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Analog Devices Inc./Maxim Integrated DS2251T-128-16#
- Part No.:
- DS2251T-128-16#
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Microcontrollers
- Package:
- 72-SIMM
- Datasheet:
-
DS2251T-128-16#.pdf
- Description:
- IC MCU 8BIT 128KB NVSRAM 72SIMM
- Quantity:
- Payment:
- Shipping:
Inventory:2,100
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Product details
Overview
DS2251T-128-16# from Maxim Integrated is an 8051-compatible soft microcontroller module with 128kB nonvolatile SRAM, 16MHz crystal support, integrated real-time clock (to 0.01s), power-fail reset/interrupt, and watchdog timer - used in battery-backed data loggers and secure embedded controllers requiring field-upgradable firmware.
For engineers reviewing the DS2251T-128-16# datasheet, DS2251T-128-16# pinout, DS2251T-128-16# application, or DS2251T-128-16# equivalent, key selection criteria include NV SRAM size (128kB), lithium-backed RTC accuracy, byte-wide bus interface (BA13–BA0/BD7–BD0), and power-fail warning at 4.25V–4.50V.
Technical Context
The DS2251T-128-16# implements a full 8051 instruction set with 128B scratchpad RAM, two 16-bit timers, on-chip UART, and 32 I/O pins - all mapped to a non-multiplexed byte-wide bus (BA13–BA0, BD7–BD0) that leaves parallel ports free for application use. Memory partitioning allows dynamic allocation between program and data segments.
Its power management architecture includes three voltage thresholds: VPFW (4.25–4.50V) for early-warning interrupt, VCCMIN (4.00–4.25V) for power-fail reset, and VLI for lithium switchover. The RTC uses an onboard 32kHz crystal and delivers SQW output (1024Hz programmable) plus INTA/INTP/INTB interrupts.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| RAM Size | 128kB nonvolatile SRAM for reprogrammable firmware and persistent data storage without external EEPROM |
| Max Crystal Speed | 16MHz oscillator frequency enabling full 8051 instruction execution at industry-standard timing | RTC Accuracy | 0.01-second resolution using internal 32kHz crystal; supports time-stamped logging and alarm interrupts |
| Power-Fail Warning | VPFW = 4.25–4.50V threshold triggers early-warning interrupt before system reset occurs |
| Operating Temp | -40°C to +85°C industrial temperature range validated for embedded systems in harsh environments |
| Supply Voltage | 5V ±10% nominal operation; maintains nonvolatile state >10 years at room temperature with lithium backup |
| Bus Interface | Non-multiplexed byte-wide address (BA13–BA0) and data (BD7–BD0) bus for memory-mapped peripherals |
Pinout & Package
DS2251T-128-16# uses a 72-pin SIMM package (4.25″ × 1.00″ × 0.25″) with gold-plated edge contacts, designed for vertical insertion into socketed motherboards. Pin assignment follows JEDEC-standard SIMM layout with dedicated NV SRAM bus and RTC signal routing.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BA0–BA13 | Byte-wide address bus | Directly accesses 16k-page boundaries of onboard NV SRAM and off-board peripherals without multiplexing |
| BD0–BD7 | Byte-wide data bus | Bi-directional 8-bit path for read/write operations; supports MOVX instructions with PE3/PE4 decoding |
| R/W | Read/Write strobe | Controls write enable to SRAM blocks; automatically write-protects program segments per partition configuration |
| VRST | Backup reset indicator | Open-drain I/O driven low during lithium backup mode; guarantees reset signaling even at VCC = 0V |
| PF | Power-fail indicator | Asserts logic 0 when VCC drops below VLI; remains valid under zero-voltage conditions due to lithium cell |
| INTA/INTP/INTB | RTC interrupt outputs | Dedicated open-drain signals for alarm, periodic, and timestamp events - each configurable via SFRs |
Key Features
| Feature | Design Value |
|---|---|
| In-system reprogramming | Bootstrap loader enables firmware updates via serial port without removing device from PCB |
| Dynamic memory partitioning | User-selectable split between program and data segments in NV SRAM, modifiable at runtime |
| Lithium-backed RTC | Onboard 32kHz crystal and battery maintain timekeeping and interrupt generation for >10 years without VCC |
| Power-fail resilience | Three-tier voltage monitoring (VPFW/VCCMIN/VLI) ensures deterministic state save, reset, and backup switchover |
| Non-multiplexed bus | Separate BA/BD buses preserve all 32 I/O pins for application use while supporting memory-mapped peripherals |
Applications
| Data Logger | Secure Industrial Controller |
|---|---|
Use Scenario: Continuous environmental sensor recording in remote utility meters with infrequent maintenance cycles. IC Role / Device Role / Timing Role: DS2251T-128-16# acts as main controller and time-stamped data repository, using its RTC and NV SRAM to store readings across power outages. Use Value: Eliminates need for external RTC and EEPROM; 128kB NV SRAM stores >1 million timestamped samples with guaranteed 10-year retention. | Use Scenario: Programmable logic controller (PLC) module requiring field-upgradable firmware and tamper-resistant state preservation. IC Role / Device Role / Timing Role: DS2251T-128-16# serves as secure execution engine with CRC-16 validation of NV RAM and power-fail interrupt-driven state capture. Use Value: Enables over-the-air firmware patches and preserves operational context during brownouts - critical for safety-critical automation sequences. |
| Medical Diagnostic Recorder | Energy Meter Firmware Hub |
Use Scenario: Portable ECG monitor capturing waveform data during patient transport where AC power is unavailable. IC Role / Device Role / Timing Role: DS2251T-128-16# functions as real-time acquisition controller and timestamped buffer, leveraging lithium-backed RTC for clinical-grade time correlation. Use Value: Maintains precise 0.01s time stamps and full waveform history across battery swaps and power interruptions - compliant with IEC 62304 Class B requirements. | Use Scenario: Smart electricity meter needing long-term energy consumption logging and tariff schedule updates via HAN interface. IC Role / Device Role / Timing Role: DS2251T-128-16# hosts metering firmware and billing data tables, using its byte-wide bus to interface with metrology ADC and communication ICs. Use Value: Supports 15+ years of daily kWh logging with automatic rollover and cryptographic signature verification of firmware updates. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microcontroller-with-NV-memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| DS2251T-64-16# | 64kB NV SRAM instead of 128kB; identical pinout, timing, and feature set | Suitable for applications with smaller firmware footprint or lower data logging depth requirements | Select when memory budget allows reduction without compromising real-time performance or RTC functionality |
| DS2251T-32-16# | 32kB NV SRAM; same 16MHz speed, RTC, and power-fail architecture as DS2251T-128-16# | Targeted at cost-sensitive designs where firmware size and data retention depth are constrained | Choose for legacy system upgrades or space-constrained modules where 128kB is unnecessary overhead |
Compared with DS2251T-64-16# and DS2251T-32-16#, the DS2251T-128-16# provides double and quadruple NV SRAM capacity respectively - enabling longer data retention intervals, larger adaptive algorithms, and multi-version firmware staging without external memory expansion.
