Analog Devices Inc./Maxim Integrated MAX944EPD

Overview

The MAX944EPD 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 internal hysteresis - enabling clean switching in battery-powered threshold detection and zero-crossing applications.

For engineers reviewing the MAX944EPD datasheet, MAX944EPD pinout, MAX944EPD application, or MAX944EPD equivalent, key selection considerations include its -40°C to +85°C operating range, 14-pin PDIP package, rail-to-rail input common-mode range extending beyond both rails, and CMOS/TTL-compatible push-pull outputs requiring no external pullups.

Technical Context

The MAX944EPD implements a bipolar process-based comparator core with fixed internal hysteresis (1mV typical input-referred trip width), enabling stable output transitions even with slow-moving or noisy input signals without external feedback components. Its input stage tolerates differential voltages up to ±2.2V and common-mode voltages from -0.3V to (V+ + 0.3V).

The output stage delivers rail-to-rail swing: VOH = V+ − 0.2V (at 400μA source), VOL = 0.2V (at 400μA sink), supporting direct interfacing to CMOS and TTL logic families. Propagation delay skew between channels is ≤10ns, and differential propagation delay is ≤10ns - critical for synchronized multi-channel sensing.

Key Specifications

Pinout & Package

MAX944EPD is housed in a 14-pin plastic DIP (PDIP) package with 0.300" wide body, through-hole mounting, and industry-standard 0.1" pin pitch. Pin 11 is GND; pins 4 and 10 are V+; all four comparator outputs (OUTA–OUTD) and corresponding inputs (INA±, INB±, INC±, IND±) are individually accessible.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM339DR and TLV3704IPW, the MAX944EPD uniquely balances 80ns speed, 350μA efficiency, -40°C to +85°C rating, and rail-to-rail operation in a through-hole PDIP - making it optimal for industrial sensing where reliability across temperature and timing precision are jointly required.

Availability

MAX944EPD is available at Aetrix Electronics and suitable for industrial PLC I/O modules, battery-powered medical monitors, automotive body control units, and test equipment requiring stable component supply across extended temperature ranges.

Supply support for MAX944EPD 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 operation, internal hysteresis, and robust input protection.

FAQ

What is the maximum supply voltage rating for the MAX944EPD?

The MAX944EPD has an absolute maximum supply voltage (V+ to GND) of +6.5V. Operation is specified from 2.7V to 5.5V. Exceeding 6.5V risks permanent damage, and sustained operation above 5.5V voids parametric guarantees. For 5V systems, ensure decoupling and transient suppression to prevent overshoot beyond 6.5V during hot-plug or load-dump events. The MAX944EPD must never be operated at 6.5V continuously.

Does the MAX944EPD include internal hysteresis, and how does it affect threshold accuracy?

Yes, the MAX944EPD features fixed internal hysteresis (~1–3mV input-referred). This eliminates external hysteresis resistors but introduces a small, predictable deadband between rising and falling input thresholds. For example, with a 1mV hysteresis, the upper trip point is ~0.5mV above the nominal threshold and the lower is ~0.5mV below. This ensures chatter-free switching on slow or noisy signals - a deliberate trade-off that enhances reliability in real-world applications where the MAX944EPD is deployed.

Can the MAX944EPD inputs safely operate below ground or above V+?

Yes. The MAX944EPD input common-mode range extends from -0.3V to (V+ + 0.3V), and inputs tolerate continuous short-circuit faults to either rail. This allows direct connection to AC-coupled signals, op-amp outputs swinging beyond rails, or level-shifted interfaces - provided differential input voltage stays within ±2.2V. This capability is confirmed in the Absolute Maximum Ratings and Electrical Characteristics tables of the MAX944EPD datasheet.

What is the output drive capability of the MAX944EPD, and does it require pull-up resistors?

The MAX944EPD features push-pull (totem-pole) CMOS/TTL-compatible outputs that actively drive high and low - no external pull-up resistors are needed. It sources 400μA to within 0.2V of V+ and sinks 400μA to within 0.2V of GND. At 4mA load, VOL rises to 0.4V and VOH drops to V+ − 0.3V. This makes the MAX944EPD ideal for driving standard logic inputs directly, unlike open-collector comparators such as the LM339.

How does the MAX944EPD compare to the MAX941 and MAX942 in terms of functionality?

The MAX944EPD is the quad version of the family and shares core specs (80ns delay, 350μA/comparator, rail-to-rail inputs, internal hysteresis) with the MAX941 (single) and MAX942 (dual), but lacks the MAX941's latch and shutdown functions. All three use the same bipolar process and pin-compatible layouts within their respective channel counts. The MAX944EPD provides four independent comparators in one 14-pin PDIP, offering higher integration density than using two MAX942EPA devices - reducing PCB area and assembly cost in multi-threshold systems.