Analog Devices Inc. HMC974LC3C

Overview

HMC974LC3C from Analog Devices is a silicon germanium (SiGe) monolithic ultra-fast window comparator with RSPECL output drivers, 88 ps input-to-output propagation delay, 11 GHz equivalent input bandwidth, and 60 ps minimum detectable pulse width. It operates in track or latch mode to determine whether an analog input lies above, below, or between two user-defined reference voltages (RT and RB), serving high-speed threshold detection in electronic warfare systems and clock/data restoration.

For engineers reviewing the HMC974LC3C datasheet, HMC974LC3C pinout, HMC974LC3C application, or HMC974LC3C equivalent, key selection considerations include its differential latch control, −3 V/3.3 V/2 V supply configuration, 16-terminal 2.9 mm × 2.9 mm LCC package, and single-ended negative logic outputs (URB, WOUTB, ORB) with 300–440 mV swing into 50 Ω.

Technical Context

The HMC974LC3C implements dual matched SiGe comparators at its input stage to ensure precise dc and dynamic matching while minimizing input capacitance. Its three independent outputs-URB (under-range), WOUTB (in-window), and ORB (over-range)-are level-latched and driven by reduced-swing PECL stages capable of delivering 400 mV into 50 Ω terminated loads.

It supports two operational modes: track mode for real-time window monitoring and latch mode enabled via complementary LE/LE inputs. Power sequencing requires VEE applied first (−3 V), followed by VCCI (3.3 V) and VCCO (2 V), with strict adherence to avoid latch-up or damage.

Key Specifications

Pinout & Package

The HMC974LC3C is housed in a 16-terminal 2.9 mm × 2.9 mm ceramic leadless chip carrier (LCC) with exposed pad requiring connection to VEE. The package is RoHS-compliant, MSL3-rated, and features gold-over-nickel terminations on alumina substrate.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADCMP572BCPZ-R7 and HMC860LC3C, the HMC974LC3C uniquely delivers triple-state single-input window detection with 88 ps delay, latch control, and RSPECL outputs-making it irreplaceable for 5+ Gbps clock/data recovery and electronic warfare pulse analysis where timing fidelity and output granularity are critical.

Availability

HMC974LC3C is available at Aetrix Electronics and suitable for automatic test equipment (ATE), high-speed instrumentation, and semiconductor test systems requiring stable component supply, long-term lifecycle assurance, and traceable sourcing for production programs.

Supply support for HMC974LC3C 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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing technologies, headquartered in Norwood, MA, with design and manufacturing expertise spanning RF, precision measurement, and high-speed data conversion.

The HMC974LC3C belongs to Analog Devices' Hittite Microwave product line, engineered specifically for microwave and millimeter-wave instrumentation, defense electronics, and high-speed test systems demanding sub-100 ps timing resolution and RF-grade signal integrity.

FAQ

What is the operating supply configuration required for the HMC974LC3C?

The HMC974LC3C requires three independent supplies: VEE = −3.0 V (pins 8, 14, and exposed pad), VCCI = +3.3 V (pins 5, 16), and VCCO = +2.0 V (pins 9, 13). Power sequencing mandates applying VEE first, then VCCI/VCCO simultaneously if equal, or VCCO last if different. This sequence prevents latch-up and ensures stable RSPECL output driver operation in the HMC974LC3C.

How does the latch mode function in the HMC974LC3C?

Latch mode in the HMC974LC3C is controlled by complementary LE and LE inputs: asserting LE low and LE high freezes the current state of URB, WOUTB, and ORB outputs until the next latch event. When both LE pins float, the device defaults to track mode, continuously updating outputs in real time. This dual-mode capability makes the HMC974LC3C suitable for both streaming analysis and edge-triggered capture without external logic.

What is the significance of the WIT pin in the HMC974LC3C interface?

The WIT (Window Input Termination) pin establishes the common-mode voltage reference for all differential inputs (WIN–RT, WIN–RB). It must be DC-biased to set VCM = 0 V (typical), enabling proper operation of the 50 Ω-terminated inputs. Incorrect WIT biasing causes input stage saturation or reduced dynamic range, directly impacting the accuracy of window detection in the HMC974LC3C.

Can the HMC974LC3C drive standard 50 Ω transmission lines directly?

Yes-the HMC974LC3C's RSPECL outputs (URB, WOUTB, ORB) are designed to drive 50 Ω loads terminated to VTERM = VCCO − 2 V (typically 0 V when VCCO = +2.0 V). Each output delivers 300–440 mV swing with 25.3 ps rise time and 21.9 ps fall time, eliminating need for external level shifters or buffers in most high-speed PCB layouts using the HMC974LC3C.

What thermal management considerations apply to the HMC974LC3C package?

The HMC974LC3C uses a 16-terminal LCC with an exposed metal base pad that must be soldered directly to a VEE-connected copper pour for effective heat dissipation. With 240 mW power dissipation and 49°C/W junction-to-case thermal resistance, maintaining ≥2 cm² of internal/external VEE copper with ≥6 thermal vias is essential to keep junction temperature ≤125°C in continuous operation of the HMC974LC3C.