Showing posts with label Mixed-Signal-Design. Show all posts
Showing posts with label Mixed-Signal-Design. Show all posts

Friday, July 01, 2016

12-Bit, 4-20mA Loop-Powered System

An Application note and Evaluation Kit from Analog Devices. This solutions helps you evaluate a part of a Process Control or Data Acquisition module that you may wish to design.

"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

12-Bit, 4-20mA Loop-Powered 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

Successful PCB Grounding - Mark Fortunato

This tutorial discusses proper printed-circuit board (PCB) grounding for mixed-signal designs. For most applications a simple method without cuts in the ground plane allows for successful PCB layouts with this kind of IC.

Successful PCB Grounding - Mark Fortunato

"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 4 and Half A to D converter with BCD Output

The Intersil ICL7135 precision A/D converter, with its multiplexed BCD output and digit drivers, combines dual-slope conversion reliability with ±1 in 20,000 count accuracy and is ideally suited for the visual display DVM/DPM market. The 2.0000V full scale capability, auto-zero, and auto-polarity are combined with true ratiometric operation, almost ideal differential linearity and true differential input. All necessary active devices are contained on a single CMOS lC, with the exception of display drivers, reference, and a clock.

ICL7135 4 and Half A to D converter with BCD Output

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
See how i used them in my projects

Wednesday, November 04, 2015

CMOS Mixed-Signal Circuit Design - R Jacob Baker

From Signals, Filters, Sampling, Aliasing to Data Converters. This book covers the fundamentals of Mixed-CMOS Design.

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.

CMOS Mixed-Signal Circuit Design - R Jacob Baker

Some Chapters
  • 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
This book will fill a hole in the technical literature for an advanced-tutorial book on mixed-signal circuit design. There are no competitors in this area. Mixed-signal design is performed in industry by a select few gurus . The techniques can be found in hard-to-digest technical papers.· Data Converter Modeling· Data Converter SNR· Noise-Shaping Data Converters· Submicron CMOS Circuit Design· Implementing Data Converters· Integrator-Based CMOS Filters· At the Bench

Ananth of delabs Notes

Some of my Mixed Circuits Analog with Digital basic ideas on design too.

Thursday, December 22, 2011

Designing Mixed Analog Chips and Circuits

These are some updates on Analog and Mixed Design pages online. A/D Converters are important because the world is full of mainly analog signals and parameters. Processing, Filtering, Analyzing and Computing data is best done by software (firmware).

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

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

MAX1169 ADC and PIC Microcontroller

What is the use of a Robot, which cannot perceive its environment in detail. Where can a Control system be effective, if it does not get a "feedback" about its actions. How could one do Analysis and Research or Verify, when he cannot Measure a parameter with good accuracy and resolution.

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.

MAX1169 ADC and PIC Microcontroller

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

ADS7816 - 12-Bit High Speed Sampling AD

ADS7816 - 12-Bit High Speed Sampling AD

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
  • 1.9mW at 200kHz
  • 150mW at 12.5kHz
  • l POWER DOWN: 3mA Max

12-Bit High Speed Micro Power Sampling Analog-to-Digital converter