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Analog Devices Inc./Maxim Integrated DS1831AS+
- Part No.:
- DS1831AS+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
DS1831AS+.pdf
- Description:
- IC SUPERVISOR 4 CHANNEL 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:211
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Product details
Overview
DS1831AS+ from Maxim Integrated is a multisupply voltage monitor IC with integrated watchdog timer, designed to supervise 5V and 3.3V power rails plus two user-configurable analog inputs (IN1/IN2). It provides open-drain reset outputs (RST5V, RST3.3V), non-maskable interrupts (NMI1), watchdog status (WDS), and pushbutton reset support. Key confirmed parameters: 5V/3.3V trip accuracy ±0.13V (typ), 10ms/100ms/1s selectable reset delays, -40°C to +85°C operating range, 16-pin SOIC (150mil) package, and internal 1.25V temperature-compensated reference.
For engineers reviewing the DS1831AS+ datasheet, DS1831AS+ pinout, DS1831AS+ application, or DS1831AS+ equivalent, this page delivers verified functional identity, exact pin roles, tolerance and delay configuration logic, watchdog timing behavior, and real-world supervision use cases in embedded microcontroller systems requiring dual-rail monitoring and software fault detection.
Technical Context
The DS1831AS+ implements two independent voltage comparators referenced to a precision 1.25V bandgap source, each with configurable trip tolerance (5%/10%/20% for 3.3V; 5%/10%/15% for 5V) via TOL3.3V/TOL5V pins and programmable reset hold time (10ms/100ms/1s) via TD3.3V/TD5V pins. Internal power is drawn from the higher of IN5V or IN3.3V, requiring ≥1.0V on at least one supply for operation.
As the DS1831A variant in SOIC package, DS1831AS+ replaces the master pushbutton reset (MPBRST) and NMI2 of DS1831 with watchdog strobe input (ST) and watchdog status output (WDS), while retaining PBRST5V/PBRST3.3V manual reset inputs. The watchdog timeout (10ms/100ms/1s) is set by TDWD pin state and triggers WDS low if ST transitions are missed - a dedicated hardware safety mechanism for firmware hang detection.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Inputs | IN5V (1.0–5.5V) and IN3.3V (1.0–5.5V); device powers from higher rail - enables operation during asymmetric brownout. |
| 5V Trip Point | 4.63V (typ) with ±0.13V tolerance; selectable 5%/10%/15% via TOL5V - supports tight or relaxed 5V rail margins. |
| 3.3V Trip Point | 3.06V (typ) with ±0.09V tolerance; selectable 5%/10%/20% via TOL3.3V - accommodates 3.3V or 3.0V system variants. |
| Reset Delay | 10ms / 100ms / 1s (min) selected by TD3.3V/TD5V logic level - ensures stable power-up before processor release. |
| Watchdog Timeout | 10ms / 100ms / 1s (min) selected by TDWD logic level - enforces minimum firmware activity frequency without software overhead. |
| Operating Temp | -40°C to +85°C - qualified for industrial and extended-temperature embedded control environments. |
| Package | 16-pin SOIC (150mil), RoHS-compliant - surface-mount compatible with standard reflow profiles. |
Pinout & Package
DS1831AS+ uses a 16-pin SOIC (150mil) package with 1.27mm pitch. All pins are electrically defined per Maxim's DS1831A datasheet Rev. 0, with no internal pull-ups on RST/WDS/NMI outputs - external 10kΩ pull-ups required for valid high-level signaling.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| IN5V | 5V supply input and power source | Primary power rail input; must exceed 1.0V for operation; supplies internal bias when > IN3.3V. |
| IN3.3V | 3.3V supply input and power source | Secondary power rail input; supplies internal bias when > IN5V; enables dual-rail brownout detection. |
| RST5V | Open-drain 5V reset output | Active-low reset signal asserted when IN5V falls below trip point; requires external pull-up. |
| RST3.3V | Open-drain 3.3V reset output | Active-low reset signal asserted when IN3.3V falls below trip point; independent timing control. |
| TOL5V | 5V tolerance select input | Configures 5V trip window: IN5V = 5%, GND = 10%, float = 15% - sets hysteresis margin at power-up. |
| TOL3.3V | 3.3V tolerance select input | Configures 3.3V trip window: IN3.3V = 5%, GND = 10%, float = 20% - supports wider-margin 3V systems. |
| TD5V | 5V reset time-delay select | Selects RST5V hold time: GND = 10ms, float = 100ms, VCC = 1s - prevents premature processor boot. |
| TD3.3V | 3.3V reset time-delay select | Selects RST3.3V hold time: GND = 10ms, float = 100ms, VCC = 1s - enables staggered rail sequencing. |
| PBRST5V | 5V pushbutton reset input | Manual reset trigger: pull low ≥20µs to force RST5V active; internally pulled up to IN5V via 100kΩ. |
| PBRST3.3V | 3.3V pushbutton reset input | Manual reset trigger: pull low ≥20µs to force RST3.3V active; internally pulled up to IN3.3V via 100kΩ. |
| ST | Watchdog strobe input | Edge-sensitive input (any transition); missing strobe within TDWD timeout asserts WDS low - detects firmware lockup. |
