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Analog Devices Inc./Maxim Integrated DS1249AB-85IND
- Part No.:
- DS1249AB-85IND
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Memory
- Package:
- 32-DIP Module (0.600", 15.24mm)
- Datasheet:
-
DS1249AB-85IND.pdf
- Description:
- IC NVSRAM 2MBIT PARALLEL 32EDIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,724
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Product details
Overview
DS1249AB-85IND from Maxim Integrated is a 2048k (2,097,152-bit) nonvolatile SRAM organized as 262,144 × 8, featuring lithium-backed data retention, ±5% VCC tolerance (4.75–5.25 V), and 70 ns read/write access time. It operates across -40°C to +85°C and automatically enables write protection when VCC drops below 4.5 V, making it ideal for industrial control systems requiring persistent memory during power loss.
For engineers reviewing the DS1249AB-85IND datasheet, DS1249AB-85IND pinout, DS1249AB-85IND application, or DS1249AB-85IND equivalent, key selection factors include its guaranteed 10-year data retention without external power, JEDEC-standard 32-pin 740-mil extended DIP package, industrial temperature rating, and self-contained lithium energy source with freshness seal activation on first power-up.
Technical Context
The DS1249AB-85IND integrates a CMOS SRAM core with autonomous power-fail detection circuitry that monitors VCC in real time. When voltage falls below the 4.50–4.75 V write-protection threshold (VTP), it immediately disables all inputs, places outputs in high-impedance state, and switches to lithium backup-no external controller or support components required.
Its interface follows standard asynchronous parallel SRAM timing: CE and OE low with WE high enables read access; CE and WE low initiates write cycles. All 18 address lines (A0–A17) and 8 bidirectional data lines (DQ0–DQ7) operate at TTL-compatible logic levels, supporting direct microprocessor bus interfacing without glue logic.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 2,097,152-bit (262,144 × 8) - supports full byte-wide data storage without banking or interleaving |
| Access Time | 70 ns - ensures compatibility with 14 MHz bus systems and legacy microcontrollers |
| VCC Range | 4.75 V to 5.25 V (±5%) - matches tight-regulation industrial 5 V rails and avoids brown-out during transient dips |
| Data Retention | 10 years minimum without power - enabled by sealed lithium cell and automatic VCC-monitored switchover |
| Operating Temp | -40°C to +85°C - qualified for uncontrolled industrial enclosures and outdoor embedded controllers |
| Write Cycles | Unlimited - eliminates wear-leveling firmware overhead and endurance monitoring |
| Package | 32-pin 740-mil extended DIP - provides through-hole mechanical stability and hand-solderable repairability |
Pinout & Package
DS1249AB-85IND uses a JEDEC-standard 32-pin Extended Dual In-line Package (EDIP), 740 mil width, wave- or hand-solderable only. Pin 1 is marked with a notch or dot; pins are numbered counter-clockwise from top-left corner.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A17 | Address Inputs | 18-bit address bus accepting 0x00000–0x3FFFF range; fully static-no refresh needed |
| DQ0–DQ7 | Data I/O | Bidirectional 8-bit data bus; high-impedance when CE or OE inactive to prevent bus contention |
| CE | Chip Enable | Active-low chip select; must be low for both read and write; controls internal power gating |
| WE | Write Enable | Active-low write strobe; falling edge initiates write; rising edge terminates cycle with tWR recovery |
| OE | Output Enable | Active-low output enable; independent of WE-allows read while writes pending elsewhere |
| VCC | Power Supply | +5 V supply (4.75–5.25 V); powers SRAM core and control logic; triggers lithium activation on first application |
| GND | Ground | Reference return path for all signals and internal switching circuits |
| NC | No Connect | Pin 16 is unconnected internally-must remain floating or tied to GND per layout guidelines |
Key Features
| Feature | Design Value |
|---|---|
| Lithium freshness seal | Lithium cell remains electrically disconnected until first VCC > VTP, preserving full 10-year retention capacity from shipment |
| Automatic write protection | Hardware-level VCC monitoring triggers unconditional write disable and input masking within 1.5 µs of out-of-tolerance detection |
| Zero-support operation | No external capacitors, regulators, or supervisory ICs required-self-contained power fail/switchover and backup management |
| TTL-compatible interface | VIH = 2.2 V min, VIL = 0.8 V max-directly interfaces with 5 V microcontrollers, FPGAs, and ASICs without level shifters |
| Industrial-grade reliability | Qualified over -40°C to +85°C with 150 µs VCC slew tolerance and UL recognition (File E99151) |
Applications
| Industrial PLC Data Logging | Medical Device Configuration Storage |
|---|---|
Use Scenario: Storing runtime parameters, calibration coefficients, and alarm history in programmable logic controllers deployed in factory automation environments with frequent power cycling. IC Role / Device Role / Timing Role: Nonvolatile SRAM providing byte-addressable, fast-access memory that retains critical operational data across unscheduled outages. Use Value: Eliminates need for EEPROM write delays or battery-backed RAM modules-ensures zero-latency data persistence with 70 ns access and unlimited writes. | Use Scenario: Holding device-specific configuration, user preferences, and diagnostic logs in portable ultrasound or infusion pumps where sterilization cycles and battery swaps interrupt main power. IC Role / Device Role / Timing Role: Self-powered memory subsystem maintaining integrity during 100+ annual power interruptions without degradation. Use Value: Guarantees 10-year data retention even after repeated thermal cycling and exposure to medical-grade cleaning agents-no field recalibration required. |
| Avionics Black Box Memory | Railway Signaling Event Recorder |
