Analog Devices Inc./Maxim Integrated MAX9109ESA+

Overview

MAX9109ESA+ from Maxim Integrated is a single, high-speed, low-power TTL-compatible voltage comparator with internal latch and 25ns propagation delay at 10mV overdrive, operating from a +4.5V to +5.5V supply. It features 500µV typical offset voltage, 2mV internal hysteresis, and wide input common-mode range (–0.2V to V_CC–1.5V), used in precision threshold detection and battery-powered infrared data receivers.

For engineers reviewing the MAX9109ESA+ datasheet, MAX9109ESA+ pinout, MAX9109ESA+ application, or MAX9109ESA+ equivalent, key selection considerations include latch-enable timing (2ns setup/hold), TTL output drive capability (3.2mA sink), SO-8 package compatibility, and absence of complementary outputs compared to dual/quad variants.

Technical Context

The MAX9109ESA+ implements a bipolar comparator core with fixed 2mV input-referred hysteresis to suppress oscillation during slow input transitions, eliminating need for external feedback resistors. Its latch function operates synchronously on LE high, capturing output state without affecting propagation delay path.

Input stage supports rail-to-rail common-mode operation down to –0.2V (200mV below ground) and up to V_CC–1.5V, enabling direct interfacing with sensors and ADC reference levels. Output stage delivers TTL logic levels (VOH ≥3.0V at 100µA, VOL ≤0.6V at 3.2mA) without pull-up resistors.

Key Specifications

Pinout & Package

MAX9109ESA+ is housed in an 8-pin SO (Small Outline) package (package code S8-2), RoHS-compliant, with 150mil body width and standard JEDEC MS-012AC outline.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM311DR and TLV3201DBVR, the MAX9109ESA+ uniquely combines 25ns speed, integrated latch, TTL output drive, and industrial temperature support in a single SO-8 package-enabling compact, deterministic threshold detection where timing predictability and state retention are essential.

Availability

MAX9109ESA+ is available at Aetrix Electronics and suitable for battery-powered infrared receivers, A/D converter timing control, and industrial line receiver designs requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant sourcing.

Supply support for MAX9109ESA+ 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, emphasizing high performance, low power, and integration.

The MAX9107/MAX9108/MAX9109 family targets high-speed, low-power threshold detection in space-constrained systems, with the MAX9109ESA+ specifically engineered for single-channel applications needing latch synchronization and TTL compatibility.

FAQ

What is the maximum capacitive load the MAX9109ESA+ output can drive while maintaining 25ns propagation delay?

The MAX9109ESA+ maintains ≤25ns propagation delay with up to 15pF capacitive load at V_OD = 10mV and R_S = 10Ω. At 30pF, delay increases to ~35ns; for heavier loads, add a buffer stage. The SO-8 package's output pin capacitance is 3.5pF, so total net load should stay ≤11.5pF for guaranteed 25ns timing in production designs using MAX9109ESA+.

Does the MAX9109ESA+ require external hysteresis resistors for stable operation?

No, the MAX9109ESA+ incorporates a fixed 2mV internal hysteresis zone, eliminating need for external positive-feedback resistors. This design ensures clean output transitions even with slow-moving inputs like thermistor outputs or filtered PWM signals. External resistors may be added only to increase hysteresis beyond 2mV - the MAX9109ESA+ functions reliably out-of-the-box without them.

Can the MAX9109ESA+ operate from a 3.3V supply?

No, the MAX9109ESA+ is specified only for 4.5V to 5.5V operation. At 3.3V, output VOH falls below TTL high threshold (≥2.4V), and internal biasing fails - confirmed by Absolute Maximum Ratings limiting V_CC–GND to 6V minimum functional voltage of 4.5V. For 3.3V systems, consider TLV3201DBVR or MAX9021AUT+ instead of MAX9109ESA+.

What is the purpose of the N.C. pins (1 and 8) on the MAX9109ESA+ SO-8 package?

Pins 1 and 8 of the MAX9109ESA+ are No Connect - not bonded internally and electrically isolated. They may be left floating, tied to GND for mechanical reinforcement, or used as thermal relief anchors per PCB layout guidelines. Neither pin affects electrical performance; routing traces or vias to them does not alter MAX9109ESA+ functionality or timing behavior.

How does the latch function of the MAX9109ESA+ behave during power-up or brown-out conditions?

During power-up, the MAX9109ESA+ latch output is undefined until V_CC exceeds 4.5V and internal biasing stabilizes (~10µs). If LE is high during brown-out (V_CC < 4.5V), the latch retains its last valid state until V_CC recovers - no reset occurs. To ensure known state, assert LE low during power sequencing or use an external POR circuit; MAX9109ESA+ has no built-in power-on reset.