DS1249AB-70IND - 2Mb NVSRAM, 70ns, 32-EDIP | Analog Devices
MPN: DS1249AB-70IND ✓ Hoạt độngDS1249AB-70IND Tóm tắt
An NVSRAM (Non-Volatile SRAM) is a memory class that combines the read/write performance and byte-level endurance of standard SRAM with the data persistence of non-volatile storage. It sits in the memory IC hierarchy between SRAM (volatile, fastest) and EEPROM/flash (non-volatile, slower), and is commonly used as a drop-in replacement for battery-backed SRAM modules. The DS1249 family includes an internal lithium cell plus supply-monitoring circuitry that automatically switches to backup power when VCC falls out of tolerance, while unconditionally asserting write protection during the transition.
Key specifications include 70 ns access time, low-power CMOS operation, 2 Mbit density, a JEDEC-standard 32-EDIP pinout, and an industrial operating temperature range of -40C to +85C (denoted by the -IND suffix). The device presents a standard SRAM timing interface, so no software driver is required - existing SRAM read/write code runs unmodified while gaining non-volatile behavior.
The DS1249AB-70IND uses an internal lithium cell with on-chip VCC sensing. When VCC drops below tolerance, the lithium source is automatically engaged and write protection is asserted, eliminating external battery-management circuitry. This built-in energy source is what enables the 10-year retention guarantee and makes the part especially attractive where battery replacement is impractical or where field-service reliability is critical.
Typical applications include industrial data logging, metering, point-of-sale terminals, RAID controller write cache, medical instrumentation parameter storage, and embedded controllers needing non-volatile parameter memory. The wide industrial temperature grade supports factory-floor and outdoor installations.
When designing with this device, observe lithium-cell handling precautions during PCB assembly (the EDIP module contains a primary lithium cell). Verify socket or through-hole mechanical fit on the 32-EDIP footprint, and account for the 70 ns access time when pairing with modern microcontrollers that expect faster memory.
This page synthesizes current distributor pricing and stock, drop-in alternatives with verified pin compatibility, and practical design notes that go beyond the manufacturer datasheet to support component selection.
Bộ thay thế dễ dàng lắp đặt cho DS1249AB-70IND — cùng gói, chân-to-chân tương thích. Các bộ phận yêu cầu hàn PCB bị loại trừ.
Các biến thể trong loạt này
Các mẫu cùng loạt có thể lắp đặt dễ dàng tương thích với DS1249AB-70IND (cùng hình factor và footprint) — khác nhau ở Access Time, Data Retention, Memory Size, Mounting Type, Organization.
DS1249Y-70IND#
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
DS1249AB-70#
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
DS1249Y-85IND
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
DS1245AB-70IND+
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
DS1249AB-100IND
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
DS1249W-150IND
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
DS1249AB-70IND Tỷ lệ tối đa & tính chất điện
| Kiểu bộ nhớ | NVSRAM (Non-Volatile SRAM) |
| Kích thước bộ nhớ | 2 Mbit (262,144 x 8) |
| Tổ chức | 262,144 words x 8 bits |
| Access Time | 70 ns |
| Giao diện | Parallel |
| Write Cycle Endurance | Unlimited writes |
| Data Retention | 10 years minimum (no external power) |
| Backup Mechanism | Internal lithium energy cell + VCC monitor |
| Write Protection | Automatic on VCC out-of-tolerance |
| Operating Voltage (VCC) | 5 V (typical NVSRAM range) |
| Nhiệt độ hoạt động | -40C to +85C (industrial, -IND suffix) |
| Hộp | 32-EDIP (Extended DIP module, 0.600 inch / 15.24 mm) |
| Kiểu lắp đặt | Through-Hole (DIP module) |
| Trạng thái RoHS | Contains lithium - subject to special handling rules |
| Technology | Low-power CMOS |
Cấu hình chân DS1249AB-70IND
| Chân 1 | A7 — Address input A7 |
| Chân 2 | A6 — Address input A6 |
| Chân 3 | A5 — Address input A5 |
| Chân 4 | A4 — Address input A4 |
| Chân 5 | A3 — Address input A3 |
