My Inquiry
My Account
Analog Devices Inc./Maxim Integrated MAX802LCSA+T
- Part No.:
- MAX802LCSA+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX802LCSA+T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,872
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
MAX802LCSA+T from Maxim Integrated is a microprocessor supervisory circuit providing reset generation, battery-backup switchover, watchdog timer, and power-fail detection for +5V systems. It asserts active-low RESET during power-up, brownout (VCC < 4.65V), and watchdog timeout (1.6s), delivers VOUT from VCC or VBATT with 5Ω/80Ω PMOS switches, and monitors PFI against 1.25V reference for low-battery or supply-fail warning in embedded controllers.
For engineers reviewing the MAX802LCSA+T datasheet, MAX802LCSA+T pinout, MAX802LCSA+T application, or MAX802LCSA+T equivalent, key selection criteria include guaranteed RESET assertion down to VCC = 1V, ±2% power-fail accuracy, 200μA quiescent current (200nA in backup mode), and compatibility with lithium batteries (3.0–3.6V) and SuperCap backup sources.
Technical Context
The MAX802LCSA+T integrates four independent functions: a precision voltage monitor with 4.65V reset threshold and 40mV hysteresis; a 1.6s watchdog timer cleared by WDI edges or RESET assertion; a dual-path battery switchover circuit that connects VOUT to VCC above threshold (5Ω switch) or to VBATT below threshold (80Ω switch); and a 1.25V reference-based power-fail comparator driving open-drain PFO.
Its internal architecture isolates the PFI comparator from reset logic-enabling flexible use as undervoltage detector for unregulated rails-and disables the comparator when VBATT powers VOUT to conserve battery current. The device guarantees RESET pulse width of 140–280ms and supports manual reset disable via floating WDI.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65V ±2% (VCC falling); ensures reliable μP reset before +5V rail collapse |
| Reset Pulse Width | 200ms typ.; meets minimum reset hold time for Intel 80C51, Z80, and similar μPs |
| Watchdog Timeout | 1.6s ±37.5%; provides deterministic recovery window for firmware hang detection |
| Quiescent Current | 200μA max at VCC = 5V; enables long-term operation in battery-backed RAM systems |
| Battery-Backup Current | 50nA typ. at VCC = 0V, VBATT = 2.8V; extends lithium cell life beyond 10 years |
| VOUT Switch Resistance | 5Ω (VCC path), 80Ω (VBATT path); limits voltage drop to ≤25mV @ 5mA, ≤200mV @ 250μA |
| Power-Fail Accuracy | ±2% over temp; enables precise early-warning detection of +5V regulator dropout |
Pinout & Package
MAX802LCSA+T is housed in an 8-pin SOIC package (SO) with standard 1.27mm pitch, RoHS-compliant lead-free finish (+ suffix), and moisture sensitivity level 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | CMOS RAM supply output | Switches between VCC (5Ω) and VBATT (80Ω) based on reset threshold crossing; delivers regulated backup power without external diodes |
| 2 - VCC | +5V main supply input | Primary power source; powers internal circuitry and triggers reset when falling below 4.65V |
| 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 voltage from unregulated supply; trips PFO low when <1.25V (±1.5%) |
| 5 - PFO | Open-drain power-fail output | Signals impending supply failure to μP interrupt pin; requires external pull-up to VCC or VOUT |
| 6 - WDI | Watchdog timer input | Toggles internal 1.6s timer; floating or high-Z state disables watchdog; edge-sensitive (50ns min pulse) |
| 7 - RESET | Active-low reset output | Drives μP reset pin low for 200ms after power-up/brownout/watchdog timeout; sinks 3.2mA @ 0.4V |
| 8 - VBATT | Backup battery input | Provides switchover source when VCC drops; requires ≥20mV headroom over VCC for connection to VOUT |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed RESET assertion to VCC = 1V | Ensures μP remains held in reset even during deep brownout, preventing erratic execution |
| ±2% power-fail accuracy (MAX802L) | Enables precise prediction of +5V regulator dropout point using external resistor divider on PFI |
| 5Ω VCC-to-VOUT switch | Minimizes voltage drop (<25mV @ 5mA), eliminating need for Schottky diode in RAM supply path |
| 80Ω VBATT-to-VOUT switch | Restricts backup current to <1μA when VCC < VBATT −1V, extending lithium battery lifetime |
| 200μA supply current (active), 50nA (backup) | Supports >5-year operation on CR2032 coin cell in always-on memory retention applications |
Applications
| Battery-Powered Controllers | Critical μP Power Monitoring |
|---|---|
|
Use Scenario: Industrial PLC controller with nonvolatile SRAM retaining configuration data during AC mains loss. IC Role / Device Role / Timing Role: Supervisory IC providing brownout-triggered RESET, seamless VBATT switchover to VOUT, and PFO-driven μP interrupt for graceful shutdown. Use Value: Prevents RAM corruption during 10–500ms AC dropout events using 3.6V lithium battery and 200nA backup current draw. |
Use Scenario: Medical infusion pump requiring fail-safe restart after power interruption. IC Role / Device Role / Timing Role: Reset generator with 4.65V threshold and 200ms pulse width ensuring full μP initialization before motor control activation. Use Value: Guarantees RESET remains asserted until VCC stabilizes above 4.65V and holds for 200ms, eliminating race conditions in safety-critical boot sequence. |
| Intelligent Instruments | Embedded Data Loggers |
|
Use Scenario: Portable multimeter storing calibration coefficients and measurement history in CMOS RAM. IC Role / Device Role / Timing Role: Dual-function supervisor: RESET generator during battery insertion and PFI-based low-battery warning via PFO interrupt. Use Value: Uses internal 1.25V reference to detect battery voltage decay to 3.0V (via R-divider), triggering alert before data loss. |
Use Scenario: Environmental sensor node logging temperature/humidity to SPI FRAM with intermittent solar charging. IC Role / Device Role / Timing Role: Watchdog-enforced firmware supervision and VOUT switchover to supercapacitor during solar panel shading events. Use Value: 1.6s watchdog timeout detects stalled I²C bus communication; 80Ω VBATT switch sustains 250μA RAM load for >30s from 0.1F SuperCap. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX802MCSA+T | 4.40V reset threshold (vs. 4.65V); identical pinout, timing, and backup features | Suitable for +5V ±10% supplies where tighter brownout margin is required | Select when system operates near lower VCC limit (4.5V) and requires earlier reset assertion |
| MAX706SCSA+T | Same 4.65V threshold but adds manual reset input (MR) and lacks PFI/PFO comparator | Used where external pushbutton reset is mandatory and power-fail warning is unnecessary | Choose when board layout includes MR trace and power-fail interrupt capability is omitted |
Compared with MAX802MCSA+T, MAX802LCSA+T provides higher reset threshold for tighter +5V regulation tolerance; compared with MAX706SCSA+T, it offers integrated power-fail detection but omits manual reset-making it optimal for fully autonomous battery-backed systems without user intervention.
