My Inquiry
My Account
Analog Devices Inc./Maxim Integrated MAX794CSE+
- Part No.:
- MAX794CSE+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX794CSE+.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,261
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
MAX794CSE+ from Maxim Integrated is a 16-pin SOIC microprocessor supervisory circuit designed for +3.0V/+3.3V systems, providing adjustable reset threshold via external resistor divider, backup-battery switchover (VBATT > VCC supported), and integrated watchdog timer with 1.6s timeout. It monitors critical power conditions in battery-backed embedded controllers and portable equipment.
For engineers reviewing the MAX794CSE+ datasheet, MAX794CSE+ pinout, MAX794CSE+ application, or MAX794CSE+ equivalent, key selection considerations include its externally programmable reset threshold (1.212V to 1.287V at RESET IN), guaranteed reset assertion down to VCC = 1V, 7ns CE IN-to-CE OUT propagation delay, and battery-freshness seal capability.
Technical Context
The MAX794CSE+ implements an adjustable reset comparator referenced to the RESET IN pin, enabling precise trip-point configuration across 1.212V–5.5V using an external voltage divider. Its internal p-channel MOSFET switch enables seamless VCC-to-battery switchover when VCC falls below VSW (2.30V–2.95V, depending on condition), with 15mV typical hysteresis to prevent oscillation.
It integrates a 1.6s watchdog timer that monitors WDI transitions and asserts WDO low on timeout; WDO can be connected to MR to generate automatic system resets. The chip-enable gating function disables CE IN during reset with ≤10µs hold time to preserve RAM write integrity, and supports both active-high and open-drain output configurations (RESET and RESET).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | Externally adjustable via RESET IN pin (1.212V–1.287V typical input threshold) |
| Watchdog Timeout | 1.6s ±25% - ensures µP activity monitoring without software intervention |
| Battery Switch Threshold | 2.30V–2.95V (VCC falling) - enables reliable switchover to 3.6V lithium battery |
| VCC Supply Current | 46µA–80µA (typical) - ultra-low quiescent current for extended battery life |
| CE Propagation Delay | ≤7ns (max) - preserves timing-critical memory access during normal operation |
| Reset Timeout Period | 200ms (guaranteed) - provides sufficient deassertion hold time for µP initialization |
| Operating Voltage Range | VCC = 2.72V–5.5V, VBATT = –0.3V–+6.0V - supports wide input tolerance and overvoltage battery |
Pinout & Package
MAX794CSE+ is housed in a 16-pin narrow SOIC (SO) package with 1.27mm pitch, RoHS-compliant lead-free finish (+ suffix). Pinout validated per Maxim's official datasheet revision 6 (19-0366).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 OUT | Supply output for CMOS RAM | Switched between VCC and BATT; connects to VCC when VCC > VRST or > VBATT |
| 2 VCC | Main supply input | Primary system power rail (3.0V/3.3V); powers internal logic and drives outputs |
| 3 RESET IN | Adjustable reset threshold input | Accepts external resistor divider to set custom reset point (1.212V–5.5V range) |
| 4 PFI | Power-fail comparator input | Monitors auxiliary voltage; triggers PFO low when below 1.212V threshold |
| 5 BATT ON | External bypass switch driver | Open-drain output indicating battery-active state; drives PMOS/NPN for >75mA loads |
| 6 GND | Ground reference | Common return path for all analog/digital functions and power switches |
| 7 PFO | Power-fail comparator output | Active-low flag signaling VCC < VSW or PFI < VPFT; also enables battery freshness seal |
| 8 MR | Manual reset input | Active-low input with 70µA internal pullup; asserts reset for ≥200ms after release |
| 9 WDO | Watchdog output | Active-low watchdog fault indicator; high during valid WDI toggling, low on timeout |
| 10 WDI | Watchdog input | Accepts µP-generated pulses; minimum pulse width 100ns; resets 1.6s timer on transition |
| 11 CE IN | Chip-enable input | Passes CE signal to CE OUT during normal operation; high-impedance during reset |
| 12 CE OUT | Chip-enable output | Gated CE signal to RAM; disabled during reset to prevent data corruption |
