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Analog Devices Inc./Maxim Integrated DS1225AD-150IND+
- Part No.:
- DS1225AD-150IND+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Memory
- Package:
- 28-DIP Module (0.600", 15.24mm)
- Datasheet:
-
DS1225AD-150IND+.pdf
- Description:
- IC NVSRAM 64KBIT PARALLEL 28EDIP
- Quantity:
- Payment:
- Shipping:
Inventory:563
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Product details
Overview
DS1225AD-150IND+ 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 access time, ±10% VCC tolerance (4.5V–5.5V), and industrial temperature range (–40°C to +85°C). It replaces volatile SRAMs and EEPROMs in real-time data logging systems where power loss protection is critical.
For engineers reviewing the DS1225AD-150IND+ datasheet, DS1225AD-150IND+ pinout, DS1225AD-150IND+ application, or DS1225AD-150IND+ equivalent, key selection criteria include guaranteed 10-year data retention without external power, automatic write protection during VCC decay, no write-cycle limits, full compatibility with 28-pin DIP-based microprocessor buses, and seamless substitution for 2764 EPROM/2864 EEPROM footprints.
Technical Context
The DS1225AD-150IND+ implements a self-contained power-fail detection and switchover architecture: internal circuitry continuously monitors VCC, triggers unconditional write protection when voltage drops below 4.25 V (VTP), and connects the lithium cell to retain RAM contents when VCC falls below ~3.0 V. During power-up, the lithium source disconnects automatically once VCC exceeds ~3.0 V.
It operates as a byte-wide parallel memory with standard SRAM timing-read cycles require CE and OE low with WE high; write cycles require CE and WE low-and supports full TTL-compatible signaling (VIH ≥ 2.2 V, VIL ≤ 0.8 V) and 5 V ±10% supply operation without external support components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 65,536 bits (8,192 × 8), directly replaces 8k × 8 volatile SRAM or EEPROM |
| Access Time | 70 ns - enables direct interface with 14 MHz Z80, 8085, or 68000-based systems without wait states |
| VCC Range | 4.5 V to 5.5 V (±10%) - accommodates wide-input industrial power rails without regulation |
| Data Retention | 10 years minimum without external power - guaranteed by design, enabled only after first VCC application |
| Write Cycles | Unlimited - no wear-out mechanism; no endurance derating over time or temperature |
| Operating Temp | –40°C to +85°C (IND grade) - qualified for embedded control, instrumentation, and telecom infrastructure |
| Package | 28-pin 720-mil extended DIP - matches 2764 EPROM/2864 EEPROM footprint; wave-solder compatible |
Pinout & Package
DS1225AD-150IND+ uses a JEDEC-standard 28-pin Extended Dual In-line Package (EDIP), 720 mil width, with through-hole mounting and wave-solder compatibility. Pin 1 is marked with a notch or dot; NC pins are internally unconnected and must remain floating.
| 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-ups required |
| DQ0–DQ7 | Bidirectional Data Bus | 8-bit parallel I/O; high-impedance when CE or OE inactive; drives TTL loads directly |
| CE | Chip Enable | Active-low chip select; initiates read/write when low; disables outputs and reduces ICCS2 to 3–5 mA when high |
| WE | Write Enable | Active-low write strobe; controls data latching; forces outputs to high-Z if asserted during read |
| OE | Output Enable | Active-low output gate; allows read data to appear on DQ lines only when CE and OE both low |
| VCC | Power Supply | +5 V ±10% input; powers logic and RAM array; monitored for fail-detect and battery switchover |
| GND | Ground Reference | Signal and power return; must be low-inductance connection to avoid noise-induced corruption |
| NC | No Connect | Pins 14 and 24 are unconnected; must not be soldered or tied to any net |
Key Features
| Feature | Design Value |
|---|---|
| Automatic Power-Fail Protection | Hardware-level VCC monitoring triggers immediate write lockout and lithium switchover within 1.5 µs of out-of-tolerance detection |
| Freshness Seal | Lithium cell electrically disconnected at factory; full energy capacity preserved until first VCC application > VTP |
| Zero-Overhead Substitution | Pinout and timing identical to 2764 EPROM and 2864 EEPROM - no PCB or firmware changes required |
| Wide-Voltage Operation | Functional across full 4.5–5.5 V range - eliminates need for tight-regulation LDO in noisy industrial supplies |
| Industrial Temperature Qualification | Guaranteed operation and data retention over –40°C to +85°C - validated per MIL-STD-883 methods |
Applications
| Industrial Data Logger | Medical Device Memory |
|---|---|
Use Scenario: Battery-backed data acquisition unit recording sensor readings during mains failure or transport. IC Role / Device Role / Timing Role: Nonvolatile SRAM storing timestamped measurements; retains data for ≥10 years without refresh or external power. Use Value: Eliminates need for EEPROM write-delay overhead and flash wear leveling; ensures deterministic 70 ns read/write latency during live capture. | Use Scenario: Patient monitor storing last 24 hours of ECG waveforms and alarm history before power restoration. IC Role / Device Role / Timing Role: Fail-safe memory buffer that locks writes and preserves RAM state instantly upon AC dropout. Use Value: Meets IEC 60601-1 data integrity requirements; avoids data loss during brownouts common in hospital-grade UPS transitions. |
| Telecom Base Station Control | Avionics Configuration Storage |
