Analog Devices Inc. HMC920LP5ETR

Overview

HMC920LP5ETR from Analog Devices is an active bias controller IC designed to regulate drain voltage and dynamically adjust gate voltage for RF power amplifiers, enabling stable Class-A biasing across temperature, supply, and process variation. It supports 3V–15V adjustable V_DRAIN, up to 500mA drain current, internal –2.5V negative voltage generation, and automated power-up sequencing - critical for microwave radio and cellular base station amplifier biasing.

For engineers reviewing the HMC920LP5ETR datasheet, HMC920LP5ETR pinout, HMC920LP5ETR application, or HMC920LP5ETR equivalent, key selection considerations include its dual-domain supply architecture (V_dd/V_DIG), ±4 mA gate drive capability, 0.03%/°C drain current stability, integrated short-circuit protection with power foldback, and RoHS-compliant 5×5 mm QFN package with exposed thermal pad.

Technical Context

The HMC920LP5ETR implements a closed-loop active bias control architecture that continuously samples amplifier drain current via ISENSE and adjusts VGATE to maintain constant IDRAIN - independent of V_dd, temperature, aging, or threshold drift. Its gate control block sources/sinks ±4 mA and interfaces with both enhancement- and depletion-mode RF amplifiers.

It integrates three regulated power domains: a 3.5V/30mA low-voltage LDO (VDIG) for digital logic and oscillator, a high-current adjustable LDOCC (3–15V, 500mA) for V_DRAIN, and a charge-pump-based –2.5V negative generator (VNEG) with 60 mA sink capability. All domains feature dedicated ground domains (AGND/DGND) and strict absolute maximum ratings to prevent cross-domain violation.

Key Specifications

Pinout & Package

The HMC920LP5ETR is housed in a RoHS-compliant 5×5 mm QFN-32 leadless package with exposed backside thermal pad (paddle = AGND). Thermal resistance is 3.9°C/W (junction-to-package bottom); PCB layout must connect paddle to analog ground plane per Hittite Application Note land pattern guidance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM334Z and MAX11322ATJ+, the HMC920LP5ETR delivers fully integrated, production-ready active bias control - eliminating 12+ external components, guaranteeing <±1% IDRAIN stability over temperature, and providing built-in safety features like power foldback and sequenced power-up - all in a single 5×5 mm QFN.

Availability

HMC920LP5ETR is available at Aetrix Electronics and suitable for cellular infrastructure, microwave radio, military radar, test instrumentation, and satellite communications requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for HMC920LP5ETR 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 RF technologies, serving aerospace, defense, communications, and industrial markets with precision signal processing solutions.

The HMC920LP5ETR belongs to Analog Devices' Hittite Microwave active bias controller product line, engineered specifically for high-reliability RF amplifier biasing in microwave and millimeter-wave systems where stability, protection, and integration are critical.

FAQ

What is the primary function of the HMC920LP5ETR in an RF amplifier design?

The HMC920LP5ETR serves as a fully integrated active bias controller that regulates both the drain supply voltage (VDRAIN) and dynamically adjusts the gate voltage (VGATE) of external RF amplifiers to maintain constant quiescent drain current (IDRAIN). It achieves this through closed-loop feedback via the ISENSE pin, compensating for temperature, supply, process, and aging effects - eliminating the need for manual calibration in production systems using the HMC920LP5ETR.

How does the HMC920LP5ETR handle power-up sequencing to protect RF amplifiers?

The HMC920LP5ETR enforces safe power-up sequencing by first pulling VGATE to VNEG (ensuring the amplifier remains off), then enabling VDRAIN only after the bias loop stabilizes. This sequence is controlled internally and signaled externally via the TRGOUT pin, which goes HIGH when stable. If EN is asserted, the HMC920LP5ETR discharges VDRAIN to GND and pulls VGATE to VNEG - preventing latch-up or gate oxide stress during turn-on/off cycles of the HMC920LP5ETR.

Can the HMC920LP5ETR bias both enhancement-mode and depletion-mode RF amplifiers?

Yes, the HMC920LP5ETR supports both enhancement- and depletion-mode amplifiers. For depletion-mode devices, it generates an internal –2.5V negative supply (VNEG) via its charge pump; for enhancement-mode devices, the negative generator can be disabled using the VNEGFB pin. The VGATE output operates from VNEG to VNEG+4.5V, allowing flexible gate bias range - confirmed in the HMC920LP5ETR functional description and mode selection table.

What protection features does the HMC920LP5ETR include to safeguard connected RF amplifiers?

The HMC920LP5ETR includes short-circuit protection with power foldback (limiting max dissipation to 4.5W), over/under-current alarm (CURALM), low-Vdd alarm (VddALM), and automated power-up sequencing. During overload, it reduces both VDRAIN and IDRAIN simultaneously rather than hard-limiting current - preserving amplifier reliability. These protections operate independently of the EN pin and do not disrupt bias regulation in the HMC920LP5ETR.

What is the recommended PCB layout practice for the HMC920LP5ETR's thermal pad and ground domains?

The exposed thermal pad (paddle) of the HMC920LP5ETR must be soldered to a solid analog ground (AGND) plane per the Hittite Application Note land pattern. AGND (Pins 11,17) and DGND (Pin 16) must connect to the paddle at a single point under the package. Charge pump components (C12, C14, D1) must route to DGND; all other analog components connect to AGND - isolating switching noise and ensuring stable operation of the HMC920LP5ETR's sensitive bias control loop.