Datasheet ADA4312-1 (Analog Devices) - 10
| Manufacturer | Analog Devices |
| Description | Wideband, Differential, High Output Current Line Driver with Shutdown |
| Pages / Page | 12 / 10 — ADA4312-1. Data Sheet. THERMAL MANAGEMENT. –40. –45. –50. 8kΩ, IQ = 11mA. … |
| Revision | A |
| File Format / Size | PDF / 444 Kb |
| Document Language | English |
ADA4312-1. Data Sheet. THERMAL MANAGEMENT. –40. –45. –50. 8kΩ, IQ = 11mA. Bc) d. –55. R (. 4kΩ, IQ = 18mA. P T. 2kΩ, I. –60. Q = 26mA. –65
Model Line for this Datasheet
Text Version of Document
link to page 10 link to page 9 link to page 11 link to page 11
ADA4312-1 Data Sheet
Note that there is a trade-off between the adjusted quiescent
THERMAL MANAGEMENT
current and the linearity (or MTPR) of the transmitted signal. The thermal pad of the ADA4312-1 is an electrically isolated Multitone power ratio (MTPR) was monitored at 5 MHz, copper pad that should be soldered to an external thermal 17 MHz, 28 MHz, 31 MHz, 59 MHz, and 82 MHz. Figure 18 ground plane. The number of thermal vias that connect the can be used to gauge the approximate degradation of MTPR exposed pad of the ADA4312-1 to the PCB can influence the vs. RIADJ and quiescent current while transmitting the G.hn thermal conductivity of the PCB assembly. Moving heat away signal across a 40 Ω differential load in the circuit shown in from the ADA4312-1 die to the ambient environment is the Figure 17. objective of a PCB designed in accordance with the guidelines
–40
found in the AN-772 Application Note. The outer layers of the PCB are the best choice to radiate heat
–45
into the environment by convection. Conducting heat away from the ADA4312-1 die into the outer layers of the PCB can
–50 8kΩ, IQ = 11mA
be accomplished with nine thermal vias connecting the exposed
Bc) d
pad to both outer layers. The vias can be spaced 0.75 mm apart
–55 R ( 4kΩ, IQ = 18mA P T
in a 3 × 3 matrix.
M 2kΩ, I –60 Q = 26mA
The ADA4312-1 evaluation board (EVAL-ADA4312-1ACPZ) represents a robust example of an effective thermal management
–65 1kΩ, IQ = 33mA 0Ω, I
approach (see Figure 19 and Figure 20).
Q = 46.5mA
For more information about thermal management, solder
–70 0 10 20 30 40 50 60 70 80 90
021 assembly techniques for LFCSP packages, and important
FREQUENCY (MHz)
11044- package mechanical and materials information, refer to the Figure 18. MTPR vs. RIADJ following link:
PCB LAYOUT
http://www.analog.com/en/technical-library/packages/csp- As is the case with many high speed line driver applications, care- chip-scale-package/lfcsp/index.html ful attention to printed circuit board (PCB) layout can improve
POWER SUPPLY BYPASSING
performance and help maintain stability while preventing excessive The ADA4312-1 should be operated on a well-regulated single die temperatures during normal operation. Differential signal +12 V power supply. Pay careful attention to power supply balance can be maintained by using symmetry in the PCB layout decoupling. Use high quality capacitors with low equivalent series of input and output signal traces. resistance (ESR), such as multilayer ceramic capacitors (MLCCs), Keeping the input and output traces as short as possible helps to minimize supply voltage ripple and power dissipation. prevent excessive parasitics from affecting overal performance Locate the 0.1 µF MLCC decoupling capacitor no more than and stability. Keep the feedback resistors and gain setting resistor one-eighth of an inch away from the V as close to the line driver as physically possible. The back termi- CC supply pin. In addition, a 10 µF tantalum capacitor is recommended to provide good nation resistors and line coupling transformer should be placed decoupling for lower frequency signals and to supply current for as close to the ADA4312-1 outputs as possible. fast, large signal changes at the ADA4312-1 outputs. Lay out For more information about high speed board layout, see A bypassing capacitors to keep return currents away from the Practical Guide to High-Speed Printed-Circuit-Board Layout inputs of the amplifiers. A large ground plane provides a low (Analog Dialogue, Volume 39, September 2005). impedance path for the return currents. Rev. A | Page 10 of 12 Document Outline Features Applications General Description Functional Block Diagram Typical Application Circuit Revision History Specifications Absolute Maximum Ratings Thermal Resistance Maximum Power Dissipation ESD Caution Pin Configuration and Function Descriptions Typical Performance Characteristics Test Circuit Applications Information Feedback Resistor Selection General Operation Half-Duplex Operation Establishing VMID Bias Control and Linearity PCB Layout Thermal Management Power Supply Bypassing Evaluation Board Outline Dimensions Ordering Guide
