Analog Devices Inc. HMC973LP3ETR

Overview

HMC973LP3ETR from Analog Devices (formerly Hittite Microwave) is a GaAs MMIC voltage-variable attenuator (VVA) operating from 0.5 to 6.0 GHz, delivering 26 dB attenuation range with single +0 to +5 V analog control, +35 dBm input IP3 linearity, and absorptive topology in a 3×3 mm QFN package. It serves as a unidirectional RF signal level controller in microwave transceivers and test instrumentation.

For engineers reviewing the HMC973LP3ETR datasheet, HMC973LP3ETR pinout, HMC973LP3ETR application, or HMC973LP3ETR equivalent, key selection criteria include its DC-coupled 50 Ω RFIN/RFOUT ports, 200–300 µA supply current, -40 to +85 °C operating temperature, RoHS-compliant MSL1 packaging, and shunt-type analog control architecture requiring no external bias networks.

Technical Context

The HMC973LP3ETR implements a GaAs FET-based shunt-type voltage-variable attenuator with absorptive termination, enabling stable impedance matching across its full 0.5–6.0 GHz band. Its unidirectional design mandates RF input at RFIN for optimal linearity, and it requires no external DC blocking on RFIN/RFOUT when DC potential matches system ground.

Control is achieved via a single 0–5 V analog voltage (Vctrl) applied to Pin 7, directly modulating attenuation without digital interface or internal DAC. The device draws only 200–300 µA from a +5 V supply (Pin 5), and all ground pins (1,2,4,9,11,12) plus the exposed paddle must be soldered to RF/DC ground per Hittite's land pattern guidelines.

Key Specifications

Pinout & Package

Package: 16-lead 3×3 mm QFN (RoHS-compliant, MSL1, matte tin finish), with exposed ground paddle requiring solder connection to PCB RF ground.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar voltage-variable attenuator applications.

Compared with HMC1082LP3E and QM11028, the HMC973LP3ETR offers the best balance of linearity (+35 dBm IP3), low supply current (200–300 µA), and single +5 V operation in a compact 3×3 mm QFN-making it optimal for space-constrained, power-sensitive 0.5–6.0 GHz infrastructure and instrumentation designs.

Availability

HMC973LP3ETR is available at Aetrix Electronics and suitable for point-to-point radio, cellular/4G infrastructure, and test instrumentation requiring stable component supply, long-term lifecycle support, and traceable RoHS-compliant sourcing.

Supply support for HMC973LP3ETR 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 acquired Hittite Microwave in 2014, integrating its high-frequency RF IC portfolio into ADI's broader signal chain solutions for communications and defense markets.

The HMC973LP3ETR belongs to Hittite's GaAs MMIC voltage-variable attenuator product line, engineered specifically for analog-controlled RF power management in microwave infrastructure where linearity, small size, and DC-coupled operation are critical.

FAQ

What is the absolute maximum RF input power rating for the HMC973LP3ETR?

The HMC973LP3ETR has an absolute maximum RF input power rating of +29 dBm. This limit applies across its full 0.5–6.0 GHz operating band and must not be exceeded to prevent permanent damage. Operation near this limit requires careful thermal management via the exposed ground paddle and PCB copper area, as continuous dissipation at elevated power levels impacts reliability and linearity performance.

Does the HMC973LP3ETR require external DC blocking capacitors on RFIN and RFOUT?

Yes, the HMC973LP3ETR requires external DC blocking capacitors on both RFIN and RFOUT if the connected RF line operates at a DC potential other than 0 V. Both ports are DC-coupled and matched to 50 Ω, so unintended DC bias can disrupt downstream components. A typical 100 pF 0402 capacitor is used in Hittite's evaluation board (PCB #131550) for this purpose.

Is the HMC973LP3ETR pin-compatible with other Hittite LP3E-series attenuators like the HMC657LP3E?

No, the HMC973LP3ETR is not pin-compatible with the HMC657LP3E. While both use 3×3 mm QFN packages, their pin functions differ significantly: HMC973LP3ETR assigns RFIN to Pin 10 and RFOUT to Pin 3, whereas HMC657LP3E uses different pin allocations and lacks Vctrl on Pin 7. PCB layout changes are required for substitution.

What is the thermal resistance (θ_JA) specification for the HMC973LP3ETR?

The HMC973LP3ETR has a channel-to-ground-paddle thermal resistance of 80 °C/W. This value assumes proper soldering of all ground pins and the exposed paddle to a multilayer PCB with adequate thermal vias. Junction temperature must remain ≤150 °C under worst-case RF + DC power dissipation; derating is required above +85 °C ambient.

Can the HMC973LP3ETR operate with Vctrl voltages below 0 V or above +5 V?

No, the HMC973LP3ETR's absolute maximum control voltage range is -0.5 V to +5.5 V, but functional operation is guaranteed only from 0 to +5 V. Applying voltage outside 0–5 V risks parametric shift, increased distortion, or latch-up. The device draws ≤100 µA at Vctrl, so driving it from a standard microcontroller GPIO or DAC output is safe and direct.