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Analog Devices Inc./Maxim Integrated DS1249W-100
- Part No.:
- DS1249W-100
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Memory
- Package:
- 32-DIP Module (0.600", 15.24mm)
- Datasheet:
-
DS1249W-100.pdf
- Description:
- IC NVSRAM 2MBIT PARALLEL 32EDIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,629
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Product details
Overview
DS1249W-100 from Maxim Integrated is a 3.3V, 2048kb (262,144 × 8) nonvolatile SRAM with lithium-backed data retention, 100ns access time, industrial temperature range (–40°C to +85°C), and JEDEC-standard 32-pin extended DIP package. It functions as a drop-in memory replacement in systems requiring persistent data storage during power loss, such as industrial controllers and legacy instrumentation.
For engineers reviewing the DS1249W-100 datasheet, DS1249W-100 pinout, DS1249W-100 application, or DS1249W-100 equivalent, key selection criteria include its 10-year data retention without external power, automatic write protection at VCC < 2.8V, unlimited write cycles, CMOS-compatible 3.3V operation, and self-contained lithium energy source with freshness seal activation on first power-up.
Technical Context
The DS1249W-100 implements a fully static NV SRAM architecture with integrated voltage-monitoring circuitry that triggers automatic lithium backup when VCC falls below ~2.5V and reverts to external supply above ~2.5V during power-up. Its control logic enforces unconditional write protection when VCC drops below 2.8V, rendering all inputs "don't care" and outputs high-impedance.
It supports standard microprocessor bus interfacing with independent CE, WE, and OE controls, enabling read cycles with CE/OE low and WE high, and write cycles with CE/WE low. Addressing uses 18 address lines (A0–A17), and data I/O occurs over an 8-bit bidirectional bus (DQ0–DQ7), with no external support circuitry required for battery management or power-fail detection.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Size | 2048kb (262,144 × 8 bits); provides byte-wide static RAM capacity compatible with 8-bit microcontrollers and legacy bus architectures. |
| Access Time | 100ns; enables direct interface with 10MHz bus systems without wait states. |
| Supply Voltage | 3.3V ±0.3V; operates within tight tolerance to ensure stable timing and compatibility with modern low-voltage logic families. |
| Data Retention | 10 years without external power; guaranteed by sealed lithium cell and internal power-switching circuit activated only during VCC loss. |
| Write Protection Threshold | VTP = 2.8V to 3.0V; initiates automatic write lock before VCC reaches unsafe levels, preventing corruption during brownout. |
| Operating Temperature | –40°C to +85°C (IND grade); qualified for deployment in uncontrolled industrial environments without derating. |
| Package | 32-pin 740mil extended DIP; supports through-hole mounting and legacy PCB layouts with standard JEDEC footprint. |
Pinout & Package
DS1249W-100 is housed in a 32-pin extended dual in-line package (EDIP), 740 mil width, with industry-standard pin spacing and lead form suitable for wave or hand soldering. Pin 1 is marked with a notch or dot per JEDEC outline MDT32#7.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A17 | Address Inputs | 18-bit address bus supporting full 262,144-word addressing; TTL/CMOS compatible input thresholds (VIH ≥ 2.2V, VIL ≤ 0.4V). |
| DQ0–DQ7 | Data I/O | Bidirectional 8-bit data bus; high-impedance during deselect or write cycles to prevent bus contention. |
| CE | Chip Enable | Active-low chip select; must be low for read/write access; controls device enable state independently of OE/WE. |
| WE | Write Enable | Active-low write strobe; falling edge (with CE low) initiates write; output drivers disabled during write if OE is active. |
| OE | Output Enable | Active-low output control; enables data drivers only during read cycles; must be high during writes. |
| VCC | Power Supply | +3.3V supply input; monitored continuously for out-of-tolerance condition; powers RAM and control logic. |
| GND | Ground | Reference return path for all signals and internal circuitry; requires low-impedance connection for reliable data retention. |
| NC | No Connect | Pin 16 is unconnected internally; must remain floating or tied to GND per layout best practice-no functional role. |
