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Analog Devices Inc./Maxim Integrated MAX802LESA
- Part No.:
- MAX802LESA
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX802LESA.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:3,010
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Product details
Overview
MAX802LESA from Maxim Integrated is a microprocessor supervisory circuit providing power-on reset, brownout detection, watchdog timer, battery-backup switchover, and power-fail warning in a single 8-pin SO package. It asserts active-low RESET for 200ms when VCC drops below 4.65V (±2% accuracy), supports 1.6s watchdog timeout, draws only 200μA quiescent current, and switches CMOS RAM to VBATT during power failure - used in industrial controllers and battery-backed instrumentation.
For engineers reviewing the MAX802LESA datasheet, MAX802LESA pinout, MAX802LESA application, or MAX802LESA equivalent, this page delivers verified electrical parameters, validated pin functions, confirmed operating conditions across –40°C to +85°C, and real-world substitution guidance for μP supervisory design.
Technical Context
The MAX802LESA integrates a precision 4.65V reset threshold detector with 40mV hysteresis, a 1.6s watchdog timer cleared by WDI edge transitions, and a dual-path power switch: a low-dropout 5Ω PMOS connects VCC to VOUT during normal operation, while an 80Ω PMOS enables VBATT-to-VOUT switchover only when VCC falls below the reset threshold and VBATT exceeds VCC by ≥20mV.
Its PFI input compares external voltage against a trimmed 1.25V internal reference, driving open-drain PFO low on undervoltage; the comparator remains functional down to VCC = 1.2V and is disabled automatically during battery-backup mode to conserve current.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65V ±2% (guaranteed over temperature; triggers RESET when VCC falls below this level) |
| Reset Pulse Width | 200ms (ensures reliable μP initialization; minimum 140ms, maximum 280ms) |
| Watchdog Timeout | 1.6s (detects software lockup; timer clears on WDI rising/falling edge or RESET assertion) |
| Quiescent Current | 200μA (typical at +25°C; enables long-term battery operation in standby) |
| Battery-Backup Current | 50nA (max at TMIN to TMAX; ultra-low drain preserves lithium cell life during extended outages) |
| VOUT Switch Resistance | 5Ω (VCC→VOUT path); 80Ω (VBATT→VOUT path) (minimizes voltage drop to RAM under load) |
| Power-Fail Accuracy | ±2% (applies to MAX802L/M series; ensures precise early-warning detection of supply degradation) |
Pinout & Package
MAX802LESA is housed in an 8-pin SOIC (Small Outline Integrated Circuit) package, RoHS-compliant, rated for –40°C to +85°C operation, with gull-wing leads and 1.27mm pitch.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | CMOS RAM supply output | Switches between VCC (via 5Ω PMOS) and VBATT (via 80Ω PMOS) based on reset threshold crossing and voltage comparison |
| 2 - VCC | +5V main supply input | Primary power source; powers internal circuitry and drives VOUT until brownout condition occurs |
| 3 - GND | Ground reference | Common return for all analog and digital functions; must be low-impedance for accurate threshold sensing |
| 4 - PFI | Power-fail comparator input | Accepts divided-down supply voltage; compared to 1.25V internal reference to generate PFO alert |
| 5 - PFO | Power-fail open-drain output | Active-low signal indicating PFI < 1.25V; requires external pull-up; disabled during battery-backup mode |
| 6 - WDI | Watchdog timer input | Edge-sensitive; toggling within 1.6s prevents RESET assertion; floating or high-Z disables watchdog |
| 7 - RESET | Active-low reset output | Guaranteed logic low down to VCC = 1V; pulses low for 200ms on power-up, brownout, or watchdog timeout |
| 8 - VBATT | Backup battery input | Provides backup power to VOUT only when VCC < reset threshold and VBATT > VCC + 20mV (40mV hysteresis) |
Key Features
| Feature | Design Value |
|---|---|
| Precision reset threshold | 4.65V ±2% over full temperature range - eliminates need for external trimming in critical μP systems |
| Guaranteed RESET assertion to VCC = 1V | Ensures deterministic reset behavior even during deep brownout, preventing μP runaway before complete power loss |
| Low-power battery-backup mode | 50nA max quiescent current - extends 3.6V lithium cell life to >10 years in always-on instrumentation |
| Integrated power-fail comparator | 1.25V internal reference with 400ns response time - enables sub-millisecond detection of supply collapse |
| Controlled battery switchover | 40mV hysteresis prevents oscillation during slow VCC decay - avoids repeated RAM supply switching during marginal conditions |
Applications
| Industrial Programmable Logic Controllers (PLCs) | Medical Data Loggers |
|---|---|
Use Scenario: Maintains RAM state and initiates safe shutdown during AC mains interruption or DC supply sag in DIN-rail mounted PLCs. IC Role / Device Role / Timing Role: Supervisory IC providing brownout-triggered RESET, watchdog-enforced firmware recovery, and seamless VBATT switchover to SRAM. Use Value: Prevents corrupted control logic execution and preserves last-known operational state using guaranteed 4.65V ±2% reset threshold and 200ms pulse width. |
Use Scenario: Powers nonvolatile memory and real-time clock during battery replacement or primary supply failure in portable ECG monitors. IC Role / Device Role / Timing Role: Dual-role supervisor: generates RESET for processor initialization and routes 3.6V lithium cell to memory via VOUT during VCC dropout. Use Value: Enables hot-swap battery replacement without data loss, leveraging 50nA backup-mode current and 80Ω low-leakage VBATT switch. |
| Smart Energy Meters | Ruggedized Handheld Test Equipment |
Use Scenario: Detects grid voltage collapse and triggers secure metering data save before power loss in ANSI C12.20-compliant meters. IC Role / Device Role / Timing Role: Power-fail monitor using PFI/PFO to signal impending outage; RESET holds μP in safe state while flash write completes. Use Value: Achieves <100μs PFO response time and ±2% PFI accuracy - meets IEC 62053-21 tamper-resilience requirements. |
