Analog Devices Inc./Maxim Integrated DS1220AB-150IND+

Overview

DS1220AB-150IND+ from Maxim Integrated (now Analog Devices) is a 16k nonvolatile static RAM (2048 × 8) with integrated lithium battery backup, ±5% V_CC tolerance (4.75–5.25 V), 100 ns access time, and industrial temperature rating (–40°C to +85°C). It directly replaces volatile 2k × 8 SRAMs and EEPROMs in data-critical embedded systems requiring zero-battery-leakage power-down retention.

For engineers reviewing the DS1220AB-150IND+ datasheet, DS1220AB-150IND+ pinout, DS1220AB-150IND+ application, or DS1220AB-150IND+ equivalent, key selection considerations include its automatic V_CC-monitored write protection, unlimited write cycles, JEDEC-standard 24-pin DIP package, and guaranteed 10-year data retention without external support circuitry.

Technical Context

The DS1220AB-150IND+ implements a self-contained power-fail detection architecture that monitors V_CC continuously; when voltage drops below 4.5 V (V_TP), it unconditionally enables write protection and switches to lithium backup at ~3.0 V. Its control logic enforces strict timing for CE/WE/OE coordination during read/write cycles, with t_ACC = 100 ns and t_WC = 100 ns under ±5% V_CC.

Unlike standard SRAMs, it integrates a freshness-sealed lithium cell electrically disconnected until first power application-ensuring full energy capacity at deployment. The device operates as a drop-in replacement for 2716 EPROM and 2816 EEPROM pinouts, supporting identical address/data/control signal mapping without bus contention risks during mixed-mode operation.

Key Specifications

Pinout & Package

DS1220AB-150IND+ uses a 24-pin 720-mil extended dual in-line package (EDIP), compatible with standard DIP sockets and wave soldering processes. Pin layout conforms to JEDEC MS-001AC.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS1220AD-100IND+, DS1220AB-150IND+ provides stricter V_CC regulation for noise-immune operation, while STK12C68-55I trades integrated lithium for capacitor-based backup-increasing design overhead but satisfying lithium-free compliance requirements.

Availability

DS1220AB-150IND+ is available at Aetrix Electronics and suitable for industrial data loggers, medical device configuration storage, and telecom base station control memory requiring stable component supply, long-lifecycle assurance, and RoHS-compliant packaging.

Supply support for DS1220AB-150IND+ 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

Analog Devices (via acquisition of Maxim Integrated) designs precision analog, mixed-signal, and nonvolatile memory solutions for high-reliability industrial, medical, and communications systems.

The DS1220AB-150IND+ belongs to Maxim's legacy NV SRAM product line, engineered specifically for applications demanding seamless, zero-maintenance data persistence during unpredictable power loss-without software intervention or external support components.

FAQ

What is the guaranteed data retention period for DS1220AB-150IND+?

The DS1220AB-150IND+ guarantees a minimum 10-year data retention period in the absence of external power, measured cumulatively from the time V_CC is first applied. This is enabled by its sealed lithium energy source and automatic switchover circuitry, which activates when V_CC falls below ~3.0 V. No external components or refresh cycles are required to maintain this specification.

Does DS1220AB-150IND+ require external circuitry for battery backup operation?

No, DS1220AB-150IND+ requires no external circuitry for battery backup operation. It integrates a lithium energy source, voltage monitor, and power-switching circuitry internally. The lithium cell remains electrically disconnected until first application of V_CC > V_TP, ensuring full capacity at deployment. All power-fail detection, write protection, and switchover functions are autonomous.

What is the operating voltage range specified for DS1220AB-150IND+?

The DS1220AB-150IND+ is specified for a V_CC operating range of 4.75 V to 5.25 V (±5%). Full functional operation-including read/write access and automatic write protection-is guaranteed across this range. Write protection activates at V_TP = 4.5–4.75 V, and lithium switchover occurs at approximately 3.0 V during power-down.

Can DS1220AB-150IND+ replace a 2716 EPROM directly on the PCB?

Yes, DS1220AB-150IND+ is pin-compatible with the 2716 EPROM and matches its 24-pin DIP pinout, including identical A0–A10, DQ0–DQ7, CE, OE, and V_CC/GND assignments. It also replicates the 2816 EEPROM pinout. No PCB changes are required-only firmware logic must be updated to remove EPROM programming sequences, as DS1220AB-150IND+ supports unlimited random writes.

Is DS1220AB-150IND+ qualified for industrial temperature operation?

Yes, DS1220AB-150IND+ is fully qualified for industrial temperature operation from –40°C to +85°C, as indicated by the "IND" suffix. Its DC and AC electrical characteristics-including t_ACC = 100 ns, ICCO1 ≤ 85 mA, and V_TP stability-are guaranteed across this range. The device meets UL recognition file E99151 and is RoHS-compliant (denoted by the "+" suffix).