Analog Devices Inc./Maxim Integrated DS1217M-1-25

Overview

DS1217M-1-25 from Maxim Integrated is a nonvolatile read/write cartridge with 128k × 8 (128 kB) memory capacity, software-controlled bank switching across 4 banks of 32 kB each, JEDEC 28-pin bytewide pinout compatibility via ribbon cable, and automatic lithium battery-backed write protection for data retention >5 years. It serves as a rugged, user-insertable memory module in industrial control panels requiring field-upgradable firmware storage.

For engineers reviewing the DS1217M-1-25 datasheet, DS1217M-1-25 pinout, DS1217M-1-25 application, or DS1217M-1-25 equivalent, key selection criteria include bank-switching protocol compliance, VCC-dependent write-enable threshold (4.5 V), JEDEC 28-pin DIP retrofit capability, and dual-battery redundancy for fail-safe data retention during power loss.

Technical Context

The DS1217M-1-25 implements a nonvolatile RAM architecture with integrated lithium batteries and an analog power-switching circuit that automatically connects backup power when VCC falls below ~3.0 V and disables writes below 4.5 V. Bank selection is performed via a 64-bit address-pattern sequence applied to A8–A11 over 16 consecutive read cycles, enabling dynamic access to one of four 32 kB banks.

It supports standard asynchronous SRAM timing: tRC = 250 ns, tACC = 250 ns, tWC = 250 ns, with CE/OE/WE control logic compliant with JEDEC bytewide memory protocols. The device maintains high-impedance outputs during invalid control signal transitions (per Notes 5–8) and includes built-in write-protection via manual switch and automatic voltage monitoring.

Key Specifications

Pinout & Package

DS1217M-1-25 uses a 30-contact card-edge cartridge package (30 Cartridge), designed for direct PCB mounting or remote connection via 28-pin DIP plug (AMP 746616-2) and 28-pin ribbon cable. Pinout follows JEDEC 28-pin bytewide memory standard with right-justified alignment (A1/B1 unconnected).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar nonvolatile memory cartridge applications.

Compared with DS1217M-1-25, DS1216M-1-25 offers identical form factor and capacity but reduced reliability due to single-battery architecture, while DS1243Y-120+ trades memory size and bank flexibility for integrated timekeeping - making DS1217M-1-25 optimal for high-integrity, field-upgradeable firmware storage.

Availability

DS1217M-1-25 is available at Aetrix Electronics and suitable for industrial HMI firmware storage, legacy PLC configuration backup, and medical device calibration data archive requiring stable component supply and long-term lifecycle support.

Supply support for DS1217M-1-25 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, communications, and computing applications.

The DS1217M-1-25 belongs to Maxim's nonvolatile memory cartridge product line, engineered specifically for rugged, field-serviceable memory expansion in legacy 5 V systems requiring battery-backed data integrity without redesign.

FAQ

What is the memory capacity and organization of the DS1217M-1-25?

The DS1217M-1-25 provides 128k × 8 (128 kB) of nonvolatile RAM, divided into four independent 32 kB banks. Bank selection is controlled entirely through software by executing a specific 64-bit address pattern on A8–A11 across 16 read cycles - no additional control lines are required. This structure enables modular firmware updates and configuration partitioning within the DS1217M-1-25's fixed physical footprint.

How does the DS1217M-1-25 ensure data retention during power loss?

The DS1217M-1-25 guarantees >5 years of data retention without external power using two redundant lithium batteries and an internal isolation switch. When VCC drops below ~3.0 V, its power-switching circuit automatically connects the higher-voltage battery to the RAM core. The DS1217M-1-25 also monitors battery health: if both cells fall below 2.0 V, a warning manifests as failed write verification after power-up - a behavior explicitly defined in the DS1217M-1-25 datasheet.

Can the DS1217M-1-25 be used in existing systems with JEDEC 28-pin DIP sockets?

Yes - the DS1217M-1-25 supports retrofit installation via a 28-pin DIP plug (AMP Part Number 746616-2) and right-justified 28-pin ribbon cable connected to its 30-contact card-edge interface. Its pinout matches JEDEC bytewide memory standards, and software-controlled bank switching preserves compatibility with legacy 28-pin address/data mappings. This capability is documented in the DS1217M-1-25 datasheet under "Remote Connection through a Ribbon Cable."

What happens to the DS1217M-1-25 during a brownout condition?

When VCC falls below 4.5 V, the DS1217M-1-25 automatically disables all write operations to prevent data corruption - a hardware-enforced feature independent of software control. If VCC continues dropping below ~3.0 V, the internal power-switching circuit engages the lithium backup source. The DS1217M-1-25 remains fully readable during this transition, and all banks retain their selected state until power is restored or a new bank is explicitly chosen.

Does the DS1217M-1-25 require external components for battery backup or write protection?

No - the DS1217M-1-25 integrates all necessary circuitry: dual lithium batteries, analog power-switching logic, voltage comparators for battery monitoring, and automatic write-disable thresholds. It requires only a stable 5 V supply (4.5–5.5 V) and standard JEDEC-compatible control signals (CE, OE, WE). No external capacitors, supervisors, or backup controllers are needed - this self-contained design is a defining feature of the DS1217M-1-25.