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 […]

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 […]

MAX3421E USB peripheral/host controller with SPI interface

MichaelZ writes: While poking around SparkFun’s website I found USB Host Shield which is only marginally interesting unless you are an Arduino fan. But the USB host controller chip is interesting. The MAX3421E is a USB Peripheral/Host Controller with SPI Interface. This is an alternate to the FTDI VNC USB host controllers. It has only […]

High temperature floating point digital signal controller

McZ writes: I have used the SM320F28335-HT microcontroller in several projects including military applications. With the floating point it is blinding fast. The standard temperature comes in a QFP and the high temp version comes in a Ceramic Pin Grid Array which is more friendly than the BGA’s. The TI compiler/IDE is cheap by high […]

App note: Monitor negative power supplies

Precision circuit monitors  negative-supply threshold: Using an IC (MAX971) that includes an open-drain comparator and a precision 1% voltage reference, this circuit monitors the magnitude of a negative supply voltage and provides a digital warning of fault conditions. To monitor multiple negative voltages, use the MAX974, which includes four comparators. Thanks for the tip rsdio!

App note: MAX16834 high-power LED driver

rsdio writes: Why regulate the voltage from your supply when you really need a controlled current to drive an LED? Any regulator is less than 100% efficient, and the losses increase as more current is drawn. It looks like the circuit in this application note would allow you to skip the voltage regulator and thus […]

App note: Long twisted pair reads digital temperature sensor

This digital temperature sensor design uses a twisted cable pair to read the sensor over long distances: This circuit is a simple and economical interface for remote IC thermal sensors. The temperature sensor (MAX6576), an absolute temperature-to-period converter that integrates the sensor with the necessary signal electronics, connects to the receiver (a MAX9140 comparator) using […]

The basics of USB battery charging: a survival guide

An introduction to USB battery charging: a survival guide Arguably the most useful part of USB’s power capabilities is the ability to charge batteries in portable devices, but there is more to battery charging than picking a power source, USB or otherwise. This is particularly true for Li+ batteries, where improper charging can not only […]

Low-Power, 8-Channel, 24-Bit Analog front-end for biopotential measurements

The  TI ADS1298R could be perfect for that EKG project you dreamed of. It has a 8 analog to digital converters with programmable gain amplifiers, an internal reference, and a clock source. The ADS1294/6/8/4R/6R/8R incorporate all of the features that are commonly required in medical electrocardiogram (ECG) and electroencephalogram (EEG) applications. FEATURES Eight Low-Noise PGAs […]