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Analog Devices Inc./Maxim Integrated DS1245AB-120
- Part No.:
- DS1245AB-120
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Memory
- Package:
- 32-DIP Module (0.600", 15.24mm)
- Datasheet:
-
DS1245AB-120.pdf
- Description:
- IC NVSRAM 1MBIT PARALLEL 32EDIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,604
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Product details
Overview
DS1245AB-120 from Maxim Integrated is a 1024k (131,072 × 8) nonvolatile static RAM with lithium backup, ±5% VCC tolerance (4.75–5.25 V), 70 ns access time, and industrial-grade temperature support (-40°C to +85°C). It replaces volatile SRAM, EEPROM, or Flash in battery-backed data logging, real-time clock memory, and configuration storage where write endurance and zero-cycle write latency are critical.
For engineers reviewing the DS1245AB-120 datasheet, DS1245AB-120 pinout, DS1245AB-120 application, or DS1245AB-120 equivalent, key selection criteria include its automatic power-fail write protection threshold (4.5 V), 10-year data retention without external power, JEDEC-standard 32-pin DIP footprint, and compatibility with microprocessor bus interfaces requiring byte-wide static RAM timing.
Technical Context
The DS1245AB-120 integrates SRAM, lithium battery, and voltage-monitoring control circuitry into a single monolithic module. Its internal power-switching logic detects VCC decay below 4.5 V and unconditionally enables write protection while switching to battery power - all within 1.5 µs.
It operates as a fully static, asynchronous parallel memory: address latching is edge-independent, read/write cycles require only CE, WE, and OE control signals, and no external support circuitry (e.g., backup controllers or capacitors) is needed for nonvolatile operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 1024 kbit (131,072 × 8) - provides full byte-accessible storage space matching legacy 128k×8 SRAM footprints |
| Access Time | 70 ns - ensures compatibility with 14 MHz Z80, 80C88, and similar microprocessor buses without wait states |
| VCC Range | 4.75 V to 5.25 V (±5%) - supports stable operation across standard 5 V supply rails with typical regulator tolerance |
| Data Retention | 10 years minimum without external power - guaranteed by sealed lithium cell and automatic disconnect freshness seal |
| Write Protection Threshold | 4.50–4.75 V - triggers immediate hardware write lock and high-Z outputs before VCC drops to unsafe levels |
| Operating Temperature | -40°C to +85°C (IND grade) - qualified for industrial control, metering, and automotive under-hood auxiliary modules |
| Package | 32-pin 740-mil Extended DIP (JEDEC MS-001) - direct drop-in replacement for existing socketed SRAM designs |
Pinout & Package
DS1245AB-120 uses a JEDEC-standard 32-pin 740-mil Extended Dual In-line Package (EDIP), with pin 1 marked by notch or dot. All pins conform to industry-standard byte-wide SRAM interface layout, enabling PCB-level compatibility with legacy 128k×8 SRAM sockets.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A16 | Address Inputs | 17-bit address bus supporting full 131,072-word addressing; TTL-compatible inputs with ≤0.8 V low / ≥2.2 V high thresholds |
| DQ0–DQ7 | Data I/O | Bi-directional 8-bit data bus; outputs enter high-impedance state when CE or OE inactive; 2 mA sink / 1 mA source drive |
| CE | Chip Enable | Active-low chip select; must be low for read/write; controls standby current (50–150 µA) and initiates power-down detection sequence |
| WE | Write Enable | Active-low write strobe; falling edge (with CE low) starts write cycle; tWR = 5 ns recovery required before next access |
| OE | Output Enable | Active-low output enable; disables outputs during writes to prevent bus contention; tOE = 35 ns output valid delay |
| VCC | Power Supply | +5 V ±5% main supply; powers SRAM core and control logic; disconnects lithium source during normal operation |
| GND | Ground | Signal and power reference plane; requires low-impedance connection to minimize noise-induced data corruption |
| NC | No Connect | Pins 1, 17, 32 - physically present but internally unconnected; must remain unconnected on PCB |
Key Features
| Feature | Design Value |
|---|---|
| Automatic Power-Fail Response | Hardware-monitored VCC detection triggers write protection and battery switchover in ≤1.5 µs - no firmware or external supervisor required |
| Lithium Freshness Seal | Internal switch electrically isolates lithium cell until first VCC > 4.25 V applied - guarantees full 10-year retention capacity at installation |
| Unlimited Write Cycles | SRAM-based architecture eliminates wear-out mechanisms - supports continuous logging or configuration updates over product lifetime |
| Zero External Support Circuitry | Self-contained backup power, voltage monitoring, and write-protection logic eliminate need for external capacitors, supervisors, or battery management ICs |
| JEDEC-DIP Pin Compatibility | Direct replacement for 128k×8 volatile SRAMs (e.g., HM628128, IS61LV1024) - same pinout, timing, and signal definitions |
Applications
| Industrial Data Logger | Smart Meter Configuration Storage |
|---|---|
|
Use Scenario: Continuous recording of sensor readings (temperature, pressure, flow) during mains power interruption. IC Role / Device Role / Timing Role: Nonvolatile SRAM holding last valid measurement set and timestamp; retains data across brownouts without write latency penalty. Use Value: Eliminates need for EEPROM emulation or Flash wear-leveling firmware; preserves integrity of time-critical process data during unscheduled power loss. |
Use Scenario: Storing tariff tables, billing registers, and tamper-event logs in electricity/water/gas meters operating in remote locations. IC Role / Device Role / Timing Role: Battery-backed memory preserving meter calibration and usage history even after 10+ years of field deployment without maintenance. Use Value: Meets ANSI C12.1 and IEC 62056 requirements for 10-year data retention; avoids costly field recalls due to memory failure. |
| PLC Configuration Memory | Embedded RTC Backup RAM |
|
