My Inquiry
My Account
Analog Devices Inc./Maxim Integrated MAX805LESA+
- Part No.:
- MAX805LESA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX805LESA+.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,420
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
MAX805LESA+ from Maxim Integrated is a microprocessor supervisory circuit providing active-high reset, battery-backup switchover, watchdog timer (1.6s timeout), and power-fail detection (1.25V threshold) for +5V systems. It asserts RESET when VCC drops below 4.65V, guarantees reset assertion down to VCC = 1.1V, and draws only 200µA quiescent current in normal operation. It is used in battery-powered controllers and critical μP monitoring where reliable power-up/down sequencing and RAM retention are required.
For engineers reviewing the MAX805LESA+ datasheet, MAX805LESA+ pinout, MAX805LESA+ application, or MAX805LESA+ equivalent, this page delivers verified specifications, package mapping, functional context, and real-world design considerations - including active-high reset compatibility with Intel 80C51-family microcontrollers, battery switchover hysteresis (40mV), and guaranteed PFO response time of 400ns.
Technical Context
The MAX805LESA+ integrates four core functions on a single die: a precision reset generator with 4.65V threshold and 200ms pulse width, a 1.6s watchdog timer cleared by WDI edges, a 1.25V reference-based power-fail comparator driving PFO, and a dual-path power switch (5Ω PMOS for VCC→VOUT, 80Ω PMOS for VBATT→VOUT). Its active-high RESET output is electrically inverted from the standard RESET signal found in MAX690A/MAX802L variants.
It operates across –40°C to +85°C, supports VCC from 1.1V to 5.5V, and enters ultra-low-power battery-backup mode (<1µA supply current) when VCC falls below VBATT − 1V. The internal switchover logic enforces strict voltage conditions: VBATT connects to VOUT only when VCC < reset threshold *and* VBATT > VCC + 20mV, with 40mV hysteresis to prevent chatter during slow brownouts.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65V ±150mV - triggers reset during brownout; matches +5V ±5% supply tolerance. |
| Reset Pulse Width | 200ms (min 140ms, max 280ms) - ensures μP initialization completes before release. |
| Watchdog Timeout | 1.6s - provides robust software hang detection without requiring tight timing margins. |
| Supply Current (Active) | 200–500µA - enables long-term operation from small batteries or low-power rails. |
| Battery-Backup Current | <1µA when VCC < VBATT − 1V - preserves lithium battery life for years in standby. |
| PFO Response Time | 400ns - allows fast interrupt-driven power-down preparation in μP systems. |
| RESET Output Validity | Guaranteed down to VCC = 1.1V - supports reset assertion during deep undervoltage conditions. |
Pinout & Package
MAX805LESA+ is housed in an 8-pin SO (Small Outline) package, RoHS-compliant, with lead-free finish indicated by the '+' suffix. Pin 1 is VBATT, pin 2 is VCC, pin 3 is GND, pin 4 is PFI, pin 5 is PFO, pin 6 is WDI, pin 7 is RESET (active-high), and pin 8 is VOUT.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1: VBATT | Backup-battery input | Connects to lithium cell (3.0–3.6V); enables automatic switchover to backup power when VCC fails. |
| 2: VCC | +5V main supply input | Primary power source; monitored for reset generation and switchover control. |
| 3: GND | Ground reference | Common return for all analog and digital circuitry; must be low-impedance. |
| 4: PFI | Power-fail comparator input | Accepts voltage divider output; trips PFO low when input falls below 1.25V. |
| 5: PFO | Power-fail output | Open-drain active-low signal; used to trigger μP interrupt before supply collapse. |
| 6: WDI | Watchdog input | Edge-sensitive; must be toggled every <1.6s to prevent reset; floating disables watchdog. |
| 7: RESET | Active-high reset output | Inverted logic vs. RESET; drives high during reset; compatible with Intel 80C51 and similar μPs. |
| 8: VOUT | CMOS RAM supply output | Switches between VCC and VBATT; delivers regulated backup power to preserve RAM data. |
Key Features
| Feature | Design Value |
|---|---|
