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Analog Devices Inc./Maxim Integrated DS1225AB-150
- Part No.:
- DS1225AB-150
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Memory
- Package:
- 28-DIP Module (0.600", 15.24mm)
- Datasheet:
-
DS1225AB-150.pdf
- Description:
- IC NVSRAM 64KBIT PARALLEL 28EDIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,716
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Product details
Overview
DS1225AB-150 from Maxim Integrated is a 64k-bit (8192 × 8) nonvolatile static RAM with integrated lithium backup, JEDEC-standard 28-pin extended DIP package, 70 ns read/write access time, ±5% VCC tolerance (4.75–5.25 V), and guaranteed 10-year data retention without external power. It replaces volatile SRAMs and EEPROMs in battery-backed memory applications such as industrial controllers and embedded data loggers.
For engineers reviewing the DS1225AB-150 datasheet, DS1225AB-150 pinout, DS1225AB-150 application, or DS1225AB-150 equivalent, key selection criteria include write-protection voltage (4.50–4.75 V), industrial temperature support (-40°C to +85°C), unlimited write cycles, low-power CMOS operation, and direct compatibility with 2764 EPROM/2864 EEPROM footprints.
Technical Context
The DS1225AB-150 integrates self-contained lithium energy source and voltage-monitoring circuitry that automatically enables backup power when VCC falls below 4.5 V and disables it upon power-up above ~3.0 V. Its internal power-switching logic ensures unconditional write protection during brownout, eliminating external supervision circuitry.
All 13 address lines (A0–A12), 8 bidirectional data lines (DQ0–DQ7), and standard control signals (CE, WE, OE) conform to byte-wide 28-pin DIP timing and electrical behavior. The device operates across full commercial or industrial temperature ranges and requires no external capacitors or support ICs for nonvolatile operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 65,536 bits (8192 × 8), directly substituting 8k × 8 SRAM/EPROM/EEPROM without address decoding changes |
| Access Time | 70 ns max - supports 14.3 MHz bus operation with standard microprocessor timing margins |
| VCC Range | 4.75 V to 5.25 V (±5%) - compatible with tightly regulated 5 V systems; write protection triggers at 4.50–4.75 V |
| Data Retention | 10 years minimum without power - enabled by factory-fresh lithium cell disconnected until first power-on |
| Operating Temp | -40°C to +85°C (IND grade) - qualified for industrial control, metering, and automotive under-hood edge cases |
| Write Cycles | Unlimited - no wear-out mechanism; eliminates EEPROM endurance limitations in high-write-rate logging |
| Package | 28-pin 720-mil extended DIP - drop-in replacement for legacy 2764/2864 sockets and PCB layouts |
Pinout & Package
DS1225AB-150 uses a JEDEC-standard 28-pin extended dual in-line package (EDIP), 720 mil width, with through-hole mounting and wave/hand soldering 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 interface; selects one of 8192 bytes; TTL-compatible inputs with ≤1.0 µA leakage |
| DQ0–DQ7 | Data I/O | Bidirectional 8-bit data bus; high-impedance when CE/OE inactive; drives 2.0 mA sink / -1.0 mA source |
| CE | Chip Enable | Active-low chip select; initiates read/write when low; controls standby current (≤10 mA) |
| WE | Write Enable | Active-low write strobe; determines write start/stop edges with CE; disables outputs when asserted |
| OE | Output Enable | Active-low output enable; used only during reads; high during writes to prevent bus contention |
| VCC | Power Supply | +5 V ±5% main supply; powers logic and RAM core; monitored continuously for backup switchover |
| GND | Ground | Reference return path for all signals and internal circuitry; decoupling capacitor required at pin |
| NC | No Connect | Two unassigned pins (pins 14 and 25); must be left unconnected per datasheet; no internal bonding |
Key Features
| Feature | Design Value |
|---|---|
| Automatic Power-Fail Protection | Monitors VCC in real time; switches to lithium backup within 1.5 µs when voltage drops below 4.5 V |
| Freshness Seal | Lithium cell electrically isolated until first VCC application > VTP, preserving full 10-year retention capacity |
| Direct EPROM/EEPROM Replacement | Pins match 2764 EPROM and 2864 EEPROM - same layout, same control timing, no adapter needed |
| Zero External Support Circuitry | No external capacitors, supervisors, or backup diodes required - fully autonomous nonvolatile operation |
| Industrial Temperature Qualification | Specified and tested over -40°C to +85°C - suitable for uncontrolled environments without derating |
Applications
| Industrial Data Logger | Programmable Logic Controller (PLC) |
|---|---|
|
Use Scenario: Continuous timestamped sensor readings stored during mains failure and recovered on reboot. IC Role / Device Role / Timing Role: Nonvolatile memory buffer retaining critical operational state and last-valid measurements. Use Value: Eliminates need for external battery-backed SRAM controller; retains data for ≥10 years without maintenance. |
Use Scenario: Storing ladder logic configuration, I/O mapping, and runtime variables across power cycles. IC Role / Device Role / Timing Role: Direct-replacement memory holding firmware parameters and persistent process data. Use Value: Enables true "instant-on" recovery after brownout; no reinitialization delay or data reload required. |
| Smart Energy Meter | Medical Diagnostic Equipment |
|
