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Analog Devices Inc./Maxim Integrated MAX6391KA31-T
- Part No.:
- MAX6391KA31-T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SOT-23-8
- Datasheet:
-
MAX6391KA31-T.pdf
- Description:
- IC SUPERVISOR 2 CHANNEL SOT23-8
- Quantity:
- Payment:
- Shipping:
Inventory:10,000
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Product details
Overview
MAX6391KA31-T from Maxim Integrated is a dual-voltage microprocessor supervisory circuit with sequenced open-drain reset outputs, factory-set 3.08V VCC reset threshold, 625mV adjustable secondary reset input (RESET IN2), fixed 140ms minimum RESET1 timeout, and guaranteed reset validity down to VCC = 1.0V - used in multivoltage power sequencing for industrial controllers and embedded systems.
For engineers reviewing the MAX6391KA31-T datasheet, MAX6391KA31-T pinout, MAX6391KA31-T application, or MAX6391KA31-T equivalent, this device delivers deterministic power-up/down reset ordering between primary and secondary supplies without external timing components when CSRT is tied to VCC, and supports custom RESET2 delay via capacitor on CSRT.
Technical Context
The MAX6391KA31-T integrates two independent voltage comparators: one monitors VCC against a factory-trimmed 3.08V threshold (VTH1), asserting RESET1; the other compares RESET IN2 against a precise 625mV internal reference (VTH2), enabling monitoring of auxiliary rails as low as 625mV via external resistor divider.
RESET1 deasserts ≥140ms after VCC exceeds 3.08V; RESET2 deasserts ≥140ms (or user-adjustable) after both VCC > 3.08V and RESET IN2 > 625mV, with RESET2 always deasserting after RESET1 on power-up and asserting before RESET1 on power-down - ensuring strict sequencing control.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Reset Threshold | 3.08V (factory-fixed, ±0.07V tolerance) - sets precise brownout detection point for primary supply |
| RESET IN2 Threshold | 625mV (internal reference, ±15mV) - enables accurate monitoring of secondary rails ≥625mV via external divider |
| RESET1 Timeout | 140ms minimum - guarantees stable processor reset hold time after VCC recovery |
| RESET2 Timeout | 140ms minimum (CSRT = VCC) or capacitor-adjustable - provides flexible sequencing delay for secondary reset |
| Supply Current | 15µA typical - enables ultra-low-power operation in battery-backed or energy-sensitive systems |
| Reset Valid Down To | VCC = 1.0V - ensures reliable reset assertion during deep brownout or slow power ramp conditions |
| Output Type | Open-drain RESET1 and RESET2 with internal 47kΩ pullup resistors (R1/R2) - allows independent VOH level setting via external connections |
Pinout & Package
MAX6391KA31-T is housed in an 8-pin SOT23-8 package (3.00mm × 1.75mm × 1.30mm body, 0.65mm pitch), specified for -40°C to +85°C operation, with lead-free option available (+T suffix).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - RESET IN2 | Secondary supply monitor input | High-impedance comparator input referenced to 625mV; connects to external resistor divider for custom threshold |
| 2 - VCC | Primary supply input & device power rail | Supplies IC bias and serves as master reset trigger; asserts both resets when falling below 3.08V |
| 3 - CSRT | RESET2 timeout configuration node | Tie to VCC for fixed 140ms RESET2 delay; connect to capacitor for user-adjustable delay (tRP2 = 2.08×10⁶ × C) |
| 4 - GND | Ground reference | Common return path for all internal circuits and external pullups |
| 5 - RESET2 | Secondary active-low open-drain reset output | Asserts when VCC < 3.08V OR RESET IN2 < 625mV; deasserts only after both recover and RESET1 deasserts |
| 6 - R2 | Internal pullup connection for RESET2 | 47kΩ resistor internally connected to RESET2; tie to external VOH for level-shifted high-state drive |
