Analog Devices Inc./Maxim Integrated DS2250T-32-16+

Overview

DS2250T-32-16+ from Maxim Integrated is an 8-bit 8051-compatible soft microcontroller module with 32kB nonvolatile SRAM, 16MHz max crystal speed, and integrated real-time clock (RTC) powered by on-board crystal. It retains full program/data memory, configuration registers, and RTC state for >10 years without VCC, enabling secure, power-fail-resilient embedded control in utility meters and industrial data loggers.

For engineers reviewing the DS2250T-32-16+ datasheet, DS2250T-32-16+ pinout, DS2250T-32-16+ application, or DS2250T-32-16+ equivalent, key selection criteria include nonvolatile RAM retention duration, RTC integration, serial bootstrap loader support, 40-pin SIMM package compatibility, and 8051 instruction set compliance for legacy firmware reuse.

Technical Context

The DS2250T-32-16+ implements a fully 8051-compatible CPU core with dual memory spaces: up to 32kB of nonvolatile SRAM usable for both program and data storage, plus dedicated RTC registers accessible via SFR bit ECE2. Its oscillator supports external crystals up to 16MHz and includes internal power-fail detection with early-warning interrupt and reset generation.

It features two on-chip timer/event counters, full-duplex UART (P3.0/P3.1), 32 parallel I/O lines across Ports 0–3, and expanded bus interface with ALE, PSEN, RD, WR, and multiplexed Port 0 address/data bus - all operating under standard 8051 timing constraints validated at 16MHz.

Key Specifications

Pinout & Package

DS2250T-32-16+ uses a 40-pin SIMM (Single In-line Memory Module) package with 0.400-inch width, 2.65-inch length, and 0.057–0.067-inch thickness per JEDEC MS-026 standard. Pin numbering follows standard SIMM layout with pins 1–20 on front edge and 21–40 on rear edge.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar soft microcontroller applications.

Compared with DS2250T-32-16+, DS2250T-64-16+ provides double NV RAM capacity without changing layout or firmware architecture, while DS2250-32-16+ removes RTC circuitry to lower system cost - making DS2250T-32-16+ the balanced choice for RTC-dependent, memory-constrained applications.

Availability

DS2250T-32-16+ is available at Aetrix Electronics and suitable for smart metering, industrial data logging, secure access control, and legacy 8051 system upgrades requiring stable component supply and long-term lifecycle assurance.

Supply support for DS2250T-32-16+ 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) is a U.S.-based semiconductor company specializing in high-reliability analog and mixed-signal ICs for industrial, automotive, and communications markets.

The DS2250(T) product line delivers "soft" microcontrollers optimized for secure, battery-free, long-life embedded applications where nonvolatile memory retention, tamper resistance, and field-upgradable firmware are critical design requirements.

FAQ

What does the '+' suffix signify in DS2250T-32-16+?

The '+' suffix in DS2250T-32-16+ indicates a lead-free and RoHS-compliant version of the device, packaged in a 40-pin SIMM format. This variant meets modern environmental regulations without altering electrical specifications, pinout, or functional behavior compared to non-RoHS versions. DS2250T-32-16+ maintains identical 32kB nonvolatile SRAM, 16MHz crystal support, and integrated RTC functionality.

Does DS2250T-32-16+ require an external crystal to operate its real-time clock?

Yes, DS2250T-32-16+ requires an external crystal connected between XTAL1 and XTAL2 pins to operate its integrated real-time clock. The datasheet specifies use of an on-board crystal, meaning the crystal is mounted directly on the DS2250T-32-16+ module's PCB - not inside the IC die. No additional RTC IC or backup battery is needed, as the module's nonvolatile SRAM and RTC registers retain state for >10 years without power.

Can DS2250T-32-16+ execute firmware updates in the field without removing it from the system?

Yes, DS2250T-32-16+ supports in-system firmware updates via its on-chip Serial Bootstrap Loader. Using standard UART communication at baud rates from 300 to 9600 bps, users can load Intel HEX files directly into its 32kB nonvolatile SRAM. This capability allows DS2250T-32-16+ to receive new application code, security patches, or configuration changes while installed in end equipment - eliminating need for programming fixtures or board removal.

How does DS2250T-32-16+ handle power failures during active operation?

DS2250T-32-16+ incorporates hardware-level power-fail management: it monitors VCC and triggers an early-warning interrupt when voltage drops below 4.15V, followed by automatic reset if VCC falls further. All nonvolatile resources - including program memory, data memory, configuration registers, and RTC state - remain intact for over 10 years without power. This ensures DS2250T-32-16+ resumes operation with zero data loss after power restoration.

Is DS2250T-32-16+ pin-compatible with standard 8051 microcontrollers like the AT89C51?

No, DS2250T-32-16+ is not pin-compatible with standard DIP-packaged 8051 microcontrollers such as the AT89C51. It uses a 40-pin SIMM form factor designed for memory-module-style insertion, with different pin assignments (e.g., P0.0–P0.7 on pins 4,6,8…18; RST on pin 17). While instruction-set compatible and functionally aligned with 8051 architecture, DS2250T-32-16+ requires a custom carrier board or socket matching its SIMM mechanical and electrical interface.