Availability
MAX802LCSA+T is available at Aetrix Electronics and suitable for battery-powered controllers, critical μP power monitoring, intelligent instruments, embedded data loggers, and industrial telemetry systems requiring stable component supply across extended product lifecycles.
Supply support for MAX802LCSA+T 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, communications, and computing applications, with emphasis on reliability and integration.
The MAX802L series belongs to Maxim's microprocessor supervisory product line, engineered specifically for robust power monitoring and battery-switchover in space-constrained, long-life embedded systems operating from +5V rails.
FAQ
What is the guaranteed minimum VCC level at which MAX802LCSA+T asserts RESET?
MAX802LCSA+T guarantees RESET remains asserted down to VCC = 1.0V, ensuring the microprocessor stays held in reset during deep brownout conditions. This specification is verified across the full 0°C to +70°C operating temperature range and allows safe operation even as the +5V supply collapses below typical logic thresholds. The device continues asserting RESET until VCC rises above 4.65V and holds for 200ms.
Does MAX802LCSA+T support lithium battery backup, and what voltage range is allowed?
Yes, MAX802LCSA+T supports direct connection of 3.0V to 3.6V lithium batteries to the VBATT pin. The datasheet specifies a maximum allowable VBATT of 4.80V to prevent substrate diode conduction when VCC approaches the reset threshold. At 3.6V VBATT and VCC = 0V, the device draws only 50nA, enabling multi-year operation on standard CR2032 cells in CMOS RAM retention applications.
How does the watchdog timer in MAX802LCSA+T behave if the WDI pin is left unconnected?
When WDI is left floating or connected to a high-impedance three-state buffer, the internal watchdog timer is disabled in MAX802LCSA+T. The device relies solely on power-supply monitoring for reset generation. This behavior is confirmed in the Pin Description section, which states "If WDI is left floating or connected to a high-impedance three-state buffer, the watchdog feature is disabled." No spurious resets occur under this condition.
Can MAX802LCSA+T monitor a negative supply rail, and how is this implemented?
Yes, MAX802LCSA+T can monitor a negative rail using an external resistor divider that references PFI to ground, as shown in Figure 7 of the datasheet. When the negative rail degrades (e.g., −12V becomes −8V), the voltage at PFI rises above 1.25V, causing PFO to transition from low to high. Accuracy depends on PFI input current (≤25nA), resistor tolerance, and VCC stability-but the comparator itself is fully isolated from reset logic, enabling this flexible configuration.
What is the purpose of the 40mV hysteresis in the battery switchover circuit of MAX802LCSA+T?
The 40mV hysteresis between VBATT and VCC prevents oscillatory switching of the VOUT path when VCC falls slowly near the switchover point. Specifically, VBATT connects to VOUT when VCC drops 20mV below VBATT, and VCC reconnects to VOUT only after rising 20mV above VBATT-creating a total 40mV dead band. This eliminates repeated toggling that could cause RAM supply glitches or excessive battery drain during marginal power conditions.
MAX802LCSA+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- 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 Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX802LCSA+T FAQ
1.How can I place an order for MAX802LCSA+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX802LCSA+T 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 MAX802LCSA+T reliable?
The price and inventory of MAX802LCSA+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX802LCSA+T is usually 5 days.
3.What payment methods are accepted for MAX802LCSA+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX802LCSA+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX802LCSA+T?
MAX802LCSA+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX802LCSA+T 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 MAX802LCSA+T?
For technical support, including MAX802LCSA+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX802LCSA+T requirements.
6.How does Aetrix verify that MAX802LCSA+T is sourced from the original manufacturer or authorized distributors?
All MAX802LCSA+T 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 MAX802LCSA+T meets industry standards.
7.What is the process for return or replacement of MAX802LCSA+T?
All MAX802LCSA+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX802LCSA+T, 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 MAX802LCSA+T part is unused and in its original packaging.
Return procedure for MAX802LCSA+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MAX802LCSA+T 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…
