Integrated Circuits

Digital Potentiometers

Digital Potentiometers(AD5204) The digital Potentiometers made by analog devices (AD5204) has 255 positions can be adjusted by the microcomputer that can receive commands from the computer. This is a great way for analog circuitry to have digital control. This is a chip with 4 digitally controlled POTs and the pots can be daisy chained to have multiple chips controled by a single SPI interface.

Voltage Regulators

Linear Regulators
LT1528	High current, Variable Voltage Regulator
TPS V-Regs	These are 3.3V and 5V LDO, Low-Noise Voltage Regulators. Very small SOT-23 SMD package. 150mA max current. Best used in battery applications.
Basic Voltage Regulators	Variable voltage regulators, set output regulators, we give you the whole breakdown. Perfect for use with an external wall-wart power supply.
The 723 Voltage Regulator	Precision Voltage Regulator. Can be used as fixed or floating, variable, linear or switching. NOTE: Only the DIP-14 version (image) has the Vz pin, which is used for negative regulators. The Metal Can and the Flat-Pack do not have enough pins so exclude the Vz.
Switching Regulators
MCP1252/3	Extremely Efficient, 120mA Flyback Switching Regulators.

Microcontrollers

• LPC2103 Low cost 70MHz ARM7TDMI-S FLASH Microcontroller from Philips. The "$49" "Coridium ARMmite" does use this chip.
• Atmel AVR 8 bit FLASH microcontrollers
• Microchip PIC 8 bit FLASH microcontrollers
• Microchip dsPIC 16 bit FLASH microcontrollers ( DsPIC30F 5011 Development Board )
• Cypress PSoC 8 bit FLASH microcontrollers

I've written a little about the various kinds of microcontrollers at Wikibooks: Embedded Systems. --DavidCary 06:15, 10 March 2007 (PST)

Op Amps

Op amps and instrumentation amps.

op amps: great for amplifying weak signals from sensors to a more useful level. Also used in filters, integrators, etc.

• LT1168 Programmable-Gain Precision Instrumentation Amplifier - Low Power, Single Resistor Gain Programmable, Precision Instrumentation Amplifier
• LT1114 Low Power Precision OP-Amps are used for amplification and filtering of the signal - Dual/Quad Low Power Precision, Picoamp Input Op Amps
• Wikibooks:Op-Amps has a "quick design process" using Daisy's theorem: "The sum of the gains = +1 in a properly-designed op amp circuit."
• "Some Op Amp Audio Design Issues" by Terry Ritter

logic gates

• NAND gate: "Using a NAND Gate for a Set/Reset Latch" (the 74HC132 Schmitt-trigger quad NAND is better than the 74HC00 quad NAND).
• "Multiplexers: the tactical Nuke of Logic Design" by Dieter Mueller 2004 (74153)

There are hundreds of other specialized logic gates. Here we only list the ones we actually use in some Open Circuit Project:

• 74HC595 eight bit shift register with output latch (used for POV display)

RF ICs/Modules

Linx Technologies makes several low power RF transmitter/receiver chips. Their range is around 500' - 1000'. They are geared for one way communication only, like keyless entry systems. They also make several serial encoding chips that make the wireless communication more secure/crack proof. Their latest chip, the HS series, is based upon the SkipJack algorithm developed by the NSA.

ADC analog to digital converter

There are a huge variety of ADCs available.

If you need 10 bits or less of resolution, counter-intuitively, it costs less to buy an ADC plus a microcontroller on one chip than to buy a stand-alone ADC.

• ATTINY13V -- lowest-price chip I know of with at least one 10 bit ADC
• ATTINY261 -- lowest $/ADC chip I know of
• LPC2101FBD48 -- lowest-price 32-bit microcontroller I know of with at least one internal 10 bit ADC

Many people (*) do EKGs with only 10 bit converters.

The Programmable Chip EEG might need more bits of resolution.

What low-cost ADC are available with at least 12 bits?

• $2.50 MCP3301 has 1 ADC input (13 bits)
• $3.50 MCP3302 has 2 ADC input (13 bits)
• $3.50 MCP3204 has 4 ADC input (12 bits)
• $4 MCP3208 has 8 ADC input (12 bits)
• $8 dsPIC30F 2011 microcontroller has 8 ADC inputs (12 bits). See dsPIC30F 5011 Development Board for details.
• $6 CY8C27443 Cypress PSoC microcontroller has 4 ADC inputs (14 bits) -- but what is the sampling rate? Also has 4 DAC outputs (9 bits).

• $56 biosemi used analog devices AD7716: four independent, simultaneous 22 bit ADCs.
• the Maxim MAX1460 includes a 16-bit ADC, 12-bit DAC, a programmable gain amp (PGA), temp sensor, and 16-bit processor. (Alas, its program is in unchangeable ROM).
• Analog Devices AduC812: 200kHz 12-bit ADC, 12-bit DAC, and flash-based 8051 MCU core.

I am astonished to discover that (a few) microcontrollers include 12 bit or more ADCs. Are there others? --DavidCary 18:48, 28 August 2007 (PDT)