Use Scenario: Holding ladder logic parameters, I/O mapping, and alarm thresholds in programmable logic controllers exposed to factory floor voltage sags. IC Role / Device Role / Timing Role: Static RAM interfaced directly to PLC microcontroller bus; automatically locks writes and switches to lithium power during AC line dropout. Use Value: Prevents configuration corruption during transient power events - maintains operational continuity without reboot or reinitialization. |
Use Scenario: Providing persistent storage for real-time clock registers, calendar data, and alarm settings in medical devices and network infrastructure equipment. IC Role / Device Role / Timing Role: Low-power SRAM backing up RTC registers during main power removal; draws <600 µA in standby with CE high. Use Value: Enables accurate timekeeping across multi-year battery-only operation; eliminates need for external RTC + separate NVRAM pairing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar nonvolatile SRAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| DS1245Y-70IND+ | Wider VCC range (4.5–5.5 V, ±10%), lower write-protect threshold (4.25 V), identical pinout and timing | Better suited for systems with looser 5 V regulation or higher ripple; slightly earlier battery switchover may reduce margin in marginal supplies | Select DS1245Y-70IND+ if system VCC varies beyond ±5%; otherwise DS1245AB-120 offers tighter voltage control for stable rail environments |
| STK12C68-A70 | Same 1024k size, 70 ns speed, and 32-pin DIP, but uses capacitor-based backup (not lithium); 5-year retention, higher standby current (1.5 mA) | Lower cost alternative where 10-year retention is not mandated; requires external supercapacitor and charging circuit | Choose STK12C68-A70 only when lithium-free design is required and shorter retention is acceptable; DS1245AB-120 delivers longer life with simpler BOM |
Compared with DS1245Y-70IND+, DS1245AB-120 provides tighter VCC regulation tolerance and delayed write protection - improving robustness in well-regulated 5 V systems. Against STK12C68-A70, DS1245AB-120 eliminates external backup components and doubles retention life, justifying its use in mission-critical industrial deployments.
Availability
DS1245AB-120 is available at Aetrix Electronics and suitable for industrial data loggers, smart metering systems, and PLC configuration memory requiring stable component supply, long-term lifecycle support, and guaranteed 10-year data retention under power-loss conditions.
Supply support for DS1245AB-120 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, communications, and computing applications.
The DS1245AB-120 belongs to Maxim's nonvolatile SRAM product line, engineered to replace volatile memory in systems where data integrity during power interruption is non-negotiable - targeting industrial automation, energy infrastructure, and embedded instrumentation.
FAQ
What is the guaranteed data retention period for DS1245AB-120?
The DS1245AB-120 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 an integrated lithium battery with an electrical freshness seal that remains disconnected until initial power-up, preserving full capacity for the rated duration.
Does DS1245AB-120 require external circuitry for battery backup operation?
No, DS1245AB-120 requires no external circuitry for nonvolatile operation. It contains a self-contained lithium energy source, voltage-monitoring logic, and automatic power-switching circuitry. Once installed and powered, DS1245AB-120 autonomously manages backup activation, write protection, and data retention without additional components.
What is the write protection voltage threshold for DS1245AB-120?
The DS1245AB-120 activates hardware write protection when VCC falls within 4.50 V to 4.75 V. At this threshold, all inputs become "don't care," outputs go high-impedance, and the lithium source is connected to preserve RAM contents - a deterministic, sub-microsecond response independent of software or external supervision.
Is DS1245AB-120 compatible with standard 32-pin DIP sockets used for 128k×8 SRAMs?
Yes, DS1245AB-120 uses a JEDEC-standard 32-pin 740-mil Extended DIP package with identical pinout, signal definitions, and timing to legacy 128k×8 volatile SRAMs such as the HM628128. It is a direct PCB-level replacement requiring no layout changes or interface modifications.
What temperature range is specified for DS1245AB-120?
The DS1245AB-120 is specified for the industrial temperature range of -40°C to +85°C. This rating applies to both DC and AC electrical characteristics and is validated per Maxim's industrial qualification standards, making DS1245AB-120 suitable for deployment in harsh environments including factory floors, outdoor metering, and transportation systems.
DS1245AB-120 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 32-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:
- 1Mbit
- Memory Organization:
- 128K x 8
- Memory Interface:
- Parallel
- Clock Frequency:
- -
- Write Cycle Time - Word, Page:
- 120ns
- Access Time:
- 120 ns
- Voltage - Supply:
- 4.75V ~ 5.25V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 32-EDIP
DS1245AB-120 FAQ
1.How can I place an order for DS1245AB-120 through Aetrix?
Please submit a Request for Quotation (RFQ) for DS1245AB-120 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 DS1245AB-120 reliable?
The price and inventory of DS1245AB-120 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS1245AB-120 is usually 5 days.
3.What payment methods are accepted for DS1245AB-120?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS1245AB-120 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DS1245AB-120?
DS1245AB-120 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DS1245AB-120 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 DS1245AB-120?
For technical support, including DS1245AB-120 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS1245AB-120 requirements.
6.How does Aetrix verify that DS1245AB-120 is sourced from the original manufacturer or authorized distributors?
All DS1245AB-120 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 DS1245AB-120 meets industry standards.
7.What is the process for return or replacement of DS1245AB-120?
All DS1245AB-120 units undergo pre-shipment inspection (PSI). If there is an issue with DS1245AB-120, 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 DS1245AB-120 part is unused and in its original packaging.
Return procedure for DS1245AB-120:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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