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Analog Devices Inc./Maxim Integrated MAX6391KA16
- Part No.:
- MAX6391KA16
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SOT-23-8
- Datasheet:
-
MAX6391KA16.pdf
- Description:
- IC SUPERVISOR 2 CHANNEL SOT23-8
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
MAX6391KA16 from Maxim Integrated is a dual-voltage microprocessor supervisory circuit with sequenced active-low open-drain reset outputs, factory-set VCC reset threshold of 1.58V (min), guaranteed reset validity down to VCC = 1.0V, and fixed 140ms (min) RESET1 timeout. It monitors master supply VCC and secondary supply RESET IN2 (adjustable down to 625mV) for power sequencing in multivoltage embedded systems.
For engineers reviewing the MAX6391KA16 datasheet, MAX6391KA16 pinout, MAX6391KA16 application, or MAX6391KA16 equivalent, key selection criteria include its dual-threshold monitoring architecture, internal 47kΩ pullup resistors on both RESET1 and RESET2, SOT23-8 package compatibility, and guaranteed operation across -40°C to +85°C industrial temperature range.
Technical Context
The MAX6391KA16 implements two independent voltage comparators: one for VCC (with fixed 1.58V threshold) and one for RESET IN2 (referenced to 625mV). RESET1 asserts only on VCC undervoltage and deasserts after ≥140ms once VCC exceeds threshold; RESET2 asserts if either VCC or RESET IN2 falls below their respective thresholds and deasserts after ≥140ms (CSRT tied to VCC) or a capacitor-adjustable delay.
RESET2 always deasserts after RESET1 during power-up and asserts before RESET1 during power-down - enforcing strict sequencing. The device uses BiCMOS process (810 transistors), draws 15µA typical supply current, and maintains valid reset output down to VCC = 1.0V, enabling reliable brownout detection in low-voltage systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Reset Threshold | 1.54V (min) to 1.61V (max) - ensures precise 1.58V nominal trip point for 1.6V–1.8V logic rails |
| RESET IN2 Threshold | 610mV to 640mV - enables monitoring of auxiliary supplies as low as 625mV via external resistor divider |
| RESET1 Timeout Period | 140ms (min) to 280ms (max) - guarantees minimum reset hold time for safe processor initialization |
| Supply Current | 15µA typical - supports ultra-low-power battery-backed or energy-constrained applications |
| Operating Temperature | -40°C to +85°C - qualified for industrial and extended-temperature embedded environments |
| Output Type | Open-drain RESET1 and RESET2 with internal 47kΩ pullups - eliminates need for external pullup resistors |
| Reset Validity Voltage | Guaranteed to VCC = 1.0V - ensures functional reset assertion during deep brownout conditions |
Pinout & Package
MAX6391KA16 is housed in an 8-pin SOT23 package (JEDEC MO178 compliant, 1.95mm × 2.80mm footprint, 1.30mm height), optimized for space-constrained PCB layouts and compatible with standard SMT reflow profiles.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - RESET IN2 | Secondary supply monitor input | High-impedance comparator input referenced to 625mV; accepts external resistor divider for custom threshold setting |
| 2 - VCC | Main supply and master reset reference | Power supply input and primary voltage monitor; all resets assert when VCC drops below 1.58V threshold |
| 3 - CSRT | RESET2 timeout configuration node | Connect to VCC for fixed 140ms RESET2 delay; connect to capacitor for user-adjustable timing (2.08ms/pF) |
| 4 - GND | Analog/digital ground reference | Common return path for all internal comparators, timers, and output drivers |
| 5 - RESET2 | Secondary active-low open-drain reset output | Asserts when VCC or RESET IN2 falls below threshold; deasserts after CSRT-defined delay; requires external pullup if R2 not used |
| 6 - R2 | Internal pullup connection for RESET2 | 47kΩ resistor internally connected to RESET2; tie to desired VOH voltage (e.g., 3.3V or 5V) for level-shifted high-state drive |
| 7 - RESET1 | Primary active-low open-drain reset output | Asserts solely on VCC undervoltage; deasserts ≥140ms after VCC recovery; timing is fully internal and unadjusted |
| 8 - R1 | Internal pullup connection for RESET1 | 47kΩ resistor internally connected to RESET1; tie to target VOH voltage to define high-level output without external components |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent voltage monitoring | Simultaneous supervision of VCC (1.58V threshold) and RESET IN2 (625mV reference) enables robust multirail sequencing |
