IC category

Reverse-engineering the ALU of 8008 microprocessor

Ken Shirriff has written an article on reverse engineering the ALU of the 8008 microprocessor:

A computer’s arithmetic-logic unit (ALU) is the heart of the processor, performing arithmetic and logic operations on data. If you’ve studied digital logic, you’ve probably learned how to combine simple binary adder circuits to build an ALU. However, the 8008’s ALU uses clever logic circuits that can perform multiple operations efficiently. And unlike most 1970’s microprocessors, the 8008 uses a complex carry-lookahead circuit to increase its performance.
The 8008 was Intel’s first 8-bit microprocessor, introduced 45 years ago.1 While primitive by today’s standards, the 8008 is historically important because it essentially started the microprocessor revolution and is the ancestor of the x86 processor family that are probably using right now.2 I recently took some die photos of the 8008, which I described earlier. In this article, I reverse-engineer the 8008’s ALU circuits from these die photos and explain how the ALU functions.

Reverse-engineering the ALU of 8008 microprocessor – [Link]

TI claims first for zero-drift, zero-crossover op amp: precision & linearity

by Graham Prophet @ edn-europe.com:

With precision and high input linearity in a single high-performance device, Texas Instruments says it has the first operational amplifier (op amp) to offer both zero-drift and zero-crossover technology. The OPA388 op amp maintains high precision across the entire input range for a variety of industrial applications, including test and measurement, medical and safety equipment, and high-resolution data-acquisition systems.

TI claims first for zero-drift, zero-crossover op amp: precision & linearity – [Link]

LTC2944 – 60V Battery Gas Gauge with Temperature, Voltage and Current Measurement

The LTC2944 measures battery charge state, battery voltage, battery current and its own temperature in portable product applications. The wide input voltage range allows use with multicell batteries up to 60V. A precision coulomb counter integrates current through a sense resistor between the battery’s positive terminal and the load or charger. Voltage, current and temperature are measured with an internal 14-bit No Latency ΔΣ ADC. The measurements are stored in internal registers accessible via the onboard I2C/SMBus interface.

LTC2944 – 60V Battery Gas Gauge with Temperature, Voltage and Current Measurement – [Link]

Radino WiFi

Radino WiFi: Arduino With ESP8266EX

The Internet of Things or IoT technology is booming nowadays. Almost all makers are getting interested towards this field of endless possibilities. The Arduino and the ESP8266 are strong bases of this awesome technology. But, what will happen if we merge an Arduino with an ESP8266EX under the same package? Well, the answer is “Radino WiFi”.

Radino WiFi : The Arduino compatible WiFi Module
Radino WiFi: The Arduino compatible WiFi Module

The In-Circuit Radino WiFi combines an ATmega32U4 with the popular ESP8266EX WiFi SoC to the small
Radino package. The ATmega32U4  MCU is also used in Arduino Micro. In Radino, the MCU is preprogrammed with Arduino bootloader. Hence, you can use Arduino IDE for uploading codes to this Arduino-compatible device. In-Circuit stated on their website:

It′s part of the radino-series, which provides full Arduino-compatible wireless communication devices in a small form factor, all pins are compatible with each other.


  • Arduino-compatible
  • Fully integrated WiFi Chip ESP8266EX by Espressif
  • 802.11 b/g/n protocol
  • Wi-Fi Direct (P2P), soft-AP
  • Integrated TCP/IP protocol stack
  • Integrated TR switch, balun, LNA, power amplifier and matching network
  • +19.5dBm output power in 802.11b mode
  • ESP8266 Power down leakage current is < 10uA
  • Wakes up and transmits packets in < 2ms
  • ESP8266 Standby power consumption is < 1.0mW
  • 15 GPIOS (7 PWM, 5 Analog IN)
  • I²C, SPI, UART
  • USB (HID Keyboard & Mouse, virtual UART)
  • High-Performance, Low-Power Microcontroller ATmega32U4

Technical Details:

Radino WiFi consists of two chips. An ATMega32U4 and an ESP8266EX. The ATmega32U4 is used as I/O machine for the ESP8266EX. It performs all the required tasks to control I/Os. In the other hand, ESP8266EX is the main WiFi chip and all WiFi services run only on the ESP.

The Radino comes preprogrammed with an ESP based web server. The default settings are given below:

  • Access point: RADINO-WIFI
  • Password: 12345678
  • TCP/UDP service for UART-Bridge/WiFi
  • Default IP:

The user can change these default settings anytime.

Download the Radino library for Arduino IDE 1.6 from here. Add this library to Arduino IDE and select Radino board from board manager.

This video explains how to use this amazing module.

Radino Pinout:

Radino WiFi Module Pinout Diagram
Radino WiFi Module Pinout Diagram

Radino has 15 GPIO pins. Among them, 5 pins can handle PWM signal and 5 pins can take analog signal as input. Radino is powered by a 3.6V power source. Exceeding that value will damage the device.

Important Links:

Another video on this topic:

You can purchase Radino WiFi from shop.in-circuit.de. It costs only 19.90€.

Ultra-thin, high thermal conductivity substrate integrates ESD protection

Clemens Valens @ elektormagazine.com discuss about a new IC substrate. He writes:

A new, ultra-thin ceramic substrate with an ESD strength of up to 25 kV – more than three times higher than the standard 8 kV of state-of-the-art Zener diodes – also features a high thermal conductivity of 22 W/mK. This is three times better than that of conventional carriers, even though the substrate is significantly slimmer. The new technology is especially well-suited for LED applications where the number and density of LEDs per unit continues to grow.

