My Inquiry
My Account
Analog Devices Inc./Maxim Integrated MAX805LCSA
- Part No.:
- MAX805LCSA
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX805LCSA.pdf
- Description:
- IC SUPERVISOR MAX805 MPU
- Quantity:
- Payment:
- Shipping:
Inventory:171
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
MAX805LCSA from Maxim Integrated is a microprocessor supervisory circuit providing active-high reset, battery-backup switchover, watchdog timer, and power-fail detection in a single 8-pin SOIC package. It asserts RESET at 4.65V threshold with 200ms pulse width, supports VCC down to 1.1V for valid reset output, draws only 200µA quiescent current, and enables CMOS RAM retention during brownout. It is used in battery-powered controllers requiring reliable power monitoring and nonvolatile memory backup.
For engineers reviewing the MAX805LCSA datasheet, MAX805LCSA pinout, MAX805LCSA application, or MAX805LCSA equivalent, this page delivers verified technical context, exact pin functions, real-world use cases, and validated alternative options - all grounded in Maxim's official specifications for the MAX805L family.
Technical Context
The MAX805LCSA integrates four core functions: (1) an active-high RESET output triggered by VCC falling below 4.65V or watchdog timeout (1.6s), (2) automatic battery switchover to VOUT when VCC drops below threshold and VBATT exceeds VCC by ≥20mV, (3) a 1.25V precision reference-based power-fail comparator (PFI/PFO), and (4) guaranteed RESET assertion down to VCC = 1.1V. Its internal PMOS switch connects VOUT to VCC (5Ω) or VBATT (80Ω) based on voltage conditions.
Unlike the MAX690A/MAX802L, the MAX805L features RESET (active-high) instead of RESET (active-low), enabling direct interface with µPs like the Intel 80C51 that require high-true reset signals. The watchdog timer clears on any WDI edge, reset assertion, or high-impedance state, and PFO is forced low during battery-backup mode to conserve current.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65V ±150mV - ensures reliable reset initiation before +5V supply collapse affects µP operation |
| Reset Pulse Width | 200ms typical - provides sufficient time for µP initialization and peripheral stabilization |
| Watchdog Timeout | 1.6s ±0.65s - detects µP lockup without requiring frequent software servicing |
| Quiescent Supply Current | 200µA max at VCC = 5V - minimizes standby power in always-on systems |
| Battery-Backup Current | 50nA typical at VCC = 0V, VBATT = 2.8V - extends lithium battery life beyond 10 years |
| VCC Operating Range | 1.1V to 5.5V - guarantees functional RESET output even during deep brownout |
| Power-Fail Reference | 1.25V ±25mV - enables accurate undervoltage warning for non-5V rails via external divider |
Pinout & Package
MAX805LCSA is housed in an 8-pin SOIC (Small Outline Integrated Circuit) package, 3.9mm × 4.9mm body, 1.27mm pitch, RoHS-compliant lead-free option available (suffix "+"). Pin 1 is marked with a beveled corner or dot.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | CMOS RAM supply output | Switches between VCC (5Ω path) and VBATT (80Ω path); maintains RAM voltage during power loss |
| 2 - VCC | +5V main supply input | Primary power source; reset generation and internal logic powered from this rail |
| 3 - GND | Ground reference | Common return for all analog and digital circuitry; must be low-impedance |
| 4 - PFI | Power-fail comparator input | Monitors divided-down supply voltage; trips PFO low when <1.25V |
| 5 - PFO | Power-fail open-drain output | Signals impending supply failure to µP interrupt line; pulled low during battery-backup mode |
| 6 - WDI | Watchdog timer input | Edge-sensitive; resets timer on rising/falling transition; floating disables watchdog |
| 7 - RESET | Active-high reset output | Drives high during normal operation; pulses high for 200ms on fault - compatible with Intel 80C51 |
| 8 - VBATT | Backup battery input | Provides switchover power; diode-isolated from substrate; max 4.80V allowed per spec |
Key Features
| Feature | Design Value |
|---|---|
| Active-High RESET Output | Enables direct connection to µPs requiring high-true reset (e.g., Intel 80C51), eliminating external inverters |
| Guaranteed Reset Down to VCC = 1.1V | Ensures deterministic system recovery even during severe brownout where other supervisors fail |
| Low-Battery Switchover Hysteresis | 40mV (20mV up/down) prevents oscillation during slow VCC decay near threshold |
| Power-Fail Comparator Accuracy | ±2% over temperature (for MAX802L/M variants; MAX805L inherits same 1.25V reference tolerance) |
| Ultra-Low Backup Mode Current | 50nA typical - reduces annual battery drain to <0.5µAh, supporting >10-year shelf life |
Applications
| Battery-Powered Controllers | Intelligent Instruments |
|---|---|
Use Scenario: Portable data loggers using lithium coin cells and SRAM retain configuration during field deployment. IC Role / Device Role / Timing Role: MAX805LCSA monitors main 5V rail, switches SRAM to 3.3V backup battery upon dropout, and asserts RESET to halt logging until stable power returns. Use Value: Prevents SRAM corruption and ensures deterministic restart after intermittent power loss - critical for regulatory compliance in industrial logging. |
Use Scenario: Handheld multimeters with EEPROM calibration storage and real-time clock. IC Role / Device Role / Timing Role: MAX805LCSA provides active-high reset to the µP, detects AC adapter removal via PFI, and triggers PFO interrupt to save settings before backup power depletes. Use Value: Enables seamless transition to backup power and preserves calibration integrity without firmware intervention. |
| Critical µP Power Monitoring | Embedded Telematics Units |
Use Scenario: Industrial PLC modules operating in unregulated 5V environments with voltage ripple and transient dropouts. IC Role / Device Role / Timing Role: MAX805LCSA continuously monitors VCC, asserts RESET within 2µs of threshold breach, and disables watchdog if WDI is three-stated during safe shutdown. Use Value: Eliminates spurious resets caused by noise while guaranteeing response to true brownout - meeting IEC 61000-4-11 immunity requirements. |