| Sequenced reset timing control | RESET2 always asserts before RESET1 on power-down and deasserts after RESET1 on power-up - prevents race conditions |
| Integrated 47kΩ pullup resistors | Eliminates two external resistors; allows independent VOH selection for RESET1 and RESET2 by connecting R1/R2 to different supply rails |
| Low-power operation | 15µA typical ICC enables use in always-on monitoring circuits without compromising battery life or thermal budget |
| Brownout immunity down to 1.0V | Valid reset signaling maintained even as VCC collapses to 1.0V - critical for graceful shutdown in low-VDD systems |
Applications
| Industrial PLC Controllers | Embedded Edge AI Modules |
|---|---|
|
Use Scenario: Power sequencing for dual-rail FPGA + microcontroller subsystems where 1.8V I/O and 1.2V core must initialize in strict order. IC Role / Device Role / Timing Role: Supervisory IC enforcing RESET1 (FPGA config) before RESET2 (MCU boot) via CSRT-timed delay and VCC/RESET IN2 cross-monitoring. Use Value: Prevents configuration corruption by guaranteeing FPGA completes bitstream load before MCU begins execution - enforced by 140ms+ RESET1 hold and delayed RESET2 release. |
Use Scenario: Reliable cold-start in battery-powered edge inference nodes using 3.3V sensor interface and 1.1V neural accelerator core. IC Role / Device Role / Timing Role: Dual-threshold supervisor asserting RESET1 on main 3.3V rail and RESET2 on scaled 1.1V core supply (via resistor divider on RESET IN2). Use Value: Ensures accelerator remains held in reset until both rails are stable - leveraging 625mV internal reference and 1.0V minimum VCC operation for fail-safe startup under weak battery conditions. |
| Medical Diagnostic Handhelds | Automotive Body Control Modules |
|
Use Scenario: Sequenced power-up of display driver (3.3V), ADC front-end (2.5V), and ARM Cortex-M4 (1.2V) in portable ultrasound units. IC Role / Device Role / Timing Role: Primary reset generator coordinating three voltage domains using RESET1 for display/ADC and RESET2 (with CSRT capacitor) for processor domain. Use Value: Eliminates need for discrete RC networks and multiple supervisors - reduces BOM count by 2 ICs and saves >12mm² PCB area in tight handheld form factor. |
Use Scenario: Monitoring 5V CAN transceiver supply and 3.3V microcontroller supply in junction box ECUs exposed to automotive load-dump transients. IC Role / Device Role / Timing Role: Sequenced supervisor detecting VCC sag and RESET IN2 dip simultaneously; immune to <100ns glitches per MR timing specs. Use Value: Maintains deterministic reset behavior during cranking events - validated by 15µA quiescent current and -40°C to +85°C qualification matching AEC-Q100 Grade 3 requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-voltage supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6392KA16 | Includes active-low manual reset (MR) input and push-pull RESET1; lacks R1 pullup (replaced by MR); same VCC threshold and RESET IN2 spec | Required where field-service reset or system-level watchdog-triggered restart is needed; not suitable if only open-drain outputs and internal pullups are desired | Select MAX6392KA16 only when manual reset functionality is mandatory; MAX6391KA16 is preferred for pure sequencing without MR pin overhead |
| TPS3808G15DBVR | Single-supply supervisor (1.5V threshold), no secondary input; push-pull RESET, no internal pullups; 350ms min timeout; SOT23-6 package | Lacks dual-monitoring capability and RESET2 sequencing; cannot replace MAX6391KA16 in multivoltage sequencing roles | Use only as fallback for single-rail applications where RESET2 functionality is omitted; requires external pullup and adds layout complexity vs. MAX6391KA16's integrated R1/R2 |
Compared with MAX6392KA16, the MAX6391KA16 offers dedicated internal pullups and pure open-drain outputs ideal for mixed-voltage pullup schemes; compared with TPS3808G15DBVR, it delivers true dual-supply sequencing with guaranteed sub-1.6V threshold accuracy and 1.0V operational floor - making it irreplaceable in tightly coupled multirail systems.
Availability
MAX6391KA16 is available at Aetrix Electronics and suitable for industrial PLC controllers, embedded edge AI modules, medical diagnostic handhelds, and automotive body control modules requiring stable component supply, long-term lifecycle support, and guaranteed -40°C to +85°C performance.