| 13 RESET | Active-high reset output | Sourcing/sinking capable; inverse of RESET; drives µP reset directly |
| 14 LOWLINE | Early power-fail warning | Active-low NMI trigger when VCC drops to VLR (≈2.85V–3.15V, depending on variant) |
| 15 RESET | Open-drain active-low reset | Requires external pullup; asserted for 200ms on power-up/brownout/MR activation |
| 16 BATT | Backup-battery input | Accepts 3.6V lithium cell; voltage may exceed VCC; enables seamless switchover |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable Reset Threshold | Configurable via external resistor divider on RESET IN, supporting system-specific trip points across 1.212V–5.5V |
| Battery-Freshness Seal | Disables battery leakage until first power cycle, preserving shelf life of 3.6V lithium backup cells |
| Guaranteed Reset to 1V | Ensures robust reset assertion even during deep brownout (VCC ≥1V), critical for fail-safe recovery |
| On-Board CE Gating | Prevents erroneous writes to CMOS RAM during undervoltage by disabling CE path within 7ns propagation delay |
| Integrated Watchdog Timer | Hardware-based 1.6s timeout eliminates reliance on software watchdog routines and prevents lockup |
Applications
| Portable Medical Monitors | Industrial PLC I/O Modules |
|---|---|
Use Scenario: Battery-powered ECG or glucose meter requiring nonvolatile RAM retention and safe shutdown during battery depletion. IC Role / Device Role / Timing Role: Supervisory controller managing VCC/BATT switchover, asserting reset before RAM corruption, and triggering LOWLINE NMI for graceful data save. Use Value: Enables 3.6V lithium battery backup with zero additional FETs; guarantees 200ms reset hold time for firmware-initiated save operations. | Use Scenario: DIN-rail mounted PLC module operating in harsh environments with fluctuating 3.3V supply rails. IC Role / Device Role / Timing Role: Power integrity monitor detecting brownouts, initiating watchdog-triggered recovery, and gating CE signals to prevent corrupted I/O register writes. Use Value: Eliminates need for discrete reset IC + external watchdog + CE buffer; reduces BOM count while ensuring deterministic reset timing. |
| Smart Utility Meters | Embedded Point-of-Sale Terminals |
Use Scenario: AMI meter storing tariff data and consumption logs in battery-backed SRAM during grid outages. IC Role / Device Role / Timing Role: Dual-role supervisor: monitors main 3.3V supply for brownout (RESET), validates backup battery health (BATT OK not present on MAX794), and gates memory access during faults. Use Value: Supports long-term battery backup with <1µA leakage in freshness-seal mode; ensures RAM integrity during 100ms–200ms grid dips. | Use Scenario: Handheld POS terminal with flash memory and real-time clock, powered by rechargeable Li-ion and requiring tamper-proof boot sequence. IC Role / Device Role / Timing Role: System-level guardian enforcing secure boot via MR-initiated reset, monitoring VCC stability during transaction processing, and enabling watchdog-driven recovery on firmware hang. Use Value: Provides hardware-enforced reset window (200ms) and 1.6s watchdog timeout-both unalterable by software-to meet PCI PTS security requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX793CSE+ | Fixed reset threshold (T/S/R variants), includes BATT OK output and uncommitted voltage monitor; no RESET IN pin | Better suited for systems requiring battery-status feedback and dual-voltage monitoring (e.g., PFI + LOWLINE) | Select MAX793CSE+ when fixed-threshold supervision and battery-health indication are required instead of programmability |
| TPS3808G33DBVR | Fixed 3.3V reset threshold, no watchdog or CE gating, lower quiescent current (1.1µA), SOT-23-6 package | Targeted at space-constrained, low-power applications without complex supervision needs | Choose TPS3808G33DBVR only for simple reset-only use cases where watchdog, battery switchover, and CE control are unnecessary |
Compared with MAX793CSE+, the MAX794CSE+ trades fixed-threshold precision and BATT OK status for full reset adjustability and simplified design flexibility; versus TPS3808G33DBVR, it delivers comprehensive supervision (watchdog, CE gating, battery control) at higher current cost but essential for mission-critical embedded systems.
