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Home > Products > Integrated Circuits (ICs) > Memory > Memory

Analog Devices Inc./Maxim Integrated DS1245AB-85+

Name: DS1245AB-85+
Brand: Analog Devices Inc./Maxim Integrated
SKU: DS1245AB-85+
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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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

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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% V_CC tolerance (4.75–5.25 V), 70 ns access time, and industrial temperature support (–40°C to +85°C). It replaces volatile SRAM, EEPROM, or Flash in battery-backed data logging, configuration storage, and real-time clock memory applications.

For engineers reviewing the DS1245AB-85+ datasheet, DS1245AB-85+ pinout, DS1245AB-85+ application, or DS1245AB-85+ equivalent, key selection criteria include write-protection voltage (4.50–4.75 V), standby current (50–150 µA at CE = V_CC–0.5 V), JEDEC 32-pin DIP compatibility, and automatic power-fail detection with seamless lithium switchover.

Technical Context

The DS1245AB-85+ integrates self-contained lithium energy source and voltage-monitoring circuitry that triggers unconditional write protection when V_CC falls below 4.50 V and switches to battery power below ~3.0 V. Its fully static architecture requires no refresh cycles and supports standard microprocessor bus timing with CE/OE/WE control logic.

It operates in three distinct modes: normal read/write (V_CC ≥ 4.75 V), data retention (V_CC < 4.50 V), and power-down transition (V_CC slew between 4.50 V and 3.0 V), with t_PD = 1.5 µs fail-detect latency and t_REC = 125 ms write-protection enable delay after power-up.

Key Specifications

Parameter	Value and Actual Design Meaning
Memory Size	1024 kbit (131,072 × 8) - provides byte-wide interface for legacy 8-bit systems without address multiplexing.
Access Time	70 ns - enables direct replacement of 128k × 8 SRAMs in 8-MHz bus systems with no wait states.
V_CC Range	4.75 V to 5.25 V (±5%) - ensures stable operation across noisy industrial 5 V rails without external regulation.
Write Protection Threshold	4.50–4.75 V - initiates automatic hardware lockout before data corruption occurs during brownout.
Data Retention	10 years minimum without external power - guaranteed by factory-fresh lithium cell disconnected until first V_CC application.
Operating Temperature	–40°C to +85°C (IND grade) - qualified for deployment in outdoor metering, industrial PLCs, and transportation control units.
Standby Current	50–150 µA (CE = V_CC–0.5 V) - enables ultra-low-power retention in always-on embedded systems with intermittent wake-up.

Pinout & Package

DS1245AB-85+ uses a JEDEC-standard 32-pin Extended DIP (740-mil) package with through-hole mounting. The package integrates SRAM, lithium battery, and control circuitry in a single hermetically sealed unit.

Pin/Terminal	Circuit Role	Design Meaning
A0–A16	Address Inputs	17-bit address bus supporting full 131,072-word addressing; TTL-compatible inputs with 0.0–0.8 V low and 2.2–V_CC high thresholds.
DQ0–DQ7	Data I/O	Bi-directional 8-bit data bus with 2 mA sink / –1 mA source drive; high-impedance on deselect or during write to prevent bus contention.
CE	Chip Enable	Active-low chip select; must be low with WE and OE to initiate valid access; controls standby current ICCS2 (50–150 µA).
WE	Write Enable	Active-low write strobe; falling edge (with CE low) starts write cycle; t_WR = 5–15 ns recovery required before next cycle.
OE	Output Enable	Active-low output control; disables drivers when high during writes to avoid contention; t_OE = 35 ns output valid delay.
V_CC	Power Supply	+5 V ±5% main supply; powers SRAM core and control logic; monitored continuously for write-protection activation.
GND	Ground	Reference return path for all signals and power; decoupling capacitor required within 1 cm of V_CC/GND pins.
NC	No Connect	Pins 1, 2, 3, 17, 32 - electrically isolated; no internal connection; must remain unconnected on PCB.

