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Analog Devices Inc./Maxim Integrated DS2229-85
- Part No.:
- DS2229-85
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Memory
- Package:
- 80-SIMM
- Datasheet:
-
DS2229-85.pdf
- Description:
- IC NVSRAM 8MBIT PARALLEL 80SIMM
- Quantity:
- Payment:
- Shipping:
Inventory:4,176
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Product details
Overview
DS2229-85 from Dallas Semiconductor (now Maxim Integrated) is an 8-Mbit (512k × 16) low-power static RAM module in an 80-pin SIP Stik form factor, featuring 85 ns access time, ±10% VCC tolerance (4.5–5.5 V), and ultra-low standby current <10 µA - enabling use in battery-backed memory subsystems for industrial controllers and legacy embedded systems.
For engineers reviewing the DS2229-85 datasheet, DS2229-85 pinout, DS2229-85 application, or DS2229-85 equivalent, key selection considerations include JEDEC-standard 80-pin SIMM compatibility, dual write-enable inputs (WEH/WEL), four independent chip enables (CE0–CE3), and verified data retention down to 2.0 V with sub-8 µA retention current.
Technical Context
The DS2229-85 implements a fully static CMOS SRAM core with no refresh required, supporting asynchronous read/write cycles where tRC = tWC = 85 ns and tACC = 85 ns. Its address space spans A0–A16 (17-bit), enabling full 512k-word decoding without external logic.
Chip select is hierarchical: CS enables internal buffers, while CE0–CE3 provide four independent enable inputs for bank selection or ultra-low-power deselection modes; when all CE inputs are high, ICCS2 ≤ 10 µA at 25°C, qualifying DS2229-85 for long-term battery-backed retention.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Organization | 512k × 16-bit (8,388,608 bits), word-wide interface |
| Access Time | 85 ns - defines minimum cycle time for reliable read/write under 5V ±10% |
| Supply Voltage | 4.5 V to 5.5 V - supports standard TTL-compatible 5V systems with margin |
| Standby Current | <10 µA (ICCS2) - enables multi-year battery backup without recharge |
| Data Retention VCC | 2.0 V minimum - retains data during brown-out or backup-only operation |
| Input/Output Capacitance | CIN = 64 pF, CI/O = 80 pF - constrains trace length and bus loading in dense PCB layouts |
| Operating Temperature | 0°C to +70°C - rated for commercial/industrial ambient environments |
Pinout & Package
DS2229-85 uses an 80-pin Single-In-Line Package (SIP) Stik with 0.100" row spacing and mechanical dimensions per JEDEC MS-026 (A = 4.65 mm, K = 2.325 mm, L = 2.45 mm). Pin 1 = GND, Pin 2 = VCC, Pin 4 = OE, Pins 5–6 = WEH/WEL, Pins 21–24 = CE3–CE0, Pin 8 = CS, Pins 52 & 36–49 = A0–A16, Pins 63–70 & 55–62 = DQ7–DQ0 / DQ15–DQ8.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pins 1, 25, 53–54, 74–77, 80) | Ground reference | Multiple dedicated ground pins reduce noise coupling and improve signal integrity on shared bus |
| VCC (Pins 2, 72) | Power supply | Dual VCC pins support low-impedance power delivery across 80-pin length |
| OE (Pin 4) | Output enable | Controls tri-state of DQ[15:0]; active-low, independent of CE/CS for flexible bus control |
| WEH/WEL (Pins 5–6) | Write enable high/low | Split WE allows byte-level write control; WEL enables lower byte (DQ[7:0]), WEH upper byte (DQ[15:8]) |
| CE0–CE3 (Pins 21–24) | Chip enable inputs | Four independent enables permit low-power partial-bank deselection or hierarchical memory mapping |
| CS (Pin 8) | Chip select | Primary buffer enable; must be high for read/write; low forces high-Z I/O and disables internal logic |
| A0–A16 (Pins 52, 36–49) | Address inputs | 17-bit address bus directly maps full 512k-word space; no address multiplexing required |
| DQ0–DQ15 (Pins 63–70, 55–62) | Data I/O | 16-bit bidirectional bus; supports simultaneous read/write of full word with proper timing control |
Key Features
| Feature | Design Value |
|---|---|
| JEDEC 80-pin SIMM compatibility | Direct drop-in replacement for legacy flash EEPROM SIMMs in existing sockets without adapter or redesign |
| Dual write-enable architecture | Enables independent control of upper/lower byte writes, reducing bus contention in 8-bit subsystems |
| Four independent chip enables | Supports up to four discrete memory banks or selective power gating to minimize system standby current |
| Battery-backed data retention | Guaranteed data hold at VCC ≥ 2.0 V with ICCDR ≤ 8 µA, enabling >5-year backup with coin cell |
| No refresh required | Eliminates external refresh controller and associated timing overhead in microcontroller-based systems |
Applications
| Industrial PLC Memory Expansion | Legacy Medical Device Data Buffer |
|---|---|
Use Scenario: Adding non-volatile scratchpad memory to programmable logic controllers handling real-time I/O logging. IC Role / Device Role / Timing Role: DS2229-85 serves as a fast, battery-backed SRAM buffer interfacing directly to 16-bit microcontroller data bus. Use Value: Enables deterministic 85 ns read/write latency and guaranteed data retention during AC power loss without firmware intervention. | Use Scenario: Storing calibration coefficients and patient session history in portable diagnostic equipment with limited board space. IC Role / Device Role / Timing Role: DS2229-85 operates as a low-leakage memory module connected to an 8051-family MCU via parallel bus. Use Value: Sub-10 µA standby current extends single-CR2032 battery life beyond 3 years while maintaining data integrity. |
| Avionics Black Box Recorder | Telecom Line Card Configuration Store |
