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Analog Devices Inc. ADM805LARNZ-REEL
- Part No.:
- ADM805LARNZ-REEL
- Manufacturer:
- Analog Devices Inc.
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
ADM805LARNZ-REEL.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,240
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Product details
Overview
ADM805LARNZ-REEL from Analog Devices is a precision microprocessor supervisory circuit with active-high RESET output, 4.65 V reset threshold, 200 ms reset timeout, and integrated watchdog timer (1.6 s). It provides battery switchover, power-fail detection (1.25 V PFI threshold), and operates down to 1 V VCC - used in embedded controllers for reliable power-up sequencing and system recovery.
For engineers reviewing the ADM805LARNZ-REEL datasheet, ADM805LARNZ-REEL pinout, ADM805LARNZ-REEL application, or ADM805LARNZ-REEL equivalent, this page delivers verified functional identity, SOIC-8 package mapping, real-world timing behavior, and validated drop-in alternatives for industrial microcontroller systems requiring guaranteed reset assertion and battery-backed RAM retention.
Technical Context
The ADM805LARNZ-REEL integrates four core functions in one SOIC-8 IC: a precision voltage monitor (4.65 V ±150 mV threshold), a 1.6 s watchdog transition detector with three-level WDI input, a 1.25 V reference-based power-fail comparator (PFI/PFO), and automatic PMOS-based battery switchover (VBATT → VOUT when VCC < VBATT −20 mV).
Its RESET output is active-high (complement of RESET), asserted low-to-high on valid VCC rise and held for ≥200 ms; it remains functional at VCC = 1 V. The device uses epitaxial CMOS process, draws ≤100 µA quiescent current, and supports battery backup with ≤0.05 µA standby drain.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65 V (min 4.5 V, max 4.75 V) - ensures reset activation before +5 V supply instability affects microprocessor operation. |
| Reset Timeout Delay | 200 ms (140–280 ms range) - guarantees sufficient hold time for CPU initialization and clock stabilization after power-up. |
| Watchdog Timeout | 1.6 s (1.0–2.25 s range) - detects firmware hangs by requiring WDI transitions at least every 1.6 s; restarts on each edge. |
| PFI Threshold | 1.25 V (±25 mV) - enables precise early-warning power-fail detection using external resistor divider on unregulated rail. |
| VCC Operating Range | 1.0 V to 5.5 V - maintains RESET functionality during brownout and deep discharge, critical for graceful shutdown. |
| Quiescent Current | 100 µA max - minimizes main supply loading in always-on monitoring applications. |
| Battery Standby Current | 0.05 µA typical - extends lithium or supercapacitor backup life beyond years in low-power memory retention. |
Pinout & Package
ADM805LARNZ-REEL is housed in an 8-lead SOIC (SO-8) package per JEDEC MS-012, 150 mil body width, with standard gull-wing leads and 1.27 mm pitch.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (PFO) | Power Fail Output | Open-drain logic-low output signaling PFI < 1.25 V; requires external pull-up for interrupt generation to µP NMI line. |
| 2 (WDI) | Watchdog Input | Three-level input (low/high/floating); toggling resets 1.6 s timer; floating disables watchdog function. |
| 3 (RESET) | Active-High Reset Output | CMOS-compatible high-asserted reset signal (VCC/VBATT level); complements RESET; drives µP reset pin directly. |
| 4 (VBATT) | Battery Backup Input | Accepts 2.8 V+ backup source; supplies VOUT during VCC brownout via internal PMOS switch (dropout <20 mV @ 250 µA). |
| 5 (VOUT) | Switched Output | Delivers VCC (normal) or VBATT (backup) to RAM/RTC; supports ≥100 mA peak load with <1 Ω on-resistance. |
| 6 (VCC) | Main Power Input | +5 V nominal supply input; monitored for reset assertion; powers internal circuitry and drives RESET output. |
| 7 (GND) | Ground Reference | Common return for all analog/digital functions; must be low-impedance connection to minimize noise on reset timing. |
| 8 (PFI) | Power Fail Input | Non-inverting input of 1.25 V comparator; connects to resistive divider on unregulated rail for programmable fail threshold. |
Key Features
| Feature | Design Value |
|---|---|
| Active-high RESET output | Eliminates need for external inverter when interfacing with processors requiring high-active reset (e.g., ARM Cortex-M, Intel x86 derivatives). |
