delay or software intervention. Use Value: Guarantees 10-year data integrity without supercapacitors or external battery management, reducing BOM count and field failure risk. |
Use Scenario: Retaining tariff schedules, tamper-event timestamps, and accumulated kWh readings during grid outages. IC Role / Device Role / Timing Role: Self-contained memory with automatic VCC-fail detection and lithium switchover at <3.0 V. Use Value: Eliminates need for separate RTC + NV memory ICs; meets IEC 62056 and ANSI C12.20 data retention requirements. |
| Telecom Line Cards | Medical Diagnostic Equipment |
Use Scenario: Preserving port configuration, alarm history, and provisioning data during hot-swap or power cycling. IC Role / Device Role / Timing Role: Parallel NV SRAM interfaced directly to local microcontroller bus with 70 ns timing. Use Value: Enables zero-downtime reconfiguration; avoids EEPROM write latency and endurance limits in high-change-rate environments. |
Use Scenario: Holding patient setup parameters, calibration offsets, and last-operating-state snapshots between power cycles. IC Role / Device Role / Timing Role: Fail-safe memory element with deterministic write-protection activation below 4.5 V. Use Value: Meets IEC 62304 Class B software safety requirements by preventing corrupted memory writes during brownout conditions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar nonvolatile SRAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| DS1225AD-70IND+ | Wider VCC range (4.5–5.5 V, ±10%), lower VTP (4.25 V); otherwise identical pinout, timing, and retention | Better suited for systems with looser power regulation or wider input transients | Select DS1225AD-70IND+ if VCC may dip below 4.75 V during normal operation but must retain data down to 4.25 V |
| STK12C68-E25I | Same 8k×8 organization and 28-pin DIP, but uses capacitor-based backup (not lithium); 5-year retention, 25 ns access | Lower cost, shorter retention, requires external capacitor and charge circuit | Choose STK12C68-E25I only if 10-year retention is not required and board space allows for 0.1–1 F tantalum capacitor |
Compared with DS1225AD-70IND+, the DS1225AB-70IND+ offers tighter VCC regulation tolerance and higher write-protection threshold-critical for stable 5 V rail systems-while STK12C68-E25I trades long-term reliability for lower BOM cost and faster access, but demands external support components.
Availability
DS1225AB-70IND+ is available at Aetrix Electronics and suitable for industrial programmable logic controllers, smart electricity meters, and telecom line cards requiring stable component supply, long-lifecycle assurance, and guaranteed nonvolatile memory performance under wide temperature and voltage variation.
Supply support for DS1225AB-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) designs precision analog, mixed-signal, and nonvolatile memory solutions for industrial, automotive, and communications markets.
The DS1225AB-70IND+ belongs to Maxim's legacy NV SRAM product line, engineered specifically for systems demanding fail-safe, maintenance-free memory backup without software or external hardware intervention.
FAQ
What is the guaranteed data retention period for DS1225AB-70IND+?
The DS1225AB-70IND+ guarantees ≥10 years of data retention in the absence of external power, measured from the time VCC is first applied and the internal lithium cell is activated. This value is design-guaranteed and based on accelerated life testing per Maxim's qualification standards-not extrapolated or estimated.
Does DS1225AB-70IND+ require external components for nonvolatile operation?
No, the DS1225AB-70IND+ requires no external capacitors, diodes, or controllers. Its integrated lithium energy source and voltage-monitoring circuitry operate autonomously. The "Freshness Seal" ensures full battery capacity is preserved until first power-up, eliminating pre-charge or conditioning steps.
Can DS1225AB-70IND+ be used as a drop-in replacement for 2764 EPROMs?
Yes, the DS1225AB-70IND+ matches the pinout, address/data bus structure, and timing of the 2764 EPROM (8k×8, 28-pin DIP). It supports identical CE/OE/WE control logic and requires no changes to existing PCB layout or firmware-only removal of UV-erasing or programming routines.
What happens to DS1225AB-70IND+ outputs during power loss?
When VCC falls below 4.5 V (VTP), the DS1225AB-70IND+ immediately disables all outputs (DQ0–DQ7 go high-impedance), ignores all address and control inputs, and switches to lithium backup. This prevents bus contention and data corruption during brownout conditions.
Is DS1225AB-70IND+ RoHS-compliant and lead-free?
Yes, the '+' suffix in DS1225AB-70IND+ explicitly denotes a lead(Pb)-free and RoHS-compliant package. It meets EU Directive 2011/65/EU and is qualified for wave soldering per JEDEC J-STD-020 moisture sensitivity level (MSL) requirements.
DS1225AB-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:
- 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:
- 70ns
- Access Time:
- 70 ns
- Voltage - Supply:
- 4.75V ~ 5.25V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 28-EDIP
DS1225AB-70IND+ FAQ
1.How can I place an order for DS1225AB-70IND+ through Aetrix?
Please submit a Request for Quotation (RFQ) for DS1225AB-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 DS1225AB-70IND+ reliable?
The price and inventory of DS1225AB-70IND+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS1225AB-70IND+ is usually 5 days.
3.What payment methods are accepted for DS1225AB-70IND+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS1225AB-70IND+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DS1225AB-70IND+?
DS1225AB-70IND+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DS1225AB-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 DS1225AB-70IND+?
For technical support, including DS1225AB-70IND+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS1225AB-70IND+ requirements.
6.How does Aetrix verify that DS1225AB-70IND+ is sourced from the original manufacturer or authorized distributors?
All DS1225AB-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 DS1225AB-70IND+ meets industry standards.
7.What is the process for return or replacement of DS1225AB-70IND+?
All DS1225AB-70IND+ units undergo pre-shipment inspection (PSI). If there is an issue with DS1225AB-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 DS1225AB-70IND+ part is unused and in its original packaging.
Return procedure for DS1225AB-70IND+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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