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Analog Devices Inc./Maxim Integrated DS1225AB-150IND
- Part No.:
- DS1225AB-150IND
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Memory
- Package:
- 28-DIP Module (0.600", 15.24mm)
- Datasheet:
-
DS1225AB-150IND.pdf
- Description:
- IC NVSRAM 64KBIT PARALLEL 28EDIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,231
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Product details
Overview
DS1225AB-150IND 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 access time, and industrial temperature range (–40°C to +85°C). It replaces volatile SRAMs and EEPROMs in mission-critical data logging systems where power loss protection is essential.
For engineers reviewing the DS1225AB-150IND datasheet, DS1225AB-150IND pinout, DS1225AB-150IND application, or DS1225AB-150IND equivalent, key selection criteria include write-protection voltage threshold (4.5 V), unlimited write cycles, automatic VCC-fail detection, ±5% VCC tolerance, and direct compatibility with 2764 EPROM/2864 EEPROM footprints.
Technical Context
The DS1225AB-150IND integrates a self-contained lithium energy source and analog voltage-monitoring circuitry that continuously tracks VCC. When supply voltage drops below 4.5 V (VTP), it unconditionally enables write protection, disables inputs, and places outputs in high-impedance state before switching to battery backup at ~3.0 V.
It operates as a byte-wide parallel memory with full static CMOS interface logic-supporting standard read/write timing per JEDEC 28-pin DIP, matching 2764 EPROM pinout, and requiring no external support circuitry for microprocessor interfacing or data retention during power loss.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 65,536 bits (8,192 × 8), directly substitutes 8k × 8 SRAM/EPROM/EEPROM |
| Access Time | 70 ns - ensures compatibility with 14 MHz Z80, 8086, and 68000-based systems |
| VCC Tolerance | ±5% (4.75 V to 5.25 V) - supports stable operation under regulated 5 V rails |
| Write Protection Threshold | 4.50–4.75 V - triggers automatic data safeguarding before brownout corruption |
| Data Retention | 10 years minimum without external power - guaranteed by internal lithium cell and sealed freshness seal |
| Operating Temperature | –40°C to +85°C - qualified for industrial control, avionics black boxes, and utility metering |
| Package | 28-pin 720-mil extended DIP - compatible with legacy through-hole PCB layouts and wave soldering |
Pinout & Package
DS1225AB-150IND uses a JEDEC-standard 28-pin extended DIP (720-mil width) with lead-free RoHS-compliant finish. The package includes internal lithium cell, voltage monitor, and power-switching circuitry fully encapsulated within the ceramic/metal hybrid module.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A12 | Address Inputs | 13-bit address bus for selecting one of 8,192 bytes; TTL-compatible, no pull-up required |
| DQ0–DQ7 | Bi-directional Data Bus | 8-bit parallel I/O with 3-state drivers; high-impedance during write or chip deselect |
| CE | Chip Enable | Active-low enable controlling device selection; initiates access when low with OE/WE |
| WE | Write Enable | Active-low signal determining read vs. write; output drivers disabled when WE low and OE active |
| OE | Output Enable | Active-low control for data output drivers; must be high during write to avoid bus contention |
| VCC | Power Supply | +5 V ±5% main supply; powers RAM core and monitoring circuitry until battery takeover |
| GND | Ground Reference | System ground return for all signals and internal battery circuit |
| NC | No Connect | Pins 14 and 25 are unconnected internally; no routing or termination required |
Key Features
| Feature | Design Value |
|---|---|
| Lithium freshness seal | Energy source electrically disconnected until first VCC application - guarantees full 10-year retention capacity |
| Automatic power-fail response | Sub-µs detection of VCC decay below 4.5 V, followed by unconditional write protect and battery switchover |
| Unlimited write endurance | No wear-out mechanism - supports continuous logging in real-time control loops without cycle limits |
| Direct EPROM/EEPROM replacement | Pinout and timing match 2764 EPROM and 2864 EEPROM - enables drop-in upgrade without layout change |
| Industrial-grade reliability | Qualified over –40°C to +85°C with 100% burn-in and UL recognition (E99151) |
Applications
| Industrial Data Logger | Avionics Black Box |
|---|---|
Use Scenario: Continuous recording of sensor readings and system states in programmable logic controllers with unpredictable mains outages. IC Role / Device Role / Timing Role: Nonvolatile memory buffer storing critical runtime data during AC failure, preserving last-known safe state. Use Value: Eliminates need for external battery management or supercapacitor hold-up circuits while guaranteeing 10-year data integrity. | Use Scenario: Crash-protected flight parameter storage in commercial aircraft recorders where power interruption must not erase pre-failure telemetry. IC Role / Device Role / Timing Role: Primary nonvolatile memory capturing timestamped engine, attitude, and control surface data at 100 Hz. Use Value: Meets DO-160 Section 22 surge/brownout immunity requirements via sub-2 µs VCC-fail detection and zero-latency write protect. |
| Smart Utility Meter | Medical Diagnostic Equipment |
