Analog Devices Inc./Maxim Integrated MAX9691ESA+T

Overview

The MAX9691ESA+T from Maxim Integrated is a single-channel, ultra-fast ECL-output comparator with 1.2ns typical propagation delay, ±11.5mV input offset voltage, and dual ±5.2V/+5V supply operation. It features differential inputs, complementary open-emitter outputs compatible with ECL logic levels, and drives 50Ω-terminated transmission lines-enabling high-speed line reception and threshold detection in >600MHz signal processing systems.

For engineers reviewing the MAX9691ESA+T datasheet, MAX9691ESA+T pinout, MAX9691ESA+T application, or MAX9691ESA+T equivalent, key selection considerations include its 100ps propagation delay skew, 150ps dispersion, latch-enable absence (distinguishing it from MAX9692/MAX9693), SO-8 package footprint, and ECL-level interface requirements for high-fidelity timing-critical comparators.

Technical Context

The MAX9691ESA+T implements a BiCMOS-based high-gain, wide-bandwidth comparator core optimized for minimal propagation delay while preserving DC matching. Its differential input stage operates over -2.5V to +3.0V common-mode range, and output stage delivers ECL-compatible logic levels (-0.76V to -1.89V) with 50Ω load drive capability.

No latch-enable function is integrated-unlike MAX9692/MAX9693-so the LE pin is absent in this variant. The device requires external 50Ω–200Ω pull-down resistors to -2.0V or 240Ω–2000Ω to -5.2V to establish valid ECL output logic states, and mandates ground-plane PCB layout with localized 0.01µF decoupling at VCC and VEE pins.

Key Specifications

Pinout & Package

MAX9691ESA+T is housed in an 8-pin SO (Small Outline) package per JEDEC MS-012, RoHS-compliant, with 1.27mm pitch and gull-wing leads. Thermal performance supports 588.2mW continuous dissipation at +70°C with 7.4mW/°C derating.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar ultra-fast ECL comparator applications.

Compared with MAX9691ESA+T, MAX9691EUA+T offers identical performance in a smaller package but reduced thermal headroom, while ADCMP572BCPZ-R7 provides lower power and single-supply convenience at the cost of ECL-level fidelity and dual-rail support.

Availability

MAX9691ESA+T is available at Aetrix Electronics and suitable for high-speed line receivers, threshold detectors, peak detectors, and high-speed triggers requiring stable component supply across industrial, test & measurement, and communications equipment lifecycles.

Supply support for MAX9691ESA+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, mixed-signal, and high-speed ICs for demanding industrial, communications, and computing applications.

The MAX9691ESA+T belongs to Maxim's ultra-fast comparator product line, engineered specifically for sub-nanosecond decision timing in ECL-based signal conditioning, high-frequency test instrumentation, and RF subsystems.

FAQ

What is the supply voltage configuration required for MAX9691ESA+T?

The MAX9691ESA+T requires dual supplies: +5V on VCC (Pin 1) and -5.2V on VEE (Pin 4). These voltages establish the ECL-compatible logic swing and internal bias points. Operation outside the Absolute Maximum Ratings (VCC: -0.3V to +6V; VEE: -6V to +0.3V) risks permanent damage. Decoupling capacitors (0.1µF ceramic) must be placed directly at each supply pin to suppress high-frequency noise that could destabilize the comparator's GHz-range bandwidth.

Does MAX9691ESA+T include a latch-enable function?

No, MAX9691ESA+T does not include a latch-enable function. It is the single-comparator variant without LE capability-unlike MAX9692 or MAX9693. The pinout omits LE entirely; only VCC, IN+, IN-, VEE, Q OUT, Q̅ OUT, GND1, and GND2 are present. If latch functionality is needed, MAX9692ESA+T (single-channel with LE) or MAX9693EEE+T (dual-channel with LE) must be selected instead.

How should the open-emitter outputs of MAX9691ESA+T be terminated?

The Q OUT and Q̅ OUT pins of MAX9691ESA+T are open-emitter and require external pull-down resistors to establish valid ECL logic levels. For VT = -2.0V, use 50Ω–200Ω resistors; for VT = -5.2V, use 240Ω–2000Ω. These resistors must connect to the appropriate negative termination voltage-not ground-and form part of the 50Ω transmission line termination. Improper resistor values or connection to ground will result in invalid output voltage levels and signal integrity degradation.

What is the maximum operating frequency supported by MAX9691ESA+T?

MAX9691ESA+T supports signal processing in excess of 600MHz, as confirmed by its 1.2ns propagation delay and validated 100MHz output response in the datasheet. This capability stems from its BiCMOS architecture and optimized layout-enabling clean switching in high-speed line receivers and triggers. Actual usable bandwidth depends on PCB layout (ground plane, microstrip routing), source impedance, and load capacitance; propagation delay increases with higher CLOAD or source impedance per characterization curves.

Why are there two ground pins (GND1 and GND2) on MAX9691ESA+T?

GND1 and GND2 serve distinct internal functions: GND1 biases the input differential pair, while GND2 biases the ECL output stage. They must be connected together externally to a solid copper ground plane to prevent ground loops and ensure stable DC operating points. Separating them on the PCB or routing them through different paths introduces noise coupling and timing jitter-degrading the 100ps skew specification and increasing propagation delay variation.