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Analog Devices Inc./Maxim Integrated DS1818R-20-U+
- Part No.:
- DS1818R-20-U+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
DS1818R-20-U+.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:4,509
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Product details
Overview
DS1818R-20-U+ from Maxim Integrated is a 3.3V fixed-threshold supervisory IC with pushbutton reset capability, active-low open-drain reset output, 150ms reset timeout, and ±20% VCC trip tolerance. It monitors power supply integrity and provides automated microprocessor reset during brownout or power-up, used in embedded control systems requiring reliable power-on initialization.
For engineers reviewing the DS1818R-20-U+ datasheet, DS1818R-20-U+ pinout, DS1818R-20-U+ application, or DS1818R-20-U+ equivalent, key selection criteria include reset threshold accuracy, pushbutton debounce timing, quiescent current, operating temperature range, and SOT-23 package compatibility with space-constrained PCB layouts.
Technical Context
The DS1818R-20-U+ implements a precision temperature-compensated voltage reference and comparator to detect VCC deviations beyond its ±20% trip window (2.47V–2.64V at 3.3V nominal). Its internal logic asserts RST low for ≥100ms after VCC recovery, ensuring processor stabilization before release.
It supports dual reset initiation modes: automatic power-fail detection and manual pushbutton reset via the RST pin, with 1µs minimum button press detection and guaranteed 100–250ms post-release reset hold time. The open-drain output includes an internal 5.5kΩ pullup resistor, eliminating external components in many designs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Trip Point | 2.47V (min) to 2.64V (max); defines precise 3.3V supply monitoring window for ±20% tolerance |
| Reset Timeout (tRST) | 100–250ms; ensures sufficient processor and power rail stabilization before deasserting reset |
| Quiescent Current (ICC) | 28–35µA; enables ultra-low-power operation in battery-backed or energy-sensitive systems |
| Operating Temp Range | -40°C to +85°C; supports industrial-grade deployment without derating |
| Internal Pullup Resistor | 3.5–7.5kΩ; reduces BOM count and board area by integrating pullup on-chip |
| Pushbutton Detect Threshold | 1µs minimum low pulse; allows robust manual reset triggering even with contact bounce |
Pinout & Package
SOT-23-3 surface-mount package with 1.3mm × 2.9mm footprint, compatible with standard reflow profiles and automated assembly.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (RST) | Active-Low Open-Drain Reset Output | Drives external microprocessor /CSP reset input; requires external pullup only if load exceeds internal 5.5kΩ capability |
| 2 (VCC) | Power Supply Input | Accepts 1.0V–5.5V; powers internal reference, comparator, and timing circuitry |
| 3 (GND) | Ground Reference | Provides return path for all internal currents and establishes voltage reference for VCC monitoring |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 3.3V ±20% Reset Threshold | Eliminates external resistor divider setup; guarantees consistent trip point across temperature and voltage |
| Integrated 5.5kΩ Pullup Resistor | Reduces component count and layout complexity while maintaining IOL ≥10mA drive strength |
| 150ms Guaranteed Reset Hold Time | Meets JEDEC JESD78 reliability requirements for microprocessor power-up sequencing |
| Pushbutton Reset with Debounce | Supports user-initiated reset without external RC network; detects sub-microsecond button pulses |
Applications
| Industrial PLC Controller | Smart Metering Module |
|---|---|
Use Scenario: Power cycling during firmware updates or grid voltage sags in utility metering hardware. IC Role / Device Role / Timing Role: Supervisory IC providing power-fail warning and controlled reset assertion to prevent flash corruption. Use Value: 150ms reset hold ensures stable VCC and MCU clock before release, preventing partial writes to nonvolatile memory. | Use Scenario: Cold-start initialization after battery replacement or mains interruption in residential smart meters. IC Role / Device Role / Timing Role: Primary reset generator coordinating power-on sequence of metrology SoC and communication subsystems. Use Value: Fixed ±20% trip point accommodates wide VCC tolerances in unregulated auxiliary supplies common in meter designs. |
| Embedded Gateway Node | Medical Diagnostic Sensor Hub |
Use Scenario: Intermittent power loss in battery-powered edge gateways deployed in remote IoT infrastructure. IC Role / Device Role / Timing Role: System-level supervisor enabling graceful shutdown and deterministic restart upon power restoration. Use Value: 35µA max ICC extends battery life between maintenance cycles without compromising reset reliability. | Use Scenario: Power-up validation prior to sensor calibration and data acquisition in portable diagnostic devices. IC Role / Device Role / Timing Role: Safety-critical reset controller ensuring full system initialization before analog front-end activation. Use Value: -40°C to +85°C operation supports clinical environments with variable ambient conditions and thermal cycling. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar supervisory IC applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX809TRD29+T | Fixed 2.93V reset threshold; no pushbutton monitoring; 140ms reset timeout | Lacks manual reset capability; suited for simpler power-monitor-only use cases | Select when pushbutton functionality is unnecessary and tighter 2.93V threshold is preferred |
| TPS3808G12DBVR | Adjustable reset threshold (via external resistor); 200ms timeout; higher 12µA typical ICC | Requires external components for threshold setting; better for designs needing custom trip points | Choose when design flexibility outweighs BOM simplicity and DS1818R-20-U+'s integrated features |
Compared with MAX809TRD29+T and TPS3808G12DBVR, the DS1818R-20-U+ uniquely combines fixed ±20% trip accuracy, integrated pushbutton support, and internal pullup in SOT-23-reducing design effort for cost-sensitive industrial controllers where manual reset and tolerance margin are critical.