Use Scenario: Capturing flight parameter snapshots in aircraft black box recorders requiring radiation-tolerant, long-retention memory. IC Role / Device Role / Timing Role: DS2229-85 functions as the primary cyclic buffer memory, accessed by a dedicated DMA controller. Use Value: Verified operation from 0°C to +70°C and data retention at 2.0 V ensures reliability during extended ground cold-soak or cabin depressurization. | Use Scenario: Holding FPGA configuration bitstreams and port mapping tables in carrier-grade DSLAM line cards. IC Role / Device Role / Timing Role: DS2229-85 provides fast-access configuration storage mapped into the processor's memory space via CS decoding. Use Value: JEDEC SIMM pinout allows hot-swap field replacement without custom socket tooling or board rework. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar SRAM module applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| IS61LV51216AL-85T | 512k×16, 85 ns, 3.3 V only (3.0–3.6 V); no CE0–CE3; single WE; 100-pin TSOP | Requires level-shifting for 5V systems; lacks battery-retention mode and multi-CE flexibility | Choose for new 3.3V designs prioritizing density over legacy compatibility |
| AS6C4008-85PCN | 512k×16, 85 ns, 5V (4.5–5.5 V); single CE, single WE; 44-pin SOJ; no data retention spec below 4.5 V | Higher standby current (~100 µA); no guaranteed sub-3V retention; incompatible pinout | Choose for cost-sensitive 5V applications where battery backup is not required |
Compared with IS61LV51216AL-85T and AS6C4008-85PCN, DS2229-85 uniquely delivers JEDEC SIMM compatibility, quad CE inputs for granular power control, and validated 2.0 V data retention - making it irreplaceable in legacy 5V battery-backed systems requiring socket-level interchangeability.
Availability
DS2229-85 is available at Aetrix Electronics and suitable for industrial PLC memory expansion, avionics black box recorders, telecom line card configuration stores, and legacy medical device data buffering requiring stable component supply and long-term lifecycle support.
Supply support for DS2229-85 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
Dallas Semiconductor, acquired by Maxim Integrated in 2001, specialized in precision analog, nonvolatile memory, and real-time clock solutions for industrial and embedded markets.
The DS2229-85 belongs to Dallas' Stik™ family of plug-in memory modules designed specifically for drop-in replacement of aging flash SIMMs in 5V, battery-backed, and space-constrained embedded systems.
FAQ
What is the maximum operating temperature range for the DS2229-85?
The DS2229-85 is specified for operation from 0°C to +70°C. This commercial/industrial temperature range is confirmed in the Absolute Maximum Ratings and DC Characteristics sections of the official datasheet. Operation outside this range may result in timing violations or data retention failure. DS2229-85 does not support extended or military temperature grades.
Does the DS2229-85 require an external clock or refresh circuitry?
No, the DS2229-85 is a fully static RAM and requires no clock input or periodic refresh cycles. Its CMOS design maintains data indefinitely as long as power and valid control signals are applied. This eliminates timing-critical refresh overhead in microcontroller or FPGA-based systems using DS2229-85.
How does the DS2229-85 achieve ultra-low standby current?
The DS2229-85 achieves <10 µA standby current (ICCS2) by driving all four CE inputs (CE0–CE3) high while maintaining CS high and WE/OE inactive. In this state, internal buffers are disabled and leakage paths minimized. DS2229-85 guarantees this performance at 25°C with VCC ≥ VCC − 0.3 V, enabling true battery-backed operation.
Can the DS2229-85 be used as a direct replacement for flash EEPROM SIMMs?
Yes - the DS2229-85 is explicitly JEDEC pin compatible with flash EEPROM SIMMs of similar density, as stated in the device description and Figure 1. It uses identical 80-pin SIP Stik mechanical and electrical pinout, requires no additional circuitry, and supports the same address/data/control protocol - making DS2229-85 a functional and physical drop-in upgrade.
What is the minimum supply voltage required to retain data in the DS2229-85?
The DS2229-85 guarantees data retention down to VCC = 2.0 V, as specified in the Low VCC Data Retention Characteristics table. At this voltage, with CE0–CE3 ≥ VCC − 0.2 V and appropriate CS control, DS2229-85 maintains stored data with ICCDR ≤ 8 µA - enabling multi-year retention on small backup batteries.
DS2229-85 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 80-SIMM
- Packaging:
- Bag
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Memory Type:
- Non-Volatile
- Memory Format:
- NVSRAM
- Technology:
- NVSRAM (Non-Volatile SRAM)
- Memory Size:
- 8Mbit
- Memory Organization:
- 512K x 16
- Memory Interface:
- Parallel
- Clock Frequency:
- -
- Write Cycle Time - Word, Page:
- 85ns
- Access Time:
- 85 ns
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Socket
- Supplier Device Package:
- 80-SIMM
DS2229-85 FAQ
1.How can I place an order for DS2229-85 through Aetrix?
Please submit a Request for Quotation (RFQ) for DS2229-85 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for DS2229-85 reliable?
The price and inventory of DS2229-85 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS2229-85 is usually 5 days.
3.What payment methods are accepted for DS2229-85?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS2229-85 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DS2229-85?
DS2229-85 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DS2229-85 order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for DS2229-85?
For technical support, including DS2229-85 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS2229-85 requirements.
6.How does Aetrix verify that DS2229-85 is sourced from the original manufacturer or authorized distributors?
All DS2229-85 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that DS2229-85 meets industry standards.
7.What is the process for return or replacement of DS2229-85?
All DS2229-85 units undergo pre-shipment inspection (PSI). If there is an issue with DS2229-85, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The DS2229-85 part is unused and in its original packaging.
Return procedure for DS2229-85:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
DS2229-85 Tags
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