My Inquiry
My Account
Analog Devices Inc./Maxim Integrated MAX805SCSA+
- Part No.:
- MAX805SCSA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- -
- Datasheet:
-
MAX805SCSA+.pdf
- Description:
- IC SUPERVISOR MPU 8-SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,668
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
MAX805SCSA+ from Maxim Integrated is a 3.3V microprocessor supervisory circuit with active-high open-drain RESET output, 2.925V reset threshold (S-suffix), 200ms reset timeout, watchdog timer (1.6s), and battery-backup switchover-designed for embedded controllers and battery-powered systems requiring reliable power monitoring and RAM retention.
For engineers reviewing the MAX805SCSA+ datasheet, MAX805SCSA+ pinout, MAX805SCSA+ application, or MAX805SCSA+ equivalent, this page delivers verified specifications, validated pin functions, confirmed operating conditions (VCC = 3.02V to 5.5V, TA = –40°C to +85°C), and real-world design implications for brownout recovery, power-fail warning, and manual reset integration.
Technical Context
The MAX805SCSA+ integrates a precision reset comparator with ±4% threshold tolerance (2.925V nominal), a 1.6s watchdog timer that clears on WDI edge transitions, and a dual-path power switch enabling VOUT to connect to VCC above 2.925V or to VBATT below 2.40V (VSW) while supporting VBATT > VCC operation. It features a dedicated PFI/PFO pair for independent power-fail detection at 1.237V with 10mV hysteresis.
Its active-high open-drain RESET output requires external pull-up and asserts for ≥200ms after VCC rise, MR release, or watchdog timeout; the device guarantees RESET assertion down to VCC = 1.0V and supports battery leakage as low as 0.4µA in backup mode-enabling long-term CMOS RAM retention during main supply failure.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 2.925V (VCC falling), ±4% tolerance - ensures reset triggers before 3.3V supply drops below system's 10% undervoltage margin (2.97V). |
| Reset Timeout Period | 200ms (typical) - provides sufficient hold time for µP initialization and clock stabilization after power recovery. |
| Watchdog Timeout | 1.6s - detects µP lockup without requiring software intervention; cleared by any WDI edge. |
| VCC Supply Current | 40µA (typ, VCC < 3.6V) - enables ultra-low-power operation in always-on monitoring applications. |
| Battery Supply Current | 0.4µA (max, TA = –40°C to +85°C) - minimizes drain on lithium backup cells during extended standby. |
| Power-Fail Threshold | 1.237V at PFI input - allows precise monitoring of auxiliary rails via resistor divider without loading. |
| Operating Temperature | –40°C to +85°C - qualified for industrial embedded environments including portable instrumentation and remote controllers. |
Pinout & Package
MAX805SCSA+ is housed in an 8-pin SOIC package (SO, 150mil width), RoHS-compliant (indicated by '+' suffix), with 0.050" pitch and gull-wing leads. Thermal performance: 471mW max power dissipation at +70°C, derating 5.88mW/°C above.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | Switched Output Rail | Connects to CMOS RAM VDD; automatically switches between VCC and VBATT based on voltage comparison - no external diode required. |
| 2 - VCC | Main Power Input | Accepts 3.02V–5.5V supply; powers internal circuitry and sources VOUT when above reset threshold and VSW. |
| 3 - GND | Ground Reference | Common return for all analog and digital functions; substrate tied to higher of VCC/VBATT - must be floated in hybrid assemblies. |
| 4 - PFI | Power-Fail Input | Monitors auxiliary rail via resistor divider; trips PFO low when input falls below 1.237V - fully isolated from reset path. |
| 5 - PFO | Power-Fail Output | Active-low open-drain signal indicating PFI undervoltage or VCC drop below 2.40V - can drive MR on MAX704/MAX806. |
| 6 - WDI | Watchdog Input | Edge-sensitive trigger (rising/falling); resets watchdog timer on transition - cannot be disabled; ties high/low causes 1.6s timeout. |
| 7 - RESET | Active-High Reset Output | Open-drain output requiring external pull-up; asserts high for ≥200ms after reset condition - compatible with bidirectional µP reset I/O. |
| 8 - VBATT | Battery Backup Input | Supports 3.6V lithium cell; connects to VOUT when VCC < 2.40V; tolerates VBATT > VCC continuously - enables seamless switchover. |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed RESET assertion to VCC = 1V | Ensures fail-safe reset even during deep brownout - prevents µP execution from corrupted memory or unstable clocks. |
| Battery-backup switchover with 2.40V VSW | Triggers switchover before VOUT drops below 2.0V RAM retention threshold - maximizes battery life and data integrity. |
| 40µA VCC supply current (typ) | Reduces system quiescent power - critical for battery-operated devices with multi-year standby requirements. |
| 1.237V PFI threshold with 10mV hysteresis | Enables accurate, noise-immune monitoring of secondary supplies (e.g., 5V, –5V, or analog rails) using simple resistor dividers. |
| 200ms reset timeout with restart-on-brownout | Prevents premature µP release during transient dips - each VCC dip below threshold restarts the timer for robust recovery. |
Applications
| Battery-Powered Embedded Controller | Intelligent Portable Instrument |
|---|---|
|
Use Scenario: A handheld multimeter operates from a 3.3V Li-ion battery and retains calibration data in CMOS RAM during sleep mode. IC Role / Device Role / Timing Role: MAX805SCSA+ monitors VCC, asserts RESET on brownout, switches VOUT to VBATT to preserve RAM, and signals low-battery via PFO. Use Value: Enables 10+ year data retention with single 3.6V coin cell; eliminates need for external diode-based backup circuitry. |
Use Scenario: An industrial pH sensor uses a 3.3V supply and must maintain real-time clock and sensor configuration across power interruptions. IC Role / Device Role / Timing Role: MAX805SCSA+ provides 200ms reset hold, 1.6s watchdog supervision, and automatic VCC/VBATT switchover for RTC backup. Use Value: Guarantees deterministic µP restart and uninterrupted timekeeping - no firmware-level reset management required. |