Use Scenario: Automotive telematics control units powered from vehicle battery with wide input range (9–16V) and cold-crank dips. IC Role / Device Role / Timing Role: MAX805LCSA interfaces with a 5V LDO; its 4.65V reset threshold aligns with LDO dropout, and RESET signal holds µP in reset until post-crank stabilization. Use Value: Prevents firmware crash during engine start-up by extending reset hold time beyond LDO recovery delay. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX802LCSA | Active-low RESET output; identical 4.65V threshold, 200ms pulse, and battery switchover | Requires external inverter for µPs needing active-high reset; otherwise pin- and function-compatible | Select MAX802LCSA only if existing design uses active-low reset logic or space for inverter exists |
| MAX813LCSA | Same active-high RESET, 4.65V threshold, and 200ms pulse; adds manual reset input (MR) and watchdog output (WDO) | Supports user-initiated reset and independent watchdog status reporting - useful in serviceable field equipment | Choose MAX813LCSA when MR or WDO functionality is required; otherwise MAX805LCSA offers lower cost and simpler BOM |
Compared with MAX802LCSA and MAX813LCSA, the MAX805LCSA provides the minimal feature set optimized for cost-sensitive, space-constrained designs where active-high reset is mandatory and manual reset or watchdog status reporting is unnecessary.
Availability
MAX805LCSA is available at Aetrix Electronics and suitable for battery-powered controllers, intelligent instruments, critical µP power monitoring, embedded telematics units, and portable medical devices requiring stable component supply across industrial temperature ranges.
Supply support for MAX805LCSA 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, mixed-signal, and power management ICs for industrial, automotive, and computing applications.
The MAX805L belongs to Maxim's microprocessor supervisory circuit product line, engineered specifically to replace discrete reset generators and battery switchover circuits in µP-based systems demanding high reliability and low power.
FAQ
What is the reset output polarity of the MAX805LCSA?
The MAX805LCSA features an active-high RESET output - it drives high during normal operation and pulses high for 200ms upon reset trigger. This differs from the MAX690A/MAX802L's active-low RESET and directly interfaces with µPs like the Intel 80C51 that require high-true reset signals. The MAX805LCSA datasheet confirms RESET remains valid down to VCC = 1.1V.
Does the MAX805LCSA support battery-backup switchover, and what are the voltage limits?
Yes, the MAX805LCSA supports automatic battery-backup switchover: when VCC falls below 4.65V and VBATT exceeds VCC by ≥20mV, it connects VBATT to VOUT through an 80Ω PMOS switch. Per Maxim's specification, the maximum allowable VBATT voltage is 4.80V to prevent substrate diode conduction. The device draws only 50nA in backup mode, enabling multi-year lithium battery life.
How does the watchdog timer in the MAX805LCSA operate, and can it be disabled?
The MAX805LCSA watchdog timer times out after 1.6s if no edge is detected on WDI. It clears on any rising or falling edge, reset assertion, or high-impedance (three-state) condition. To disable it, leave WDI floating or connect it to a high-impedance buffer - the internal 35% VCC bias ensures a non-logic level that halts timing. Driving WDI permanently high or low triggers reset every ~1.8s (tWD + tRS).
What is the accuracy of the power-fail comparator in the MAX805LCSA?
The MAX805LCSA uses a precision 1.25V internal reference for its PFI comparator, with ±25mV tolerance (±2%) over temperature - matching the MAX802L/M specification cited in the datasheet. This enables accurate power-fail warning for non-5V rails via external resistor dividers. PFO is forced low during battery-backup mode to minimize current draw from VBATT.
Is the MAX805LCSA pin-compatible with other parts in the MAX80xL family?
Yes, the MAX805LCSA is pin-compatible with MAX690A, MAX802L, and MAX813L in the 8-pin SOIC package. All share identical pinout: VOUT, VCC, GND, PFI, PFO, WDI, RESET, VBATT. However, RESET polarity differs - MAX805LCSA outputs active-high RESET, while MAX690A/MAX802L output active-low RESET. No PCB changes are needed beyond adjusting reset logic polarity in firmware or external circuitry.
MAX805LCSA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Bulk
- 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:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX805LCSA FAQ
1.How can I place an order for MAX805LCSA through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX805LCSA 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 MAX805LCSA reliable?
The price and inventory of MAX805LCSA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX805LCSA is usually 5 days.
3.What payment methods are accepted for MAX805LCSA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX805LCSA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX805LCSA?
MAX805LCSA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX805LCSA 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 MAX805LCSA?
For technical support, including MAX805LCSA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX805LCSA requirements.
6.How does Aetrix verify that MAX805LCSA is sourced from the original manufacturer or authorized distributors?
All MAX805LCSA 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 MAX805LCSA meets industry standards.
7.What is the process for return or replacement of MAX805LCSA?
All MAX805LCSA units undergo pre-shipment inspection (PSI). If there is an issue with MAX805LCSA, 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 MAX805LCSA part is unused and in its original packaging.
Return procedure for MAX805LCSA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MAX805LCSA 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…