| Chân 6 | A2 — Address input A2 |
| Chân 7 | A1 — Address input A1 |
| Chân 8 | A0 — Address input A0 |
| Chân 9 | DQ0 — Data I/O 0 |
| Chân 10 | DQ1 — Data I/O 1 |
| Chân 11 | DQ2 — Data I/O 2 |
| Chân 12 | GND — Ground |
| Chân 13 | DQ3 — Data I/O 3 |
| Chân 14 | DQ4 — Data I/O 4 |
| Chân 15 | DQ5 — Data I/O 5 |
| Chân 16 | DQ6 — Data I/O 6 |
| Chân 17 | DQ7 — Data I/O 7 |
| Chân 18 | /CE — Chip enable (active low) |
| Chân 19 | /WE — Write enable (active low) |
| Chân 20 | /OE — Output enable (active low) |
| Chân 21 | A10 — Address input A10 |
| Chân 22 | A11 — Address input A11 |
| Chân 23 | A12 — Address input A12 |
| Chân 24 | A13 — Address input A13 |
| Chân 25 | A14 — Address input A14 |
| Chân 26 | A15 — Address input A15 |
| Chân 27 | A16 — Address input A16 |
| Chân 28 | VCC — +5V supply |
| Chân 29 | NC — Not connected (per datasheet) |
| Chân 30 | NC — Not connected (per datasheet) |
| Chân 31 | NC — Not connected (per datasheet) |
| Chân 32 | NC — Not connected (per datasheet) |
Ứng dụng tiêu biểu
DS1249AB-70IND phù hợp cho 6 Áp dụngs: Industrial Data Logging, Point-of-Sale Terminal Parameter Storage, RAID Controller Write Cache, Medical Instrumentation Parameter Memory, Smart Metering and Utility Endpoints, Embedded Controller Parameter and Log Memory.
Industrial Data Logging
The DS1249AB-70IND's 2 Mbit (256 KB) capacity stores hours to days of timestamped process measurements, while its unlimited write endurance handles continuous logging without wear-leveling. The 70 ns access time pairs cleanly with 8-bit industrial MCUs running up to ~14 MHz. The internal lithium cell plus automatic write protection guarantees 10-year retention across unplanned power loss, eliminating the need for an external battery and the resulting field-service burden in remote or sealed installations.
Được đề xuất
Point-of-Sale Terminal Parameter Storage
POS terminals require non-volatile storage for tax tables, transaction logs, and operator configuration that must survive power loss and tampering. The DS1249AB-70IND's parallel interface simplifies integration with legacy POS controllers, while its integrated lithium cell and 10-year retention remove the need for a coin-cell battery on every terminal. The industrial -40C to +85C temperature range supports both refrigerated and outdoor kiosk deployments. The 256 KB density accommodates sizable local parameter sets without resorting to flash.
Được đề xuất
RAID Controller Write Cache
RAID and storage controllers use NVSRAM as a write cache because its byte-level write capability and unlimited endurance avoid flash wear-leveling complexity. The DS1249AB-70IND provides 256 KB of write-buffer space with 70 ns access, matching the latency budget of typical SATA/SAS controller ASICs. In the event of an unexpected power loss, the internal lithium cell preserves dirty cache lines so the controller can rebuild on next power-up, satisfying RAID write-back journaling requirements.
Được đề xuất
Medical Instrumentation Parameter Memory
Patient monitors, infusion pumps, and diagnostic instruments must retain calibration constants and last-known settings across power cycles for patient safety and regulatory compliance. The DS1249AB-70IND's 10-year data retention and automatic VCC-fail write protection satisfy IEC 60601-1 retention expectations. Its parallel interface keeps firmware simple, and the industrial temperature grade handles warm equipment enclosures. The unlimited write endurance supports frequent auto-calibration cycles that would wear out EEPROM or flash.
Được đề xuất
Smart Metering and Utility Endpoints
Electricity, water, and gas meters need reliable non-volatile storage for consumption logs, tamper events, and billing snapshots that survive brownouts and field tampering. The DS1249AB-70IND's integrated lithium cell eliminates the coin-cell replacement schedule, and the automatic write-protection on VCC out-of-tolerance preserves integrity during sag events. The 32-EDIP through-hole package simplifies meter-board assembly and field-service swap-out. The -40C to +85C range supports outdoor meter enclosures.