ADA4312-1 Data Sheet
Note that there is a trade-off between the adjusted quiescent
THERMAL MANAGEMENT
current and the linearity (or MTPR) of the transmitted signal. The thermal pad of the ADA4312-1 is an electrically isolated Multitone power ratio (MTPR) was monitored at 5 MHz, copper pad that should be soldered to an external thermal 17 MHz, 28 MHz, 31 MHz, 59 MHz, and 82 MHz. Figure 18 ground plane. The number of thermal vias that connect the can be used to gauge the approximate degradation of MTPR exposed pad of the ADA4312-1 to the PCB can influence the vs. RIADJ and quiescent current while transmitting the G.hn thermal conductivity of the PCB assembly. Moving heat away signal across a 40 Ω differential load in the circuit shown in from the ADA4312-1 die to the ambient environment is the Figure 17. objective of a PCB designed in accordance with the guidelines
–40
found in the AN-772 Application Note. The outer layers of the PCB are the best choice to radiate heat
–45
into the environment by convection. Conducting heat away from the ADA4312-1 die into the outer layers of the PCB can
–50 8kΩ, IQ = 11mA
be accomplished with nine thermal vias connecting the exposed
Bc) d
pad to both outer layers. The vias can be spaced 0.75 mm apart
–55 R ( 4kΩ, IQ = 18mA P T
in a 3 × 3 matrix.
M 2kΩ, I –60 Q = 26mA
The ADA4312-1 evaluation board (EVAL-ADA4312-1ACPZ) represents a robust example of an effective thermal management
–65 1kΩ, IQ = 33mA 0Ω, I
approach (see Figure 19 and Figure 20).
Q = 46.5mA
For more information about thermal management, solder
–70 0 10 20 30 40 50 60 70 80 90
021 assembly techniques for LFCSP packages, and important
FREQUENCY (MHz)
11044- package mechanical and materials information, refer to the Figure 18. MTPR vs. RIADJ following link:
PCB LAYOUT
http://www.analog.com/en/technical-library/packages/csp- As is the case with many high speed line driver applications, care- chip-scale-package/lfcsp/index.html ful attention to printed circuit board (PCB) layout can improve
POWER SUPPLY BYPASSING
performance and help maintain stability while preventing excessive The ADA4312-1 should be operated on a well-regulated single die temperatures during normal operation. Differential signal +12 V power supply. Pay careful attention to power supply balance can be maintained by using symmetry in the PCB layout decoupling. Use high quality capacitors with low equivalent series of input and output signal traces. resistance (ESR), such as multilayer ceramic capacitors (MLCCs), Keeping the input and output traces as short as possible helps to minimize supply voltage ripple and power dissipation. prevent excessive parasitics from affecting overal performance Locate the 0.1 µF MLCC decoupling capacitor no more than and stability. Keep the feedback resistors and gain setting resistor one-eighth of an inch away from the V as close to the line driver as physically possible. The back termi- CC supply pin. In addition, a 10 µF tantalum capacitor is recommended to provide good nation resistors and line coupling transformer should be placed decoupling for lower frequency signals and to supply current for as close to the ADA4312-1 outputs as possible. fast, large signal changes at the ADA4312-1 outputs. Lay out For more information about high speed board layout, see A bypassing capacitors to keep return currents away from the Practical Guide to High-Speed Printed-Circuit-Board Layout inputs of the amplifiers. A large ground plane provides a low (Analog Dialogue, Volume 39, September 2005). impedance path for the return currents. Rev. A | Page 10 of 12 Document Outline Features Applications General Description Functional Block Diagram Typical Application Circuit Revision History Specifications Absolute Maximum Ratings Thermal Resistance Maximum Power Dissipation ESD Caution Pin Configuration and Function Descriptions Typical Performance Characteristics Test Circuit Applications Information Feedback Resistor Selection General Operation Half-Duplex Operation Establishing VMID Bias Control and Linearity PCB Layout Thermal Management Power Supply Bypassing Evaluation Board Outline Dimensions Ordering Guide
