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Analog Devices Inc./Maxim Integrated DS1245AB-85
- Part No.:
- DS1245AB-85
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Memory
- Package:
- 32-DIP Module (0.600", 15.24mm)
- Datasheet:
-
DS1245AB-85.pdf
- Description:
- IC NVSRAM 1MBIT PARALLEL 32EDIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,213
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Product details
Overview
DS1245AB-85 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 temperature range (–40°C to +85°C). It replaces volatile SRAM, EEPROM, or Flash in battery-backed memory applications requiring data retention during power loss.
For engineers reviewing the DS1245AB-85 datasheet, DS1245AB-85 pinout, DS1245AB-85 application, or DS1245AB-85 equivalent, key selection criteria include write-protection threshold (4.50–4.75 V), 10-year data retention without external power, JEDEC 32-pin DIP compatibility, and automatic lithium switchover at ~3.0 V.
Technical Context
The DS1245AB-85 integrates SRAM, lithium battery, and voltage-monitoring control circuitry in a single monolithic package. Its self-contained power-fail detection triggers unconditional write protection and high-impedance outputs when VCC drops below 4.5 V, then switches to lithium backup at ~3.0 V.
It operates as a byte-wide parallel memory with standard microprocessor interface timing: CE/OE/WE control logic, 17 address lines (A0–A16), and 8 bidirectional data lines (DQ0–DQ7). No external support circuitry is required for nonvolatile operation or microprocessor interfacing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 1024 kbit (131,072 × 8), directly replaces 128k × 8 SRAMs in existing designs |
| Access time | 70 ns - ensures compatibility with 14 MHz bus systems and legacy microcontrollers |
| VCC operating range | 4.75 V to 5.25 V (±5%) - supports stable operation under regulated 5 V rails with typical supply variation |
| Data retention | 10 years minimum without external power - guaranteed by integrated lithium cell and freshness seal |
| Write protection threshold | 4.50–4.75 V - initiates automatic lockout before data corruption occurs during brownout |
| Temperature range | –40°C to +85°C (IND grade) - qualified for industrial control, instrumentation, and telecom infrastructure |
| Package | 32-pin 740-mil extended DIP (JEDEC standard) - drop-in compatible with legacy socketed SRAM layouts |
Pinout & Package
DS1245AB-85 uses a JEDEC-standard 32-pin extended DIP (740-mil) package with integrated lithium battery and control circuitry. The package is wave- or hand-solderable only (not reflow-compatible).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A16 | Address inputs | 17-bit address bus supporting full 131,072-word addressing; TTL-compatible input thresholds |
| DQ0–DQ7 | Data I/O | Bidirectional 8-bit data bus; high-impedance on deselect or power-down to prevent bus contention |
| CE | Chip Enable | Active-low chip select; controls device enable and participates in write-cycle timing (tWC, tWR) |
| WE | Write Enable | Active-low write strobe; determines write start/stop edges with CE per AC timing specs |
| OE | Output Enable | Active-low output control; enables read data drivers only when CE is also active |
| VCC | Power supply | +5 V ±5% main supply; powers SRAM core and monitoring circuitry; disconnects lithium until first power-up |
| GND | Ground | Reference return for all signals and internal circuitry; requires low-impedance PCB connection |
| NC | No connect | Pins 1, 17, 32 - electrically isolated; no internal connection or function |
Key Features
| Feature | Design Value |
|---|---|
| Automatic power-fail response | Monitors VCC continuously; asserts write protection and high-Z outputs within 1.5 µs of out-of-tolerance detection |
| Lithium freshness seal | Energy source remains electrically disconnected until first VCC > 4.25 V application - preserves full 10-year retention capacity |
| Unlimited write cycles | No endurance limit on SRAM writes - eliminates wear-leveling firmware and write-cycle management overhead |
| Standardized pinout | JEDEC 32-pin DIP layout matches industry-standard 128k × 8 SRAM footprints - enables direct replacement without PCB change |
| Low-power standby | 600 µA max ICCS1 (CE = 2.2 V) - reduces system power budget during idle periods while retaining data |
Applications
| Industrial Data Logger | Medical Device Memory |
|---|---|
Use Scenario: Continuous acquisition of sensor readings in remote field equipment with intermittent power or scheduled maintenance windows. IC Role / Device Role / Timing Role: Nonvolatile SRAM storing real-time operational logs, calibration data, and fault history with zero write latency and guaranteed retention during grid outages. Use Value: Eliminates need for EEPROM write-delay polling or Flash erase cycles - enables deterministic logging at 10 kHz sample rates without data loss. | Use Scenario: Storing patient therapy parameters, treatment history, and safety-critical configuration in portable infusion pumps and diagnostic monitors. IC Role / Device Role / Timing Role: Battery-backed memory preserving life-critical settings across power cycles, sterilization events, and battery swaps. Use Value: Meets IEC 62304 Class C software requirements via 10-year retention and automatic write protection during voltage sag - avoids recalibration after power interruption. |
| Telecom Base Station Control | Programmable Logic Controller (PLC) |