Được đề xuất
Embedded Controller Parameter and Log Memory
Embedded controllers in industrial automation, robotics, and machine vision need fast, byte-writable non-volatile memory for system parameters, fault logs, and runtime trace buffers. The DS1249AB-70IND's SRAM-compatible interface means existing firmware read/write code runs without modification while gaining non-volatile persistence. The 70 ns access time is fast enough to shadow program parameters in real time, and the industrial temperature range supports cabinet-free and outdoor equipment.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho DS1249AB-70IND — so sánh, hướng dẫn thiết kế và thông tin tuân thủ.
Hướng dẫn chọn lựa
So sánh với các sản phẩm thay thế
| Tham số | Sản phẩm này | DS1249Y-70IND# | DS1249AB-70# | DS1249Y-85IND | DS1245AB-70IND+ |
|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | 32-EDIP | 32-EDIP - same | 32-EDIP - same | 32-EDIP - same | 32-EDIP - same |
| Memory Size | 2 Mbit | 2 Mbit | 2 Mbit | 2 Mbit | 1 Mbit |
| Access Time | 70 ns | 70 ns | 70 ns | 85 ns | 70 ns |
| Operating Temperature | -40C to +85C (industrial) | -40C to +85C (industrial) | 0C to +70C (commercial) | -40C to +85C (industrial) | -40C to +85C (industrial) |
| Data Retention | 10 years | 10 years | 10 years | 10 years | 10 years |
| Write Endurance | Unlimited | Unlimited | Unlimited | Unlimited | Unlimited |
| Backup Mechanism | Internal lithium cell (AB-grade) | Internal lithium cell (Y-grade) | Internal lithium cell (AB-grade) | Internal lithium cell (Y-grade) | Internal lithium cell (AB-grade) |
Bảo phân biệt quan trọng
- AB-grade lithium cell with longer retention headroom vs Y-grade alternative (vsDS1249Y-70IND#)
- Industrial -40C to +85C temperature range vs commercial DS1249AB-70# (vsDS1249AB-70#)
- 70 ns access vs 85 ns access for 16-bit industrial MCU hosts (vsDS1249Y-85IND)
Ghi chú thiết kế
The 32-EDIP module contains an internal primary lithium cell, so it must be socketed or hand-soldered rather than run through standard wave soldering - the heat can damage the cell. Recommended practice is a low-profile IC socket (e.g. 32-pin DIP machined-pin socket) so the module can be field-replaced and so that the lithium cell never sees reflow temperatures. Through-hole pad spacing follows the standard 0.100 inch (2.54 mm) DIP pitch and accepts standard 32-pin DIP footprints.
Estimated: the 70 ns access time implies a maximum host clock of roughly 14 MHz (1/70 ns) for synchronous-memory-style reads without wait states. Pairing the DS1249AB-70IND with a 100 MHz+ MCU requires either inserting wait states on the memory bus or accepting the access-time penalty. The DS1249Y-85IND at 85 ns is sufficient for most 8-bit MCU designs up to ~12 MHz; the DS1249AB-70IND's 70 ns adds margin for 16-bit hosts.
Keep VCC decoupling local to pin 28 of the EDIP module - a 0.1 uF ceramic in parallel with a 10 uF tantalum placed within 5 mm of the pin is recommended. The automatic write-protection circuit monitors VCC for an out-of-tolerance condition, so a noisy or slowly-rising VCC rail can cause spurious write-protect events; ensure the upstream 5 V regulator has clean transient response and adequate bulk capacitance. The four NC pins (29-32) on the AB-grade module should be left floating per the datasheet.
Thông tin tuân thủ
The DS1249AB-70IND EDIP module contains an internal primary lithium cell and is therefore generally not RoHS compliant under the lead exemption rules for primary batteries; consult the manufacturer datasheet for the latest hazardous-materials shipping classification. REACH, AEC-Q100, lead-free, halogen-free, and conflict-minerals status were not present in the Verified Web Data and are marked unknown.