Availability
DS2251T-128-16# is available at Aetrix Electronics and suitable for data loggers, secure industrial controllers, medical diagnostic recorders, and energy meter firmware hubs requiring stable component supply and long-term lifecycle support.
Supply support for DS2251T-128-16# 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 high-reliability analog and mixed-signal ICs for industrial, automotive, and computing applications.
The DS2251T-128-16# belongs to Maxim's secure microcontroller family, engineered for systems demanding nonvolatile firmware upgradability, battery-backed timekeeping, and deterministic power-fail response in unattended deployments.
FAQ
What is the maximum crystal frequency supported by the DS2251T-128-16#?
The DS2251T-128-16# supports a maximum crystal frequency of 16MHz, as specified in the Ordering Information table and confirmed in AC Characteristics section #1. This enables full-speed 8051-compatible instruction execution with timing margins validated across -40°C to +85°C. The DS2251T-128-16# does not support higher frequencies; exceeding 16MHz violates the device's absolute maximum rating and may cause undefined behavior or failure to boot.
Does the DS2251T-128-16# include a built-in real-time clock?
Yes, the DS2251T-128-16# integrates a permanently powered real-time clock with 0.01-second resolution, driven by an onboard 32kHz crystal. It provides three interrupt outputs (INTA, INTP, INTB), a programmable 1024Hz square-wave output (SQW), and retains time/date during VCC loss via lithium backup - all documented in the Description and PIN DESCRIPTION sections.
How much nonvolatile memory does the DS2251T-128-16# provide?
The DS2251T-128-16# provides 128kbytes of nonvolatile SRAM for both program and data storage, as explicitly stated in the Ordering Information table and Features section. This NV SRAM retains content for over 10 years at room temperature without VCC, eliminating need for external EEPROM or flash memory in applications like data logging and firmware updates.
What power-fail protection features are implemented in the DS2251T-128-16#?
The DS2251T-128-16# implements three-tier power-fail protection: early-warning interrupt at VPFW (4.25–4.50V), power-fail reset at VCCMIN (4.00–4.25V), and automatic lithium switchover at VLI. These functions are hardware-enforced and guarantee state preservation, reset signaling (VRST), and backup power indication (PF) - all verified in DC CHARACTERISTICS and POWER MANAGEMENT sections.
Is the DS2251T-128-16# RoHS-compliant?
Yes, the DS2251T-128-16# is RoHS-compliant, as indicated by the "#" suffix in the part number per the Ordering Information table. This denotes a lead-exempt RoHS package meeting EU Directive 2011/65/EU requirements, with full compliance documentation available from Maxim Integrated's product change notices dated 06/13/06.
DS2251T-128-16# Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package/Case:
- 72-SIMM
- Series:
- DS225x
- Packaging:
- Tray
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Core Processor:
- 8051
- Core Size:
- 8-Bit
- Speed:
- 16MHz
- Connectivity:
- SIO, UART/USART
- Peripherals:
- Power-Fail Reset, WDT
- Number of I/O:
- 32
- Program Memory Size:
- 128KB (128K x 8)
- Program Memory Type:
- NVSRAM
- EEPROM Size:
- -
- RAM Size:
- -
- Voltage - Supply (Vcc/Vdd):
- 4.5V ~ 5.5V
- Data Converters:
- -
- Oscillator Type:
- External
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
DS2251T-128-16# FAQ
1.How can I place an order for DS2251T-128-16# through Aetrix?
Please submit a Request for Quotation (RFQ) for DS2251T-128-16# 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 DS2251T-128-16# reliable?
The price and inventory of DS2251T-128-16# are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS2251T-128-16# is usually 5 days.
3.What payment methods are accepted for DS2251T-128-16#?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS2251T-128-16# transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DS2251T-128-16#?
DS2251T-128-16# orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DS2251T-128-16# 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 DS2251T-128-16#?
For technical support, including DS2251T-128-16# datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS2251T-128-16# requirements.
6.How does Aetrix verify that DS2251T-128-16# is sourced from the original manufacturer or authorized distributors?
All DS2251T-128-16# 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 DS2251T-128-16# meets industry standards.
7.What is the process for return or replacement of DS2251T-128-16#?
All DS2251T-128-16# units undergo pre-shipment inspection (PSI). If there is an issue with DS2251T-128-16#, 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 DS2251T-128-16# part is unused and in its original packaging.
Return procedure for DS2251T-128-16#:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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