Supply support for MAX6391KA16 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, computing, and communications applications.
The MAX6391/MAX6392 product line was engineered specifically for multivoltage microprocessor system supervision, delivering sequenced reset outputs with dual-threshold monitoring and minimal external components in ultra-small packages.
FAQ
What is the exact factory-set VCC reset threshold voltage for MAX6391KA16?
The MAX6391KA16 has a factory-trimmed VCC reset threshold of 1.58V nominal, with guaranteed minimum and maximum values of 1.54V and 1.61V respectively across the full -40°C to +85°C temperature range. This precise threshold enables reliable supervision of 1.6V–1.8V logic supplies without external calibration, and is confirmed in the Electrical Characteristics table under "VCC Reset Threshold (VTH1)".
Does MAX6391KA16 support adjustable RESET2 timeout, and how is it configured?
Yes, MAX6391KA16 supports user-adjustable RESET2 timeout via the CSRT pin. Connecting an external capacitor from CSRT to ground sets the delay using the formula tRP2 ≈ 2.08 × 10⁶ × CCSRT (seconds), e.g., 1500pF yields ~3.1ms. For fixed 140ms (min) timeout, tie CSRT directly to VCC - the internal circuitry disables the ramp generator and activates a dedicated counter chain. Both configurations are fully supported and documented in the Applications Information section.
How does MAX6391KA16 ensure correct power-up sequencing between RESET1 and RESET2?
MAX6391KA16 enforces strict power-up sequencing by design: RESET1 deasserts ≥140ms after VCC exceeds its 1.58V threshold, while RESET2 remains asserted until *both* VCC and RESET IN2 exceed their thresholds *and* the CSRT-defined delay elapses. Since RESET2 deassertion is gated by RESET1 deassertion (per timing diagram Figure 2), RESET2 always releases after RESET1 - preventing premature activation of downstream circuitry.
Can MAX6391KA16 monitor a 1.2V supply as the secondary voltage, and what external components are required?
Yes, MAX6391KA16 can monitor a 1.2V supply on RESET IN2 using an external resistor divider. With the internal 625mV reference, a 1.2V rail requires R3/R4 ratio such that 1.2V × R4/(R3+R4) = 0.625V - e.g., R4 = 500kΩ and R3 ≈ 460kΩ. Only two precision resistors are needed; no op-amps or additional ICs. The device guarantees RESET2 assertion within 10µs when the divided voltage falls below 625mV.
What is the purpose of pins R1 and R2 on MAX6391KA16, and how should they be used?
Pins R1 and R2 on MAX6391KA16 provide internal 47kΩ pullup resistors for RESET1 and RESET2, respectively. To set the high-level output voltage (VOH) of each open-drain reset signal, connect R1 to the desired pullup rail (e.g., 3.3V) for RESET1, and R2 to another rail (e.g., 5V) for RESET2 - enabling independent level shifting without external resistors. Leaving R1/R2 unconnected disables the internal pullup, requiring external components.
MAX6391KA16 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- SOT-23-8
- Packaging:
- Bulk
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Multi-Voltage Supervisor
- Number of Voltages Monitored:
- 2
- Voltage - Threshold:
- 1.58V, Adj
- Output:
- Open Drain or Open Collector
- Reset:
- Active Low
- Reset Timeout:
- 140ms/Adjustable Minimum
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-8
MAX6391KA16 FAQ
1.How can I place an order for MAX6391KA16 through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6391KA16 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 MAX6391KA16 reliable?
The price and inventory of MAX6391KA16 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6391KA16 is usually 5 days.
3.What payment methods are accepted for MAX6391KA16?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6391KA16 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6391KA16?
MAX6391KA16 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6391KA16 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 MAX6391KA16?
For technical support, including MAX6391KA16 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6391KA16 requirements.
6.How does Aetrix verify that MAX6391KA16 is sourced from the original manufacturer or authorized distributors?
All MAX6391KA16 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 MAX6391KA16 meets industry standards.
7.What is the process for return or replacement of MAX6391KA16?
All MAX6391KA16 units undergo pre-shipment inspection (PSI). If there is an issue with MAX6391KA16, 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 MAX6391KA16 part is unused and in its original packaging.
Return procedure for MAX6391KA16:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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