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Analog Devices Inc./Maxim Integrated DS1211S
- Part No.:
- DS1211S
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Controllers
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
DS1211S.pdf
- Description:
- IC CONTROLLER 8-CHIP NV 20-SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,939
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Product details
Overview
DS1211S from Maxim Integrated (formerly Dallas Semiconductor) is a nonvolatile controller IC that converts up to eight CMOS RAMs into battery-backed nonvolatile memory systems. It features 3-to-8 address decoding, power-fail detection with optional 5% or 10% tolerance, automatic battery switchover, and consumes <100 nA battery current in standby. Used in industrial data logging and real-time clock backup systems.
For engineers reviewing the DS1211S datasheet, DS1211S pinout, DS1211S application, or DS1211S equivalent, key selection criteria include VCCO/VBAT1/VBAT2 supply routing, CE0–CE7 output timing alignment with RAM access cycles, TOL threshold configuration, PF signal assertion behavior during brownout, and compatibility with lithium battery redundancy schemes.
Technical Context
The DS1211S integrates a precision voltage monitor for VCCI with user-selectable 5% or 10% tolerance via TOL pin, enabling configurable power-fail detection. Its internal 3-to-8 decoder drives CE0–CE7 outputs synchronously with A/B/C address inputs to enable individual RAM chips.
On VCCI dropout, the device inhibits all CE outputs, asserts PF, and switches VCCO to VBAT1 or VBAT2 (with priority logic). Battery test occurs at power-up using internal leakage-current sensing, supporting redundant battery validation without external circuitry.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCCI Supply Range | 4.5V to 5.5V - defines valid operating window for main system power monitoring |
| VCCO Output Range | 2.7V to 5.5V - supports direct connection to diverse CMOS RAM VDD rails |
| Battery Current (Standby) | <100 nA - enables multi-year operation on primary lithium cells |
| Power-Fail Threshold | Selectable 4.75V (5%) or 4.5V (10%) - sets VCCI dropout point for PF assertion |
| Decoder Outputs | CE0–CE7 active-low - drives up to eight RAM chip-enable inputs with address-decoded timing |
| Address Inputs | A, B, C - 3-bit binary input selecting one of eight CE outputs |
| PF Output | Active-low open-drain - signals processor interrupt on detected VCCI undervoltage |
Pinout & Package
DS1211S is available in 20-pin DIP (300-mil) and 20-pin SOIC (300-mil) packages. Both share identical pinout and thermal characteristics per Maxim DS1211 datasheet Rev. 3.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A, B, C | Address Inputs | Binary select lines determining which CE0–CE7 output is asserted |
| CE | Global Chip Enable Input | Must be low to activate decoder; overrides individual CE outputs when high |
| CE0–CE7 | Chip Enable Outputs | Active-low outputs driving RAM /CE pins; only one asserted per A/B/C combination |
| GND | Ground Reference | Common return for VCCI, VCCO, VBAT1, VBAT2, and logic circuits |
| VBAT1 / VBAT2 | Battery Supply Inputs | Redundant lithium cell inputs; internal priority logic selects VBAT1 unless open or depleted |
| VCCI | Main Power Input | Monitored +5V supply; source of power-fail detection and internal logic bias |
| VCCO | RAM Output Supply | Switched output rail delivering power to RAMs during main supply failure |
| TOL | Tolerance Select | High = 5% VCCI tolerance (4.75V), Low = 10% (4.5V); sets PF trip point |
| PF | Power-Fail Output | Open-drain signal asserting low during VCCI dropout; used for CPU interrupt or latch control |
| NC | No Connection | Pin 11 is unconnected; must remain floating or grounded per layout guidelines |
Key Features
| Feature | Design Value |
|---|---|
| Configurable Power-Fail Threshold | TOL pin selects 5% or 10% VCCI tolerance, enabling design flexibility across varying supply stability requirements |
| Redundant Battery Support | VBAT1/VBAT2 dual-input architecture with automatic failover ensures >99.9% RAM data retention uptime in mission-critical systems |
| Ultra-Low Battery Drain | <100 nA standby current extends lithium battery life beyond 10 years in typical industrial environments |
| Integrated 3-to-8 Decoder | Eliminates need for external address decoding logic when managing up to eight discrete CMOS RAM devices |
| Power-Up Battery Test | Automatic self-test at VCCI application verifies battery health before enabling VCCO switching, preventing silent data loss |
Applications
| Industrial Data Logger | Real-Time Clock Module |
|---|---|
Use Scenario: Continuous timestamped sensor data storage in remote telemetry units with intermittent mains power. IC Role / Device Role / Timing Role: Nonvolatile controller maintaining SRAM integrity during grid outages and enabling seamless resume after recovery. Use Value: Prevents loss of critical time-series datasets by sustaining RAM power via VBAT1/VBAT2 switchover and asserting PF to trigger controlled save routines. | Use Scenario: Embedded RTC subsystem requiring persistent timekeeping and alarm registers across extended power interruptions. IC Role / Device Role / Timing Role: Supplies uninterrupted VCCO to RTC+SRAM combo ICs while monitoring VCCI for brownout events. Use Value: Guarantees clock accuracy and register retention for >10 years using primary lithium cells, validated by on-power-up battery test. |
| Medical Device Memory Backup | POS Terminal Configuration Storage |
Use Scenario: Patient parameter history and calibration data retention in portable diagnostic equipment with battery-only operation. IC Role / Device Role / Timing Role: Enables write-protection and battery switchover for multiple SRAM banks storing clinical settings and event logs. Use Value: Meets IEC 62304 safety requirements by eliminating data corruption risk during VCCI transients via unconditional CE inhibition. | Use Scenario: Secure storage of tax rates, pricing tables, and transaction journals in retail terminals subject to frequent unplanned shutdowns. IC Role / Device Role / Timing Role: Controls CE lines of eight separate SRAMs holding distinct configuration zones, coordinated by A/B/C address decoding. Use Value: Supports field-upgradable firmware and regulatory compliance through deterministic, low-latency CE0–CE7 activation aligned with microcontroller memory access timing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar nonvolatile RAM controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| DS1212S | 16-output decoder (vs. 8), identical VCCI/VCCO/PF/VTOL functionality and battery management | Supports larger memory arrays requiring >8 RAM chips; same footprint but different pin mapping for CE8–CE15 | Select DS1212S only when expanding beyond eight RAM devices; not pin-compatible with DS1211S |
| MAX6900 | Integrated RTC + NV SRAM controller; no external RAM support; single-battery only; no address decoder | Targeted at compact RTC+memory modules; lacks CE0–CE7 outputs and A/B/C inputs | Choose MAX6900 for space-constrained designs needing combined timekeeping and small nonvolatile storage, not RAM expansion |
Compared with DS1212S and MAX6900, the DS1211S uniquely balances 8-RAM scalability, dual-battery redundancy, and minimal standby current-making it optimal for industrial memory backup where board area, reliability, and long-term data retention are prioritized over integrated timekeeping or ultra-high channel count.
