Analog Devices Inc./Maxim Integrated MAX977ESD+

Overview

MAX977ESD+ from Maxim Integrated is a dual high-speed/low-power comparator with auto-standby functionality, optimized for +3V/+5V single-supply operation. It features 28ns propagation delay in high-speed mode, 3µA supply current in low-power mode, and independently adjustable timeout periods per channel via external capacitors. It serves as a rail-to-rail output threshold detector in battery-powered RF ID tag receivers.

For engineers reviewing the MAX977ESD+ datasheet, MAX977ESD+ pinout, MAX977ESD+ application, or MAX977ESD+ equivalent, key selection criteria include dual-channel independent auto-standby timing control, ground-sensing input capability down to –0.2V, internal hysteresis in high-speed mode, and SO-14 package compatibility with industrial temperature range (–40°C to +85°C).

Technical Context

The MAX977ESD+ integrates two independent comparators, each with three operating modes: high-speed (28ns t_PD, 250µA ICC), auto-standby (triggered by output idle timeout), and low-power (480ns t_PD, ≤5µA ICC). Each channel uses separate STOA/STOB pins to set timeout via external capacitors (t_ASB = 10 × C_STO µs, C in pF).

Its input stage supports common-mode voltage from –0.2V to (V_CC – 1.2V), differential rail-to-rail input range, and rail-to-rail CMOS/TTL-compatible outputs without pull-ups. Internal hysteresis (0.3–4mV) ensures clean switching with slow-moving signals in high-speed mode.

Key Specifications

Pinout & Package

The MAX977ESD+ is housed in a 14-pin SO (Small Outline) package (package code S14-1), with exposed pad not electrically connected. Pin pitch is 1.27mm, body width 3.9mm, and JEDEC MS-012 compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM393DR and TLV3702IDR, the MAX977ESD+ uniquely delivers adaptive dual-speed operation with per-channel timeout control - enabling optimal trade-offs between response latency and energy consumption in intermittent-signal detection systems.

Availability

MAX977ESD+ is available at Aetrix Electronics and suitable for battery-powered systems, RF ID tags, and keyless entry modules requiring stable component supply across automotive and industrial temperature ranges.

Supply support for MAX977ESD+ 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, automotive, and communications markets.

The MAX975/MAX977 family was engineered specifically for ultra-low-power, high-speed threshold detection in intermittently active wireless sensor nodes - balancing nanosecond response with sub-µA standby current.

FAQ

What are the key timing parameters that define auto-standby behavior in the MAX977ESD+?

The MAX977ESD+ enters auto-standby when its output remains unchanged for a timeout period set by an external capacitor on STOA or STOB: t_ASB = 10 × C_STO µs (C in pF). Wake-up occurs within 1.6µs of an output transition. The MAX977ESD+ also supports programmable low-power enable time (1.1µs) and high-speed enable time (0.7µs), all guaranteed by design across –40°C to +85°C.

How does the MAX977ESD+ achieve rail-to-rail input operation while maintaining –0.2V common-mode capability?

The MAX977ESD+ uses a specialized input stage that extends the common-mode range to –0.2V relative to GND, allowing direct connection to ground-referenced sensors like IR photodiodes. Its differential input voltage range spans rail-to-rail (GND to V_CC), ensuring correct output logic state even when one input is at GND and the other at V_CC. This is validated across the full operating temperature range.

Can the STAT outputs of the MAX977ESD+ be used to power external circuitry, and what are the limits?

Yes - each STAT pin (STATA and STATB) can source up to 3mA of current when high, enabling direct powering of LEDs, level-shifters, or enable inputs on companion ICs. This feature is fully specified across –40°C to +85°C and supports automatic power sequencing: STAT goes high during auto-standby or low-power mode, providing a hardware-controlled wake-up signal without MCU intervention.

What is the role of the LP pin in the MAX977ESD+, and how should it be managed for noise immunity?

The LP pin globally controls operating mode: driven high to force both comparators into ≤5µA low-power mode; driven low to enable high-speed or auto-standby operation. Because LP is noise-sensitive, Maxim specifies that fall times >10µs require a 0.1µF bypass capacitor to GND. The MAX977ESD+ datasheet guarantees LP input current ≤±1nA, making it compatible with standard CMOS logic interfaces.

How does internal hysteresis in the MAX977ESD+ improve performance in high-speed mode?

The MAX977ESD+ provides 0.3–4mV input-referred hysteresis exclusively in high-speed mode, creating distinct upper and lower trip points (V_TRIP+, V_TRIP–) to prevent oscillation during slow-moving or noisy input transitions. This eliminates need for external hysteresis resistors in threshold-detection applications like IR receivers and digital-line receivers, while maintaining 28ns propagation delay specification.