Overview
The HMC980-SX, produced by Analog Devices Inc., is an advanced active bias controller designed to automatically adjust the gate voltage of an external amplifier to maintain a constant bias current. This component is particularly useful in applications requiring stable biasing across various supply, temperature, and process variations. The HMC980-SX eliminates the need for calibration procedures, ensuring consistent RF performance without the complexities of manual adjustments.
Key Specifications
| Parameter | Min | Typ | Max | Units |
|---|---|---|---|---|
| Supply Voltage (VDD) | 5 | - | 16.5 | V |
| Drain Voltage (VDrain) | 5 | - | 16.5 | V |
| Drain Current (IDrain) | - | - | 1.6 | A |
| Gate Current | ±4 | - | - | mA |
| Internal Negative Voltage Generation | - | - | - | - |
| VDIG Voltage | 3.3 | - | 5.0 | V |
| VDIG Current | - | 3.5 | - | mA |
| Die Size | - | - | - | 1.4 x 2.26 x 0.25 mm |
Key Features
- Automatic Gate Voltage Adjustment: No calibration required to maintain constant quiescent bias current through the amplifier.
- Bias Stability: Excellent stability over supply, temperature, and process variations.
- Adjustable Drain Current: Up to 1.6 A, adjustable via an external resistor.
- Gate Current Control: Can sink or source gate current (±4 mA) to compensate for gate current variations.
- Internal Negative Voltage Generation: Can be disabled if an external negative supply is available.
- Power-Up and Power-Down Sequencing: Ensures safe sequencing to prevent voltage application to the amplifier until the gate voltage is properly set.
- Over/Under Current Alarm: Built-in hysteresis for current monitoring.
- Fast Enable/Disable and Trigger-Out Output: For daisy chaining and control.
Applications
- Microwave Radio & VSAT: Used in satellite communication systems.
- Military & Space: Suitable for high-reliability and harsh environment applications.
- Test Instrumentation: For precise biasing in test equipment.
- Fiber Optic Modulator Driver Biasing: In fiber optic communication systems.
- CatV Laser Driver Biasing: In cable television systems.
- Cellular Base Station & Wireless Infrastructure Equipment: For stable biasing in wireless communication systems.
Q & A
- What is the primary function of the HMC980-SX?
The primary function of the HMC980-SX is to automatically adjust the gate voltage of an external amplifier to maintain a constant bias current.
- What is the range of supply voltage for the HMC980-SX?
The supply voltage range for the HMC980-SX is from 5V to 16.5V.
- How does the HMC980-SX handle temperature variations?
The HMC980-SX maintains excellent bias stability over temperature variations, ensuring consistent performance.
- Can the HMC980-SX be used with both enhancement and depletion mode amplifiers?
Yes, the HMC980-SX can be used with both enhancement and depletion mode amplifiers.
- What is the maximum drain current the HMC980-SX can handle?
The maximum drain current the HMC980-SX can handle is up to 1.6 A.
- Does the HMC980-SX require an external negative voltage supply?
No, the HMC980-SX has an internal negative voltage generator, but it can be disabled if an external negative supply is available.
- How does the HMC980-SX ensure safe power-up and power-down sequencing?
The HMC980-SX ensures safe sequencing by controlling an internal MOSFET switch that prevents voltage application to the amplifier until the gate voltage is properly set.
- What is the purpose of the over/under current alarm in the HMC980-SX?
The over/under current alarm with built-in hysteresis monitors the current and alerts for any deviations, ensuring the amplifier operates within safe limits.
- Can the HMC980-SX be used in high-volume production without calibration?
Yes, the HMC980-SX eliminates the need for calibration procedures, making it suitable for high-volume production.
- What are some common applications of the HMC980-SX?
The HMC980-SX is used in microwave radio, VSAT, military and space, test instrumentation, fiber optic modulator driver biasing, CatV laser driver biasing, and cellular base stations.