Key Features
| Feature | Design Value |
|---|---|
| Automatic Power-Fail Write Protection | Hardware-enforced lockout triggered at VCC ≤ 2.8V, eliminating need for external supervisor ICs or firmware intervention. |
| Lithium Freshness Seal | Lithium cell electrically disconnected until first VCC application > VTP, preserving full 10-year retention capacity from shipment date. |
| Unlimited Write Cycles | No endurance limit on SRAM writes-enables frequent logging or configuration updates without wear-out concerns. |
| Zero-Support-Circuitry Operation | Self-contained voltage monitor, power switch, and lithium source eliminate external capacitors, diodes, or regulators for backup functionality. |
| 100ns Read/Write Timing | Meets cycle timing requirements of 10MHz microprocessors and legacy bus systems without wait-state insertion. |
Applications
| Industrial PLC Data Logging | Medical Device Configuration Storage |
|---|---|
Use Scenario: Storing runtime parameters, calibration coefficients, and event logs in programmable logic controllers deployed in factory automation environments with intermittent power. IC Role / Device Role / Timing Role: Nonvolatile SRAM providing immediate-read/write access and guaranteed 10-year data retention during unexpected AC loss or battery depletion. Use Value: Eliminates need for EEPROM wear-leveling or flash programming delays; preserves critical operational history across power cycles without software overhead. | Use Scenario: Holding user-configurable settings (e.g., alarm thresholds, display preferences) and last-known vital sign snapshots in portable diagnostic equipment. IC Role / Device Role / Timing Role: Battery-backed memory ensuring zero-latency access to configuration data upon power-on and immunity to data loss during battery swaps. Use Value: Meets IEC 62304 Class B safety requirements for data persistence without volatile cache layers or external backup controllers. |
| Avionics Black Box Memory Buffer | Legacy Test Equipment Firmware State Save |
Use Scenario: Capturing real-time flight sensor data in airborne recorders where power interruption may occur during emergency shutdown or generator failure. IC Role / Device Role / Timing Role: High-reliability NV SRAM with –40°C to +85°C operation and automatic VCC-fail response, acting as primary buffer before data compression and archival. Use Value: Guarantees capture of final seconds of telemetry even under rapid VCC collapse, meeting DO-160 Section 22 transient immunity requirements. | Use Scenario: Preserving instrument calibration state, test sequence pointers, and measurement offsets in benchtop oscilloscopes and signal generators with aging PCB designs. IC Role / Device Role / Timing Role: Pin-compatible SRAM upgrade replacing obsolete volatile memory, delivering seamless integration into existing 32-pin DIP sockets without redesign. Use Value: Restores field reliability lost after decades of capacitor aging in original backup circuits-no firmware changes required. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar nonvolatile SRAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| STK12C68-100 | 5V-only supply (4.5–5.5V); 10-year retention; same 32-pin DIP but different pinout (A15/A16 swapped, no NC pin) | Requires 5V system redesign; incompatible with 3.3V buses; not suitable for mixed-voltage or low-power deployments | Select only if legacy 5V design mandates identical footprint and voltage domain. |
| DS1248W-100 | Same 3.3V supply and 100ns speed, but 1024kb (128k × 8) density; identical pinout and industrial temp grade | Half the memory capacity; insufficient for applications needing full 256k-word buffer space | Choose when board space or cost constraints justify reduced capacity and verified software memory map compatibility. |
Compared with STK12C68-100 and DS1248W-100, DS1249W-100 uniquely delivers 2048kb density at 3.3V in a pinout-identical industrial-grade package-making it the only option for upgrading legacy 32-pin DIP-based systems requiring both voltage compatibility and full memory bandwidth without layout change.
Availability
DS1249W-100 is available at Aetrix Electronics and suitable for industrial PLC data logging, medical device configuration storage, and avionics black box memory buffering requiring stable component supply, long-lifecycle assurance, and RoHS-compliant through-hole packaging.