Use Scenario: Remote radio unit retaining calibration tables, fault logs, and firmware patch metadata across repeated cold starts. IC Role / Device Role / Timing Role: Primary configuration store interfaced directly to ARM9 or MIPS microcontroller via 8-bit parallel bus. Use Value: Supports unlimited field updates without endurance concerns; operates reliably at –40°C ambient during tower-mounted deployment. | Use Scenario: Flight management computer preserving navigation waypoints and system health records during engine shutdown. IC Role / Device Role / Timing Role: Certified nonvolatile memory holding DO-254-compliant configuration data with traceable retention guarantee. Use Value: Provides 10-year archival integrity without periodic refresh or battery replacement - critical for long-life airframe programs. |
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 64k NV SRAM architecture but with 100 ns access time and 5 V ±5% supply (4.75–5.25 V) | Lower speed grade; suited for legacy 8-bit systems with relaxed timing budgets | Select when system clock < 10 MHz and tighter VCC regulation is available |
| STK12C68-A70I | 64k NV SRAM with 70 ns access, 5 V ±10%, but uses SOIC-28 package instead of DIP | Surface-mount only; requires PCB redesign; lacks EDIP mechanical compatibility | Choose for space-constrained designs where through-hole DIP is not feasible |
Compared with DS1225Y-70IND+ and STK12C68-A70I, the DS1225AD-150IND+ uniquely combines 70 ns speed, ±10% VCC tolerance, industrial temperature rating, and 28-pin DIP packaging - enabling drop-in upgrades in legacy systems without layout or firmware modification.
Availability
DS1225AD-150IND+ is available at Aetrix Electronics and suitable for industrial data loggers, medical patient monitors, telecom base station controllers, avionics configuration storage, and embedded control systems requiring stable component supply across long production lifecycles.
Supply support for DS1225AD-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 power management ICs for industrial, automotive, and communications markets.
The DS1225AB/AD product line was designed specifically to deliver plug-compatible, battery-backed SRAM solutions for legacy microprocessor systems needing zero-footprint upgrades from volatile memory or slow EEPROMs.
FAQ
What is the guaranteed data retention period for DS1225AD-150IND+?
The DS1225AD-150IND+ guarantees a minimum 10-year data retention period in the absence of external power, measured cumulatively from the time VCC is first applied. This retention is enabled by the internal lithium energy source, which remains disconnected until initial power-up to preserve full capacity. The specification is design-guaranteed and not 100% tested per unit.
Does DS1225AD-150IND+ require external circuitry for battery backup operation?
No, the DS1225AD-150IND+ requires no external circuitry for battery backup operation. Its integrated lithium cell and power-fail detection/control circuitry operate autonomously. The device monitors VCC continuously and switches to battery power within 1.5 µs when voltage drops below 4.25 V, ensuring uninterrupted data retention without additional components.
Is DS1225AD-150IND+ pin-compatible with standard 28-pin EPROMs and EEPROMs?
Yes, the DS1225AD-150IND+ is pin-compatible with the 2764 EPROM and 2864 EEPROM, sharing identical pin assignments, signal definitions, and 28-pin extended DIP footprint. This allows direct substitution in existing sockets without PCB or firmware changes, while delivering faster 70 ns access and unlimited write cycles compared to those older devices.
What is the operating voltage range for DS1225AD-150IND+?
The DS1225AD-150IND+ operates over a VCC range of 4.5 V to 5.5 V (±10%), supporting wide-input industrial power supplies. It provides full functional capability above 4.5 V and initiates automatic write protection when VCC drops to 4.25 V. This wider tolerance eliminates the need for tight-regulation LDOs in ruggedized applications.
How does the "Freshness Seal" function in DS1225AD-150IND+?
The Freshness Seal in DS1225AD-150IND+ electrically disconnects the internal lithium energy source until VCC is first applied above the threshold voltage (VTP = 4.25–4.5 V). This preserves full battery capacity during storage and shipping. Once powered, the seal is permanently removed, and the lithium cell becomes active for backup operation during subsequent power failures.
DS1225AD-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:
- 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:
- 150ns
- Access Time:
- 150 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-150IND+ FAQ
1.How can I place an order for DS1225AD-150IND+ through Aetrix?
Please submit a Request for Quotation (RFQ) for DS1225AD-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 DS1225AD-150IND+ reliable?
The price and inventory of DS1225AD-150IND+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS1225AD-150IND+ is usually 5 days.
3.What payment methods are accepted for DS1225AD-150IND+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS1225AD-150IND+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DS1225AD-150IND+?
DS1225AD-150IND+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DS1225AD-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 DS1225AD-150IND+?
For technical support, including DS1225AD-150IND+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS1225AD-150IND+ requirements.
6.How does Aetrix verify that DS1225AD-150IND+ is sourced from the original manufacturer or authorized distributors?
All DS1225AD-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 DS1225AD-150IND+ meets industry standards.
7.What is the process for return or replacement of DS1225AD-150IND+?
All DS1225AD-150IND+ units undergo pre-shipment inspection (PSI). If there is an issue with DS1225AD-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 DS1225AD-150IND+ part is unused and in its original packaging.
Return procedure for DS1225AD-150IND+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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