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Analog Devices Inc./Maxim Integrated DS1231S-50N
- Part No.:
- DS1231S-50N
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 16-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
DS1231S-50N.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,871
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Product details
Overview
DS1231S-50N from Maxim Integrated is a power monitor IC designed to detect impending power failure and initiate orderly processor shutdown before VCC drops below 4.25 V (TOL = VCC), provide non-maskable interrupt (NMI) on input voltage decay, and automatically restart the system after stable power restoration. It features dual comparators, selectable 5% or 10% VCC threshold detection, and supports both high-impedance and current-source input modes for early AC/DC line monitoring in industrial embedded systems.
For engineers reviewing the DS1231S-50N datasheet, DS1231S-50N pinout, DS1231S-50N application, or DS1231S-50N equivalent, key selection considerations include its dual-reset outputs (RST active-high and RST open-drain), NMI generation timing (tIPD ≤ 1.1 µs), VCC trip point accuracy (±0.12 V at 4.37 V typical), and compatibility with UL-approved opto-isolators for line-isolated sensing.
Technical Context
The DS1231S-50N implements two independent comparators: one monitors VCC against a temperature-compensated reference to assert RST/RST when VCC falls below a user-selectable threshold (4.25 V or 4.75 V), while the other monitors the IN pin to generate NMI based on MODE pin configuration - either high-impedance (VTP− = 2.3 V) or 30 µA current-source (VTP+ = 2.5 V). Hysteresis of ±60 mV ensures noise immunity on both inputs.
Its internal digital sampler and delay logic coordinate reset assertion timing: RST remains active for ≥150 ms on power-up, and RST deasserts only after VCC stabilizes within nominal limits and IN exceeds its trip threshold. The device requires no external capacitors and operates across 4.5–5.5 V supply with ICC ≤ 2.0 mA.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Trip Point (TOL = VCC) | 4.25–4.49 V - triggers RST/RST when +5 V rail drops below 5% tolerance, enabling last-cycle processor halt |
| VCC Trip Point (TOL = GND) | 4.50–4.74 V - enables 10% VCC monitoring for less aggressive shutdown timing |
| IN Trip Voltage (MODE = VCC) | 2.3 V (VTP−) - high-impedance input for resistor-divider sensing of pre-regulator voltages |
| IN Trip Voltage (MODE = GND) | 2.5 V (VTP+) - 30 µA current-source input compatible with opto-isolator LED drive |
| RST Output Type | Active-high push-pull - drives microprocessor reset directly without pull-up |
| RST Output Type | Active-low open-drain - requires external pull-up; sinks ≥2.0 mA at 0.4 V |
| NMI Propagation Delay | ≤1.1 µs - ensures rapid warning of input voltage decay before VCC collapse |
| Power-Up Reset Duration | 150–1000 ms - holds processor in reset until VCC and IN stabilize post-power-on |
Pinout & Package
DS1231S-50N is housed in a 16-pin SOIC (300 mil) surface-mount package. Pin assignments are validated per Maxim's DS1231/S datasheet Rev. 022698.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (IN) | Input voltage sense | Configurable as high-Z (MODE=VCC) or 30 µA current source (MODE=GND) for early power-loss detection |
| 2 (MODE) | Input mode select | Connect to VCC for high-impedance sensing; connect to GND for opto-isolator-compatible current sourcing |
| 3 (TOL) | VCC threshold select | Ground for 10% VCC trip (4.75 V); connect to VCC for 5% VCC trip (4.25 V) |
| 4 (GND) | Ground reference | Analog and digital ground common return path |
| 5 (RST) | Reset output (active-high) | Push-pull output; asserts high to halt processor during brownout |
| 6 (VCC) | +5 V supply | Operates from 4.5–5.5 V; powers internal reference and comparators |
| 7 (NMI) | Non-maskable interrupt | Open-drain output; signals earliest power anomaly to processor NMI pin |
