Embedded Systems Conference
Breaking News
Newest First | Oldest First | Threaded View
User Rank
re: Discrete audio amplifier basics - Part 2: JFETs, MOSFETs and other circuit configurations
kendallcp   7/20/2010 12:34:31 PM
It's lovely to see such extended treatment of JFET amplifiers. How many other people out there get the same rather wistful feeling that I do, though? The big semiconductor manufacturers have culled their JFET ranges to extinction, leaving the market mostly to specialist vendors such as Linear Systems. Depletion-mode FETs have the wonderful characteristic of being conducting when no gate potential is applied; this behaviour is really hard to replicate otherhow. There are a few depletion MOS devices out there; single-source and in quite large packages. I feel rather sad that the JFET is slowly fading from our design consciousness. What do you think?

User Rank
re: Discrete audio amplifier basics - Part 2: JFETs, MOSFETs and other circuit configurations
WKetel   4/1/2010 12:18:46 AM
This explanation of the symbols is useful. Now I need to convince others that it has value.

User Rank
re: Discrete audio amplifier basics - Part 2: JFETs, MOSFETs and other circuit configurations
bcarso   3/28/2010 8:09:16 PM
You need to establish a base bias suffficent to operate the lower device in/near the pinchoff region, i.e., where its output impedance is reasonably high. You do not want the base voltage to (partially) track with the circuit output voltage---this tends to defeat the purpose of the cascade, which is to minimize the voltage swing on the drain of the input device, thus reducing drain-gate capacitance multiplication ("Miller effect"). In some cases it is advantageous to derive the base voltage from a sample of the actual circuit input voltage, reducing the effective FET input capacitance further---however, this will result in negative input impedance at high frequencies and potential instabilities.

User Rank
re: Discrete audio amplifier basics - Part 2: JFETs, MOSFETs and other circuit configurations
wreeve   3/28/2010 4:39:18 AM
I would like to explore the cascode configuration of fig. 9.15 but with Q2 replaced with a BJT. My question concerns biasing of Q2 when it is a BJT in a common base configuration. Does it matter if the base biasing resistor is connected directly to Vcc or the bottom of R2 where the Output is tapped? How do both arrangements affect the overall cascode circuit gain?

In conjunction with unveiling of EE Times’ Silicon 60 list, journalist & Silicon 60 researcher Peter Clarke hosts a conversation on startups in the electronics industry. One of Silicon Valley's great contributions to the world has been the demonstration of how the application of entrepreneurship and venture capital to electronics and semiconductor hardware can create wealth with developments in semiconductors, displays, design automation, MEMS and across the breadth of hardware developments. But in recent years concerns have been raised that traditional venture capital has turned its back on hardware-related startups in favor of software and Internet applications and services. Panelists from incubators join Peter Clarke in debate.
Most Recent Comments
javier ruiz
Flash Poll
Top Comments of the Week
Like Us on Facebook

Datasheets.com Parts Search

185 million searchable parts
(please enter a part number or hit search to begin)
Special Video Section
The LTC®4015 is a complete synchronous buck controller/ ...
The LT®3042 is a high performance low dropout linear ...
Chwan-Jye Foo (C.J Foo), product marketing manager for ...
The LT®3752/LT3752-1 are current mode PWM controllers ...
LED lighting is an important feature in today’s and future ...
Active balancing of series connected battery stacks exists ...
After a four-year absence, Infineon returns to Mobile World ...
A laptop’s 65-watt adapter can be made 6 times smaller and ...
An industry network should have device and data security at ...
The LTC2975 is a four-channel PMBus Power System Manager ...
In this video, a new high speed CMOS output comparator ...
The LT8640 is a 42V, 5A synchronous step-down regulator ...
The LTC2000 high-speed DAC has low noise and excellent ...
How do you protect the load and ensure output continues to ...
General-purpose DACs have applications in instrumentation, ...
Linear Technology demonstrates its latest measurement ...
Demos from Maxim Integrated at Electronica 2014 show ...
Bosch CEO Stefan Finkbeiner shows off latest combo and ...
STMicroelectronics demoed this simple gesture control ...
Keysight shows you what signals lurk in real-time at 510MHz ...