Key Features

Feature	Design Value
Automatic Power-Fail Response	Hardware-monitored V_CC triggers write protection and lithium switchover within 1.5 µs, eliminating firmware dependency for data integrity.
Lithium Freshness Seal	Factory-disconnected battery retains full capacity until first V_CC > 4.25 V application-ensures 10-year retention from installation date.
Unlimited Write Cycles	No endurance limit on SRAM writes-supports high-frequency logging (e.g., sensor sampling at 1 kHz) without wear-out concerns.
Standardized Pinout	JEDEC 32-pin DIP footprint matches legacy 128k × 8 SRAMs-enables drop-in replacement without PCB redesign.
Industrial Temperature Qualification	–40°C to +85°C operation verified per MIL-STD-883 methods-suitable for uncontrolled environments like utility substations or vehicle ECUs.

Applications

Smart Energy Metering	Industrial PLC Configuration Storage
Use Scenario: Storing tariff schedules, consumption logs, and tamper-event timestamps in electricity meters deployed outdoors. IC Role / Device Role / Timing Role: Nonvolatile memory holding critical billing data during grid outages or meter removal. Use Value: 10-year data retention and automatic write-protection at 4.5 V ensure regulatory compliance (IEC 62056) without supercapacitor or external battery management.	Use Scenario: Preserving ladder logic parameters, I/O mapping, and calibration coefficients in programmable logic controllers operating in factory floors. IC Role / Device Role / Timing Role: Battery-backed SRAM retaining runtime configuration across power cycles and firmware updates. Use Value: 70 ns access time enables real-time parameter recall during scan cycles; ±5% V_CC tolerance accommodates fluctuating 24 VDC-to-5 V conversion.
Medical Device Calibration Memory	Avionics Black Box Data Buffer
Use Scenario: Storing sensor calibration constants and usage history in portable diagnostic equipment subject to periodic sterilization and battery replacement. IC Role / Device Role / Timing Role: Tamper-resistant, long-life memory for FDA-required device traceability and performance validation. Use Value: Factory-sealed lithium guarantees retention over 10 years-even if device sits unused in inventory-meeting ISO 13485 shelf-life requirements.	Use Scenario: Capturing flight control actuator commands and sensor telemetry in aircraft flight data recorders during transient power loss. IC Role / Device Role / Timing Role: High-reliability buffer maintaining last 30 seconds of critical data during engine shutdown or generator failure. Use Value: Sub-µs power-fail detection (t_PD = 1.5 µs) and immediate lithium switchover prevent data gaps in DO-178C-certified recording systems.

Smart Energy Metering

Industrial PLC Configuration Storage

Use Scenario: Storing tariff schedules, consumption logs, and tamper-event timestamps in electricity meters deployed outdoors.

IC Role / Device Role / Timing Role: Nonvolatile memory holding critical billing data during grid outages or meter removal.

Use Value: 10-year data retention and automatic write-protection at 4.5 V ensure regulatory compliance (IEC 62056) without supercapacitor or external battery management.

Use Scenario: Preserving ladder logic parameters, I/O mapping, and calibration coefficients in programmable logic controllers operating in factory floors.

IC Role / Device Role / Timing Role: Battery-backed SRAM retaining runtime configuration across power cycles and firmware updates.

Use Value: 70 ns access time enables real-time parameter recall during scan cycles; ±5% V_CC tolerance accommodates fluctuating 24 VDC-to-5 V conversion.

Medical Device Calibration Memory

Avionics Black Box Data Buffer

Use Scenario: Storing sensor calibration constants and usage history in portable diagnostic equipment subject to periodic sterilization and battery replacement.

IC Role / Device Role / Timing Role: Tamper-resistant, long-life memory for FDA-required device traceability and performance validation.

Use Value: Factory-sealed lithium guarantees retention over 10 years-even if device sits unused in inventory-meeting ISO 13485 shelf-life requirements.

