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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:1,859
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Product details
Overview
DS1225AB-70IND from Maxim Integrated is a 64k-bit (8k × 8) nonvolatile static RAM with integrated lithium battery backup, designed as a direct replacement for volatile SRAMs and EEPROMs in mission-critical memory retention applications. It delivers 70 ns read/write access time, operates over -40°C to +85°C, supports ±5% VCC tolerance (4.75 V–5.25 V), and guarantees ≥10 years data retention without external power.
For engineers reviewing the DS1225AB-70IND datasheet, DS1225AB-70IND pinout, DS1225AB-70IND application, or DS1225AB-70IND equivalent, key selection criteria include industrial-temperature nonvolatile memory substitution, battery-backed SRAM timing compliance, write-protection voltage threshold (4.50–4.75 V), and JEDEC-standard 28-pin DIP compatibility with 2764 EPROM/2864 EEPROM footprints.
Technical Context
The DS1225AB-70IND integrates self-contained lithium energy source and voltage-monitoring circuitry that automatically enables battery backup when VCC falls below 4.5 V and disables it upon power-up above ~3.0 V. Its control logic enforces unconditional write protection during power loss, placing all inputs in "don't care" state and outputs in high-impedance mode.
It implements standard parallel SRAM interface timing: CE and OE active-low for reads, CE and WE active-low for writes, with tACC = 70 ns, tWC = 70 ns, and tOE = 35 ns. Address range A0–A12 (13 bits) and bidirectional DQ0–DQ7 (8-bit bus) conform fully to byte-wide 28-pin DIP pinout and timing requirements of legacy microprocessor systems.
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 read/write - meets timing for 14 MHz Z80, 8086, and 68000-based systems |
| VCC Range | 4.75 V to 5.25 V (±5%) - ensures stable operation across industrial-grade 5 V rails |
| Data Retention | ≥10 years without power - enabled by sealed lithium cell disconnected until first power-on |
| Operating Temp | -40°C to +85°C - qualified for industrial control, avionics, and telecom infrastructure |
| Write Cycles | Unlimited - no wear-out mechanism unlike EEPROM or Flash |
| Write Protect Threshold | 4.50–4.75 V (VTP) - triggers automatic battery switchover and input lockout before data corruption |
Pinout & Package
DS1225AB-70IND uses a JEDEC-standard 28-pin Encapsulated Dual In-line Package (EDIP), 720-mil width, with lead-free RoHS-compliant finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A12 | Address Inputs | 13-bit address bus for selecting one of 8,192 memory locations |
| DQ0–DQ7 | Data I/O | Bidirectional 8-bit data bus compatible with microprocessor data paths |
| CE | Chip Enable | Active-low chip select; must be low with WE or OE for valid access |
| WE | Write Enable | Active-low write strobe; controls direction of DQ bus and initiates write cycle |
| OE | Output Enable | Active-low output enable; places DQ lines in high-Z when inactive (high) |
| VCC | Power Supply | +5 V ±5% main supply; powers logic and enables lithium disconnect circuit |
| GND | Ground | Reference return path for all signals and internal switching circuits |
| NC | No Connect | Pins 14 and 24 are unconnected; no internal bonding or function |
Key Features
| Feature | Design Value |
|---|---|
| Automatic Power-Fail Detection | Monitors VCC continuously; triggers lithium switchover within 1.5 µs when VCC drops below VTP |
| Freshness Seal | Lithium cell electrically isolated until first VCC application > VTP, preserving full 10-year capacity |
| Direct EPROM/EEPROM Replacement | Pins match 2764 EPROM and 2864 EEPROM - no PCB redesign required for drop-in upgrade |
| Zero-External-Support Interface | Requires no external capacitors, regulators, or control logic - fully self-contained NV SRAM |
| Industrial Temperature Qualification | Guaranteed functionality and timing across -40°C to +85°C ambient, including battery switchover behavior |
Applications
| Industrial PLC Data Logging | Avionics Flight Recorder Memory |
|---|---|
Use Scenario: Retaining real-time sensor logs and configuration settings during unexpected AC mains failure or brownout events. IC Role / Device Role / Timing Role: Nonvolatile SRAM providing immediate, glitch-free memory holdover without software intervention or external backup controllers. Use Value: Eliminates need for external battery management ICs and preserves timestamped data integrity across power cycles with <1.5 µs detection latency. | Use Scenario: Storing critical flight parameters (altitude, attitude, engine status) in certified black box recorders subject to extreme thermal cycling. IC Role / Device Role / Timing Role: Primary memory buffer with guaranteed 10-year data retention at -40°C to +85°C, meeting DO-160 environmental test profiles. Use Value: Meets FAA/EASA requirements for crash-survivable memory without supplemental temperature-compensated battery circuits. |