Use Scenario: Capturing flight control commands, sensor timestamps, and fault codes in aircraft cockpit voice and data recorders subject to extreme vibration and rapid power loss. IC Role / Device Role / Timing Role: Fail-safe memory buffer that autonomously switches to lithium backup within 1.5 µs of VCC decay, preventing data corruption during crash-induced power collapse. Use Value: Meets DO-160 Section 22 surge immunity requirements via hardware-enforced write protection-no software intervention needed. | Use Scenario: Recording train position, signal status, and braking events in wayside signaling systems operating in rail yards with electromagnetic interference and grid instability. IC Role / Device Role / Timing Role: Industrial-grade NV SRAM delivering deterministic 70 ns access and guaranteed retention under -40°C cold starts and +85°C summer ambient. Use Value: Supports EN 50121-3-2 EMC compliance by eliminating external backup circuitry that could radiate or couple noise into safety-critical signal paths. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar nonvolatile SRAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| DS1249Y-70IND | Wider VCC tolerance (±10%, 4.5–5.5 V); lower VTP (4.25–4.5 V); same pinout, speed, and retention | Better suited for systems with poorly regulated 5 V supplies or wide-input DC-DC converters | Select DS1249Y-70IND if supply variation exceeds ±5%; otherwise DS1249AB-85IND offers tighter voltage margin for stable rails |
| STK12C68-AI50 | Same 2048k size and 5 V operation but 50 ns access time; uses external capacitor for backup; no freshness seal | Requires external 0.1 F capacitor and charge circuit; shorter retention (typically 5–7 years) | Choose STK12C68-AI50 only if faster access is mandatory and external capacitor integration is acceptable |
Compared with DS1249Y-70IND and STK12C68-AI50, DS1249AB-85IND delivers optimal balance of voltage precision, autonomous reliability, and drop-in replaceability in fixed 5 V industrial designs-its sealed lithium cell and ±5% regulation eliminate capacitor aging concerns and simplify BOM management.
Availability
DS1249AB-85IND is available at Aetrix Electronics and suitable for industrial control systems, medical device data logging, and railway signaling equipment requiring stable component supply, long-lifecycle assurance, and RoHS-compliant through-hole packaging.
Supply support for DS1249AB-85IND 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 analog, mixed-signal, and high-reliability ICs for industrial, automotive, and communications markets.
The DS1249AB-85IND belongs to Maxim's nonvolatile SRAM product line, engineered specifically for mission-critical applications where data integrity must survive unpredictable power loss without external supervision or support components.
FAQ
What is the guaranteed data retention period for DS1249AB-85IND?
The DS1249AB-85IND guarantees a minimum of 10 years of data retention in the absence of external power. This is achieved through an integrated, sealed lithium energy source that activates automatically during power loss. The 10-year figure represents cumulative time without VCC, beginning from first power application, and is assured by component selection and process control-not extrapolated or estimated.
Does DS1249AB-85IND require external components for battery backup operation?
No, DS1249AB-85IND requires no external components for battery backup operation. Its internal lithium cell and power-fail detection circuitry are fully self-contained. The device automatically disconnects the lithium source until first VCC application (freshness seal), then manages switchover, write protection, and retention without capacitors, regulators, or supervisory ICs.
What is the difference between DS1249AB-85IND and DS1249Y-70IND?
The DS1249AB-85IND specifies a tighter ±5% VCC tolerance (4.75–5.25 V) and higher write-protection threshold (4.50–4.75 V), while DS1249Y-70IND supports ±10% (4.5–5.5 V) and triggers protection at 4.25–4.5 V. Both share identical pinout, speed (70 ns), temperature range (-40°C to +85°C), and retention-making them functionally interchangeable only when supply regulation aligns with their respective VCC windows.
Can DS1249AB-85IND be used in place of standard SRAMs without design changes?
Yes, DS1249AB-85IND is pin-compatible and functionally identical to standard 262,144 × 8 SRAMs during normal operation-same address/data/control signals, timing, and logic levels. No PCB or firmware changes are needed. Its nonvolatile behavior activates only during power loss, making it a seamless upgrade path for systems needing enhanced data survivability.
Is DS1249AB-85IND RoHS compliant?
Yes, DS1249AB-85IND is RoHS compliant. Per Maxim's ordering information, the "#" suffix denotes RoHS compliance, including exemption allowances for lead (Pb) where permitted under EU RoHS Directive Annex III. Full compliance documentation and material declarations are available through Analog Devices' product portal.
DS1249AB-85IND 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:
- 2Mbit
- Memory Organization:
- 256K x 8
- Memory Interface:
- Parallel
- Clock Frequency:
- -
- Write Cycle Time - Word, Page:
- 85ns
- Access Time:
- 85 ns
- Voltage - Supply:
- 4.75V ~ 5.25V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 32-EDIP
DS1249AB-85IND FAQ
1.How can I place an order for DS1249AB-85IND through Aetrix?
Please submit a Request for Quotation (RFQ) for DS1249AB-85IND 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 DS1249AB-85IND reliable?
The price and inventory of DS1249AB-85IND are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS1249AB-85IND is usually 5 days.
3.What payment methods are accepted for DS1249AB-85IND?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS1249AB-85IND transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DS1249AB-85IND?
DS1249AB-85IND orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DS1249AB-85IND 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 DS1249AB-85IND?
For technical support, including DS1249AB-85IND datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS1249AB-85IND requirements.
6.How does Aetrix verify that DS1249AB-85IND is sourced from the original manufacturer or authorized distributors?
All DS1249AB-85IND 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 DS1249AB-85IND meets industry standards.
7.What is the process for return or replacement of DS1249AB-85IND?
All DS1249AB-85IND units undergo pre-shipment inspection (PSI). If there is an issue with DS1249AB-85IND, 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 DS1249AB-85IND part is unused and in its original packaging.
Return procedure for DS1249AB-85IND:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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