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Analog Devices Inc./Maxim Integrated MAX6840XSD3+T
- Part No.:
- MAX6840XSD3+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SC-82A, SOT-343
- Datasheet:
-
MAX6840XSD3+T.pdf
- Description:
- IC MPU SUPERVISOR SC70-4
- Quantity:
- Payment:
- Shipping:
Inventory:1,815
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Product details
Overview
MAX6840XSD3+T from Maxim Integrated is an ultra-low-voltage, open-drain active-low microprocessor reset circuit in SC70-4 package, designed to monitor supply voltages via external resistive divider at RESET-IN pin with 444mV internal reference. It provides 210ms reset timeout, operates down to VCC = 1.1V, and draws only 7.5µA typical supply current. Used for reliable power-on/brownout reset in portable 1.2V–1.8V digital systems.
For engineers reviewing the MAX6840XSD3+T datasheet, MAX6840XSD3+T pinout, MAX6840XSD3+T application, or MAX6840XSD3+T equivalent, key selection criteria include its adjustable threshold architecture (RESET-IN), open-drain active-low output requiring external pullup, guaranteed reset validity down to VCC = 0.55V, and immunity to sub-100ns MR glitches - critical for battery-powered µP supervision.
Technical Context
The MAX6840XSD3+T implements a precision comparator with 444mV internal reference voltage (±3.0% over temperature) referenced to RESET-IN, enabling user-defined trip points via external resistor divider. Reset assertion occurs when RESET-IN falls below this threshold, independent of VCC monitoring.
Its open-drain RESET output supports level-shifting across voltage domains and interfaces directly with bidirectional µP reset pins. The device guarantees reset assertion during VCC ramp-down and maintains reset for exactly 210ms after RESET-IN rises above threshold, with no manual reset input - distinguishing it from MR-equipped variants like MAX6835/MAX6836.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Timeout Period | 210ms - fixed delay ensures sufficient µP initialization time after monitored supply stabilizes |
| RESET-IN Threshold Voltage | 444mV ±3.0% - stable reference enabling precise external trip-point setting for supplies as low as 0.44V |
| Supply Current | 7.5µA typ at 1.2V - enables multi-year operation in coin-cell–powered devices |
| VCC Operating Range | 1.1V to 3.3V - supports core logic supplies while maintaining RESET-IN accuracy |
| Reset Output Type | Open-drain active-low - allows pullup to higher voltage rail (up to 6V) for level-shifted reset signaling |
| Reset Validity Down to VCC | 0.55V - guarantees valid LOW state on RESET until VCC drops below functional minimum |
| RESET-IN Leakage Current | ±25nA - permits use of high-value resistors (>100kΩ) in divider network without threshold error |
Pinout & Package
MAX6840XSD3+T is housed in a 4-pin SC70-4 package (2.0mm × 2.1mm, 0.65mm pitch), RoHS-compliant with "+T" suffix indicating lead-free finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RESET-IN | High-impedance input for external voltage divider; reset asserts when voltage falls below 444mV reference |
| 2 | VCC | Power supply input (1.1V–3.3V); powers internal circuitry and sets operating range for RESET-IN accuracy |
| 3 | GND | Analog and digital ground reference; must be low-impedance connection for stable threshold operation |
| 4 | RESET | Open-drain active-low output; requires external pullup resistor to define HIGH level and sink capability |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable Reset Threshold | Enabled via RESET-IN pin with 444mV internal reference - supports custom trip points from 0.44V to >3V using two external resistors |
| Low-Power Supervision | 7.5µA typical ICC - minimizes quiescent drain in always-on battery backup paths |
| Open-Drain Level-Shifting Output | RESET sinks up to 200µA at VCC ≥ 1.5V - enables reset assertion across disparate supply domains (e.g., 1.2V core → 3.3V I/O) |
| Guaranteed Reset Below 1.1V | Valid reset assertion down to VCC = 0.55V - ensures µP remains held in reset even during deep brownout |
| High-Noise Immunity | Immune to fast transients on RESET-IN due to comparator hysteresis and internal filtering - eliminates false resets in EMI-prone environments |
Applications
| Wearable Health Monitors | Industrial Sensor Nodes |
|---|---|
Use Scenario: Coin-cell–powered ECG patch continuously monitors heart rhythm and logs data during intermittent BLE transmission. IC Role / Device Role / Timing Role: MAX6840XSD3+T supervises the 1.2V LDO output powering the MCU and analog front-end, asserting reset if battery voltage sags below 1.05V (set via 100kΩ/47kΩ divider on RESET-IN). Use Value: 210ms timeout prevents premature MCU wake-up during battery recovery; 7.5µA current extends operational life beyond 18 months. |
Use Scenario: Wireless temperature sensor node deployed in factory machinery uses a 1.5V buck converter to power its ultra-low-power MCU and MEMS sensor. IC Role / Device Role / Timing Role: MAX6840XSD3+T monitors the 1.5V rail via RESET-IN to detect converter dropout, holding the MCU in reset until stable operation resumes. Use Value: Open-drain RESET pulled to 3.3V enables direct interface with host controller's 3.3V-tolerant reset input - no level shifter required. |
| Portable Medical Diagnostics | Smart Metering Modules |
Use Scenario: Handheld blood glucose meter employs a single AAA cell and switches between 1.2V (MCU core) and 3.0V (LCD backlight) rails. IC Role / Device Role / Timing Role: MAX6840XSD3+T supervises the 1.2V core rail using RESET-IN; its open-drain RESET is pulled to 3.0V to drive both MCU reset and LCD enable logic. Use Value: Level-shifting capability eliminates discrete MOSFET reset translators, reducing BOM count and PCB area in space-constrained housing. |
Use Scenario: Electricity meter with isolated RS-485 communication uses separate 1.8V (MCU) and 5.0V (transceiver) supplies. IC Role / Device Role / Timing Role: MAX6840XSD3+T monitors 1.8V MCU supply via RESET-IN and drives open-drain RESET pulled to 5.0V, ensuring transceiver reset aligns with MCU reset timing. Use Value: 210ms timeout matches MCU boot ROM initialization window; ±3.0% threshold accuracy ensures consistent trip point across -40°C to +85°C field operation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar voltage supervisor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6837XSD3+T | Push-pull active-low RESET output; includes debounced MR input; same RESET-IN architecture and 210ms timeout | Requires MR signal for system-initiated reset; no external pullup needed on RESET | Select when manual reset capability and simplified RESET routing (no pullup) are required |
| TLV809KDBZR | Fixed 3.08V reset threshold; SOT-23-3; 140ms timeout; no RESET-IN or MR; 0.5µA supply current | Only suitable for fixed 3.3V supply monitoring; lacks adjustability and multi-rail flexibility | Select only for cost-sensitive, single-supply 3.3V applications where adjustable threshold is unnecessary |
Compared with MAX6840XSD3+T, MAX6837XSD3+T adds manual reset functionality but loses level-shifting capability, while TLV809KDBZR offers ultra-low current but sacrifices all configurability - making MAX6840XSD3+T uniquely suited for adjustable, multi-rail, battery-critical designs.