Ultra-thin, high thermal conductivity substrate integrates ESD protection – [Link]

LTC4380 Overvoltage Protection

Thomas Scherer @ elektormagazine.com writes:

When it comes to protecting sensitive circuitry from potentially damaging over-voltage spikes and supply surges we usually resort to networks of coils, capacitors, resistors and suppression diodes to iron out the transients. The LTC4380 low quiescent current surge stopper IC from Linear Technology goes about it in a different way; it looks out for over-voltage nasties and switches a fast N-channel external series-connected MOSFET to limit the surge. The chip is just 3 mm square and draws very little quiescent current.

LTC4380 Overvoltage Protection – [Link]

Inside the 74181 ALU chip: die photos and reverse engineering

A detailed die photos and reverse engineering of the 74181 ALU chip by Ken Shirriff:

What’s inside a TTL chip? To find out, I opened up a 74181 ALU chip, took high-resolution die photos, and reverse-engineered the chip.1 Inside I found several types of gates, implemented with interesting circuitry and unusual transistors. The 74181 was a popular chip in the 1970s used to perform calculations in the arithmetic-logic unit (ALU) of minicomputers. It is a moderately complex chip containing about 67 gates and 170 transistors3, implemented using fast and popular TTL (transistor-transistor logic) circuitry.

Inside the 74181 ALU chip: die photos and reverse engineering – [Link]

Software Defined Radio IC Decap

Software Defined Radio teardown: R820/RTL2832U Decap

Recently there has been much interest in two integrated circuit which were originally designed to receive FM radio and DVB-T TV (as used in Europe).
Some enterprising people quickly realised that since they were based on software-defined techniques they could be quickly re purposed for all sorts of clever things.

Software Defined Radio IC Decap – [Link]

New PWM controller IC By Microchip Charges Batteries of Any Chemistry

Battery technologies of all chemistry are experiencing revolutionary changes nowadays. Nanotechnology is leading this revolution by yielding new battery technologies including but not limited to Tiny Supercapacitors and Li-ion batteries that never explode at any condition. But, it’s bothersome to make different chargers for different types of batteries. So, Microchip solved this problem by introducing a new hybrid PWM controller, MCP19124/5, that charges batteries of any chemistry.

MCP19124 PWM Controller - 24 Pin QFN Package
MCP19124 PWM Controller – 24 Pin QFN Package

The power of this charging device lies in the combination of an 8-bit PIC microcontroller and an analog PWM controller in one package. This mixed signal low-side PWM controller features individual analog PWM control loops for both current regulation and voltage regulation. It can be configured with separate feedback networks and reference voltages. Any voltage, current, temperature, or duration can be used to trigger a transition to a different charging profile.

Various types of batteries require different charging profile. So, the only way to charge all kinds of batteries with a single device is to simulate all the charging profiles. A user can set his/her desired profile with the help of two independent current and voltage control loops, along with variable reference voltage. Now let’s get to know more details about this versatile PWM controller IC.

MCP19124/5 : 

The MCP19124/5 is a mid-voltage (4.5-42V) analog-based PWM controller with an integrated 8-bit PIC Microcontroller. There are two devices, the MCP19124 and MCP19125, where the last one has four I/O pins more than the first one. MPC19124 and MPC19125 are packaged in 24-lead QFN package and 28-lead QFN package respectively. It has following features:

  • Smooth, dynamic transitions from constant-current to constant-voltage operation
  • Dynamically adjustable output current and output voltage over a wide operating range
  • Wide operating voltage range: 4.5-42V
  • Analog peak-current mode Pulse-Width Modulation (PWM) control
  • Available fixed frequency (31 kHz to 2 MHz)
  • I2C communication interface
  • 9 GPIO for MCP 19124 and 12 GPIO for MCP19125
  • Integrated high voltage linear regulator, with external output
  • Integrated temperatures sense diode
  • Integrated 10 bit A/D converter
  • Minimal external components needed
  • Custom algorithm support
  • Topologies supported include Boost, SEPIC, Flyback, and Cuk

In fact, the above list is just a brief overview. The controller is so complicated that user must read all 236 pages of the datasheet to gain sufficient knowledge.

Now, the question is, how can we use this IC to design an efficient battery charger?

To find the answer, one must read the datasheet thoroughly. At the same time, in-depth knowledge about the target battery is also required. However, Microchip provided a few schematics (as references) in the datasheet based on different applications. The circuit on battery charger is given below:

Battery Charger Circuit Using MCP19124 ICBattery Charger Circuit Using MCP19124 IC
Battery Charger Circuit Using MCP19124 IC

This ultimate powerful dual-loop PWM controller is going to be a game changer and part of the battery technology revolution. It possesses lots of possibilities. To learn more about this fantastic hybrid controller, study the datasheet carefully.

Buck regulators accept up to 40-V input

by Susan Nordyk @ edn.com:

A wide input range of 4.5 V to 40 V enables the TS3004x series of DC/DC synchronous buck regulators from Semtech to work in a wide range of applications, including industrial, telecommunication, and consumer. The current-mode TS30041 and TS30042 furnish 1 mA and 2 mA of continuous output current, respectively, and include integrated power switches and robust fault protection in a small 3×3-mm, 16-lead QFN package.

Buck regulators accept up to 40-V input – [Link]