Availability
MAX794CSE+ is available at Aetrix Electronics and suitable for industrial PLC modules, portable medical monitors, smart utility meters, and embedded point-of-sale terminals requiring stable component supply and long-lifecycle support.
Supply support for MAX794CSE+ 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 MAX793/MAX794/MAX795 product line was engineered specifically for robust, battery-backed microprocessor supervision in 3.0V/3.3V embedded systems-emphasizing reliability under brownout, seamless backup switchover, and hardware-enforced system recovery.
FAQ
What is the reset threshold configuration method for MAX794CSE+?
The MAX794CSE+ uses an external resistor divider connected to the RESET IN pin to set the reset threshold voltage. The internal comparator compares VCC to this divided voltage, allowing precise adjustment across 1.212V–5.5V. The formula is VRST = VRST_IN × (R1/R2 + 1), and VRST_IN has a typical value of 1.240V with ±2.5% tolerance. This method gives designers full control over trip point without changing the MAX794CSE+ itself.
Does MAX794CSE+ support battery voltage higher than VCC?
Yes, MAX794CSE+ explicitly supports VBATT > VCC - up to +6.0V - enabling direct use of standard 3.6V lithium batteries in 3.0V/3.3V systems. Its internal p-channel MOSFET switch automatically transfers OUT from VCC to BATT when VCC falls below the switch threshold (VSW ≈ 2.30V–2.95V), with 15mV hysteresis to prevent chatter. This eliminates need for external diodes or OR-ing controllers.
How does the watchdog timer in MAX794CSE+ operate?
The MAX794CSE+ watchdog timer has a fixed 1.6s timeout period and monitors transitions on the WDI pin. If WDI remains static (high or low) longer than 1.6s, WDO goes low. A transition on WDI clears the timer and returns WDO high. WDO can be wired to MR to generate automatic resets on timeout. Unlike some supervisors, the MAX794CSE+ watchdog cannot be disabled - it operates continuously whenever VCC > VSW.
Can MAX794CSE+ be used without a backup battery?
Yes, MAX794CSE+ functions fully without a backup battery. Connect BATT to VCC (or leave floating if unused per datasheet guidance), and the device operates as a standard supervisory circuit with reset, watchdog, LOWLINE, and CE gating. All core features - including RESET assertion down to VCC = 1V, 200ms timeout, and WDI monitoring - remain active. Battery-related pins (BATT, BATT ON, PFO for seal) are simply inactive or ignored.
What is the purpose of the battery freshness seal in MAX794CSE+?
The battery freshness seal in MAX794CSE+ minimizes self-discharge of the backup battery prior to first use. Enabled by grounding PFO while bringing VCC above VRST and then cycling VCC down, it disconnects the battery from internal circuitry until system power is applied. This preserves shelf life of 3.6V lithium cells - critical for devices shipped with pre-installed batteries - and ensures full capacity remains available at end-customer deployment.
MAX794CSE+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 16-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:
- Adjustable/Selectable
- Output:
- Open Drain, Push-Pull
- Reset:
- Active High/Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
MAX794CSE+ FAQ
1.How can I place an order for MAX794CSE+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX794CSE+ 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 MAX794CSE+ reliable?
The price and inventory of MAX794CSE+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX794CSE+ is usually 5 days.
3.What payment methods are accepted for MAX794CSE+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX794CSE+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX794CSE+?
MAX794CSE+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX794CSE+ 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 MAX794CSE+?
For technical support, including MAX794CSE+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX794CSE+ requirements.
6.How does Aetrix verify that MAX794CSE+ is sourced from the original manufacturer or authorized distributors?
All MAX794CSE+ 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 MAX794CSE+ meets industry standards.
7.What is the process for return or replacement of MAX794CSE+?
All MAX794CSE+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX794CSE+, 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 MAX794CSE+ part is unused and in its original packaging.
Return procedure for MAX794CSE+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MAX794CSE+ 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…