| Critical µP Power Monitoring | Portable Medical Device |
|
Use Scenario: A patient monitor's main controller relies on stable 3.3V rail; transient glitches must not cause spurious resets. IC Role / Device Role / Timing Role: MAX805SCSA+ rejects sub-40µs VCC transients (100mV overdrive) and asserts RESET only on sustained undervoltage. Use Value: Prevents false reboots during EMI events or switching regulator noise - improves clinical reliability and audit trail integrity. |
Use Scenario: A wearable ECG recorder runs on rechargeable battery and must retain last 30 seconds of waveform upon power loss. IC Role / Device Role / Timing Role: MAX805SCSA+ triggers controlled shutdown via PFO interrupt and maintains RAM power via VBATT switchover. Use Value: Achieves zero-data-loss power fail response - meets IEC 62304 Class B software safety requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX805TCSA+ | Reset threshold 3.075V (T-suffix), same package and pinout - tighter 3.3V ±5% supply tolerance support. | Preferred for systems with regulated 3.3V ±5% rails where earlier reset assertion is acceptable. | Select MAX805TCSA+ when main supply stability exceeds ±5%; otherwise MAX805SCSA+ better matches ±10% 3.3V designs. |
| MAX805RCSA+ | Reset threshold 2.625V (R-suffix), identical timing and interface - optimized for 3.0V ±10% systems. | Suitable for legacy 3.0V µP platforms or mixed-voltage systems needing lower trip point. | Choose MAX805RCSA+ only if VCC nominal is 3.0V and brownout margin must extend below 2.7V. |
Compared with MAX805TCSA+ and MAX805RCSA+, the MAX805SCSA+ offers the optimal reset threshold (2.925V) for modern 3.3V ±10% supplies - balancing early fault detection against nuisance tripping during normal regulation ripple, while maintaining full functional and pin compatibility across the MAX805 family.
Availability
MAX805SCSA+ is available at Aetrix Electronics and suitable for battery-powered computers and controllers, intelligent instruments, and critical µP power monitoring requiring stable component supply, long-lifecycle support, and guaranteed RoHS compliance.
Supply support for MAX805SCSA+ 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, medical, and communications applications.
The MAX805SCSA+ belongs to Maxim's microprocessor supervisory circuit product line, engineered specifically for reliable power monitoring, reset generation, and battery-backed RAM retention in 3.0V/3.3V embedded systems.
FAQ
What is the exact reset threshold voltage for MAX805SCSA+?
The MAX805SCSA+ has a nominal reset threshold of 2.925V (S-suffix), specified as 2.85V (min) to 3.00V (max) for VCC falling, with ±4% tolerance. This value is guaranteed across –40°C to +85°C and ensures reset assertion before 3.3V supply drops below 2.97V - matching typical 3.3V ±10% system tolerances.
Does MAX805SCSA+ support battery voltage higher than VCC?
Yes, MAX805SCSA+ explicitly supports VBATT exceeding VCC during normal operation. Its internal battery switchover circuit activates when VCC falls below 2.40V (VSW), connecting VBATT to VOUT through a 140Ω switch - enabling use of standard 3.6V lithium cells with 3.3V main supplies without external level-shifting.
How does the watchdog timer function in MAX805SCSA+?
The MAX805SCSA+ watchdog timer has a fixed 1.6s timeout (1.12s to 2.24s over temperature). It clears on any rising or falling edge at WDI and triggers RESET if WDI remains static beyond timeout. Unlike older families, the watchdog cannot be disabled - ensuring continuous supervision of µP activity in safety-critical applications.
What is the purpose of the PFI and PFO pins on MAX805SCSA+?
PFI is a dedicated 1.237V reference input for monitoring auxiliary power rails via resistor dividers; PFO is its open-drain output that goes low when PFI falls below threshold or VCC drops below 2.40V. These pins operate independently of the reset comparator - allowing simultaneous power-fail warning and reset control without shared timing constraints.
Can MAX805SCSA+ operate without a backup battery?
Yes, MAX805SCSA+ can operate without a backup battery: connect both VBATT and VOUT to VCC. However, battery-backup functionality (RAM retention during power loss) is disabled. For non-battery applications, consider alternatives like MAX706SCSA+ which omit switchover circuitry and reduce cost and quiescent current further.
MAX805SCSA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- *
- Package/Case:
- -
- Packaging:
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- -
- Number of Voltages Monitored:
- -
- Voltage - Threshold:
- -
- Output:
- -
- Reset:
- -
- Reset Timeout:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- -
- Supplier Device Package:
- -
MAX805SCSA+ FAQ
1.How can I place an order for MAX805SCSA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX805SCSA+ 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 MAX805SCSA+ reliable?
The price and inventory of MAX805SCSA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX805SCSA+ is usually 5 days.
3.What payment methods are accepted for MAX805SCSA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX805SCSA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX805SCSA+?
MAX805SCSA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX805SCSA+ 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 MAX805SCSA+?
For technical support, including MAX805SCSA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX805SCSA+ requirements.
6.How does Aetrix verify that MAX805SCSA+ is sourced from the original manufacturer or authorized distributors?
All MAX805SCSA+ 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 MAX805SCSA+ meets industry standards.
7.What is the process for return or replacement of MAX805SCSA+?
All MAX805SCSA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX805SCSA+, 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 MAX805SCSA+ part is unused and in its original packaging.
Return procedure for MAX805SCSA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MAX805SCSA+ 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…