Use Scenario: Maintaining configuration tables, channel maps, and alarm buffers in cellular baseband units exposed to wide ambient temperature swings. IC Role / Device Role / Timing Role: Industrial-grade NV SRAM interfacing directly with FPGA or ARM-based control processors via parallel bus. Use Value: –40°C to +85°C operation and 70 ns access ensure deterministic boot-time parameter loading and runtime register shadowing without thermal derating. | Use Scenario: Retaining ladder logic state, I/O mapping, and recipe data in factory-floor PLCs subject to frequent power cycling and electrical noise. IC Role / Device Role / Timing Role: Drop-in replacement for legacy SRAMs in DIN-rail mounted controllers, providing seamless nonvolatility without firmware modification. Use Value: JEDEC 32-pin DIP compatibility allows field upgrades of existing PLC backplanes; automatic lithium switchover prevents program corruption during brownouts. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar nonvolatile SRAM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| DS1245Y-85 | Wider VCC tolerance (±10%, 4.5–5.5 V); lower write-protection threshold (4.25–4.5 V); same speed/temp/package | Suitable for unregulated 5 V supplies or systems with higher ripple; less margin before write protect activates | Select DS1245Y-85 if supply regulation is looser than ±5%; otherwise DS1245AB-85 provides tighter brownout immunity. |
| STK12C68-85 | Same 1024k size, 70 ns, –40°C to +85°C, but uses external battery and separate controller IC; not monolithic | Requires additional PCB area and design effort for battery integration and power-switching logic | Choose DS1245AB-85 for simplified BOM and layout - monolithic integration eliminates discrete backup circuit design. |
Compared with DS1245Y-85 and STK12C68-85, DS1245AB-85 delivers superior design simplicity through fully integrated lithium backup and tighter VCC monitoring, enabling robust nonvolatile storage in space-constrained industrial systems without external components or layout changes.
Availability
DS1245AB-85 is available at Aetrix Electronics and suitable for industrial data loggers, medical device memory, and telecom base station control requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for DS1245AB-85 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, medical, and communications markets.
The DS1245AB-85 belongs to Maxim's nonvolatile SRAM product line, designed specifically for applications demanding zero-write-latency, long-term data retention, and seamless replacement of volatile memory in mission-critical systems.
FAQ
What is the guaranteed data retention period for DS1245AB-85?
The DS1245AB-85 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 the integrated lithium energy source, which remains disconnected until initial power-up to preserve full capacity. The retention specification is based on component selection, process control, and design validation-not production testing.
Does DS1245AB-85 require external circuitry for nonvolatile operation?
No, DS1245AB-85 requires no external circuitry for nonvolatile operation. It integrates the SRAM array, lithium battery, voltage-monitoring circuitry, and power-switching logic into a single JEDEC 32-pin DIP package. The device automatically detects VCC decay, enables write protection, and switches to lithium backup without any external components or firmware intervention.
What is the write-protection voltage threshold for DS1245AB-85?
The DS1245AB-85 asserts unconditional write protection when VCC falls within the range of 4.50 V to 4.75 V. This threshold is tighter than the DS1245Y variant (4.25–4.5 V), providing greater immunity against data corruption during marginal brownout conditions in systems with well-regulated ±5% 5 V supplies.
Can DS1245AB-85 be used as a direct replacement for standard 128k × 8 SRAMs?
Yes, DS1245AB-85 is a pin-compatible, functionally enhanced drop-in replacement for 128k × 8 volatile SRAMs. It uses the JEDEC-standard 32-pin DIP footprint, identical address/data/control signal assignments, and TTL-compatible timing - allowing direct substitution without PCB or firmware changes in existing designs.
Is DS1245AB-85 compatible with reflow soldering processes?
No, DS1245AB-85 in the 32-pin DIP package is rated for wave or hand soldering only. Its integrated lithium battery cannot withstand reflow temperatures. For surface-mount applications, the DS1245ABP-85 PowerCap Module variant must be used with a separately ordered DS9034PC+ PowerCap - the PCM is reflow-solderable, and the PowerCap snaps on post-assembly.
DS1245AB-85 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:
- 85ns
- Access Time:
- 85 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-85 FAQ
1.How can I place an order for DS1245AB-85 through Aetrix?
Please submit a Request for Quotation (RFQ) for DS1245AB-85 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-85 reliable?
The price and inventory of DS1245AB-85 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS1245AB-85 is usually 5 days.
3.What payment methods are accepted for DS1245AB-85?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS1245AB-85 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DS1245AB-85?
DS1245AB-85 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DS1245AB-85 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-85?
For technical support, including DS1245AB-85 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS1245AB-85 requirements.
6.How does Aetrix verify that DS1245AB-85 is sourced from the original manufacturer or authorized distributors?
All DS1245AB-85 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-85 meets industry standards.
7.What is the process for return or replacement of DS1245AB-85?
All DS1245AB-85 units undergo pre-shipment inspection (PSI). If there is an issue with DS1245AB-85, 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-85 part is unused and in its original packaging.
Return procedure for DS1245AB-85:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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