| 7 - RESET1 | Primary active-low open-drain reset output | Asserts solely on VCC < 3.08V; deasserts ≥140ms after VCC > 3.08V - independent of RESET IN2 status |
| 8 - R1 | Internal pullup connection for RESET1 | 47kΩ resistor internally connected to RESET1; tie to external VOH for independent high-level pullup |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent voltage monitoring | Simultaneous 3.08V VCC and 625mV RESET IN2 thresholds enable true multivoltage system supervision |
| Guaranteed reset validity to 1.0V VCC | Ensures functional reset assertion even during severe brownout or slow-ramp power-up scenarios |
| Sequenced reset timing control | Hardware-enforced RESET2 deassertion after RESET1 on power-up prevents race conditions in dual-processor systems |
| No external timing components required | Fixed 140ms timeouts eliminate need for RC networks - reduces BOM count and layout area |
| Configurable RESET2 delay | Capacitor on CSRT enables fine-tuned delay adjustment (e.g., 3.1ms with 1500pF) for custom sequencing windows |
Applications
| Industrial PLC Controllers | Embedded Multivoltage Systems |
|---|---|
|
Use Scenario: Power sequencing across 3.3V I/O, 1.8V core, and 5V analog rails in programmable logic controllers. IC Role / Device Role / Timing Role: Primary supervisor enforcing power-up order: 3.3V rail first (via RESET1), then 1.8V rail (via RESET2) after 140ms delay. Use Value: Prevents latch-up or undefined state in mixed-voltage FPGA/CPLD interfaces by guaranteeing strict rail activation sequence. |
Use Scenario: Dual-processor board with ARM host and DSP coprocessor requiring staggered reset release. IC Role / Device Role / Timing Role: Generates RESET1 for ARM (3.08V VCC monitor) and RESET2 for DSP (monitors 1.2V rail via divider on RESET IN2). Use Value: Eliminates need for discrete reset ICs or FPGA-based sequencing logic - reduces component count and firmware dependency. |
| Servers/Workstations | Set-Top Boxes |
|
Use Scenario: Monitoring redundant 12V/5V/3.3V power supplies in rack-mounted server management units. IC Role / Device Role / Timing Role: Uses RESET IN2 to supervise auxiliary 5V standby rail while VCC monitors main 3.3V logic rail. Use Value: Enables early fault detection on standby rail without compromising primary reset integrity - improves system reliability metrics. |
Use Scenario: Consumer STB with HDMI PHY, video decoder, and SoC requiring coordinated power-on reset. IC Role / Device Role / Timing Role: RESET1 controls SoC reset; RESET2 (delayed) releases HDMI PHY after SoC initialization completes. Use Value: Avoids hot-plug detection failures by ensuring PHY is held in reset until SoC firmware configures link training parameters. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-voltage supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6392KA31-T | Includes active-low manual reset (MR) input and push-pull RESET1; lacks R1 pullup resistor | Required where hardware-initiated system reset (e.g., front-panel button) is needed alongside sequenced power-up | Select MAX6392KA31-T if MR functionality is mandatory; otherwise MAX6391KA31-T offers simpler open-drain-only interface |
| TPS3808G33DBVR | Single-supply supervisor (3.3V fixed threshold); no secondary monitor input or sequenced outputs | Only suitable for single-rail systems; cannot replace dual-monitoring or sequencing capability of MAX6391KA31-T | Use TPS3808G33DBVR only for cost-sensitive single-voltage applications where RESET2 sequencing is unnecessary |
Compared with MAX6392KA31-T, the MAX6391KA31-T provides identical voltage monitoring and sequencing but omits manual reset - simplifying design where external reset initiation is handled elsewhere. Compared with TPS3808G33DBVR, it adds critical dual-rail supervision and deterministic inter-reset timing essential for multivoltage platforms.