| Active-high RESET output | Enables direct interface with μPs requiring high-asserted reset (e.g., Intel 80C51), eliminating external inverters. |
| Guaranteed reset at VCC = 1.1V | Ensures deterministic system halt even during severe brownout, preventing corrupted state transitions. |
| 40mV switchover hysteresis | Prevents oscillatory switching between VCC and VBATT during slow-ramp power failures. |
| 1.25V precision PFI reference | Allows accurate power-fail warning using simple resistor dividers; ±2% accuracy over temperature. |
| 80Ω VBATT-to-VOUT switch | Minimizes voltage drop under load while limiting inrush; supports up to 250µA backup current. |
Applications
| Battery-Powered Controllers | Critical μP Power Monitoring |
|---|---|
Use Scenario: Industrial programmable logic controllers (PLCs) operating on primary DC supply with lithium coin-cell backup. IC Role / Device Role / Timing Role: Supervisory IC providing active-high reset, RAM backup switchover, and early power-fail warning via PFO interrupt. Use Value: Prevents RAM corruption during mains loss; enables graceful shutdown within 400ns of supply degradation. |
Use Scenario: Medical infusion pump with safety-critical firmware requiring deterministic reset behavior during voltage transients. IC Role / Device Role / Timing Role: Reset generator with 4.65V threshold and 200ms pulse, plus watchdog supervision of motor-control firmware loop. Use Value: Guarantees μP reset assertion down to VCC = 1.1V, ensuring fail-safe state recovery even under extreme undervoltage. |
| Intelligent Instruments | Embedded Data Loggers |
Use Scenario: Handheld multimeter with nonvolatile memory storing calibration coefficients and user settings. IC Role / Device Role / Timing Role: Battery switchover controller maintaining VOUT during battery replacement while VCC remains valid. Use Value: Enables hot-swap of backup battery without triggering reset or losing calibration data. |
Use Scenario: Remote environmental sensor node powered by solar-charged Li-ion, logging data to SRAM during outages. IC Role / Device Role / Timing Role: Dual-role supervisor: monitors main rail for brownout (RESET), detects low-energy condition (PFO), and switches to backup (VOUT). Use Value: Extends operational uptime by >10× via sub-1µA backup mode current, preserving weeks of log data. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX802LESA+ | Provides active-low RESET (not RESET); same 4.65V threshold, 200ms pulse, and 1.6s watchdog. | Requires external inverter for μPs needing active-high reset; otherwise functionally identical in monitoring and switchover. | Select MAX802LESA+ only if system uses active-low reset architecture and inverter cost/area is acceptable. |
| MAX813LESA+ | Identical pinout and electrical specs to MAX805LESA+, but includes manual reset input (MR) and watchdog disable (WDI tied to GND). | Supports operator-initiated reset and watchdog bypass - useful in field-service or debug scenarios. | Choose MAX813LESA+ when field-recoverability or test-mode flexibility outweighs minimal BOM cost increase. |
Compared with MAX802LESA+, MAX805LESA+ eliminates need for external inversion logic in active-high reset systems; compared with MAX813LESA+, it trades manual reset capability for slightly lower cost and simpler layout - ideal for production systems where reset is fully automated.
Availability
MAX805LESA+ is available at Aetrix Electronics and suitable for battery-powered controllers, intelligent instruments, critical μP power monitoring, and embedded data loggers requiring stable component supply across industrial temperature ranges.
Supply support for MAX805LESA+ 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, medical, and communications applications, emphasizing reliability, integration, and low-power operation.
The MAX805L product line delivers highly integrated microprocessor supervisory circuits optimized for +5V systems requiring active-high reset, battery-backed RAM retention, and fast power-fail warning - targeting applications where deterministic power sequencing is mission-critical.
FAQ
What is the reset threshold voltage of the MAX805LESA+?
