Analog Devices Inc./Maxim Integrated MAX6837IXSD2+T

Overview

MAX6837IXSD2+T from Maxim Integrated is an ultra-low-voltage, open-drain active-low microprocessor reset circuit in SC70-4 package, designed to monitor +1.2V to +1.8V supplies with factory-set 1.388V reset threshold (suffix I), 30ms reset timeout (suffix D2), and guaranteed reset assertion down to VCC = 0.55V. It features a debounced manual reset input (MR), 7.5µA typical supply current, and operates across –40°C to +85°C for portable and battery-powered µP systems.

For engineers reviewing the MAX6837IXSD2+T datasheet, MAX6837IXSD2+T pinout, MAX6837IXSD2+T application, or MAX6837IXSD2+T equivalent, key selection criteria include its open-drain RESET output requiring external pullup, MR input with internal 20kΩ pullup, ±2.5% threshold accuracy over temperature, and compatibility with low-voltage core supplies in space-constrained embedded designs.

Technical Context

The MAX6837IXSD2+T implements a precision voltage comparator with 444mV internal reference, comparing VCC against a factory-trimmed threshold derived from that reference. Its reset logic asserts open-drain RESET low when VCC falls below 1.388V or MR is pulled low, holding it low for exactly 30ms after VCC recovers or MR is released.

It integrates glitch rejection on MR (100ns minimum pulse rejection), ignores fast VCC transients via hysteresis (0.75% of VTH), and maintains valid reset output down to 0.55V VCC - critical for brownout detection in sub-1.5V digital systems where supply collapse must trigger controlled shutdown before logic corruption occurs.

Key Specifications

Pinout & Package

MAX6837IXSD2+T is housed in a 4-pin SC70-4 package (2.0mm × 2.1mm, 0.65mm pitch), optimized for high-density PCB layouts in portable electronics.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar voltage supervisor applications.

Compared with MAX6837IXSD2+T, the MAX6837IXSD3+T offers identical supervision accuracy and interface but extends reset hold time for slower-ramping supplies, while the TPS3123E13DBVR trades MR support and ultra-low current for simpler push-pull output and wider availability - neither is pin-compatible, and both require layout changes.

Availability

MAX6837IXSD2+T is available at Aetrix Electronics and suitable for wearable health monitors, industrial sensor nodes, portable medical infusion pumps, low-power IoT edge controllers, and battery-powered microcontroller systems requiring stable component supply with guaranteed long-term sourcing.

Supply support for MAX6837IXSD2+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 and mixed-signal ICs for power, sensing, and connectivity in demanding environments.

The MAX6832–MAX6840 family was engineered specifically for ultra-low-voltage microprocessor reset and brownout detection in portable, battery-operated, and energy-constrained embedded systems.

FAQ

What is the exact reset threshold voltage of the MAX6837IXSD2+T?

The MAX6837IXSD2+T has a factory-set reset threshold of 1.388V, with ±2.5% accuracy over the full –40°C to +85°C operating temperature range. This value is defined by the 'I' suffix in the part number and is trimmed during production using Maxim's precision reference architecture. The threshold remains stable under varying load and supply conditions, making MAX6837IXSD2+T suitable for monitoring 1.4V nominal core supplies without external calibration.

Does the MAX6837IXSD2+T require an external pullup resistor on the RESET pin?

Yes, the MAX6837IXSD2+T features an open-drain active-low RESET output, which requires an external pullup resistor to establish a valid logic-high level. The resistor may connect to any voltage between 0V and 6V - including a higher supply rail than VCC - enabling level-shifting applications. Typical values range from 10kΩ to 100kΩ depending on bus capacitance and rise-time requirements. Without this pullup, RESET cannot assert a high state, and the MAX6837IXSD2+T will not function correctly in most system configurations.

Can the MAX6837IXSD2+T operate reliably when VCC drops below 1.0V?

Yes, the MAX6837IXSD2+T guarantees valid reset assertion down to VCC = 0.55V, with full functionality maintained across its specified 0.55V to 3.6V supply range. Its internal comparator and logic remain operational well into brownout conditions, ensuring the RESET signal stays asserted until VCC recovers above 1.388V and the 30ms timeout expires. This behavior is confirmed in the Absolute Maximum Ratings and Electrical Characteristics tables, making MAX6837IXSD2+T appropriate for deep-brownout protection in ultra-low-power systems.

Is the manual reset (MR) input on the MAX6837IXSD2+T debounced internally?

Yes, the MR input on the MAX6837IXSD2+T includes built-in hardware debounce, eliminating the need for external RC filters or firmware debouncing. It rejects glitches as short as 100ns and requires a minimum pulse width of 2µs to register a valid reset request. The input also features an internal 20kΩ pullup resistor to VCC, allowing direct connection of a momentary switch to ground without additional components. This integrated debounce is a key differentiator of MAX6837IXSD2+T versus basic reset supervisors.

What is the maximum timeout period supported by the MAX6837IXSD2+T?

MAX6837IXSD2+T supports a fixed 30ms reset timeout period, indicated by the 'D2' suffix in the part number. While the broader MAX6832–MAX6840 family offers five timeout options (70µs, 1.5ms, 30ms, 210ms, and 1.68s), the specific variant MAX6837IXSD2+T is configured exclusively for the 30ms option. This duration is optimized for fast-recovery low-voltage systems where extended reset hold times are unnecessary and board space is constrained. Other timeout variants require distinct part numbers.