A current-sensor would be useful in a lab power supply. This app note is about chaining two current-sense chips to use at high voltages: Using a transistor as shown, you can double the allowed voltage limit on a current-sense amplifier by stacking two such amplifiers one upon the other. The voltage signal from the bottom […]
Category Archives: app notes
App note: High-voltage, programmable-gain current monitor
Another article that might help with bench power supply designs: This circuit monitors current flow at high voltage (48V and higher) using a standard 5V difference amplifier (MAX4198) referenced to ground. It also employs a digital potentiometer (MAX5402) for gain adjustment. Thanks rsdio!
App note: Linkwitz equalizer puts the bass in subwoofers
rsdio writes: If anyone is building a subwoofer crossover, this is a great article! Nice use of opamps too. The linearity and high power-handling capability of modern low-frequency loudspeakers have made it easy to electronically extend the bass response. This extension is especially useful in second-order systems like a closed box, where cone excursions are […]
MAX31855 cold-junction compensated thermocouple-to-digital converter
Drone writes: Here is another MAXIM unobtainium installment The new MAX31855 is a rather nice cold-junction compensated thermocouple-to-digital converter. It takes the likes of the MAX6675 to the next level. This part is supposedly going to become available around the end of June 2011. From the product page: “The MAX31855 performs cold-junction compensation and digitizes […]
App note: Parallel LED drivers for maximum current
rsdio writes: This looks like a handy utilization of the basic bipolar transistor current mirror, based on the DMMT5401. For once, the key component is not a Maxim part, but Diodes Inc. ;-) Using a pair of matched transistors to translate a high-side current-sense signal down to a ground reference, this circuit lets you parallel […]
Designing PCBs for automotive applications
This application note gives PCB design tips for reducing EMI in automotive environments. A lot of the advise can be applied to any PCB layout. Electromagnetic interference (EMI) and electromagnetic compatibility (EMC) testing is an important part of design verification for serializer/deserializer (SerDes) devices in automotive applications. EMI and EMC must be considered early in […]
App Note: Versatility of CTMU
This Microchip application note explores the many uses for the Charge Time Measurement Unit (CTMU). CTMU is a flexible analog module that provides accurate differential time measurement between pulse sources, as well as asynchronous pulse generation. Together with other on-chip analog modules, the CTMU can be used to precisely measure time, measure capacitance, measure relative […]
Chip powers LED lamps in MR16 halogen bulb systems
This driver is used in LED replacement lamps for MR16 halogen bulb sockets. It’s compatible with common dimmers: The MAX16840, an LED driver that employs a proprietary architecture to ensure flicker-free, dimmable operation with electronic transformers and cut-angle dimmers. Maxim’s patent-pending approach enables the design of retrofit LED lamps that can replace halogen MR16s without […]
1.8V/3V sim card power supply with level translator
McZ found a sim card power supply with level translator: The TXS4555 is a complete Smart Identity Module (SIM) card solution for interfacing wireless baseband processors with a SIM card to store I/O for mobile handset applications. The device complies with ISO/IEC Smart-Card Interface requirements as well as GSM and 3G mobile standards. It includes […]
App note: DC voltage controls PWM dimming of high-brightness LEDs
An app note on a LED-driver circuit: This LED-driver circuit includes a hysteretic controller U1 (MAX16820), related power components, and a control circuit based on the quad op amp U2 (LMX324). U1 drives five HB LEDs from a 24V source, using only inductor L1, MOSFET Q1, and catch diode D1. Thanks rsdio!
LM0901a1411090451C polis operational amplifier
Akos tips us to the LM0901a1411090451C polis operational amplifier: The LM0901A1141090451C is a macropower, low performance, degraded circuit operational amplifier designed to have a no load power dissipation of less than 0.553W at Vs = ±1pV and less than 200W at Vs = ±2pV. Open loop gain is greater than 0.001k and input bias current […]
14bit 125MSPS low-power ADC
MichaelZ tipped us to the ADS9412x a 14-/12-Bit, 65/125MSPS, ultralow-power analog to digital converter: • Ultralow Power with 1.8V Single Supply: – 103mW Total Power at 65MSPS – 153mW Total Power at 125MSPS • Programmable Gain up to 6dB for SNR/SFDR Trade-Off • DC Offset Correction • Differential input voltage range 2 VPP Thanks McZ!
MAX2209A RF power detector
The MAX2209A is an efficient and fast RF power detector: Fast RF step-response allows faster tracking of the output envelope, ensuring more efficient and more accurate PA control Shutdown feature allows lower overall current consumption Small size saves board space You can check out the complete datasheet. Thanks rsdio!
Using the EUSART
The term UART (Universal Asynchronous Receiver Transmitter) is the technical term for the good old serial port found on most MCUs. The term USART similarly refers to a serial port capable of handling both synchronous and asynchronous operation. Over the past few years, Microchip has been integrating an updated serial port into many of their […]
App note: Simple constant-power driver
This app note describes a simple, inexpensive constant power driver: A combination current-sense amplifier and multiplier (MAX4211F) senses both the current through and voltage across the load, and supplies at one of its outputs (POUT) a voltage proportional to the continuous product of those variables, i.e., proportional to the load’s instantaneous power. External op amps […]
App note: Precision current sink and source circuits
rsdio tipped us to an app note on precision current sink and source circuits: The precision current mirrors shown allow you to transform one type of 4–20mA transmitter to another, or to create a repeater for the purpose of extending the length of the current loop. The circuits include an input-sink/output-sink mirror and an input-source/output-source […]
App note: Load-power monitor improves high-side current measurements
This amplifier with an analog voltage multiplier could be useful in a bench power supply: Combining a high-side current-sense amplifier with an analog voltage multiplier, the MAX4211 can easily measure the power dissipated in a load. One multiplier input connects to the load voltage, and the other to an internal analog of the load current—that […]
Dual sim card reader with voltage translation
McZ found a sim card reader with integrated voltage translation: The TXS02326 is a complete dual-supply standby Smart Identity Module (SIM) card solution for interfacing wireless baseband processors with two individual SIM subscriber cards to store data for mobile handset applications. It is a custom device which is used to extend a single SIM/UICC interface […]
App Note: Grid-connected solar microinverter using a dsPIC® DSC
In this advanced app note Microchip details the theory behind converting solar energy into usable electric power. Starting with a discussion of the electrical characteristics of photovoltaic (PV) cells, they move onto the tech behind inverters and the mathematics involved with their proper design and use. Finally a microinverter reference design is presented, using a […]
Voltage regulator chip roundup
McZ and rsdio tipped us to a bunch of new and wonderful voltage regulator chips. Tiny regulators, high current regulators, and high voltage regulators. TPS84620: 4.5V to 14.5V input, 6A switching regulator needs only three external parts MAX15040: 2.4V to 3.6V input, 4A switching regulator is the smallest yet MAX15050/MAX15051: 2.9V to 5.5V input, 4A […]