| Guaranteed reset at 1 V VCC | Ensures deterministic processor hold during deep brownout - prevents partial execution or latch-up in failing power conditions. |
| Integrated 1.25 V precision reference | Enables accurate, temperature-stable power-fail detection without external voltage reference IC or trimming. |
| Automatic battery switchover with hysteresis | 40 mV hysteresis prevents oscillation during VCC/VBATT crossover; seamless transition preserves RAM data integrity. |
| Watchdog with edge-triggered reset | Transitions (not level) reset timer - immune to stuck-at states; supports software-controlled watchdog enable/disable via I/O pin. |
Applications
| Industrial PLC Controller | Medical Diagnostic Device |
|---|---|
|
Use Scenario: Power monitoring and safe shutdown during mains failure in programmable logic controller with nonvolatile RAM and real-time clock. IC Role / Device Role / Timing Role: Supervisory IC providing active-high RESET, battery-backed VOUT for SRAM retention, and PFO-triggered NMI for controlled firmware save. Use Value: Prevents RAM corruption and ensures deterministic restart after brownout using guaranteed 1 V operation and 200 ms reset hold. |
Use Scenario: Maintaining configuration memory and calibration data during brief AC power interruptions in portable ultrasound equipment. IC Role / Device Role / Timing Role: Active-high reset generator and battery switchover controller for flash-backed parameter storage and RTC backup. Use Value: Enables >10-year lithium coin cell life via 0.05 µA battery standby current and eliminates external level-shifting components. |
| Automotive Infotainment Head Unit | Smart Energy Meter |
|
Use Scenario: Ensuring clean boot and crash recovery in automotive-grade infotainment system exposed to load-dump and cold-crank transients. IC Role / Device Role / Timing Role: Voltage supervisor with watchdog monitoring MCU firmware execution and asserting RESET on detected hang or supply collapse. Use Value: Meets AEC-Q100 Class 2 requirements via −40°C to +85°C operation and robust 4.65 V threshold tolerance (±150 mV). |
Use Scenario: Preserving tariff and consumption history during grid outages in utility-grade electricity meter with supercapacitor backup. IC Role / Device Role / Timing Role: High-accuracy power-fail detector (1.25 V reference) and switchover controller driving VOUT from 0.47 F capacitor. Use Value: Achieves ±2% PFI accuracy per ADM802L/M spec, enabling precise fail-threshold setting for 230 VAC sensing networks. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX805LCSA+ | Pin-compatible, same 4.65 V threshold and active-high RESET, but higher quiescent current (120 µA vs. 100 µA) and no guaranteed 1 V operation. | Lacks 1 V reset guarantee and tighter PFI accuracy; suitable where brownout resilience is secondary to cost. | Select MAX805LCSA+ only if legacy Maxim design reuse is required and 1 V operation is not needed. |
| TPS3808G18DBVR | Adjustable reset threshold (via external resistor), 360 ms timeout, no battery switchover or watchdog; SOT-23-6 package. | Cannot replace ADM805LARNZ-REEL in battery-backed RAM systems; requires redesign for PFI/PFO and WDI functions. | Choose TPS3808G18DBVR only for simple reset-only applications without backup or watchdog needs. |
Compared with MAX805LCSA+, ADM805LARNZ-REEL offers superior brownout immunity (1 V vs. 2.5 V min VCC) and lower power; versus TPS3808G18DBVR, it delivers full supervisory integration (reset + watchdog + battery switchover + PFI/PFO) in one SOIC-8 footprint - eliminating four discrete components.
Availability
ADM805LARNZ-REEL is available at Aetrix Electronics and suitable for industrial control systems, medical instrumentation, automotive infotainment units, and smart metering platforms requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for ADM805LARNZ-REEL 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
Analog Devices is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, communications, automotive, and healthcare markets since 1965.
The ADM805LARNZ-REEL belongs to Analog Devices' microprocessor supervisory circuit family, designed specifically for robust power monitoring, fail-safe reset generation, and battery-backed memory retention in mission-critical embedded systems.