Availability
MAX6391KA31-T is available at Aetrix Electronics and suitable for industrial controllers, embedded multivoltage systems, and set-top boxes requiring stable component supply, long-term lifecycle support, and guaranteed reset timing behavior across temperature.
Supply support for MAX6391KA31-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 demanding industrial, automotive, and communications applications.
The MAX6391/MAX6392 product line delivers integrated dual-supply supervision with hardware-enforced reset sequencing - specifically engineered for reliability-critical multivoltage embedded systems where discrete solutions increase failure risk and board space.
FAQ
What is the factory-set VCC reset threshold voltage for MAX6391KA31-T?
The MAX6391KA31-T has a factory-trimmed VCC reset threshold of 3.08V (nominal), with a guaranteed range of 3.00V to 3.15V over the full -40°C to +85°C temperature range. This value is laser-trimmed during production and is not user-adjustable. The MAX6391KA31-T uses this fixed threshold to assert RESET1 whenever VCC falls below that level, ensuring consistent brownout detection across all units.
Can MAX6391KA31-T monitor a 1.2V supply as the secondary voltage?
Yes - the MAX6391KA31-T can monitor a 1.2V supply using the RESET IN2 pin with an external resistor divider. Since the internal reference is 625mV, a divider with R3 = 940kΩ and R4 = 500kΩ yields VRST ≈ 1.2V. The MAX6391KA31-T's high-impedance RESET IN2 input draws only 50nA, minimizing divider current and power loss. This enables accurate supervision of sub-3V rails without additional ICs.
How is the RESET2 timeout period configured on MAX6391KA31-T?
The MAX6391KA31-T supports two RESET2 timeout modes: fixed or adjustable. Connect CSRT to VCC for a guaranteed ≥140ms delay; connect CSRT to a capacitor (e.g., 1500pF to ground) for user-adjustable delay calculated as tRP2 = 2.08 × 10⁶ × C seconds. The MAX6391KA31-T's internal 600nA current source charges the capacitor to a 1.25V threshold, enabling precise, temperature-stable timing without external RC tolerances.
Does MAX6391KA31-T provide internal pullup resistors for its reset outputs?
Yes - the MAX6391KA31-T integrates two 47kΩ internal pullup resistors: R1 connected to RESET1 and R2 connected to RESET2. These allow direct connection to external VOH voltages (e.g., 3.3V or 5V) via pins 8 and 6 respectively, eliminating external pullup components. This feature enables level-shifting of reset signals to match downstream logic families while maintaining open-drain flexibility.
Is MAX6391KA31-T compatible with lead-free PCB assembly processes?
Yes - the MAX6391KA31-T is available in lead-free packaging. The "-T" suffix denotes standard RoHS-compliant tape-and-reel packaging; lead-free versions use the "+T" suffix per Maxim's ordering convention. Both variants meet JEDEC J-STD-020 moisture sensitivity level 1 (MSL-1) and support standard reflow profiles up to 260°C peak, making the MAX6391KA31-T suitable for modern lead-free manufacturing lines.
MAX6391KA31-T 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:
- 3.08V, 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
MAX6391KA31-T FAQ
1.How can I place an order for MAX6391KA31-T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6391KA31-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 MAX6391KA31-T reliable?
The price and inventory of MAX6391KA31-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6391KA31-T is usually 5 days.
3.What payment methods are accepted for MAX6391KA31-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6391KA31-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6391KA31-T?
MAX6391KA31-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6391KA31-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 MAX6391KA31-T?
For technical support, including MAX6391KA31-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6391KA31-T requirements.
6.How does Aetrix verify that MAX6391KA31-T is sourced from the original manufacturer or authorized distributors?
All MAX6391KA31-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 MAX6391KA31-T meets industry standards.
7.What is the process for return or replacement of MAX6391KA31-T?
All MAX6391KA31-T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6391KA31-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 MAX6391KA31-T part is unused and in its original packaging.
Return procedure for MAX6391KA31-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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