| WDS | Watchdog status output | Open-drain active-low pulse (≥100µs) on watchdog timeout; connects directly to PBRST5V/PBRST3.3V for auto-reset. |
| NMI1 | Non-maskable interrupt output | Open-drain comparator output referenced to 1.25V; pulses low when IN1 < 1.25V - monitors auxiliary voltages. |
| IN1 | First auxiliary sense input | High-impedance analog input; used with external resistor divider to scale upstream voltages to 1.25V trip point. |
| IN2 | Second auxiliary sense input | Unused in DS1831AS+ (DS1831B function); left unconnected or grounded - no internal connection. |
| GND | Ground reference | Analog and digital ground common node; must be low-impedance return path for all monitored supplies. |
Key Features
| Feature | Design Value |
|---|---|
| Dual-rail power supervision | Simultaneous monitoring of 5V and 3.3V supplies with independent trip points, tolerances, and reset delays - eliminates need for discrete supervisors per rail. |
| Hardware watchdog timer | Standalone ST-input watchdog with three timeout options (10ms/100ms/1s) and dedicated WDS output - provides fail-safe recovery without CPU intervention. |
| User-configurable trip accuracy | TOL5V/TOL3.3V pins enable selection of 5%/10%/15% (5V) or 5%/10%/20% (3.3V) tolerance windows - balances noise immunity vs. margin sensitivity. |
| Flexible reset timing | TD5V/TD3.3V pins allow independent 10ms/100ms/1s hold times per rail - supports power sequencing in multi-voltage systems. |
| Open-drain NMI output | NMI1 provides edge-triggered, hysteresis-equipped (100µV) interrupt for auxiliary voltage monitoring - enables early warning of upstream supply degradation. |
Applications
| Industrial PLC Controller | Medical Diagnostic Device |
|---|---|
|
Use Scenario: A programmable logic controller supervises 5V I/O bus and 3.3V FPGA core voltage while detecting overvoltage on 24V field power via IN1. IC Role / Device Role / Timing Role: DS1831AS+ acts as primary power-on reset generator and watchdog supervisor, asserting RST5V/RST3.3V during brownout and pulsing WDS if main firmware hangs. Use Value: Prevents corrupted I/O states and FPGA configuration loss by ensuring clean reset sequencing and automatic recovery from software faults - critical for deterministic control loop execution. |
Use Scenario: Portable ultrasound unit monitors battery-derived 5V analog front-end and 3.3V digital subsystem, with NMI1 tracking 12V transducer driver supply. IC Role / Device Role / Timing Role: DS1831AS+ serves as safety-critical power integrity monitor, holding resets until both rails stabilize and triggering WDS if image processing firmware stalls. Use Value: Guarantees safe shutdown and restart upon power anomaly or software freeze - satisfies IEC 62304 Class C software safety requirements for life-critical imaging. |
| Automotive Infotainment Head Unit | Telecom Remote Radio Unit |
|
Use Scenario: In-vehicle infotainment system supervises 5V USB host power and 3.3V SoC core, with ST input driven by SoC watchdog timer output. IC Role / Device Role / Timing Role: DS1831AS+ functions as secondary hardware watchdog, cross-checking SoC self-monitoring and forcing full system reset if ST signal freezes. Use Value: Adds redundancy against single-point failure in automotive-grade systems - meets ISO 26262 ASIL-B requirements for functional safety monitoring. |
Use Scenario: Outdoor 4G/5G radio unit monitors 5V backplane and 3.3V FPGA configuration voltage under wide temperature swings (-40°C to +85°C). IC Role / Device Role / Timing Role: DS1831AS+ provides temperature-stable reset generation using its internal 1.25V reference, with TD5V/TD3.3V set to 100ms for robust cold-start behavior. Use Value: Ensures reliable boot across environmental extremes by eliminating reference drift-induced false resets - improves field uptime in uncontrolled enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar multisupply monitoring applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6369ESA+ | Single-supply (3.3V only) supervisor with watchdog; no 5V monitoring or dual-rail tolerance configuration. | Lacks independent 5V/3.3V supervision and auxiliary sense inputs - suitable only for 3.3V-only systems. | Choose MAX6369ESA+ only if system uses only 3.3V rail and requires lower pin count; DS1831AS+ remains necessary for true dual-rail designs. |
| TPS3808G33DBVR | 3.3V supervisor with adjustable reset delay and watchdog, but no 5V input or TOL configuration - fixed 3.3V trip at 3.06V. | No support for 5V rail monitoring or user-selectable tolerance; limited to single-rail applications. | Use TPS3808G33DBVR where cost and footprint are prioritized over flexibility; DS1831AS+ is required when 5V/3.3V coexistence and configurability are mandatory. |
Compared with MAX6369ESA+ and TPS3808G33DBVR, DS1831AS+ uniquely delivers simultaneous 5V/3.3V supervision with per-rail tolerance and delay programming, plus a dedicated hardware watchdog - making it the only option for complex embedded systems requiring coordinated multi-rail reset and fail-safe software monitoring.
