Datasheet HMC788A (Analog Devices) - 9
| Manufacturer | Analog Devices |
| Description | 0.01 GHz to 10 GHz, MMIC, GaAs, pHEMT RF Gain Block |
| Pages / Page | 12 / 9 — Data Sheet. HMC788A. THEORY OF OPERATION. BASIC CONNECTIONS |
| Revision | C |
| File Format / Size | PDF / 213 Kb |
| Document Language | English |
Data Sheet. HMC788A. THEORY OF OPERATION. BASIC CONNECTIONS
Text Version of Document
link to page 10
Data Sheet HMC788A THEORY OF OPERATION
The HMC788A is designed with a Darlington feedback pair that It is critical to supply very low inductance ground connections exhibits reduced sensitivity to normal process variations and yields to the GND pin as well as to the backside exposed pad, ensuring excellent gain stability over temperature while requiring minimal stable operation. It is recommended that the NIC pins also be external bias components. The amplifier can be operated from a connected to GND. 5 V supply by adding a choke inductor from the amplifier The HMC788A is designed to operate with a supply voltage of output to VCC. 5 V, which is connected through an external RF choke between
BASIC CONNECTIONS
the supply voltage and the output pin, RFOUT. The inductance of The HMC788A RF gain block is a fixed gain amplifier with single- the RF choke must be approximately 6 µH, and care must be ended input and output ports featuring impedances nominal y taken to ensure that the lowest series self resonant frequency of equal to 50 Ω over the 0.01 GHz to 10 GHz frequency range. The this choke is wel above the maximum frequency of operation input and output impedances are sufficiently stable across for the HMC788A. Consequently, a dc blocking capacitor must variations in temperature and supply voltage such that the be connected between the bias connection to RFOUT and the HMC788A can be directly inserted into a 50 Ω system with no output load. The value of this capacitor is not critical, but it is impedance matching circuitry required. recommended to be 100 pF or larger. The input pin, RF Bypass the bias supply voltage, VCC, using a large value capacitance IN, is dc-coupled and ac matched to 50 Ω. A dc blocking capacitor must be connected between the source that (approximately 2.2 µF or larger) and a smaller, high frequency drives the HMC788A and the RF bypass capacitor (approximately 100 pF). IN pin. The recommended connections and components are shown in the Evaluation PCB section. Rev. C | Page 9 of 12 Document Outline Features Applications Functional Block Diagram General Description Revision History Specifications Electrical Specifications Absolute Maximum Ratings Thermal Resistance ESD Caution Pin Configuration and Function Descriptions Interface Schematics Typical Performance Characteristics Theory of Operation Basic Connections Applications Information Evaluation PCB Outline Dimensions Ordering Guide
Data Sheet HMC788A THEORY OF OPERATION
The HMC788A is designed with a Darlington feedback pair that It is critical to supply very low inductance ground connections exhibits reduced sensitivity to normal process variations and yields to the GND pin as well as to the backside exposed pad, ensuring excellent gain stability over temperature while requiring minimal stable operation. It is recommended that the NIC pins also be external bias components. The amplifier can be operated from a connected to GND. 5 V supply by adding a choke inductor from the amplifier The HMC788A is designed to operate with a supply voltage of output to VCC. 5 V, which is connected through an external RF choke between
BASIC CONNECTIONS
the supply voltage and the output pin, RFOUT. The inductance of The HMC788A RF gain block is a fixed gain amplifier with single- the RF choke must be approximately 6 µH, and care must be ended input and output ports featuring impedances nominal y taken to ensure that the lowest series self resonant frequency of equal to 50 Ω over the 0.01 GHz to 10 GHz frequency range. The this choke is wel above the maximum frequency of operation input and output impedances are sufficiently stable across for the HMC788A. Consequently, a dc blocking capacitor must variations in temperature and supply voltage such that the be connected between the bias connection to RFOUT and the HMC788A can be directly inserted into a 50 Ω system with no output load. The value of this capacitor is not critical, but it is impedance matching circuitry required. recommended to be 100 pF or larger. The input pin, RF Bypass the bias supply voltage, VCC, using a large value capacitance IN, is dc-coupled and ac matched to 50 Ω. A dc blocking capacitor must be connected between the source that (approximately 2.2 µF or larger) and a smaller, high frequency drives the HMC788A and the RF bypass capacitor (approximately 100 pF). IN pin. The recommended connections and components are shown in the Evaluation PCB section. Rev. C | Page 9 of 12 Document Outline Features Applications Functional Block Diagram General Description Revision History Specifications Electrical Specifications Absolute Maximum Ratings Thermal Resistance ESD Caution Pin Configuration and Function Descriptions Interface Schematics Typical Performance Characteristics Theory of Operation Basic Connections Applications Information Evaluation PCB Outline Dimensions Ordering Guide