Availability
DS1818R-20-U+ is available at Aetrix Electronics and suitable for industrial PLC controllers, smart metering modules, and embedded gateway nodes requiring stable component supply and long-term manufacturability.
Supply support for DS1818R-20-U+ 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 high reliability and integration.
The DS1818R-20-U+ belongs to Maxim's EconoReset™ family of supervisory ICs, engineered specifically for cost-effective, space-efficient power monitoring and reset generation in resource-constrained embedded systems.
FAQ
What is the exact VCC trip voltage range for DS1818R-20-U+?
The DS1818R-20-U+ has a guaranteed VCC trip point range of 2.47V (minimum) to 2.64V (maximum), corresponding to ±20% tolerance around a nominal 3.3V supply. This specification is tested and validated across the full -40°C to +85°C operating temperature range and is defined in the DC Electrical Characteristics table of the official Maxim datasheet for DS1818R-20-U+.
Does DS1818R-20-U+ require an external pullup resistor on the RST pin?
No, DS1818R-20-U+ integrates a 5.5kΩ internal pullup resistor on the RST pin, eliminating the need for an external component in most applications. An external pullup may be added only if the load demands exceed the internal resistor's capability-such as when driving multiple inputs or longer traces-but this is not required for standard microprocessor reset interface per the DS1818R-20-U+ datasheet specifications.
How does the pushbutton reset function work on DS1818R-20-U+?
The DS1818R-20-U+ monitors the RST pin for low pulses: pulling RST below 0.4V for ≥1µs triggers a manual reset. Upon release, the DS1818R-20-U+ holds RST low for 100–250ms to ensure clean debounced reset assertion. This feature operates independently of VCC monitoring and is fully specified in the AC Electrical Characteristics section of the DS1818R-20-U+ datasheet.
What is the maximum supply voltage rating for DS1818R-20-U+?
The absolute maximum VCC rating for DS1818R-20-U+ is +7.0V, but recommended DC operating conditions specify VCC between 1.0V and 5.5V. Operation above 5.5V risks permanent damage and is outside guaranteed performance limits. All electrical characteristics-including trip point, reset timeout, and quiescent current-are validated only within the 1.0V–5.5V range per the DS1818R-20-U+ datasheet.
Is DS1818R-20-U+ compatible with TO-92 and SOT-23 packages interchangeably?
No-DS1818R-20-U+ is exclusively offered in the SOT-23-3 package, as indicated by the "U+" suffix and confirmed in Maxim's official ordering information. While the DS1818 family includes TO-92 variants (e.g., DS1818R-20+), the DS1818R-20-U+ designation specifies the SOT-23 variant with identical pinout but different mechanical dimensions and thermal characteristics.
DS1818R-20-U+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- EconoReset
- Package/Case:
- TO-236-3, SC-59, SOT-23-3
- Packaging:
- Tube
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Simple Reset/Power-On Reset
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 3.3V
- Output:
- Open Drain or Open Collector
- Reset:
- Active Low
- Reset Timeout:
- 100ms Minimum
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-3
DS1818R-20-U+ FAQ
1.How can I place an order for DS1818R-20-U+ through Aetrix?
Please submit a Request for Quotation (RFQ) for DS1818R-20-U+ 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 DS1818R-20-U+ reliable?
The price and inventory of DS1818R-20-U+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS1818R-20-U+ is usually 5 days.
3.What payment methods are accepted for DS1818R-20-U+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS1818R-20-U+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DS1818R-20-U+?
DS1818R-20-U+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DS1818R-20-U+ 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 DS1818R-20-U+?
For technical support, including DS1818R-20-U+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS1818R-20-U+ requirements.
6.How does Aetrix verify that DS1818R-20-U+ is sourced from the original manufacturer or authorized distributors?
All DS1818R-20-U+ 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 DS1818R-20-U+ meets industry standards.
7.What is the process for return or replacement of DS1818R-20-U+?
All DS1818R-20-U+ units undergo pre-shipment inspection (PSI). If there is an issue with DS1818R-20-U+, 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 DS1818R-20-U+ part is unused and in its original packaging.
Return procedure for DS1818R-20-U+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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