| 8 (RST) | Reset output (active-low) | Open-drain; requires external pull-up; complements RST for mixed-logic systems |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent reset outputs | RST (push-pull, active-high) and RST (open-drain, active-low) enable flexible interface with diverse microprocessor reset architectures |
| Selectable VCC monitoring threshold | 5% or 10% trip points via TOL pin eliminate need for external resistive dividers on VCC rail |
| Configurable input sensing mode | MODE pin selects between high-impedance (for resistor-divider) or 30 µA current-source (for opto-isolator) input interface |
| No external timing capacitors required | Internal digital delay and sampling eliminate capacitor aging, drift, and board space for reset timing |
| Guaranteed power-up reset duration | Minimum 150 ms active reset ensures reliable initialization even with slow-rising or noisy VCC rails |
Applications
| Industrial PLC Power Supervision | Medical Device UPS Monitoring |
|---|---|
Use Scenario: Monitors AC mains-derived DC bus before linear regulator to detect grid sag or outage 20–100 ms before VCC dropout. IC Role / Device Role / Timing Role: DS1231S-50N acts as primary power-failure predictor, generating NMI at VTP+ = 2.5 V on MODE=GND, then asserting RST at VCCTP = 4.25 V to halt CPU before memory corruption. Use Value: Enables deterministic save-to-EEPROM sequence using NMI service routine, with ≥150 ms guaranteed reset hold time for safe state capture. | Use Scenario: Interfaces to isolated AC line via UL-certified opto-isolator to warn of incoming power loss in battery-backed diagnostic equipment. IC Role / Device Role / Timing Role: DS1231S-50N serves as galvanically isolated power-loss detector; IN pin sources 30 µA to opto-LED, triggering NMI before backup battery engages. Use Value: Provides ≥50 ms warning margin between NMI and RST assertion, allowing firmware to log critical vitals and prepare for seamless battery switchover. |
| Telecom Shelf Power Management | Automotive Infotainment Head Unit |
Use Scenario: Monitors +5 V backplane supply in carrier-grade shelf; detects brownout caused by upstream DC-DC converter fault. IC Role / Device Role / Timing Role: DS1231S-50N uses TOL=GND to set 10% VCC threshold (4.5 V), asserting RST to reset DSP and FPGA before data pipeline corruption occurs. Use Value: Prevents partial writes to flash memory by halting execution at first sign of regulated rail instability, eliminating field-replaceable unit failures. | Use Scenario: Detects ignition-switched 12 V battery decay in vehicle infotainment system, where DC-DC output may remain stable longer than input. IC Role / Device Role / Timing Role: DS1231S-50N configures IN pin in high-Z mode (MODE=VCC) to sense pre-DC-DC 12 V rail via resistor divider, issuing NMI before VCC collapse. Use Value: Allows graceful UI shutdown and audio fade-out using NMI handler, avoiding abrupt black screen or speaker pop during engine start-stop cycles. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar power monitor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX690TSA+ | Single active-low reset output; no NMI or dual-reset capability; fixed 4.65 V reset threshold | Lacks early-warning interrupt; suitable only for basic power-on reset, not power-failure prediction | Choose MAX690TSA+ only if NMI functionality and adjustable VCC threshold are unnecessary |
| TPS3823-50DBVR | Single reset output (active-low); 5% VCC threshold only; no configurable input sensing or NMI | Designed for simple microcontroller reset, not multi-stage shutdown coordination | Use TPS3823-50DBVR when board space is constrained and only basic brownout reset is required |
Compared with MAX690TSA+ and TPS3823-50DBVR, DS1231S-50N uniquely supports predictive power-loss response via NMI, dual-reset signaling, and input-mode flexibility-critical for systems requiring deterministic shutdown sequencing and line-isolated monitoring.
Availability
DS1231S-50N is available at Aetrix Electronics and suitable for industrial PLC power supervision, medical device UPS monitoring, and telecom shelf power management requiring stable component supply and long-term lifecycle support.
