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Analog Devices Inc./Maxim Integrated DS1225AD-70IND+
- 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:
- Payment:
- Shipping:
Inventory:3,342
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Product details
Overview
DS1225AD-70IND+ 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, and industrial temperature range (–40°C to +85°C). It replaces volatile SRAMs and EEPROMs in systems requiring automatic data retention during power loss, such as industrial PLCs and embedded data loggers.
For engineers reviewing the DS1225AD-70IND+ datasheet, DS1225AD-70IND+ pinout, DS1225AD-70IND+ application, or DS1225AD-70IND+ equivalent, key selection criteria include VCC tolerance (±10%), write-protection threshold (4.25 V), data retention guarantee (10 years), and compatibility with 2764 EPROM/2864 EEPROM footprints.
Technical Context
The DS1225AD-70IND+ integrates self-contained lithium power switching circuitry that monitors VCC continuously and triggers automatic write protection when voltage falls below 4.25 V. At ~3.0 V, it seamlessly switches to internal battery power while placing all I/Os in high-impedance state.
It operates as a fully static, byte-wide memory with no external support circuitry required. Its timing conforms to standard SRAM protocols: CE/OE-controlled read cycles and WE/CE-synchronized writes, with tACC = 70 ns, tWC = 70 ns, and tOE = 35 ns under VCC = 5 V ±10%.
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 - ensures compatibility with 14 MHz Z80, 8086, and 68000-based bus systems |
| VCC Range | 4.5 V to 5.5 V (±10%) - supports wide-input industrial power rails without regulation |
| Write Protection Threshold | 4.25 V (min) - initiates automatic data safeguarding before brownout corruption occurs |
| Data Retention | 10 years minimum without external power - guaranteed by sealed lithium cell and freshness seal activation on first power-up |
| Operating Temperature | –40°C to +85°C - qualified for uncontrolled industrial enclosures and outdoor telemetry nodes |
| Package | 28-pin 720-mil extended DIP - matches legacy board layouts for drop-in replacement |
Pinout & Package
DS1225AD-70IND+ uses a JEDEC-standard 28-pin extended dual in-line package (EDIP), 720 mil width, RoHS-compliant (indicated by '+' suffix).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A12 | Address Inputs | 13-bit address bus for selecting one of 8,192 memory locations |
| DQ0–DQ7 | Bidirectional Data Bus | 8-bit parallel interface compatible with microprocessor data buses |
| CE | Chip Enable | Active-low chip select; enables memory access only when low |
| WE | Write Enable | Active-low control for write cycles; disables outputs during write if OE is active |
| OE | Output Enable | Active-low control for read data output drivers; high during writes to prevent bus contention |
| VCC | Power Supply | +5 V supply input; powers logic and controls lithium switch activation threshold |
| GND | Ground Reference | Common return path for logic and backup circuitry |
| NC | No Connect | Pins 14 and 24 are internally unused; must remain unconnected |
Key Features
| Feature | Design Value |
|---|---|
| Automatic Power-Fail Detection | Monitors VCC continuously and initiates write protection within 1.5 µs of out-of-tolerance condition |
| Freshness Seal Activation | Lithium cell remains electrically disconnected until first VCC > VTP, preserving full 10-year retention capacity |
| Unlimited Write Cycles | No endurance limit - supports continuous logging or real-time configuration updates without wear-out |
| Direct Pin Compatibility | Matches 2764 EPROM and 2864 EEPROM pinouts, enabling hardware reuse without PCB redesign |
| Low-Power CMOS Operation | Standby current ≤5 mA (ICCS2) and operating current ≤85 mA (industrial temp) reduce thermal load |
Applications
| Industrial Data Logger | PLC Configuration Memory |
|---|---|
Use Scenario: Continuous timestamped sensor readings stored during mains failure and recovered on reboot. IC Role / Device Role / Timing Role: Nonvolatile SRAM providing immediate-access, battery-backed storage with zero software overhead. Use Value: Eliminates need for external EEPROM write delays or flash wear-leveling firmware; retains data across 10+ years of intermittent operation. | Use Scenario: Storing ladder logic parameters and I/O mapping in programmable logic controllers deployed in factory environments. IC Role / Device Role / Timing Role: Direct-replacement memory holding critical runtime configuration with immunity to voltage sags. Use Value: Prevents configuration loss during brownouts common in motor-driven industrial power systems. |
