Friday, July 01, 2016
"In the circuit, the ADuCM360 is connected to a Type T thermocouple and a 100 Ω platinum resistance temperature detector (RTD). The RTD is used for cold junction compensation. The low power Cortex-M3 core converts the ADC readings to a real temperature value. The Type T temperature range supported is −200°C to +350°C, and this temperature range is converted to an output current range of 4 mA to 20 mA."
12-Bit, 4-20mA Loop-Powered Thermocouple Measurement System
The thermocouple used in this application is a Type T (copper-constantan) that has a temperature range of −200°C to +350°C. Its sensitivity is approximately 40 μV/°C, which means that the ADC in bipolar mode, with a PGA gain of 32, can cover the entire temperature range of the thermocouple.
The RTD was used for cold junction compensation. The particular one used in this circuit was a platinum 100 Ω RTD, Enercorp PCS 1.1503.1. It is available in a 0805, surface-mount package. This RTD has a temperature variation of 0.385 Ω/°C.
Friday, June 03, 2016
"Ground Is Not an Equipotential - At this point it is important to understand that a ground plane, despite what we were taught it EE101, is not an equipotential. First of all, no matter how thick the copper is for your ground plane, it does have resistance. Therefore, if the analog and digital return currents (or any two currents) share a portion of the ground plane (i.e., their currents flow through the same metal) there will be crosstalk between the two as the copper resistance causes IR voltage drops."
Successful PCB Grounding - Mark Fortunato
"With the basics of current flow on a PCB understood, we can start using this knowledge to properly handle the grounding of mixed analog-digital ICs. Ultimately, the goal is to ensure that the digital and analog currents do not share portions of the same return path."
"Many problems with mixed-signal PCB design can be avoided by following this simple advice: pay attention to where the current flows. For most cases all we have to do is remember two basic principles: DC and low frequencies flow mostly in the straight-line path of least resistance between source and load; and high-frequency signals follow the path of least impedance, which is directly under the signal trace. In-between frequencies flow by both paths and in between the two paths."
Sunday, February 07, 2016
ICL7135 Device Information
- Accuracy Guaranteed to ±1 Count Over Entire ±20000 Counts (2.0000V Full Scale)
- Guaranteed Zero Reading for 0V Input
- 1pA Typical Input Leakage Current
- True Differential Input
- True Polarity at Zero Count for Precise Null Detection
- Single Reference Voltage Required
- Overrange and Underrange Signals Available for Auto-Range Capability
- All Outputs TTL Compatible
- Blinking Outputs Gives Visual Indication of Overrange
- Six Auxiliary Inputs/Outputs are Available for Interfacing to UARTs, Microprocessors, or Other Circuitry
- Multiplexed BCD Outputs
Wednesday, November 04, 2015
CMOS Mixed-Signal Circuit Design - R Jacob Baker
Published by Wiley-IEEE, ISBN 978-0-470-29026-2, 2nd Edition, 2009. The book's author is R. Jacob Baker. Examples, Tutorials, and Videos.
- Chapter 3 Analog Filters 73
- Chapter 4 Digital Filters 119
- Chapter 6 Data Converter Design Basics 203
- Chapter 8 Bandpass Data Converters 285
- Chapter 9 A High-Speed Data Converter 301
Ananth of delabs Notes
Some of my Mixed Circuits Analog with Digital basic ideas on design too.
Thursday, December 22, 2011
These days the term of firmware can only be used for very small devices. This is because we have more memory, flash and computation ability in tiny footprints. So even a mini gadget can have a Tiny OS sometimes even a Virtual Machine. What is a VM it is is a OS in a OS. Java, .Net.
Time-interleaved Analog-to-digital Converters
TIADCs and TI-ADCs an Article by Dr. Christian Vogel.
"The idea of a time-interleaved ADC (TIADC) is to use a system of M parallel channels, which alternately take one sample (time-interleaved sampling). Thereby, the sampling frequency of one channel does not need to fulfill the Nyquist criterion; however, when in the digital domain all samples are merged into one output sequence the overall sampling frequency fulfills the Nyquist criterion"
The Designer's Guide Community - A Guide to Simulation & Modeling for Analog & RF Circuit Designers
A Site where analog, mixed-signal and RF circuit designers come to learn about simulation, modeling and design. There are a number of very practical papers on simulation and modeling on the Analysis, Modeling, and Theory pages. A collection of useful example models can be found on the Verilog-AMS page.
Designing Analog Chips by Hans Camenzind
Hans Camenzind book on Analog CMOS design is a good reference for students and covers Power Electronic concepts like Switching Regulators and Low Drop-Out Regulators. The Delta-Sigma Converter A/D and Zero-Crossing Detectors on Mixed Design. Communications circuits like Timers and Oscillators . Phase-Locked Loops and Filters too.
Tuesday, August 09, 2011
ADC are the Eyes and Ears for a uC, this brings the Real world as Numbers within the CPU. Without ADC a uC is like a Frog in the Well and has to create an Imaginary World for himself. That is beyond the scope of Engineering.
Bring your favorite PIC Microcontroller to his senses. Give him an ability to Perceive the Reality around him. Get him an Analog to Digital Converter and don't forget to code.
MAX1169 ADC is better than 4 1/2 Digit Value. For me the Intersil chip is a Benchmark. Beyond 5 1/2 Resolution may be needed only for Scientific Research.
I would say, 2 1/2 is like Analog Meters/Bar Graphs, 3 1/2 for Control systems, 4 1/2 for T&M and beyond 5 1/2 is for R&D.
Anantha Narayan delabs
Abstract: This application note describes how to interface a MAX1169 analog-to-digital converter (ADC) to a PIC microcontroller. It includes an example circuit and software for a PIC18F442. The software contains function calls to interface the ADC to the PIC microcontroller using the internal MSSP I²C port at 400kHz.
Interfacing the MAX1169 ADC to a PIC Microcontroller - Maxim
Wednesday, April 08, 2009
The ADS7816 is a 12-bit, 200kHz sampling analog to- digital converter. It features low power operation with automatic power down, a synchronous serial interface, and a differential input. The reference voltage can be varied from 100mV to 5V, with a corresponding resolution from 24mV to 1.22mV. - From TI Applications
- l 200kHz SAMPLING RATE
- l MICRO POWER:
- 1.9mW at 200kHz
- 150mW at 12.5kHz
- l POWER DOWN: 3mA Max
- l 8-PIN MINI-DIP, SOIC, AND
- l DIFFERENTIAL INPUT
- l SERIAL INTERFACE