Analog Devices Inc./Maxim Integrated MAX6843UKD1-T

Overview

The MAX6843UKD1-T from Maxim Integrated is an ultra-low-voltage microprocessor supervisory circuit with adjustable reset threshold via RESET IN input, 1.5ms reset timeout, active-low push-pull RESET output, and operation down to VCC = 0.55V. It monitors power supplies from +0.9V to +1.5V in portable and battery-powered systems, ensuring reliable µP reset during brownout and power-up sequences.

For engineers reviewing the MAX6843UKD1-T datasheet, MAX6843UKD1-T pinout, MAX6843UKD1-T application, or MAX6843UKD1-T equivalent, this device delivers precise voltage monitoring with ±2.5% threshold accuracy over temperature, manual reset immunity to 150ns glitches, and low 5.7µA supply current - critical for space-constrained, low-power embedded designs.

Technical Context

The MAX6843UKD1-T implements a precision comparator referenced to a 187.4mV internal bandgap voltage (relative to VCC), enabling externally adjustable reset thresholds via resistive divider on RESET IN. Its reset assertion is triggered either by falling RESET IN voltage below threshold or by assertion of the debounced MR input.

Reset remains asserted for a fixed 1.5ms timeout after RESET IN rises above threshold or MR is released. The active-low push-pull RESET output guarantees valid logic levels down to VCC = 0.55V and sinks up to 80µA while asserted, eliminating need for external pullup components.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5 - surface-mount, footprint-compatible with industry-standard 5-lead SOT-23, optimized for compact portable PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6844UKD1-T, the MAX6843UKD1-T provides native active-low reset polarity essential for most µPs, while both share identical adjustability, timing, and low-power performance. Against TPS3808G15DBVR, MAX6843UKD1-T enables precise sub-1.5V monitoring and cuts quiescent current by >70%, making it optimal for ultra-low-voltage, battery-sensitive applications.

Availability

MAX6843UKD1-T is available at Aetrix Electronics and suitable for portable/battery-powered equipment, critical µP and µC power monitoring, and telecom/networking equipment requiring stable component supply across industrial temperature range and long production lifecycles.

Supply support for MAX6843UKD1-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 management, sensing, and interface applications in industrial, computing, and communications markets.

The MAX6841–MAX6845 family was engineered specifically for ultra-low-voltage microprocessor supervision in portable and battery-operated systems, delivering accurate reset generation with minimal external components and ultra-low quiescent current.

FAQ

What is the reset timeout period for MAX6843UKD1-T?

The MAX6843UKD1-T has a typical reset active timeout period of 1.5ms, as indicated by the "D1" suffix in its part number. This fixed delay ensures the reset signal remains asserted long enough for microprocessors to complete power-up initialization, and is guaranteed over the full -40°C to +85°C operating temperature range. The timeout begins after VCC or RESET IN rises above the threshold and MR is released.

How do I set the reset threshold voltage for MAX6843UKD1-T?

The MAX6843UKD1-T uses an adjustable reset threshold via its RESET IN pin, which compares the external voltage to an internal 187.4mV reference (relative to VCC). To set a specific VCC threshold (e.g., 1.0V), connect a resistor divider between VCC and GND, with the midpoint feeding RESET IN. For example, with VCC = 1.0V and VRSTIN = 187.4mV, R1 ≈ 26.3kΩ and R2 = 100kΩ yields the target threshold. The MAX6843UKD1-T datasheet provides the exact formula and design examples.

Does MAX6843UKD1-T support operation below 1.0V?

Yes, the MAX6843UKD1-T operates with VCC as low as +0.55V and monitors supplies down to +0.9V. Its internal circuitry remains functional and guarantees valid active-low RESET output down to 0.55V, making it suitable for modern ultra-low-voltage SoCs and FPGAs. The device draws only 5.7µA at 0.9V, preserving battery life in sub-1V applications.

What is the function of the MR pin on MAX6843UKD1-T?

The MR (Manual Reset) pin on MAX6843UKD1-T is an active-low, debounced input with an internal 20kΩ pullup to VCC. Pulling MR low forces an immediate reset regardless of VCC or RESET IN status, and reset remains asserted for the full 1.5ms timeout after MR returns high. Its 150ns glitch rejection eliminates need for external filtering, and it accepts CMOS-level signals or open-drain drivers - simplifying integration into test and field-service reset circuits.

Can MAX6843UKD1-T replace a fixed-threshold supervisor like MAX6326?

No - the MAX6843UKD1-T is not a drop-in replacement for fixed-threshold supervisors such as the MAX6326. While both are SOT23-5 reset ICs, the MAX6326 has factory-trimmed thresholds (e.g., 3.08V) and no RESET IN pin. The MAX6843UKD1-T requires external resistor configuration for threshold setting and targets sub-1.5V rails. Substitution would require redesign of the threshold network and validation of timing, leakage, and noise immunity - it is a functional alternative only for adjustable low-voltage supervision, not a pin-compatible replacement.