Analog Devices Inc./Maxim Integrated MAX991ESA+T

Overview

MAX991ESA+T from Maxim Integrated is a dual, micropower, rail-to-rail input/output comparator with push-pull outputs, operating from +2.5V to +5.5V single supply or ±1.25V to ±2.75V dual supplies. It delivers 120ns propagation delay, 48μA per comparator quiescent current, and ±0.5mV typical input offset voltage. It is used in battery-powered zero-crossing detectors and threshold discriminators where low power and fast response are critical.

For engineers reviewing the MAX991ESA+T datasheet, MAX991ESA+T pinout, MAX991ESA+T application, or MAX991ESA+T equivalent, key selection considerations include its dual-channel push-pull output architecture, rail-to-rail common-mode range extending 250mV beyond rails, 8mA output drive capability, and guaranteed operation from –40°C to +85°C in the 8-pin μMAX package.

Technical Context

The MAX991ESA+T integrates two independent comparators sharing a common supply domain, each featuring internal 2.5mV hysteresis to prevent chatter on slow-moving inputs. Its input stage supports common-mode voltages from VEE – 0.25V to VCC + 0.25V, enabling direct sensing of signals beyond supply rails without phase reversal.

The push-pull output stage actively sources and sinks up to 8mA while maintaining rail-to-rail swing, eliminating need for external pull-up resistors. Supply-current surges during switching are minimized-only ~100μA increase at 1MHz transition frequency-reducing supply-line glitches and easing decoupling requirements.

Key Specifications

Pinout & Package

The MAX991ESA+T is housed in an 8-pin μMAX® package (U8-1), measuring 3.0mm × 3.0mm × 0.8mm with exposed pad for thermal enhancement. This ultra-small outline supports high-density PCB layouts in space-constrained portable electronics.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM393DR and TLV3702IDR, the MAX991ESA+T uniquely balances 120ns speed, 48μA efficiency, 8mA drive, and true rail-to-rail I/O-making it optimal for compact, battery-sensitive systems requiring robust analog decision-making without external support circuitry.

Availability

MAX991ESA+T is available at Aetrix Electronics and suitable for portable medical monitors, industrial sensor nodes, and battery-powered test equipment requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for MAX991ESA+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 industrial, communications, and consumer applications, with emphasis on power efficiency and integration.

The MAX991ESA+T belongs to Maxim's high-speed micropower comparator family, engineered specifically for low-voltage, battery-constrained systems demanding fast, accurate, and glitch-immune signal comparison without external support components.

FAQ

What is the maximum capacitive load the MAX991ESA+T can drive while maintaining 120ns propagation delay?

The MAX991ESA+T maintains ≤120ns propagation delay for 100mV overdrive with up to 50pF capacitive load at VCC = 5V. At 200pF, delay increases to 40ns for rise/fall times but remains ≤120ns for propagation. For loads >50pF, layout parasitics and trace inductance become dominant-keep output traces short and avoid stubs to preserve timing fidelity in the MAX991ESA+T.

Does the MAX991ESA+T support dual-supply operation, and what are the valid voltage ranges?

Yes, the MAX991ESA+T supports dual-supply operation from ±1.25V to ±2.75V (i.e., VCC = +1.25V to +2.75V, VEE = –1.25V to –2.75V). Total supply voltage (VCC – VEE) must not exceed 6V. In dual mode, inputs operate from VEE – 0.25V to VCC + 0.25V, and outputs swing rail-to-rail-enabling bipolar signal conditioning in the MAX991ESA+T without level-shifting circuitry.

Can the MAX991ESA+T be used in a window comparator configuration, and how is it implemented?

Yes, the MAX991ESA+T's dual independent comparators make it ideal for window comparator designs. Connect one comparator (INA+/INA−) to detect upper threshold and the other (INB+/INB−) to lower threshold, with OUTA and OUTB feeding logic AND/NAND gates or MCU GPIOs. Internal hysteresis (±2.5mV) reduces noise sensitivity-no external resistors needed unless wider hysteresis is required. This dual-channel architecture simplifies window detection in the MAX991ESA+T versus using two discrete single comparators.

What is the output voltage swing capability of the MAX991ESA+T under 8mA load at 2.7V supply?

At VCC = 2.7V and ISINK = 3.5mA, the MAX991ESA+T guarantees VOL ≤ 0.3V (typical 0.15V); at ISOURCE = 3.5mA, VOH ≥ 2.4V (typical 2.55V). While rated for 8mA drive, the 3.5mA condition reflects the specified test point for 2.7V operation. Full 8mA drive is validated at 5V (VOL ≤ 0.4V, VOH ≥ 4.6V). Thus, the MAX991ESA+T delivers near rail-to-rail swing even at low supply, supporting reliable logic interfacing across its entire voltage range.

Is the μMAX package of the MAX991ESA+T thermally enhanced, and what PCB layout guidance applies?

Yes, the MAX991ESA+T μMAX package (U8-1) features an exposed thermal pad that must be soldered to a minimum 100mm² copper pour tied to VEE for optimal thermal performance. Layout requires a 6×6 array of 0.3mm vias under the pad connecting to inner ground planes. Place a 0.1μF ceramic decoupling capacitor within 2mm of the VCC pin. These practices reduce junction temperature rise by >20°C and ensure stable operation of the MAX991ESA+T in continuous high-speed switching.