Analog Devices Inc./Maxim Integrated MAX6839XSD0

Overview

MAX6839XSD0 from Maxim Integrated is a push-pull, active-high microprocessor supervisory circuit in 4-pin SC70 packaging, designed to monitor supply voltage via an adjustable RESET-IN input (typical threshold 444mV) and assert reset for 1.5ms (D1 option) when that input falls below threshold. It operates from VCC = 1.1V to 3.3V, draws only 7.5µA typical supply current, and guarantees valid reset output down to VCC = 0.75V - ideal for low-voltage portable systems requiring precise brownout detection.

For engineers reviewing the MAX6839XSD0 datasheet, MAX6839XSD0 pinout, MAX6839XSD0 application, or MAX6839XSD0 equivalent, this device serves as a precision, ultra-low-power reset supervisor for sub-1.2V monitored rails using external resistor-divider configuration, with immunity to short VCC transients and guaranteed timing accuracy across -40°C to +85°C.

Technical Context

The MAX6839XSD0 uses an internal 444mV reference comparator to monitor voltage applied at the RESET-IN pin, not VCC directly - enabling flexible monitoring of supplies as low as 0.44V via external resistive divider. Its reset assertion is triggered solely by RESET-IN crossing threshold, independent of VCC level beyond the minimum 1.1V required for comparator accuracy.

It features a push-pull active-high RESET output with VOH ≥ 0.8×VCC (at ISOURCE = 10µA, VCC ≥ 0.85V) and VOL ≤ 0.2×VCC (at ISINK = 200µA, VCC ≥ 1.5V), ensuring robust interface with µP reset inputs. The D1 timeout option provides a fixed 1.5ms reset-active period after RESET-IN rises above threshold.

Key Specifications

Pinout & Package

MAX6839XSD0 is housed in a 4-pin SC70 package (3.0mm × 1.8mm × 0.9mm), optimized for space-constrained portable designs. Pin 1 is RESET-IN, Pin 2 is VCC, Pin 3 is GND, and Pin 4 is RESET (push-pull, active-high).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar microprocessor supervisory applications.

Compared with MAX6839XSD0, MAX6836XSD0 offers identical timing and packaging but trades adjustable threshold for manual reset functionality, while MAX6381XR29D3+T provides significantly lower current draw at the cost of fixed high-voltage threshold and loss of sub-1.2V monitoring capability.

Availability

MAX6839XSD0 is available at Aetrix Electronics and suitable for battery-powered wearables, portable medical devices, low-voltage microcontroller systems, and energy-harvesting sensor nodes requiring stable component supply with guaranteed long-term availability.

Supply support for MAX6839XSD0 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, communications, and consumer applications.

The MAX6832–MAX6840 family was designed specifically for ultra-low-voltage microprocessor supervision in space- and power-constrained portable electronics, emphasizing sub-1.2V monitoring, nanoscale leakage control, and SC70 footprint efficiency.

FAQ

What is the exact reset timeout period for MAX6839XSD0?

The MAX6839XSD0 has a fixed reset-active timeout period of 1.5ms (D1 option), measured from the moment RESET-IN rises above its 444mV threshold until RESET returns low. This value is guaranteed over -40°C to +85°C and is independent of VCC within the 1.1V–3.3V operating range. The timeout is internally generated and does not require external components.

How do I configure MAX6839XSD0 to monitor a 0.8V supply?

To monitor a 0.8V supply with MAX6839XSD0, connect a resistive divider between the 0.8V rail and GND, with the midpoint fed to the RESET-IN pin. Using VRSTIN = 444mV, set R2 = 200kΩ and calculate R1 = R2 × ((0.8V / 0.444V) − 1) ≈ 161kΩ. The MAX6839XSD0 will assert RESET when the divided voltage falls below 444mV, corresponding to ~0.8V at the monitored rail.

Does MAX6839XSD0 monitor VCC or the RESET-IN pin?

The MAX6839XSD0 monitors only the RESET-IN pin - not VCC. Its internal comparator compares the voltage at RESET-IN to a 444mV reference. VCC (1.1V–3.3V) powers the device and sets output drive strength, but reset assertion is triggered exclusively by RESET-IN crossing threshold. This decouples monitoring function from supply voltage constraints.

What is the minimum VCC required for MAX6839XSD0 to maintain RESET-IN accuracy?

The MAX6839XSD0 requires a minimum VCC of 1.1V to guarantee RESET-IN threshold accuracy of ±3.0% over temperature. Below 1.1V, the internal reference and comparator may not operate within specification, though the device remains functional down to VCC = 0.55V for other families (not applicable to MAX6839XSD0 per its datasheet conditions).

Can MAX6839XSD0 drive a reset input that requires active-low signaling?

No - MAX6839XSD0 has a push-pull active-high RESET output and cannot directly drive an active-low reset input. To interface with such µPs, add an inverter (e.g., SN74LVC1G04) or use a compatible alternative like MAX6838XSD0 (active-low push-pull) or MAX6840XSD0 (active-low open-drain). The MAX6839XSD0's output logic polarity is fixed and non-inverting.