Analog Devices Inc./Maxim Integrated MAX944CSD

Overview

MAX944CSD from Maxim Integrated is a quad high-speed comparator optimized for 3V/5V single-supply systems, featuring rail-to-rail inputs, 80ns propagation delay (5mV overdrive), 350μA per comparator supply current, and CMOS/TTL-compatible outputs. It operates from 2.7V to 5.5V and is used in threshold detection, zero-crossing sensing, and line receiver circuits where low power and fast response are critical.

For engineers reviewing the MAX944CSD datasheet, MAX944CSD pinout, MAX944CSD application, or MAX944CSD equivalent, key selection criteria include guaranteed 80ns propagation delay at 5mV overdrive, rail-to-rail input common-mode range extending beyond supply rails, output swing within 0.4V of V+ or GND, internal hysteresis for noise immunity, and compatibility with 14-pin SO packaging for space-constrained PCB layouts.

Technical Context

The MAX944CSD implements a bipolar process-based comparator core with internal hysteresis (1mV typical input-referred width), eliminating external feedback components. Its rail-to-rail input stage accepts voltages from –0.2V to V+ + 0.2V, enabling direct interface with sensors and DACs operating near supply rails.

Each of the four comparators features a current-driven output stage that sources/sinks up to 4mA while maintaining VOH ≥ V+ – 0.4V and VOL ≤ 0.4V. Propagation delay skew between channels is ≤10ns, supporting synchronized multi-channel decision logic in sampling and timing-critical applications.

Key Specifications

Pinout & Package

The MAX944CSD is housed in a 14-pin narrow SO (Small Outline) package with standard 1.27mm pitch, JEDEC MS-012AC compliant footprint, and RoHS-compliant lead finish.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad comparator applications.

Compared with LM339DR and TLV3201IDR, the MAX944CSD uniquely balances 80ns speed, 1.4mA total quiescent current, true quad integration in 14-pin SO, and rail-to-rail input capability-making it optimal for space-constrained, medium-speed, battery-aware systems requiring four parallel comparisons.

Availability

MAX944CSD is available at Aetrix Electronics and suitable for battery-powered systems, threshold detectors/discriminators, and line receivers requiring stable component supply across industrial temperature ranges and long production lifecycles.

Supply support for MAX944CSD 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 MAX94x family was designed specifically for high-speed, low-power, single-supply comparator applications in portable and 3V/5V embedded systems-emphasizing rail-to-rail input operation, internal hysteresis, and robust I/O tolerance.

FAQ

What is the maximum supply voltage rating for the MAX944CSD?

The MAX944CSD has an absolute maximum supply voltage (V+ to GND) of +6.5V. However, its specified operational range is 2.7V to 5.5V. Operating above 5.5V may cause parametric degradation or permanent damage, even if within the absolute maximum rating. Always maintain V+ within 2.7V–5.5V for reliable performance of the MAX944CSD in production designs.

Does the MAX944CSD include internal hysteresis, and how does it affect threshold accuracy?

Yes, the MAX944CSD includes fixed internal hysteresis with a typical input-referred width of 1mV. This hysteresis prevents output oscillation during slow-moving or noisy input transitions near the trip point. While it introduces a small uncertainty band around the nominal threshold, it eliminates the need for external hysteresis resistors and improves system reliability-especially critical in the MAX944CSD's intended use cases like zero-crossing and line reception.

Can the MAX944CSD inputs safely handle voltages below ground or above V+?

Yes, the MAX944CSD input common-mode range extends from –0.2V to V+ + 0.2V, and all input pins tolerate continuous short-circuit faults to either supply rail. This rail-to-rail plus margin capability allows direct interfacing with AC-coupled signals, sensor outputs swinging beyond supplies, and legacy 5V logic driving 3.3V domains-without external clamping diodes or level shifters in the MAX944CSD signal path.

What is the output drive capability of the MAX944CSD, and is it compatible with 3.3V logic?

The MAX944CSD outputs drive to within 0.4V of V+ (VOH ≥ V+ – 0.4V) and 0.4V of GND (VOL ≤ 0.4V) while sourcing or sinking up to 4mA. At V+ = 3.3V, this yields VOH ≥ 2.9V and VOL ≤ 0.4V-fully compatible with 3.3V CMOS and LVTTL logic families. No external pull-ups are needed, making the MAX944CSD directly interoperable with modern microcontrollers and FPGAs.

How does the MAX944CSD compare to the MAX942 dual comparator in terms of pin compatibility and layout reuse?

The MAX944CSD (14-pin SO) and MAX942 (8-pin SO) are not pin-compatible due to differing channel count, pin count, and pin assignments. The MAX944CSD uses pins 1–3, 5–7, 9–10, 12–14 for its four channels and GND/V+, whereas the MAX942 uses pins 1–3, 5–7 for two channels and GND/V+. Layout reuse is not possible; however, both share identical electrical specs per channel (80ns delay, 350μA, rail-to-rail inputs), enabling functional migration with board redesign.