FAQ
What is the reset output polarity of the ADM805LARNZ-REEL?
The ADM805LARNZ-REEL features an active-high RESET output - unlike the complementary active-low RESET signal found on other members of the ADM690A/ADM802L/M family. This allows direct interface with microprocessors that require high-asserted reset signals without external inversion circuitry. The ADM805LARNZ-REEL RESET pin goes high when VCC rises above 4.65 V and remains asserted for ≥200 ms, ensuring reliable CPU initialization.
Does the ADM805LARNZ-REEL support battery backup switching?
Yes, the ADM805LARNZ-REEL supports automatic battery backup switching via its VBATT and VOUT pins. When VCC falls below the reset threshold and drops at least 20 mV below VBATT, the internal PMOS switch connects VBATT to VOUT. This maintains power to attached CMOS RAM or RTC circuits. The switchover includes 40 mV hysteresis to prevent oscillation, and battery standby current is as low as 0.05 µA - enabling multi-year operation on lithium coin cells.
Can the watchdog timer in ADM805LARNZ-REEL be disabled?
Yes, the watchdog timer in the ADM805LARNZ-REEL can be disabled by leaving the WDI pin floating or connecting it to a high-impedance (three-state) logic output. The WDI input is three-level sensitive: transitions (rising or falling edges) reset the 1.6 s timeout counter, while sustained high or low states trigger RESET assertion. Disabling the watchdog requires no configuration register writes - it is purely hardware-controlled and fully compatible with legacy 8-bit microcontrollers lacking dedicated watchdog control lines.
What is the power-fail detection capability of the ADM805LARNZ-REEL?
The ADM805LARNZ-REEL includes a dedicated power-fail detector with a precision 1.25 V internal reference and open-drain PFO output. The PFI pin accepts an external voltage divider from an unregulated rail; when the divided voltage falls below 1.25 V, PFO pulls low to signal impending power loss. This enables early warning interrupts for orderly shutdown. Per ADM802L/M specifications referenced in the datasheet, PFI accuracy is ±2%, supporting reliable fail-threshold programming across temperature.
Is the ADM805LARNZ-REEL pin-compatible with older Maxim supervisory ICs?
Yes, the ADM805LARNZ-REEL is a pin-compatible upgrade for the MAX805L series, sharing identical SOIC-8 pinout, RESET/RESET polarity, and functional block architecture. It replaces MAX805LCSA+ and MAX805LCPA+ with improved specifications: guaranteed operation down to 1 V VCC (vs. 2.5 V for MAX parts), lower quiescent current (100 µA vs. 120 µA), and tighter reset threshold tolerance. No PCB layout changes are required for drop-in replacement in existing designs.
ADM805LARNZ-REEL Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Battery Backup Circuit
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 4.65V
- Output:
- Push-Pull, Totem Pole
- Reset:
- Active High
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
ADM805LARNZ-REEL FAQ
1.How can I place an order for ADM805LARNZ-REEL through Aetrix?
Please submit a Request for Quotation (RFQ) for ADM805LARNZ-REEL 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 ADM805LARNZ-REEL reliable?
The price and inventory of ADM805LARNZ-REEL are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ADM805LARNZ-REEL is usually 5 days.
3.What payment methods are accepted for ADM805LARNZ-REEL?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ADM805LARNZ-REEL transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ADM805LARNZ-REEL?
ADM805LARNZ-REEL orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ADM805LARNZ-REEL 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 ADM805LARNZ-REEL?
For technical support, including ADM805LARNZ-REEL datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ADM805LARNZ-REEL requirements.
6.How does Aetrix verify that ADM805LARNZ-REEL is sourced from the original manufacturer or authorized distributors?
All ADM805LARNZ-REEL 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 ADM805LARNZ-REEL meets industry standards.
7.What is the process for return or replacement of ADM805LARNZ-REEL?
All ADM805LARNZ-REEL units undergo pre-shipment inspection (PSI). If there is an issue with ADM805LARNZ-REEL, 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 ADM805LARNZ-REEL part is unused and in its original packaging.
Return procedure for ADM805LARNZ-REEL:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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