| Medical Device Event Recorder | Avionics Black Box Buffer |
Use Scenario: Capturing diagnostic events and fault codes in portable ultrasound or infusion pumps with unpredictable power cycles. IC Role / Device Role / Timing Role: High-reliability, low-latency memory buffer retaining last 8 kB of operational history. Use Value: Meets IEC 62304 Class C data integrity requirements without external backup capacitors or supervisory ICs. | Use Scenario: Temporary storage of flight parameter snapshots prior to secure transfer to long-term flash in aircraft monitoring units. IC Role / Device Role / Timing Role: Fast-access, tamper-resistant memory stage synchronized to ARINC 429 or MIL-STD-1553 timing windows. Use Value: Guarantees capture of final 8 kB of pre-crash telemetry even during abrupt power loss. |
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 70 ns speed, but uses older lithium chemistry with 5-year retention guarantee and higher standby current (15 mA) | Not rated for extended 10-year field deployment; suitable for short-life test equipment | Select DS1225Y-70IND+ only where cost sensitivity outweighs retention longevity and power budget constraints |
| STK12C68-A70I | Pin-compatible 8k×8 NV SRAM with 70 ns access, but requires external capacitor for power-fail detection and has 5-year retention | Lacks integrated power-switching logic; demands additional BOM components and layout space | Choose STK12C68-A70I only when existing designs already include discrete power-fail circuitry and capacitor footprint |
Compared with DS1225Y-70IND+ and STK12C68-A70I, the DS1225AD-70IND+ delivers superior long-term data integrity (10 years vs. 5), lower system-level component count (no external cap or supervisor), and tighter VTP tolerance (4.25 V vs. 4.5 V), making it optimal for mission-critical industrial and medical deployments.
Availability
DS1225AD-70IND+ is available at Aetrix Electronics and suitable for industrial data loggers, PLC configuration storage, and medical event recorders requiring stable component supply across extended product lifecycles.
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 high-reliability power solutions for industrial, medical, and communications markets.
The DS1225AD-70IND+ belongs to Maxim's legacy nonvolatile SRAM product line, engineered specifically for systems demanding seamless, zero-software-intervention data retention during uncontrolled power interruptions.
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 VCC is first applied and the internal lithium cell is activated. This specification is design-guaranteed per Maxim's reliability testing and documented in the device's datasheet revision history and DC characteristics table.
Does DS1225AD-70IND+ require external support components for battery backup operation?
No, the DS1225AD-70IND+ requires no external components for nonvolatile operation. Its integrated lithium energy source and power-switching circuitry automatically engage during power loss, and the freshness seal ensures full battery capacity is preserved until first power-up. No capacitors, supervisors, or charge pumps are needed.
Is DS1225AD-70IND+ pin-compatible with standard 2764 EPROMs?
Yes, the DS1225AD-70IND+ 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 hardware substitution without PCB modification.
What is the write-protection voltage threshold for DS1225AD-70IND+?
The DS1225AD-70IND+ initiates automatic write protection when VCC falls below 4.25 V (minimum), with typical activation at 4.37 V and maximum at 4.5 V. This threshold is tighter than the DS1225AB variant (4.5 V min) and ensures earlier safeguarding against marginal supply conditions.
Can DS1225AD-70IND+ operate across the full industrial temperature range?
Yes, the DS1225AD-70IND+ is fully specified and tested for continuous operation from –40°C to +85°C. All AC and DC electrical characteristics-including 70 ns access time, 4.5 V to 5.5 V VCC range, and 10-year retention-are validated across this industrial temperature range per datasheet Note 10.
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:
- 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:
- 4.5V ~ 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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