Supply support for DS1249W-100 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 high-reliability power management solutions for industrial, medical, and aerospace applications.
The DS1249W-100 belongs to Maxim's nonvolatile SRAM product line, engineered specifically for mission-critical systems where data integrity during power interruption is non-negotiable and external support circuitry must be minimized.
FAQ
What is the guaranteed data retention period for DS1249W-100 when external power is removed?
The DS1249W-100 guarantees a minimum of 10 years of data retention in the absence of external power. This specification assumes the lithium energy source is activated on first power application and accounts for cumulative time spent in battery-backup mode. The internal power-switching circuit isolates the lithium cell until VCC drops below ~2.5V, preserving capacity for the full rated duration.
Does DS1249W-100 require external components to implement nonvolatile operation?
No, DS1249W-100 requires no external components for nonvolatile operation. It integrates a lithium energy source, voltage-monitoring circuitry, and automatic power-switching logic. The device self-activates backup on VCC decay below ~2.5V and disables the lithium source during normal operation-eliminating the need for external supervisors, diodes, or hold-up capacitors.
What is the function of the NC pin on DS1249W-100, and how should it be handled on the PCB?
Pin 16 on DS1249W-100 is designated NC (No Connect) and is unconnected internally. It must not be used for grounding, decoupling, or signal routing. Per Maxim's package documentation, this pin should remain electrically floating or be tied to GND solely for mechanical stability-no electrical function is assigned, and connecting it to any active node may compromise reliability.
How does DS1249W-100 behave during power-up and power-down transitions?
During power-down, DS1249W-100 detects VCC decay via internal monitoring and activates lithium backup when VCC falls below ~2.5V, simultaneously enabling unconditional write protection. During power-up, it reconnects VCC to the RAM and disconnects the lithium source once VCC exceeds ~2.5V, resuming full read/write operation only after VCC stabilizes above 3.0V-ensuring clean initialization without metastability.
Is DS1249W-100 compatible with 5V logic interfaces?
No, DS1249W-100 is strictly a 3.3V device with absolute maximum VCC of +4.6V and recommended operating range of 3.0V to 3.6V. Its input thresholds (VIH ≥ 2.2V, VIL ≤ 0.4V) are optimized for 3.3V CMOS levels. Direct connection to 5V buses risks violating absolute maximum ratings and may cause latch-up or premature failure-level-shifting circuitry is required for 5V system integration.
DS1249W-100 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:
- 100ns
- Access Time:
- 100 ns
- Voltage - Supply:
- 3V ~ 3.6V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 32-EDIP
DS1249W-100 FAQ
1.How can I place an order for DS1249W-100 through Aetrix?
Please submit a Request for Quotation (RFQ) for DS1249W-100 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 DS1249W-100 reliable?
The price and inventory of DS1249W-100 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS1249W-100 is usually 5 days.
3.What payment methods are accepted for DS1249W-100?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS1249W-100 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DS1249W-100?
DS1249W-100 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DS1249W-100 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 DS1249W-100?
For technical support, including DS1249W-100 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS1249W-100 requirements.
6.How does Aetrix verify that DS1249W-100 is sourced from the original manufacturer or authorized distributors?
All DS1249W-100 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 DS1249W-100 meets industry standards.
7.What is the process for return or replacement of DS1249W-100?
All DS1249W-100 units undergo pre-shipment inspection (PSI). If there is an issue with DS1249W-100, 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 DS1249W-100 part is unused and in its original packaging.
Return procedure for DS1249W-100:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
DS1249W-100 Tags
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M24C02-WMN6TP
STMicroelectronics
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AT24C02C-XHM-T
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AT21CS01-STUM10-T
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24LC01BT-I/OT
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M24C02-FMC6TG
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AT24CS02-SSHM-T
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93LC46BT-I/OT
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AT24C04C-SSHM-T
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24LC01BT-I/SN
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24AA02UIDT-I/OT
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