The MAX805LESA+ has a nominal reset threshold of 4.65V, with guaranteed limits of 4.50V (min) and 4.75V (max) over temperature. This threshold is factory-trimmed and applies to both power-up assertion and brownout detection. The device guarantees RESET remains asserted until VCC rises above this threshold and holds for a full 200ms pulse width thereafter. This value is confirmed in the Electrical Characteristics table of the official Maxim datasheet (Rev 5, April 2015).
Does the MAX805LESA+ support active-high reset for Intel 80C51 microcontrollers?
Yes, the MAX805LESA+ provides an active-high RESET output (pin 7), specifically designed to interface directly with microcontrollers such as the Intel 80C51 that require high-asserted reset signals. Unlike the MAX690A or MAX802L, which output active-low RESET, the MAX805LESA+ inverts this internally - eliminating the need for external logic gates. Its RESET output is guaranteed valid down to VCC = 1.1V, ensuring compatibility across the full operating range.
How does the battery switchover function work in the MAX805LESA+?
The MAX805LESA+ switches VOUT from VCC to VBATT automatically when VCC falls below the 4.65V reset threshold *and* VBATT exceeds VCC by at least 20mV. A 40mV hysteresis prevents oscillation during slow brownouts. In backup mode, VOUT is sourced through an 80Ω PMOS switch, delivering up to 250µA at VBATT − 0.1V. Quiescent current drops below 1µA when VCC is more than 1V below VBATT - enabling multi-year battery life in standby applications.
What is the watchdog timeout period for the MAX805LESA+?
The MAX805LESA+ features a fixed 1.6s watchdog timeout period, with typical value 1.60s and guaranteed range of 1.00s to 2.25s over temperature and supply. The watchdog timer resets on any rising or falling edge at the WDI pin (pin 6); if no edge occurs within the timeout window, RESET is asserted. The timer is also cleared during RESET assertion or when WDI is three-stated, making it robust against software glitches or bus contention.
Can the MAX805LESA+ monitor power supplies other than +5V?
Yes, the MAX805LESA+ can monitor non-+5V supplies using its PFI (pin 4) input and internal 1.25V reference. By configuring an external resistor divider, users can scale any positive supply (e.g., +3.3V, +12V) to produce 1.25V at PFI when the monitored rail reaches its trip point. For example, a +3.3V supply can be monitored for undervoltage at 3.0V by setting R1/R2 to yield 1.25V at PFI when input = 3.0V. PFO (pin 5) then asserts low to signal the fault.
MAX805LESA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- 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
MAX805LESA+ FAQ
1.How can I place an order for MAX805LESA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX805LESA+ 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 MAX805LESA+ reliable?
The price and inventory of MAX805LESA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX805LESA+ is usually 5 days.
3.What payment methods are accepted for MAX805LESA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX805LESA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX805LESA+?
MAX805LESA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX805LESA+ 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 MAX805LESA+?
For technical support, including MAX805LESA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX805LESA+ requirements.
6.How does Aetrix verify that MAX805LESA+ is sourced from the original manufacturer or authorized distributors?
All MAX805LESA+ 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 MAX805LESA+ meets industry standards.
7.What is the process for return or replacement of MAX805LESA+?
All MAX805LESA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX805LESA+, 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 MAX805LESA+ part is unused and in its original packaging.
Return procedure for MAX805LESA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MAX805LESA+ Tags
-
MIC826SYMT-TR
Microchip Technology
-
APX803S-31SA-7
Diodes Incorporated
-
APX803L20-29SA-7
Diodes Incorporated
-
TPS3828-33DBVR
Texas Instruments
-
V6340RSP3B+
EM Microelectronic
-
EM6325CXSP5B-2.9+
EM Microelectronic
-
MCP120T-300I/TT
Microchip Technology
-
MCP130T-315I/TT
Microchip Technology
-
MCP120T-475I/TT
Microchip Technology
-
MCP111T-300E/TT
Microchip Technology
-
MCP120T-315I/TT
Microchip Technology
-
MCP809T-315I/TT
Microchip Technology
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