Availability
DS1211S is available at Aetrix Electronics and suitable for industrial data loggers, real-time clock modules, medical device memory backup, and POS terminal configuration storage requiring stable component supply and long-lifecycle support.
Supply support for DS1211S 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 (acquired by Analog Devices in 2021) designs precision analog, mixed-signal, and power-management ICs for industrial, automotive, and communications applications.
The DS1211S belongs to Maxim's legacy nonvolatile memory controller family, engineered specifically to enable reliable, low-power, battery-backed RAM systems in harsh or intermittently powered environments.
FAQ
What is the function of the TOL pin on the DS1211S?
The TOL pin on the DS1211S selects the power-fail detection threshold: logic high configures a 5% VCCI tolerance (4.75V), while logic low sets a 10% tolerance (4.5V). This directly determines the VCCI voltage level at which the PF output asserts and VCCO switches to battery. The DS1211S uses this pin to adapt to varying power supply stability requirements without external components.
How does the DS1211S handle redundant batteries connected to VBAT1 and VBAT2?
The DS1211S implements priority-based battery selection: VBAT1 is used by default, and VBAT2 activates only if VBAT1 is absent or fails the on-power-up test. Internal circuitry monitors both inputs continuously, ensuring uninterrupted VCCO delivery during transitions. This dual-battery scheme is integral to the DS1211S design and requires no external diode-orring or control logic.
Can the DS1211S drive more than eight CMOS RAMs?
No-the DS1211S provides exactly eight chip-enable outputs (CE0–CE7) driven by its internal 3-to-8 decoder. To control more than eight RAMs, multiple DS1211S devices must be used with decoded address partitioning, or the higher-channel DS1212S (16 outputs) should be selected. The DS1211S pinout and logic do not support expansion beyond eight outputs.
What is the purpose of the CE input pin on the DS1211S?
CE is a global chip-enable input that must be held low for the DS1211S to operate: only when CE is low will the A/B/C address inputs be decoded and CE0–CE7 outputs activated. If CE is high, all CE outputs remain inactive regardless of A/B/C state-providing hardware-level override for system-wide RAM disablement. This feature is unique to the DS1211S among its family variants.
Does the DS1211S require external components for basic nonvolatile RAM operation?
The DS1211S operates autonomously with only VCCI, VBAT1/VBAT2, and RAM connections-no external resistors, capacitors, or logic are required for core functionality. Optional pull-ups on PF or CE may be added per system interface needs, but the DS1211S internal design eliminates external voltage dividers, comparators, or decoding gates needed in discrete solutions.
DS1211S Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Controller Type:
- Nonvolatile RAM
- Voltage - Supply:
- 4.75V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
DS1211S FAQ
1.How can I place an order for DS1211S through Aetrix?
Please submit a Request for Quotation (RFQ) for DS1211S 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 DS1211S reliable?
The price and inventory of DS1211S are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS1211S is usually 5 days.
3.What payment methods are accepted for DS1211S?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS1211S transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DS1211S?
DS1211S orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DS1211S 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 DS1211S?
For technical support, including DS1211S datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS1211S requirements.
6.How does Aetrix verify that DS1211S is sourced from the original manufacturer or authorized distributors?
All DS1211S 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 DS1211S meets industry standards.
7.What is the process for return or replacement of DS1211S?
All DS1211S units undergo pre-shipment inspection (PSI). If there is an issue with DS1211S, 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 DS1211S part is unused and in its original packaging.
Return procedure for DS1211S:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
DS1211S Tags
-
BQ2201SN-N
Texas Instruments
-
DS1314S+
Analog Devices Inc./Maxim Integrated
-
BQ2205LYPW
Texas Instruments
-
MXD1210CSA+
Analog Devices Inc./Maxim Integrated
-
MXD1210CPA+
Analog Devices Inc./Maxim Integrated
-
4RCD0232KC1ATG
Renesas
-
DS1312S-2+
Analog Devices Inc./Maxim Integrated
-
DS1314S-2+T&R
Analog Devices Inc./Maxim Integrated
-
DS1321S+
Analog Devices Inc./Maxim Integrated
-
DS1312S+
Analog Devices Inc./Maxim Integrated
-
MXD1210ESA+
Analog Devices Inc./Maxim Integrated
-
DS1321E+
Analog Devices Inc./Maxim Integrated
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