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Analog Devices Inc./Maxim Integrated MAX794ESE+T
- Part No.:
- MAX794ESE+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX794ESE+T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,300
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Product details
Overview
MAX794ESE+T from Maxim Integrated is a 3.0V/3.3V adjustable microprocessor supervisory circuit with externally programmable reset threshold, backup-battery switchover (VBATT > VCC supported), independent watchdog timer (1.6s timeout), and chip-enable gating for CMOS RAM protection. It operates across –40°C to +85°C and features active-low RESET, active-high RESET, and BATT ON driver output - used in battery-backed embedded controllers requiring reliable power monitoring and brownout recovery.
For engineers reviewing the MAX794ESE+T datasheet, MAX794ESE+T pinout, MAX794ESE+T application, or MAX794ESE+T equivalent, key selection criteria include its adjustable reset threshold via external resistor divider, guaranteed reset assertion down to VCC = 1V, battery-freshness seal capability, and 7ns max CE IN-to-CE OUT propagation delay under normal operation.
Technical Context
The MAX794ESE+T implements an adjustable reset comparator using the RESET IN pin with a precision 1.240V internal reference; reset threshold is set by external R1/R2 divider per VRST = VRST_IN × (R1/R2 + 1), covering VSW (2.55V) to 5.5V. Its battery switchover logic uses dual comparators with 15mV typical hysteresis to prevent oscillation during VCC transitions near VSW.
It integrates a 1.6s watchdog timer that clears on any WDI transition (low-to-high or high-to-low); WDO asserts low on timeout and returns high on next WDI edge. CE gating operates as a transmission gate with enable/disable controlled by reset state, providing 10µs hold time when CE IN is low at reset assertion.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | Externally adjustable from 2.55V to 5.5V via resistor divider on RESET IN pin - enables precise match to system VCC tolerance. |
| Watchdog Timeout | 1.6s nominal - provides deterministic fault detection window for µP software hang recovery. |
| Reset Assertion Range | Guaranteed to assert RESET for VCC down to 1V - ensures robust reset during deep brownout or battery-only operation. |
| Battery Switchover | VSW = 2.55V (min), 2.80V (typ), 2.95V (max) - allows use of 3.6V lithium cells with 3.0V/3.3V systems without level-shifting. |
| CE Propagation Delay | 7ns max - preserves timing integrity for high-speed µP address/data bus gating during undervoltage events. |
| Operating Temp Range | –40°C to +85°C - qualified for industrial and extended-temperature embedded applications. |
| Supply Current (VCC) | 46µA typ at +25°C - minimizes quiescent load on main supply during normal operation. |
Pinout & Package
MAX794ESE+T is housed in a 16-pin narrow SO (SOIC-16) package with 1.27mm pitch, JEDEC MS-012AC compliant, body size 10.3mm × 5.3mm × 1.75mm.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| OUT (Pin 1) | Supply output for CMOS RAM | Switches between VCC and BATT based on comparator decisions; supports up to 75mA load in battery mode. |
| RESET IN (Pin 3) | Adjustable reset threshold input | Accepts external voltage divider; internal 1.240V reference sets VRST = VRST_IN × (R1/R2 + 1). |
| VCC (Pin 2) | Main supply input | Operates from 2.72V to 5.5V; powers internal circuitry and drives RESET, CE OUT, WDO outputs. |
| PFO (Pin 7) | Power-fail comparator output / freshness seal enable | Open-drain output; pulled low when PFI < VPFT or VCC < VSW; used to latch battery freshness seal. |
| RESET (Pin 15) | Active-low open-drain reset output | Asserts low for ≥200ms on power-up/brownout/MR; requires external pullup (4.7kΩ–1MΩ) to VCC. |
| CE OUT (Pin 12) | Chip-enable gated output | Passes CE IN only when reset is deasserted; holds low for 10µs if CE IN is low at reset assertion. |
| GND (Pin 6) | Ground reference | Common return for VCC, BATT, and all digital/analog functions; must be low-impedance connection. |
| PFI (Pin 4) | Power-fail comparator input | Monitors external voltage; threshold fixed at 1.240V; connect to VCC if unused. |
| WDO (Pin 9) | Watchdog output | Active-low open-drain; asserts low after 1.6s WDI inactivity; can be wired to MR for automatic reset on fault. |
