Tag Archive for Teardown

Teardown & Analysis of a Keysight InfiniMax III N2802A 25GHz Active Probe


In this episode Shahriar takes a close look at one of Keysight (Agilent) InfiniMax III active probes. The model N2802A offers 25GHz of analog bandwidth, 17.5pS of rise time and a total differential input capacitance of 32fF at 10k-Ohm input impedance. The front-end amplifier of this active probe is designed in an in-house InP process, the same process responsible for the front-end of the X-Series Keysight oscilloscopes.

The teardown of the probe shows the control circuitry in the main probe body built around a PIC 16F877 microcontroller coupled to a DAC, EEPROM memory and various high-current and precision op-amps for biasing. The main front-end microwave module reveals the InP ASIC and supporting microwave circuity. There seems to be a dual-path design to provide a large DC common-mode offset capability as well as a high-bandwidth.

National Instruments VirtualBench Review, Teardown & Experiments


In this episode Shahriar gets a hold of a National Instruments VirtualBench! This instrument combines a mixed-signal oscilloscope, function generator, digital multimeter, programmable power supply and digital I/Os in one compact and portable unit. The teardown of the unit reveals a two-board construction with a core single processor which handles all instrument functionality simultaneously.

The unit software (which is embedded inside the instrument memory) is examined in detaile before performing any experiments. Using the VirtualBench, a Si5351 multi-synthesizer clock generator IC is characterized including output signal analyses and I2C decoding. Next by using the function generator and oscilloscope the response of a band-pass 15MHz filter is measured.

Keithley DMM7510 7.5-Digit Multimeter Review, Teardown & Experiments


In this episode Shahriar takes a detailed look at the new Keithley DMM7510 7.5-Digit Multimeter. Boasting Keithley’s touchscreen GUI interface, 100mV, 1-Ohm and 10uA ranges makes this multimeter a precision instrument for a variety of applications. The multimeter is also capable of 1MS/s digitization functionality.

The teardown of the unit reveals the complex multi-board construction and analog board design intricacies. After a brief performance verification and GUI overview the multimeter is used in several experiments including measuring the conductivity of a flame, digitizing a large dynamic range multi-tone signal and DC-DC converter noise analysis. Furthermore, the scripting capability of the unit is employed to estimate the location of a short in an Ethernet cable and measure the dielectric constant of a parallel plate capacitor.

Teardown, Repair & Analysis of a Rohde & Schwarz FSH3 3.0GHz Portable Spectrum Analyzer


In this episode Shahriar examines a faulty R&S FSH3 100kHz – 3.0GHz Portable Spectrum Analyzer. This exceptionally dirty unit does not power on and is missing a power supply and battery. After verifying the correct operation of the battery charger circuit and keypad the problem is traces to a damaged SOT-23-6 MOSFET device which is part of a fly-back DC-DC converter. A replacement MOSFET with a lower current rating proves to be a failure as the device fails on startup. A higher rated MOSFET resolves the problem and device begins to operate correctly.

The block diagram of the system as well as a detailed block diagram of the RF section is presented and correlated with the teardown of the RF section. The super-heterodyne down-conversion circuits and components are examined.

Siglent SDM3055A 5.5-Digit Multimeter Review, Teardown & Experiments


In this episode Shahriar reviews the Siglent SDM3055A 5.5-Digit Multimeter. After a brief look at the instrument’s datasheet, a full teardown is presented. The instrument utilizes a two-board design and a large LCD screen. The SDM3055A provides a comprehensive set of measurements including capacitance as well as various graphing capabilities including histogram, trend and bar graphs. USB and LAN connections are standard and a USB-GPIB can also be purchased. The performance of the instrument is verified through experiments with various functions and setups.

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