Analog Devices Inc. HMC980LP4ETR

Overview

HMC980LP4ETR from Analog Devices is a high-current active bias controller IC designed to automatically regulate gate voltage for RF power amplifiers, supporting drain currents up to 1.6 A, supply voltages from 5 V to 16.5 V, and operation across −40°C to +85°C. It enables safe power-up/power-down sequencing, integrates an internal negative voltage generator (−2.46 V), and provides dual gate control (VGATE and VG2) for depletion- or enhancement-mode Class A amplifiers in microwave infrastructure.

For engineers reviewing the HMC980LP4ETR datasheet, HMC980LP4ETR pinout, HMC980LP4ETR application, or HMC980LP4ETR equivalent, key selection considerations include its 24-lead 4 mm × 4 mm LFCSP package, ±4 mA gate current sourcing/sinking capability, adjustable drain current ranges via S0/S1 logic inputs, overcurrent/undercurrent alarm with hysteresis, and TRIGOUT daisy-chain support for multi-amplifier systems.

Technical Context

The HMC980LP4ETR implements a closed-loop VGATE control architecture that continuously adjusts gate voltage using feedback from an external ISENSE resistor to maintain constant drain current despite supply, temperature, and process variation. Its internal MOSFET switch (R_{DS_ON} = 0.7 Ω to 2.8 Ω, selectable via S0/S1) delivers VDRAIN while enforcing strict power sequencing: VGATE is pulled to VNEG before VDRAIN is applied, ensuring amplifier pinch-off at startup.

It features dual-domain operation-high-voltage domain (VDD: 5–16.5 V) for RF amplifier supply and low-voltage domain (VDIG: 3.3–5 V) for digital logic-with independent ESD protection (HBM Class 1C). The integrated charge pump (300 kHz) generates −2.46 V for depletion-mode biasing, and VG2 output (1 V to VDD − 1.3 V) supports secondary-gate amplifiers without loop control.

Key Specifications

Pinout & Package

Package: 24-lead, 4 mm × 4 mm LFCSP (HCP-24-21), RoHS-compliant, with exposed thermal pad (EPAD) connected to ground plane for thermal and electrical integrity.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar active bias controller applications.

Compared with LM3478MM/NOPB and MAX2034ETA+, the HMC980LP4ETR delivers fully integrated, calibration-free RF amplifier biasing-including VDRAIN switching, VGATE/VG2 control, VNEG generation, and alarm monitoring-in a single 4 mm × 4 mm package, reducing design cycle time by ~6 weeks and PCB area by 45%.

Availability

HMC980LP4ETR is available at Aetrix Electronics and suitable for microwave radio systems, VSAT terminals, military radar transceivers, and fiber optic modulator driver biasing requiring stable component supply, long-term lifecycle assurance, and traceable sourcing for defense and telecom deployments.

Supply support for HMC980LP4ETR 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 RF ICs, serving precision instrumentation, communications, and aerospace markets with rigorously tested, application-optimized silicon.

The HMC980LP4ETR belongs to Analog Devices' Hittite Microwave product line, engineered specifically for high-frequency RF amplifier biasing in demanding microwave infrastructure, where stability, sequencing integrity, and integration density are critical.

FAQ

What is the primary function of the HMC980LP4ETR in an RF amplifier system?

The HMC980LP4ETR serves as a fully integrated active bias controller that automatically regulates gate voltage to maintain constant drain current in RF power amplifiers. It replaces manual calibration and discrete bias networks by implementing a closed-loop control system using an external ISENSE resistor. The HMC980LP4ETR supports both depletion- and enhancement-mode devices, provides safe power-up/down sequencing, and integrates features like internal negative voltage generation and dual-gate control-making it essential for stable, repeatable RF amplifier operation in microwave infrastructure.

Can the HMC980LP4ETR bias both depletion-mode and enhancement-mode amplifiers?

Yes, the HMC980LP4ETR supports both depletion-mode and enhancement-mode Class A amplifiers. Configuration is achieved via the VGATEFB pin: floating VGATEFB enables depletion-mode operation (using internal or external VNEG), while grounding VGATEFB selects enhancement-mode biasing. The device's integrated negative voltage generator (−2.46 V) eliminates the need for external negative supplies when biasing depletion-mode amplifiers, and its wide VDD range (5 V to 16.5 V) accommodates diverse amplifier supply requirements. This flexibility makes the HMC980LP4ETR suitable for multi-platform RF designs without hardware changes.

How does the HMC980LP4ETR ensure safe power-up and power-down sequencing?

The HMC980LP4ETR enforces hardware-level power sequencing to protect RF amplifiers. During power-up, it first pulls VGATE to VNEG to pinch off the amplifier, then applies VDRAIN, and finally enables VG2-ensuring no drain voltage is present until the gate is fully biased. During shutdown or disable, the sequence reverses: VG2 is disabled, VDRAIN is discharged, and VGATE is pulled to VNEG. This behavior is intrinsic to the HMC980LP4ETR's internal logic and requires no external timing circuitry. The EN pin controls this entire sequence, and TRIGOUT provides synchronization for cascaded devices, making the HMC980LP4ETR ideal for multi-amplifier phased arrays and modular transceivers.

What is the role of the S0 and S1 pins on the HMC980LP4ETR?

The S0 and S1 pins on the HMC980LP4ETR configure the R_{DS_ON} of the internal VDD-to-VDRAIN MOSFET switch and select the target drain current range. Four combinations define distinct R_{DS_ON} values (0.7 Ω to 2.8 Ω) and corresponding drain current bands (0.05–0.3 A, 0.3–0.6 A, 0.6–1.2 A, and 1.2–1.6 A). These pins have internal pull-ups to VDIG, so floating defaults to high. Selecting the appropriate S0/S1 state minimizes conduction loss and thermal stress while matching the amplifier's quiescent current requirement-enabling optimized efficiency and reliability across diverse RF power levels without redesigning the bias network.

Does the HMC980LP4ETR require external components for basic operation?

Yes, the HMC980LP4ETR requires several external components for functional operation: a precision ISENSE resistor (e.g., 0.5%, ±25 ppm) to set target drain current; decoupling capacitors (4.7 µF + 10 nF on VDD/VDIG, 10 µF on VNEG, 2.2 µF on VGATE); a 1 µF flying capacitor and 10 µF reservoir capacitor plus two diodes for the internal negative voltage generator; and a 10 kΩ resistor on FIXBIAS for optimal accuracy. Optional components include resistors for ALML/ISET/ALMH alarm thresholds and VG2_CONT divider. All recommended values and configurations are detailed in the Analog Devices HMC980LP4E datasheet Rev. C, and omitting any required component compromises stability, accuracy, or safety.