| MR (Pin 8) | Manual reset input | Active-low with 70µA internal pullup; asserts reset for 200ms after rising edge; TTL/CMOS compatible. |
| WDI (Pin 10) | Watchdog input | Edge-sensitive; detects pulses ≥100ns; resets 1.6s timer on any transition (high↔low). |
| LOWLINE (Pin 14) | Early power-fail warning output | Active-low; asserts when VCC falls to VLR (VLOWLINE − VRST = 5–60mV); used for NMI generation prior to reset. |
| BATT (Pin 16) | Backup battery input | Supports VBATT > VCC (e.g., 3.6V Li); leakage <1µA with freshness seal enabled. |
| BATT ON (Pin 5) | Battery-on status driver | Active-high push-pull output; signals BATT-to-OUT switchover; drives external PMOS base/gate for >75mA loads. |
| CE IN (Pin 11) | Chip-enable input | High-impedance when reset asserted; series 46Ω resistance when enabled; connects to µP CE or memory decoder. |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable Reset Threshold | Set via external resistor divider on RESET IN - eliminates need for multiple fixed-threshold variants. |
| Battery Freshness Seal | Disables BATT path until first power cycle - preserves shelf life of backup lithium cell. |
| Watchdog Timer | 1.6s timeout with edge-triggered clear - prevents false triggers from noise or slow edges. |
| Chip-Enable Gating | 7ns max propagation delay and 10µs hold time - protects CMOS RAM write cycles during power collapse. |
| Low-Line Early Warning | LOWLINE output asserts before reset - enables NMI-based graceful shutdown or data save. |
Applications
| Battery-Powered Embedded Controllers | Industrial Data Loggers |
|---|---|
Use Scenario: Portable sensor node powered by primary Li-ion and backed by coin-cell battery, operating unattended for months. IC Role / Device Role / Timing Role: Supervises VCC brownout, switches RAM supply to BATT at 2.55V, asserts RESET before µP executes corrupted code, and triggers LOWLINE NMI for last-chance data save. Use Value: Prevents data loss during battery swap or low-VCC events; extends usable runtime via seamless switchover and 1µA battery leakage. | Use Scenario: DIN-rail mounted environmental monitor in factory setting with 24VDC input and isolated 3.3V rail. IC Role / Device Role / Timing Role: Monitors 3.3V µP supply; asserts RESET on line sag; uses WDI/WDO loop to detect firmware lockup; gates CE to EEPROM during undervoltage. Use Value: Ensures deterministic recovery from power disturbances and software faults without field service intervention. |
| Medical Point-of-Care Devices | Smart Energy Meters |
Use Scenario: Handheld diagnostic tool with flash memory storage and real-time clock, requiring FDA-grade reliability. IC Role / Device Role / Timing Role: Provides VCC supervision, battery-backed RAM retention, manual reset via front-panel button (MR), and watchdog-enforced firmware health check. Use Value: Meets IEC 62304 safety requirements for reset assurance and fail-safe behavior during power transitions. | Use Scenario: Revenue-grade electricity meter with tamper detection, RTC, and nonvolatile event logging. IC Role / Device Role / Timing Role: Supervises 3.3V supply feeding metrology SoC; uses PFI to monitor auxiliary 5V rail; asserts BATT ON to enable backup PMOS switch for RTC power. Use Value: Guarantees accurate timekeeping and event timestamping during mains failure via controlled BATT switchover. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX793ESE+T | Fixed reset threshold (3.00V–3.15V), includes BATT OK output, no RESET IN pin | Lacks adjustability; suited for systems with stable 3.3V ±5% rails where external threshold tuning isn't needed | Select when design uses standard 3.3V supply and requires battery-status feedback (BATT OK) instead of programmability |
| TPS3808G33DBVR | Fixed 3.3V reset threshold, 200ms reset timeout, no watchdog or CE gating, SOT-23-6 package | No battery switchover, no WDI/WDO, no LOWLINE or PFI - minimal feature set for basic reset-only use | Choose for space-constrained designs needing only reset supervision without backup power management |
Compared with MAX793ESE+T and TPS3808G33DBVR, the MAX794ESE+T uniquely combines adjustable reset, integrated watchdog, CE gating, and battery switchover in a single 16-pin SOIC - making it optimal for complex embedded systems requiring coordinated power, memory, and fault-recovery control.