Availability
DS1831AS+ is available at Aetrix Electronics and suitable for industrial automation, medical diagnostics, automotive infotainment, and telecom infrastructure applications requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for DS1831AS+ 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 markets, with emphasis on reliability, low power, and integration.
The DS1831AS+ belongs to Maxim's Micromonitor™ family of power-supervisory ICs, engineered specifically for robust, multi-rail voltage monitoring and watchdog protection in mission-critical embedded systems.
FAQ
What is the function of the ST pin on the DS1831AS+?
The ST (strobe) pin on the DS1831AS+ is the watchdog timer input. It must receive a rising or falling edge at least once per configured timeout period (10ms/100ms/1s, set by TDWD) to prevent the WDS output from pulsing low. This provides hardware-enforced firmware liveness checking independent of the host processor's internal watchdog - a key safety feature in the DS1831AS+ design.
Does DS1831AS+ support monitoring of voltages other than 5V and 3.3V?
Yes, DS1831AS+ supports monitoring of additional voltages via IN1, which connects to an internal 1.25V-referenced comparator. By using an external resistor divider, users can scale higher voltages (e.g., 12V, 24V) down to the 1.25V trip threshold. IN2 is not functional in DS1831AS+ (it is reserved for DS1831B's PBST feature) and must remain unconnected or grounded.
How does DS1831AS+ determine its internal power source?
DS1831AS+ draws internal operating current from whichever supply - IN5V or IN3.3V - is at the higher voltage level. This architecture ensures continued functionality even during asymmetric brownout conditions where one rail collapses before the other. Operation requires ≥1.0V on at least one supply; accurate monitoring requires ≥1.5V on either IN5V or IN3.3V.
Can DS1831AS+ generate reset signals with different hold times for 5V and 3.3V rails?
Yes, DS1831AS+ supports independent reset timing for each rail. TD5V configures RST5V hold time (10ms/100ms/1s), while TD3.3V configures RST3.3V hold time (10ms/100ms/1s). This enables precise power sequencing - for example, holding 3.3V reset longer than 5V reset to ensure FPGA configuration completes before logic activation.
Is the DS1831AS+ watchdog timer disableable?
No, the DS1831AS+ watchdog timer cannot be disabled. The ST input must be actively strobed at intervals ≤ the selected timeout (set by TDWD) to prevent WDS from asserting. While disconnecting WDS removes the output signal, the underlying watchdog circuit remains active - meaning the device will still consume current and respond to ST inactivity as specified.
DS1831AS+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- MicroMonitor™
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Multi-Voltage Supervisor
- Number of Voltages Monitored:
- 4
- Voltage - Threshold:
- 3.3V, 5V, Adj
- Output:
- Open Drain or Open Collector
- Reset:
- Active Low
- Reset Timeout:
- 10ms; 100ms; 1,000ms Minimum
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
DS1831AS+ FAQ
1.How can I place an order for DS1831AS+ through Aetrix?
Please submit a Request for Quotation (RFQ) for DS1831AS+ 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 DS1831AS+ reliable?
The price and inventory of DS1831AS+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS1831AS+ is usually 5 days.
3.What payment methods are accepted for DS1831AS+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS1831AS+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DS1831AS+?
DS1831AS+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DS1831AS+ 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 DS1831AS+?
For technical support, including DS1831AS+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS1831AS+ requirements.
6.How does Aetrix verify that DS1831AS+ is sourced from the original manufacturer or authorized distributors?
All DS1831AS+ 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 DS1831AS+ meets industry standards.
7.What is the process for return or replacement of DS1831AS+?
All DS1831AS+ units undergo pre-shipment inspection (PSI). If there is an issue with DS1831AS+, 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 DS1831AS+ part is unused and in its original packaging.
Return procedure for DS1831AS+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
DS1831AS+ Tags
-
MIC826SYMT-TR
Microchip Technology
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APX803L20-29SA-7
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