Use Scenario: Recording kWh consumption, tamper events, and billing intervals during grid outages. IC Role / Device Role / Timing Role: Tamper-resistant, long-retention storage for regulatory-compliant energy data archives. Use Value: Meets IEC 62056-21 retention requirements; no external RTC or backup power management IC needed. |
Use Scenario: Capturing patient ECG waveforms and diagnostic settings during emergency power transitions. IC Role / Device Role / Timing Role: Fail-safe memory preserving waveform buffers and calibration constants during AC loss. Use Value: Ensures continuity of life-critical data; avoids waveform truncation or parameter reset during backup switchover. |
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), lower write-protection threshold (4.25–4.5 V), ±10% tolerance | Better suited for loosely regulated 5 V supplies; slightly earlier backup activation may reduce margin in stable systems | Select DS1225AD-70IND+ if system VCC varies beyond ±5%; otherwise DS1225AB-150 offers tighter voltage control |
| STK12C68-A70I | Same 8k×8 organization, 70 ns speed, but uses capacitor-based backup (no lithium); 10-year retention not guaranteed | Lower cost, RoHS-compliant, but requires external supercapacitor and charging circuit; shorter retention in high-temp environments | Choose STK12C68-A70I only when lithium-free design is mandatory; DS1225AB-150 provides superior reliability and zero-support operation |
Compared with DS1225AD-70IND+, DS1225AB-150 gives tighter VCC control and higher write-protection voltage-ideal for stable 5 V rails-while STK12C68-A70I trades lithium autonomy for capacitor-based simplicity, sacrificing guaranteed 10-year retention and requiring additional support components.
Availability
DS1225AB-150 is available at Aetrix Electronics and suitable for industrial data loggers, programmable logic controllers, and smart energy meters requiring stable component supply, long-term lifecycle support, and guaranteed nonvolatile memory performance.
Supply support for DS1225AB-150 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, medical, and communications systems.
The DS1225AB-150 belongs to Maxim's NV SRAM family, engineered specifically to eliminate external backup circuitry while delivering guaranteed 10-year data retention in harsh, power-unstable environments.
FAQ
What is the guaranteed data retention period for DS1225AB-150?
The DS1225AB-150 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 a factory-fresh lithium cell disconnected until initial power-on, and confirmed by design-not 100% tested per unit.
Does DS1225AB-150 require external support components for nonvolatile operation?
No, DS1225AB-150 requires no external capacitors, supervisors, diodes, or charging circuits. Its integrated lithium energy source and voltage-monitoring control circuitry operate autonomously-only VCC, GND, and standard memory interface signals are needed for full functionality.
Is DS1225AB-150 pin-compatible with standard EPROMs or EEPROMs?
Yes, DS1225AB-150 matches the pinout and timing of the 2764 EPROM and 2864 EEPROM, enabling direct socket replacement in existing 28-pin DIP layouts without PCB modification or firmware changes.
What is the write-protection trigger voltage for DS1225AB-150?
The DS1225AB-150 enters unconditional write-protect mode when VCC falls within 4.50 V to 4.75 V (VTP). Below this range, all inputs become "don't care," outputs go high-impedance, and the lithium source activates to preserve RAM contents.
Can DS1225AB-150 operate across industrial temperature ranges?
Yes, DS1225AB-150 is qualified for -40°C to +85°C operation when ordered with the IND suffix (e.g., DS1225AB-70IND+). The DS1225AB-150 variant shown here is specified for commercial temperature range (0°C to +70°C) unless otherwise marked.
DS1225AB-150 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:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 28-EDIP
DS1225AB-150 FAQ
1.How can I place an order for DS1225AB-150 through Aetrix?
Please submit a Request for Quotation (RFQ) for DS1225AB-150 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-150 reliable?
The price and inventory of DS1225AB-150 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS1225AB-150 is usually 5 days.
3.What payment methods are accepted for DS1225AB-150?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS1225AB-150 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DS1225AB-150?
DS1225AB-150 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DS1225AB-150 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-150?
For technical support, including DS1225AB-150 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS1225AB-150 requirements.
6.How does Aetrix verify that DS1225AB-150 is sourced from the original manufacturer or authorized distributors?
All DS1225AB-150 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-150 meets industry standards.
7.What is the process for return or replacement of DS1225AB-150?
All DS1225AB-150 units undergo pre-shipment inspection (PSI). If there is an issue with DS1225AB-150, 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-150 part is unused and in its original packaging.
Return procedure for DS1225AB-150:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
DS1225AB-150 Tags
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M24C02-WMN6TP
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AT24C02C-XHM-T
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AT21CS01-STUM10-T
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M24C02-FMC6TG
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AT24CS02-SSHM-T
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AT24C04C-SSHM-T
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