Analog Devices Inc./Maxim Integrated MAX6843UKD0+

Overview

The MAX6843UKD0+ from Maxim Integrated is an ultra-low-voltage microprocessor supervisory circuit with adjustable reset threshold via RESET IN input, 150µs fixed timeout period (voltage detector mode), ±2.5% threshold accuracy over temperature, and active-low push-pull RESET output - designed for reliable power monitoring in 0.9V–1.5V digital systems such as portable battery-powered controllers and telecom baseband modules.

For engineers reviewing the MAX6843UKD0+ datasheet, MAX6843UKD0+ pinout, MAX6843UKD0+ application, or MAX6843UKD0+ equivalent, key selection criteria include its 187.4mV referenced RESET IN threshold, guaranteed reset validity down to VCC = 0.55V, 5.7µA typical supply current, immunity to sub-150ns VCC transients, and SOT23-5 package compatibility with space-constrained embedded designs.

Technical Context

The MAX6843UKD0+ implements a precision voltage comparator referenced to VCC, where RESET IN threshold is fixed at 187.4mV relative to VCC - enabling externally adjustable monitoring of supplies from 0.9V to 1.5V using a resistive divider. Its internal timer asserts reset for exactly 150µs after VCC or RESET IN recovers above threshold, with no external capacitor required.

It features a debounced manual reset (MR) input with 20kΩ internal pullup, 1µs minimum pulse width support, and 150ns glitch rejection. The active-low push-pull RESET output drives low to 0.2×VCC at 10µA sink current and remains functional down to VCC = 0.55V, ensuring deterministic behavior during brownout recovery.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, surface-mount, lead-free (indicated by '+' suffix), footprint-compatible with industry-standard SOT-23 layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6844UKD0+, the MAX6843UKD0+ provides native compatibility with conventional active-low microprocessor reset inputs; compared with TPS3123E12DBVR, it trades slightly higher quiescent current for full threshold adjustability and shorter 150µs response - critical for voltage detector use cases and fast-recovery systems.

Availability

MAX6843UKD0+ is available at Aetrix Electronics and suitable for portable equipment, telecom baseband modules, and industrial sensor nodes requiring stable component supply with guaranteed long-term availability and lead-free compliance.

Supply support for MAX6843UKD0+ 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 interface applications in industrial, communications, and consumer systems.

The MAX6843UKD0+ belongs to the MAX6841–MAX6845 ultra-low-voltage µP supervisory family, engineered specifically to replace discrete reset solutions in sub-1.5V digital systems while delivering factory-trimmed or user-adjustable thresholds and zero-component timing.

FAQ

What is the exact reset timeout period for MAX6843UKD0+?

The MAX6843UKD0+ has a fixed 150µs reset timeout period, designated as the "voltage detector version" in the datasheet. This value is internally programmed and does not require external components. It defines the minimum duration that the active-low RESET output remains asserted after VCC or RESET IN rises above the threshold. This short, precise delay makes the MAX6843UKD0+ ideal for applications needing rapid reset confirmation without timing capacitor variability.

How is the reset threshold set on MAX6843UKD0+?

The MAX6843UKD0+ uses its RESET IN pin to accept an externally derived voltage referenced to VCC, with an internal comparator threshold of 187.4mV relative to VCC. A simple two-resistor divider from VCC to GND sets the trip point - for example, to monitor a 1.0V supply, R1 = 4.22kΩ and R2 = 100kΩ yields ~187mV at RESET IN. The MAX6843UKD0+'s high-impedance input (±25nA leakage) enables use of large resistors to minimize divider current draw.

Does MAX6843UKD0+ support operation below 1.0V?

Yes, the MAX6843UKD0+ operates and asserts valid reset down to VCC = 0.55V. Its push-pull RESET output remains functional with defined VOL ≤ 0.2×VCC at 10µA sink current even at this level. Below 0.55V, the output enters high-impedance state - but since most microprocessors cease operation below ~0.6V, this aligns with system-level failure boundaries. The MAX6843UKD0+'s guaranteed operation to 0.55V ensures robust brownout detection in ultra-low-voltage designs.

What is the function of the MR pin on MAX6843UKD0+?

The MR (Manual Reset) pin on MAX6843UKD0+ is an active-low input with a built-in 20kΩ pullup resistor to VCC. Driving MR low forces immediate reset assertion, independent of VCC or RESET IN status. Reset remains active for the full 150µs timeout after MR returns high. This enables hardware-initiated resets via pushbutton or system controller signals. No external debounce is needed due to 150ns glitch rejection and internal synchronization - a key reliability feature of the MAX6843UKD0+.

Can MAX6843UKD0+ be used with a 3.3V microprocessor reset input?

Yes, the MAX6843UKD0+'s active-low push-pull RESET output is compatible with 3.3V logic inputs when VCC ≥ 0.83V. Its VOH reaches 0.8×VCC when sourcing 40µA, and VOL stays ≤ 0.2×VCC when sinking 10µA. For direct connection to a 3.3V µP reset pin, ensure the µP's input high threshold is ≤ 0.8×VCC (e.g., VCC = 1.5V → VOH = 1.2V, sufficient for TTL-compatible inputs). If CMOS-level compatibility is required, verify the µP's VIH min against the MAX6843UKD0+'s actual VOH under load.