| Medical Infusion Pump Configuration | Telecom Base Station Alarms |
Use Scenario: Preserving drug dosage history, calibration offsets, and user-defined therapy profiles during battery swaps or power interruptions. IC Role / Device Role / Timing Role: Fail-safe memory holding life-critical therapy parameters with automatic write-protection activation below 4.5 V. Use Value: Ensures regulatory compliance (IEC 62304 Class B) by preventing parameter corruption during undervoltage conditions. | Use Scenario: Capturing and retaining network fault alarms, uptime statistics, and firmware rollback points in outdoor macrocell base stations. IC Role / Device Role / Timing Role: Industrial-grade NV SRAM interfacing directly with ARM9 or MIPS-based baseband processors via parallel bus. Use Value: Delivers deterministic 70 ns access while surviving extended outdoor thermal stress (-40°C startup, +85°C sustained operation). |
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-protect threshold (4.25–4.5 V) | Better suited for noisy or poorly regulated 5 V supplies where voltage dips below 4.75 V are frequent | Select DS1225AD-70IND+ if system VCC varies beyond ±5% but still requires industrial temp support |
| STK12C68-A70I | Same 8k × 8 organization and 70 ns speed; uses capacitor-based backup (no lithium); shorter retention (~5 years) | Lower cost, RoHS-compliant alternative where 10-year retention is not mandatory and capacitor recharge is acceptable | Choose STK12C68-A70I for cost-sensitive industrial designs with infrequent power loss and shorter product lifecycle |
Compared with DS1225AD-70IND+, the DS1225AB-70IND offers tighter VCC regulation and higher write-protect threshold-critical for stable 5 V rail environments-while STK12C68-A70I trades lithium longevity for capacitor simplicity and reduced bill-of-materials cost.
Availability
DS1225AB-70IND is available at Aetrix Electronics and suitable for industrial PLC data logging, avionics flight recorder memory, and medical infusion pump configuration requiring stable component supply with guaranteed long-term availability and traceable sourcing.
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) is a semiconductor company specializing in precision analog, mixed-signal, and power management ICs for industrial, automotive, and communications markets.
The DS1225AB-70IND belongs to Maxim's nonvolatile SRAM product line, engineered specifically for zero-software, zero-support memory retention in safety-critical systems where data integrity during power interruption is non-negotiable.
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 specification is design-guaranteed and based on accelerated lifetime testing per JEDEC standards-not 100% tested per unit but validated across process lots and temperature extremes.
Does DS1225AB-70IND require external components for battery backup operation?
No, the DS1225AB-70IND requires no external components for battery backup operation. Its integrated lithium energy source, voltage monitor, and power-switching circuitry are fully self-contained. The device ships with the lithium cell electrically disconnected ("freshness seal") and only engages it automatically when VCC drops below 4.5 V, eliminating need for external capacitors, regulators, or control logic.
Is DS1225AB-70IND pin-compatible with standard 28-pin EPROMs?
Yes, DS1225AB-70IND is pin-compatible with the 2764 EPROM and 2864 EEPROM, sharing identical 28-pin DIP pinout and signal assignments (A0–A12, DQ0–DQ7, CE, OE, WE, VCC, GND). This allows direct hardware substitution without PCB modification, provided system timing accommodates 70 ns access and write-protection behavior is accounted for in firmware.
What is the write-protection voltage threshold for DS1225AB-70IND?
The DS1225AB-70IND activates automatic write protection when VCC falls within the range of 4.50 V to 4.75 V (VTP). Below this threshold, the device disables all inputs, places outputs in high-impedance, and switches to lithium power-preventing partial writes and data corruption during brownout conditions.
Can DS1225AB-70IND operate across the full industrial temperature range?
Yes, DS1225AB-70IND is fully specified and tested for continuous operation from -40°C to +85°C. All electrical characteristics-including 70 ns access time, standby current (≤10 mA), and write-protection response latency (≤1.5 µs)-are guaranteed across this range, making it suitable for deployment in harsh industrial and outdoor environments.
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:
- 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:
- 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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