Use Scenario: Tamper-resistant energy consumption logging in residential electricity meters exposed to grid instability and thermal cycling. IC Role / Device Role / Timing Role: Secure, long-term storage of billing intervals and event timestamps with cryptographic checksums. Use Value: Maintains regulatory compliance (ANSI C12.1, IEC 62056) with guaranteed 10-year retention across –40°C to +85°C ambient. | Use Scenario: Storing calibration coefficients, patient session logs, and fault history in portable ultrasound and ECG devices with intermittent battery operation. IC Role / Device Role / Timing Role: Fail-safe configuration memory ensuring consistent image processing parameters after unexpected shutdown. Use Value: Prevents recalibration drift and diagnostic errors by retaining factory-trimmed values without external backup power design. |
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 tolerance (±10%, 4.5–5.5 V); lower write-protection threshold (4.25 V) | Better suited for unregulated 5 V supplies with higher ripple; less margin before write protect engages | Select DS1225AD-70IND+ only if system VCC varies beyond ±5% or requires earlier battery switchover |
| STK12C68-E25I | Same 8k×8 NV SRAM function but uses different lithium switch architecture; 25 ns access time; SOIC-28 package | Requires PCB redesign due to surface-mount packaging; faster access but reduced mechanical robustness in vibration-prone environments | Choose STK12C68-E25I only when board space is constrained and high-speed access outweighs through-hole reliability needs |
Compared with DS1225AD-70IND+, the DS1225AB-150IND offers tighter VCC regulation tolerance and higher write-protection voltage-critical for stable 5 V rail systems. Against STK12C68-E25I, it provides proven through-hole ruggedness and identical legacy footprint compatibility, avoiding requalification of mechanical and thermal performance.
Availability
DS1225AB-150IND is available at Aetrix Electronics and suitable for industrial data loggers, avionics black boxes, and smart utility meters requiring stable component supply, long-lifecycle assurance, and RoHS-compliant through-hole memory solutions.
Supply support for DS1225AB-150IND 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 precision analog, mixed-signal, and high-reliability ICs for industrial, automotive, and communications markets.
The DS1225AB-150IND belongs to Maxim's legacy nonvolatile SRAM product line, engineered specifically for fail-safe data retention in safety-critical systems where external backup power is impractical or prohibited.
FAQ
What is the guaranteed data retention period for DS1225AB-150IND?
The DS1225AB-150IND guarantees a minimum 10-year data retention period in the absence of external power, measured from the time VCC is first applied. This is ensured by the internal lithium cell's freshness seal and hermetic encapsulation-no periodic refresh or external power is needed to maintain stored data throughout the rated lifetime.
Does DS1225AB-150IND require any external components for battery backup operation?
No, the DS1225AB-150IND requires zero external components for nonvolatile operation. Its integrated lithium energy source, voltage-monitoring circuitry, and automatic power-switching logic are fully self-contained within the 28-pin DIP package. No capacitors, diodes, or supervisory ICs are needed for data retention during power loss.
Is DS1225AB-150IND pin-compatible with standard 2764 EPROMs?
Yes, the DS1225AB-150IND is fully pin-compatible with the 2764 EPROM and 2864 EEPROM, sharing identical 28-pin DIP pinout, address/data bus mapping, and CE/OE/WE control signal assignments. This allows direct substitution in existing designs without PCB modification or firmware changes.
What is the write-protection voltage threshold for DS1225AB-150IND?
The DS1225AB-150IND asserts unconditional write protection when VCC falls within the range of 4.50 V to 4.75 V (typical 4.62 V), as specified by its VTP parameter. This threshold ensures early safeguarding of memory contents before supply collapse reaches levels that could cause data corruption during write operations.
Can DS1225AB-150IND operate outside the industrial temperature range?
No-the "IND" suffix in DS1225AB-150IND explicitly denotes qualification and guaranteed operation over –40°C to +85°C. While the device may function outside this range, electrical parameters such as access time, standby current, and write-protection timing are not characterized or warranted beyond those limits.
DS1225AB-150IND 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:
- 150ns
- Access Time:
- 150 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-150IND FAQ
1.How can I place an order for DS1225AB-150IND through Aetrix?
Please submit a Request for Quotation (RFQ) for DS1225AB-150IND 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-150IND reliable?
The price and inventory of DS1225AB-150IND are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS1225AB-150IND is usually 5 days.
3.What payment methods are accepted for DS1225AB-150IND?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS1225AB-150IND transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DS1225AB-150IND?
DS1225AB-150IND orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DS1225AB-150IND 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-150IND?
For technical support, including DS1225AB-150IND datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS1225AB-150IND requirements.
6.How does Aetrix verify that DS1225AB-150IND is sourced from the original manufacturer or authorized distributors?
All DS1225AB-150IND 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-150IND meets industry standards.
7.What is the process for return or replacement of DS1225AB-150IND?
All DS1225AB-150IND units undergo pre-shipment inspection (PSI). If there is an issue with DS1225AB-150IND, 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-150IND part is unused and in its original packaging.
Return procedure for DS1225AB-150IND:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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