Availability
MAX794ESE+T is available at Aetrix Electronics and suitable for battery-powered embedded controllers, industrial data loggers, medical point-of-care devices, and smart energy meters requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for MAX794ESE+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, mixed-signal, and power management ICs for industrial, automotive, communications, and computing applications.
The MAX793/MAX794/MAX795 family was engineered specifically for 3.0V/3.3V microprocessor supervision in battery-backed systems - delivering integrated reset, watchdog, power-fail warning, and RAM protection in a single compact package.
FAQ
What is the reset threshold range supported by the MAX794ESE+T?
The MAX794ESE+T supports an externally programmable reset threshold from 2.55V to 5.5V, set via a resistor divider on the RESET IN pin using the internal 1.240V reference. The formula is VRST = 1.240V × (R1/R2 + 1). This allows precise matching to custom supply tolerances - unlike fixed-threshold alternatives such as the MAX793ESE+T.
How does the battery freshness seal work on the MAX794ESE+T?
The MAX794ESE+T battery freshness seal disconnects the BATT pin from internal circuitry until first power-up. To enable it: apply battery to BATT, ground PFO, bring VCC above VRST, wait for reset timeout (~200ms), then cycle VCC low and high. Once enabled, leakage drops to <1µA. The seal remains active until VCC exceeds VRST again - preserving shelf life of lithium backup cells.
Can the MAX794ESE+T drive external MOSFETs for higher battery current?
Yes - the MAX794ESE+T includes a dedicated BATT ON output (Pin 5) that goes high when the device switches to battery backup. This push-pull signal is designed to directly drive the gate/base of external PMOS or PNP transistors, enabling >75mA battery current delivery beyond the internal 250µA limit of the OUT pin - critical for powering larger RAM banks or RTC circuits.
What is the function of the LOWLINE output on the MAX794ESE+T?
The LOWLINE output on the MAX794ESE+T is an active-low early warning signal that asserts when VCC falls to VLR = VRST − (5–60mV), typically ~20–30mV below the reset threshold. It provides a programmable "early brownout" indication - commonly used to trigger a non-maskable interrupt (NMI) for last-chance data save or graceful shutdown before RESET activates.
Does the MAX794ESE+T require external components for basic operation?
Yes - the MAX794ESE+T requires external components for core functions: a resistor divider on RESET IN to set the threshold, a pullup resistor (4.7kΩ–1MΩ) on RESET, and a 0.1µF bypass capacitor on VCC. Optional components include a PMOS transistor driven by BATT ON for high-current battery switching, and a diode-OR network connecting WDO to MR for automatic watchdog-initiated resets.
MAX794ESE+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 16-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:
- Adjustable/Selectable
- Output:
- Open Drain, Push-Pull
- Reset:
- Active High/Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
MAX794ESE+T FAQ
1.How can I place an order for MAX794ESE+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX794ESE+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 MAX794ESE+T reliable?
The price and inventory of MAX794ESE+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX794ESE+T is usually 5 days.
3.What payment methods are accepted for MAX794ESE+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX794ESE+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX794ESE+T?
MAX794ESE+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX794ESE+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 MAX794ESE+T?
For technical support, including MAX794ESE+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX794ESE+T requirements.
6.How does Aetrix verify that MAX794ESE+T is sourced from the original manufacturer or authorized distributors?
All MAX794ESE+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 MAX794ESE+T meets industry standards.
7.What is the process for return or replacement of MAX794ESE+T?
All MAX794ESE+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX794ESE+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 MAX794ESE+T part is unused and in its original packaging.
Return procedure for MAX794ESE+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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