Analog Devices Inc./Maxim Integrated DS2045AB-100#

Overview

DS2045AB-100# from Maxim Integrated is a 1Mb (128k × 8) reflowable nonvolatile SRAM module integrating static RAM, NV controller, and rechargeable manganese lithium (ML) battery in a single 256-ball BGA package. It provides unconditional write protection at VCC < 4.75V, automatic battery switchover during power failure, and open-drain RST output for microprocessor supervision in industrial data retention applications.

For engineers reviewing the DS2045AB-100# datasheet, DS2045AB-100# pinout, DS2045AB-100# application, or DS2045AB-100# equivalent, key selection criteria include 100ns access time, ±5% VCC tolerance, industrial temperature range (–40°C to +85°C), 3-year data retention per charge, and compatibility with standard BGA reflow assembly without battery removal.

Technical Context

The DS2045AB-100# implements dual-voltage monitoring with a fixed 5% trip point (VTP = 4.75V min), triggering unconditional SRAM write protection and RST assertion within 3.0µs of VCC failure detection. Its internal charger regulates ML battery charging above VTP and supports full charge in 96 hours.

Power management logic isolates the SRAM from external VCC when voltage drops below ~2.7V (VSW), switching to battery backup while forcing all I/O into high-impedance state. During power-up, RST remains active until VCC exceeds VTP for ≥125ms (tREC) and tRPU timeout (225–525ms) completes.

Key Specifications

Pinout & Package

DS2045AB-100# uses a 256-ball PBGA module (27mm²) with 17 address inputs (A0–A16), 8 bidirectional data lines (DQ0–DQ7), three control signals (CE, WE, OE), open-drain RST, VCC, and multiple GND balls. No-connect (N.C.) balls are distributed across inner rows to support routing and thermal relief.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS2045AB-70# and DS2045Y-100#, the DS2045AB-100# balances cost-effective timing margin (100ns) with robust ±5% supply rejection - ideal for stable 5V industrial power domains where extended speed headroom is unnecessary and voltage precision is prioritized.

Availability

DS2045AB-100# is available at Aetrix Electronics and suitable for RAID systems, industrial controllers, and fire alarm panels requiring stable component supply with guaranteed long-term data retention and reflow-compatible packaging.

Supply support for DS2045AB-100# 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 power management ICs for industrial, computing, and communications markets.

The DS2045AB-100# belongs to Maxim's nonvolatile SRAM product line, engineered specifically for mission-critical data retention in systems where battery replacement is impractical and solder-reflow compatibility is mandatory.

FAQ

What is the guaranteed data retention period for DS2045AB-100# under normal operating conditions?

The DS2045AB-100# guarantees 3 years of data retention per full charge cycle at +25°C ambient, based on component selection, process control, and design validation. This assumes initial 96-hour charging at VCC > 4.75V and no more than two 230°C convection reflow exposures. Retention time decreases at elevated temperatures but remains functional across the full –40°C to +85°C operating range.

Does DS2045AB-100# require external circuitry to interface with a microprocessor?

No, DS2045AB-100# requires no external support circuitry for basic operation. It integrates its own ML battery, charger, voltage monitor, and power-switching logic. Only an external pullup resistor (1kΩ–10kΩ) on the RST pin is needed to realize a logic-high level; all other signals (CE, WE, OE, A0–A16, DQ0–DQ7) connect directly to microprocessor buses.

How does the power-fail detection and RST assertion timing work in DS2045AB-100#?

DS2045AB-100# detects VCC failure when voltage falls below 4.75V (VTP), asserting RST low within 3.0µs (tRPD). RST remains active until VCC rises above VTP and stays there for ≥225ms (tRPU min). This delay exceeds the 125ms tREC required for SRAM readiness, ensuring the microprocessor receives a clean, synchronized reset after memory stabilization.

Can DS2045AB-100# be soldered using standard lead-free reflow profiles?

Yes, DS2045AB-100# is qualified for standard Pb-free reflow per IPC/JEDEC J-STD-020, with a peak temperature of 225°C (+0/–5°C) for 10–30 seconds within 5°C of peak. Its internal ML battery is designed to survive this profile without capacity loss or safety hazard, enabling true single-pass BGA assembly without battery isolation steps.

What is the function of the N.C. (no connection) balls on the DS2045AB-100# BGA package?

The N.C. balls on DS2045AB-100# (e.g., B1–B4, C17–C20, A5–A16, U5–U16) serve routing and thermal relief functions - they are electrically isolated from internal circuitry and must not be connected to any net. Their presence simplifies PCB layout by providing spacing between signal and power balls while maintaining mechanical stability and thermal dissipation characteristics of the 27mm² BGA substrate.