Availability
MAX6840XSD3+T is available at Aetrix Electronics and suitable for portable medical diagnostics, industrial wireless sensors, wearable health monitors, and smart metering modules requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for MAX6840XSD3+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 computing applications.
The MAX6832–MAX6840 family delivers ultra-low-voltage, low-quiescent-current reset supervision for battery-powered and energy-harvesting systems where supply margin is minimal and reliability under brownout is critical.
FAQ
What is the exact reset timeout period specified for MAX6840XSD3+T?
The MAX6840XSD3+T has a fixed reset active timeout period of 210ms, as indicated by the "D3" suffix in its part number. This duration is guaranteed over the full operating temperature range (-40°C to +85°C) and ensures the microprocessor remains held in reset long enough to complete power stabilization and internal initialization after the monitored supply (via RESET-IN) recovers above the trip threshold.
Does MAX6840XSD3+T monitor VCC directly, or does it rely solely on the RESET-IN pin?
The MAX6840XSD3+T does not monitor VCC for reset generation - it uses only the RESET-IN pin as the sensing input. VCC serves solely as the device's power supply (1.1V to 3.3V) and enables accurate operation of the internal 444mV reference and comparator. Reset assertion occurs exclusively when the voltage at RESET-IN falls below 444mV, regardless of VCC level - provided VCC remains within specification.
What pullup voltage and resistor value are recommended for the open-drain RESET output of MAX6840XSD3+T?
The RESET output of MAX6840XSD3+T supports pullup to any voltage between 0V and 6.0V. A standard 10kΩ resistor to 3.3V is commonly used. For low-current applications, values up to 100kΩ are acceptable. The device guarantees RESET can sink 200µA at VCC ≥ 1.5V, so the chosen resistor must ensure voltage drop across it stays below VOH requirements of the driven input when RESET is asserted (LOW).
Can MAX6840XSD3+T be used to supervise a 0.6V supply rail?
Yes - MAX6840XSD3+T can supervise a 0.6V rail using an external resistor divider on RESET-IN. With VRSTIN = 444mV, a divider ratio of R1/R2 = (0.6V / 0.444V) − 1 ≈ 0.35 yields R1 = 70.3kΩ when R2 = 200kΩ. The device's ±25nA RESET-IN leakage ensures minimal error, and VCC ≥ 1.1V must be maintained to guarantee threshold accuracy per the datasheet.
Is there a manual reset (MR) input on MAX6840XSD3+T?
No, MAX6840XSD3+T does not include a manual reset (MR) input. It belongs to the MAX6838/MAX6839/MAX6840 subgroup, which replaces MR with RESET-IN for adjustable threshold supervision. If manual reset functionality is required, MAX6837XSD3+T - which features both RESET-IN and debounced MR - is the functionally closest alternative in the same family.
MAX6840XSD3+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- SC-82A, SOT-343
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Simple Reset/Power-On Reset
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- Adjustable/Selectable
- Output:
- Open Drain or Open Collector
- Reset:
- Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SC-70-4
MAX6840XSD3+T FAQ
1.How can I place an order for MAX6840XSD3+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6840XSD3+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 MAX6840XSD3+T reliable?
The price and inventory of MAX6840XSD3+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6840XSD3+T is usually 5 days.
3.What payment methods are accepted for MAX6840XSD3+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6840XSD3+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6840XSD3+T?
MAX6840XSD3+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6840XSD3+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 MAX6840XSD3+T?
For technical support, including MAX6840XSD3+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6840XSD3+T requirements.
6.How does Aetrix verify that MAX6840XSD3+T is sourced from the original manufacturer or authorized distributors?
All MAX6840XSD3+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 MAX6840XSD3+T meets industry standards.
7.What is the process for return or replacement of MAX6840XSD3+T?
All MAX6840XSD3+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6840XSD3+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 MAX6840XSD3+T part is unused and in its original packaging.
Return procedure for MAX6840XSD3+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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