How to Combine a Low-Pass Filter and an ADC Driver for a 20-Vp-p Signal

Driving an analog-to-digital converter (ADC) for optimum mixed-signal performance is a design challenge. Figure 1 shows a standard ADC driver circuit. During ADC acquisition time, the sampling capacitor kicks back an exponentially decaying voltage and current into the RC filter. A mixed-signal ADC driver circuit’s optimum performance depends on multiple variables. The driver’s settling time, … Read more

The Shannon decoder: A (much) faster alternative to the PWM DAC

Readers will recognize the famous name Claude Elwood Shannon, widely renowned as the “father of information theory” and originator of many discoveries and inventions. Among these is an elegant and pioneering (First published in 1948!) design idea for a DAC called the Shannon Decoder (SD) sketched in Figure 1 (illustration modified from the Data Conversion … Read more

PCIe 3.0 packet switch allows flexible port configuration

The PI7C9X3G1224GP PCIe 3.0 packet switch from Diodes accommodates 24 lanes of Gen3 SerDes in 3-port to 12-port configurations. For fan-out purposes, any port of the packet switch can be configured as upstream and connected to multiple downstream ports. Host-to-host communication is possible through cross-domain end-point configuration of up to three dedicated ports. Suitable for … Read more

Single-pair PoE controllers drive smart factories

ADI’s LTC4296-1 and LTC9111 single-pair PoE controllers provide power and data to remote, hard-to-access endpoint devices over a single-pair cable. The controllers enable powered, last-mile connectivity for factory and building automation through real-time power management, telemetry, and very low standby power consumption. Single-pair Power over Ethernet (SPoE) augments single-pair Ethernet (SPE) to provide more reliable, … Read more

Building a personal workstation: picking up the pieces

Assuming you’ve already read last month’s tale of woe (if not, I highly recommend a perusal of it, as well as the two preparatory pieces that preceded it, before continuing), you already know that my gamble on an “open box” AMD high-end desktop PC microprocessor—one that ended up actually being not only “used” but “used … Read more

Cancel PWM DAC ripple and power supply noise

Several years ago, I published a design idea (See Figure 1: “Cancel PWM DAC ripple with analog subtraction,” November 28, 2017) showing a simple trick for the cancellation of PWM output ripple. It employs passive summation of the usual PWM signal with its AC-coupled inverse, thus dramatically attenuating the undesired AC (ripple) component without affecting … Read more

3D perception software reduces LiDAR sensor false alarms

Quanergy has upgraded its QORTEX DTC 3D perception software to improve the accuracy of its MQ-8 series of LiDAR flow-management sensors. Accuracy improvements and the reduction of false alarms are the result of what the company believes is the industry’s first motion-based noise reduction mechanism and first occlusion filter/object stitching mechanism. QORTEX LiDAR-based software provides … Read more

Disassembling a wireless charger with a magnetic personality

With every iPhone generation, with varying degrees of success, Apple strives to come up with at least one “killer” new feature that will motivate not only potential Android switchers but also iOS upgraders. For the iPhone 12, there were (at least) two: first-time 5G connectivity, and the underlying motivation for this particular teardown, MagSafe. Long-time … Read more