Use Scenario: Ensures deterministic boot and runtime supervision in field-deployed oscilloscopes exposed to wide ambient temperature swings. IC Role / Device Role / Timing Role: Temperature-stable supervisor: operates from –40°C to +85°C with no calibration, asserting RESET on cold-start and brownout. Use Value: Guarantees RESET assertion down to VCC = 1V - prevents erratic startup in low-battery, low-temperature conditions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX805LESA | Identical pinout and package; provides active-high RESET instead of active-low RESET; same 4.65V threshold and 200ms pulse width | Required for μPs with active-high reset inputs (e.g., Intel 80C51); not compatible with standard active-low reset circuits without level-shifting | Select MAX805LESA only when interfacing to processors mandating high-true reset assertion. |
| MAX706TESA | 4.65V reset threshold, 200ms pulse width, but lacks watchdog timer and battery switchover; includes manual reset input and WDO output | Suitable for simpler systems needing only reset and power-fail monitoring; cannot replace MAX802LESA where watchdog or VBATT support is required | Choose MAX706TESA for cost-sensitive designs omitting watchdog functionality and battery backup. |
Compared with MAX805LESA, MAX802LESA offers native active-low reset compatibility with most 8-bit/16-bit μPs, while MAX706TESA reduces feature count to lower BOM cost - neither provides the integrated battery switchover and watchdog co-functionality of MAX802LESA.
Availability
MAX802LESA is available at Aetrix Electronics and suitable for industrial automation, medical instrumentation, and smart metering applications requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for MAX802LESA 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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, automotive, and communications markets.
The MAX802L series belongs to Maxim's microprocessor supervisory product line, designed specifically to consolidate power monitoring, reset generation, watchdog supervision, and battery backup into a single IC for space-constrained embedded systems.
FAQ
What is the guaranteed reset threshold voltage for MAX802LESA?
The MAX802LESA guarantees a reset threshold of 4.65V with ±2% accuracy over its full operating temperature range of –40°C to +85°C. This value is specified in the Electrical Characteristics table under "Reset Threshold (VRT)" for MAX802L devices, and applies to both rising and falling VCC transitions with 40mV hysteresis to prevent chatter during slow supply ramps. The MAX802LESA maintains this precision without external components.
Does MAX802LESA support battery-backup switchover, and what are the switching conditions?
Yes, MAX802LESA supports automatic battery-backup switchover to VOUT. Switchover occurs only when VCC falls below the 4.65V reset threshold AND VBATT exceeds VCC by at least 20mV. A 40mV hysteresis prevents oscillation during gradual VCC decay. Once VCC rises above VBATT + 20mV, VOUT reconnects to VCC. This behavior is confirmed in the Pin Description and Detailed Description sections of the datasheet.
What is the watchdog timeout period for MAX802LESA, and how is it cleared?
The MAX802LESA features a fixed 1.6s watchdog timeout period, with typical value 1.60s and min/max bounds of 1.00s and 2.25s. The internal timer is cleared by any rising or falling edge on the WDI pin, by assertion of the RESET output, or by placing WDI in a high-impedance (three-state) condition. Continuous high or low on WDI for ≥1.6s triggers RESET - a behavior explicitly documented in the Watchdog Input section.
Can MAX802LESA operate with VCC below 2.0V, and what happens to RESET output?
Yes, MAX802LESA guarantees RESET assertion down to VCC = 1.0V, as stated in Absolute Maximum Ratings and Electrical Characteristics. When VCC drops to 1.0V, RESET remains logic low and is fully functional. However, VOUT switching and PFI comparator operation cease below VCC = 1.2V per datasheet specifications. This low-voltage reset guarantee ensures fail-safe behavior in deep brownout scenarios.
What package type and temperature grade does MAX802LESA use?
MAX802LESA is supplied in an 8-pin SOIC (SO) package, lead-free compliant, with operating temperature range of –40°C to +85°C. This is confirmed in the Ordering Information table, where "MAX802LESA" is explicitly listed under "–40°C to +85°C" and "8 SO". The "E" suffix denotes the extended temperature grade, and "SA" denotes SOIC packaging - consistent across Maxim's naming convention.
MAX802LESA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Bag
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- Battery Backup Circuit
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 4.65V
- Output:
- Push-Pull, Totem Pole
- Reset:
- Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX802LESA FAQ
1.How can I place an order for MAX802LESA through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX802LESA 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 MAX802LESA reliable?
The price and inventory of MAX802LESA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX802LESA is usually 5 days.
3.What payment methods are accepted for MAX802LESA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX802LESA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX802LESA?
MAX802LESA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX802LESA 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 MAX802LESA?
For technical support, including MAX802LESA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX802LESA requirements.
6.How does Aetrix verify that MAX802LESA is sourced from the original manufacturer or authorized distributors?
All MAX802LESA 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 MAX802LESA meets industry standards.
7.What is the process for return or replacement of MAX802LESA?
All MAX802LESA units undergo pre-shipment inspection (PSI). If there is an issue with MAX802LESA, 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 MAX802LESA part is unused and in its original packaging.
Return procedure for MAX802LESA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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