Use Scenario: Capturing flight control actuator commands and sensor telemetry in aircraft flight data recorders during transient power loss.

IC Role / Device Role / Timing Role: High-reliability buffer maintaining last 30 seconds of critical data during engine shutdown or generator failure.

Use Value: Sub-µs power-fail detection (t_PD = 1.5 µs) and immediate lithium switchover prevent data gaps in DO-178C-certified recording systems.

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 V_CC range (4.5–5.5 V, ±10%), lower write-protection threshold (4.25–4.5 V), same 70 ns speed and 10-year retention.	Better suited for systems with poorly regulated 5 V supplies but less margin for brownout detection near 4.5 V.	Select DS1245Y-85+ only if supply variation exceeds ±5%; otherwise DS1245AB-85+ offers tighter voltage guardband for critical data lockout.
STK12C68-A85	Same 1024k size and 85°C rating, but uses external lithium coin cell; 85 ns access time; no integrated freshness seal.	Requires additional board space and soldering for battery holder; retention depends on user-installed cell quality and age.	Choose STK12C68-A85 only when cost sensitivity outweighs reliability and qualification burden; DS1245AB-85+ eliminates battery integration risk.

Compared with DS1245Y-85+, DS1245AB-85+ provides stricter voltage monitoring for earlier write-lock activation, while STK12C68-A85 trades integrated reliability for modularity-making DS1245AB-85+ optimal for safety-critical, field-deployed systems requiring zero-integration liability.

Availability

DS1245AB-85+ is available at Aetrix Electronics and suitable for smart metering, industrial PLCs, medical diagnostics, and avionics black box systems requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant through-hole 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) designs precision analog, mixed-signal, and nonvolatile memory ICs for industrial, medical, and automotive applications.

The DS1245AB-85+ belongs to Maxim's nonvolatile SRAM product line, engineered specifically for mission-critical data retention in systems where power interruption is frequent or unpredictable.

FAQ

What is the guaranteed data retention period for DS1245AB-85+?

The DS1245AB-85+ guarantees minimum 10 years of data retention in the absence of external power, measured from the time V_CC is first applied above 4.25 V. This is ensured by a factory-fresh lithium cell electrically disconnected until initial power-up, with retention validated by component selection, process control, and design-not production-tested per unit.

Does DS1245AB-85+ require external support circuitry for microprocessor interfacing?

No, DS1245AB-85+ requires no external support circuitry for microprocessor interfacing. Its TTL-compatible address/data/control pins, built-in voltage monitoring, and automatic lithium switchover eliminate the need for external supervisors, batteries, or write-protection logic-enabling direct connection to 8-bit parallel buses.

How does DS1245AB-85+ handle power failure during a write operation?

DS1245AB-85+ detects V_CC decay in real time and activates unconditional write protection within 1.5 µs (t_PD) when voltage drops below 4.50 V. All inputs become "don't care," outputs go high-impedance, and the lithium source engages below ~3.0 V-preventing partial writes and ensuring data integrity even mid-cycle.

Is DS1245AB-85+ pin-compatible with standard 128k × 8 SRAMs?

Yes, DS1245AB-85+ uses a JEDEC-standard 32-pin Extended DIP (740-mil) package with identical pinout to legacy 128k × 8 SRAMs. Its A0–A16, DQ0–DQ7, CE, WE, OE, V_CC, and GND assignments match industry-standard byte-wide SRAMs-enabling true drop-in replacement without layout changes.

What is the difference between DS1245AB-85+ and DS1245AB-70+?

The DS1245AB-85+ and DS1245AB-70+ share identical functionality, pinout, and temperature rating (–40°C to +85°C), differing only in speed grade: both specify 70 ns access time, but the "-85+" suffix denotes industrial temperature qualification with full AC/DC specs guaranteed across –40°C to +85°C, whereas "-70+" is commercial grade (0°C to +70°C).

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:: Active

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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