Supply support for DS1231S-50N 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 and mixed-signal ICs for industrial, automotive, and communications applications, emphasizing reliability and integration.
The DS1231S-50N belongs to Maxim's power monitoring product line, engineered specifically for deterministic power-failure response in systems where nonvolatile memory integrity and orderly processor shutdown are mission-critical.
FAQ
What is the function of the MODE pin on the DS1231S-50N?
The MODE pin on the DS1231S-50N selects the electrical behavior of the IN pin: when tied to VCC, IN becomes a high-impedance input (VTP− = 2.3 V) for resistor-divider sensing; when grounded, IN sources 30 µA (VTP+ = 2.5 V) to drive opto-isolator LEDs. This dual-mode capability allows DS1231S-50N to interface safely with both low-voltage DC rails and isolated high-voltage AC lines without external components.
How does the TOL pin affect the DS1231S-50N's reset behavior?
The TOL pin on the DS1231S-50N sets the VCC trip threshold: connecting TOL to GND selects a 10% tolerance (VCCTP = 4.50–4.74 V), while connecting it to VCC selects 5% tolerance (VCCTP = 4.25–4.49 V). This direct hardware selection eliminates calibration resistors and ensures DS1231S-50N delivers precise, repeatable reset timing aligned with system-level power supply hold-up requirements.
Does the DS1231S-50N require external pull-up resistors?
Yes - the DS1231S-50N's RST (pin 8) output is open-drain and requires an external pull-up resistor to VCC; RST (pin 5) is push-pull and does not. The NMI output (pin 7) is also open-drain and needs a pull-up. Typical values range from 4.7 kΩ to 10 kΩ. This design allows DS1231S-50N to interface with mixed-voltage logic families and avoids contention during reset assertion.
What is the maximum input voltage allowed on the IN pin of the DS1231S-50N?
The DS1231S-50N specifies an absolute maximum input voltage of VCC + 0.5 V on the IN pin - i.e., ≤5.5 V when VCC = 5.0 V. To monitor higher voltages (e.g., AC rectified lines), external circuitry such as resistor dividers (MODE = VCC) or zener-clamped opto-isolators (MODE = GND) must scale the signal. Exceeding 5.5 V risks permanent damage to DS1231S-50N's input stage.
Can the DS1231S-50N be used in automotive applications?
The DS1231S-50N is rated for 0°C to +70°C operation (commercial grade); an industrial version (–40°C to +85°C) exists but is not the DS1231S-50N variant. For under-hood automotive use, the DS1231S-50N is unsuitable due to temperature limitations. However, it is qualified for cabin-mounted infotainment head units where ambient temperatures remain within its specified range - provided input sensing is adapted for 12 V battery transients using appropriate external protection.
DS1231S-50N Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 16-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- Simple Reset/Power-On Reset
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 4.37V, 4.62V
- Output:
- Open Drain or Open Collector
- Reset:
- Active High/Active Low
- Reset Timeout:
- 150ms Minimum
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
DS1231S-50N FAQ
1.How can I place an order for DS1231S-50N through Aetrix?
Please submit a Request for Quotation (RFQ) for DS1231S-50N 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 DS1231S-50N reliable?
The price and inventory of DS1231S-50N are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS1231S-50N is usually 5 days.
3.What payment methods are accepted for DS1231S-50N?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS1231S-50N transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DS1231S-50N?
DS1231S-50N orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DS1231S-50N 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 DS1231S-50N?
For technical support, including DS1231S-50N datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS1231S-50N requirements.
6.How does Aetrix verify that DS1231S-50N is sourced from the original manufacturer or authorized distributors?
All DS1231S-50N 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 DS1231S-50N meets industry standards.
7.What is the process for return or replacement of DS1231S-50N?
All DS1231S-50N units undergo pre-shipment inspection (PSI). If there is an issue with DS1231S-50N, 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 DS1231S-50N part is unused and in its original packaging.
Return procedure for DS1231S-50N:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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