Analog Devices Inc. AD96685BRZ

Overview

AD96685BRZ from Analog Devices is a single ultrafast ECL-compatible voltage comparator with 2.5 ns propagation delay, 50 ps delay dispersion, and dual complementary open-emitter outputs. It operates from +5 V and –5.2 V supplies, supports input common-mode range from –2.5 V to +5 V, and is used in high-speed sampling circuits and threshold detection where precise timing alignment is critical.

For engineers reviewing the AD96685BRZ datasheet, AD96685BRZ pinout, AD96685BRZ application, or AD96685BRZ equivalent, key selection criteria include propagation delay consistency under varying overdrive, latch-enable timing margins (2.0 ns min pulse width), ECL-level output drive capability into 50 Ω to –2.0 V, and industrial temperature operation (–25°C to +85°C).

Technical Context

The AD96685BRZ implements a fast differential input stage with 200 kΩ input resistance and 2 pF input capacitance, enabling stable propagation delay across –2.5 V to +5 V common-mode range. Its level-sensitive latch enable input supports track-hold or sample-hold operation with 0.5 ns minimum setup/hold time relative to input transitions.

Outputs are open-emitter ECL-compatible signals requiring external 50–200 Ω pull-down resistors to –2.0 V. Propagation delay dispersion of 50 ps (measured from 100 mV to 1 V overdrive) ensures minimal timing skew in multi-channel or clock-aligned systems.

Key Specifications

Pinout & Package

AD96685BRZ is housed in a 16-pin SOIC package (R-16A outline), with exposed pad not present and standard JEDEC MS-012AC dimensions (10.00 × 6.20 mm body, 1.75 mm max height). Pin 1 is marked by notch or bevel.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX9601ASA+ and TLV3501CD, the AD96685BRZ uniquely delivers ECL-compatible open-emitter outputs, –2.5 V input capability, and integrated latch control-making it irreplaceable in high-speed test equipment and instrumentation requiring precise timing alignment and legacy ECL interface support.

Availability

AD96685BRZ is available at Aetrix Electronics and suitable for high-speed sampling circuits, threshold detectors, window comparators, and peak detector triggers requiring stable component supply across industrial temperature ranges.

Supply support for AD96685BRZ 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

Analog Devices is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, founded in 1965 and headquartered in Wilmington, MA.

The AD96685BRZ belongs to Analog Devices' Ultrafast Comparators product line, engineered specifically for precision timing-critical applications including automated test equipment, high-speed data acquisition, and real-time signal conditioning.

FAQ

What is the maximum input overdrive range supported by the AD96685BRZ while maintaining specified propagation delay dispersion?

The AD96685BRZ maintains 50 ps propagation delay dispersion across a 100 mV to 1 V input overdrive range, as confirmed in the "SWITCHING PERFORMANCES" table of the REV. D datasheet. This specification ensures consistent timing behavior for signals exceeding the switching threshold by up to 1 V, critical for robust operation in noisy or amplitude-variable environments. The AD96685BRZ achieves this via proprietary differential input architecture optimized for overdrive insensitivity.

Can the AD96685BRZ operate with a single positive supply, or does it require dual-rail voltage sources?

The AD96685BRZ requires dual-rail supplies: +5.0 V and –5.2 V, as explicitly stated in the "Power Supplies" feature list and electrical specifications. Its ECL-compatible open-emitter outputs and input stage architecture depend on the negative rail for proper biasing and level translation. Attempting single-supply operation will result in non-functional outputs and undefined input behavior. The AD96685BRZ is not designed for single-supply use.

How should unused pins be handled on the AD96685BRZ, particularly NC and ground pins?

The AD96685BRZ has three NC (No Connect) pins (pins 4, 7, and 12 per SOIC pinout), which must remain unconnected-no routing or grounding. GROUND 1 (pin 15) and GROUND 2 (pin 8) are separate analog and digital grounds and must both be connected to a low-impedance ground plane at a single point near the device. Leaving either ground floating violates the functional description and risks increased noise, latch-up, or timing instability in the AD96685BRZ.

Is the AD96685BRZ pin-compatible with the AD96687 dual comparator family members?

No, the AD96685BRZ is not pin-compatible with any AD96687 variant. The AD96685BRZ uses a 16-pin SOIC with dedicated single-comparator pinout (including one LATCH ENABLE, two outputs, and dual grounds), whereas AD96687BQ/BR/BP use 16-pin DIP/SOIC or 20-pin PLCC packages with duplicated input/output sets and dual latch enable inputs. Pin counts, functions, and physical layouts differ fundamentally-PCB redesign is required to substitute between AD96685BRZ and AD96687 devices.

What termination network is required for proper operation of the AD96685BRZ's open-emitter outputs?

The AD96685BRZ's Q and Q̅ outputs require external 50–200 Ω pull-down resistors connected to –2.0 V, as specified in the "FEATURES" section and "DIGITAL OUTPUTS" table. This termination establishes valid ECL logic levels (–1.1 V for HIGH, –1.5 V for LOW) and matches 50 Ω transmission lines to prevent reflections. Using +V or ground termination, or omitting pull-downs entirely, will cause incorrect logic states and degraded edge rates in the AD96685BRZ.