Saturday, October 14, 2017

Wide-Bandwidth Dual JFET Opamp LF353

These devices are low cost, high speed, dual JFET input operational amplifiers with an internally trimmed input offset voltage.

They require low supply current yet maintain a large gain bandwidth product and fast slew rate. In addition, well matched high voltage JFET input devices provide very low input bias and offset currents.

Wide-Bandwidth Dual JFET Opamp LF353

LF353 - Wide Bandwidth Dual JFET Input Operational Amplifier

Some Highlights
  • Gain Bandwidth 4 MHz
  • Slew Rate 13 Volts/usec
  • Offset Voltage 10 mV
  • Low Input Bias Current: 50pA
  • High Input Impedance: 1 Tera Ohms

Dual Low-Noise JFET Opamp TL072-TI

The JFET-input operational amplifiers in the TL07x series are designed as low-noise versions of the TL08x series amplifiers with low input bias and offset currents and fast slew rate.

Quadrature Oscillator - 100 kHz - TL072-TI - TL072-TI  Opamp


The low harmonic distortion and low noise make the TL07x series ideally suited for high-fidelity and audio preamplifier applications. Each amplifier features JFET inputs (for high input impedance) coupled with bipolar output stages integrated on a single monolithic chip.

  • Low Power Consumption
  • Low Input Bias and Offset Currents
  • Low Noise
  • High Input Impedance JFET Input Stage
  • High Slew Rate - 13 V/µs Typ
  • Common-Mode Input Voltage Range Includes VCC+

Friday, October 13, 2017

CA3140 and CA3130 Special Opamps

CA3140 and CA3130 are originally RCA part numbers( i feel). They are amazing close to ideal opamps, the input offset has to be trimmed. I used to use it when high input impedance is required. 1.5T ohm 10pA is the specs. A Electrometer can be made with just one opamp.

CA3130 has the additional Merit of swinging to the rails, if you are on a +/- 12V supply, the output will be +/-12V. This is a feature required in control applications.

These devices are now available with Intersil.

CA3140 -4.5MHz, BiMOS Operational Amplifier with MOSFET Input/Bipolar Output

The CA3140A and CA3140 BiMOS operational amplifiers feature gate protected MOSFET (PMOS) transistors in the input circuit to provide very high input impedance, very low input current, and high speed performance. The CA3140A and CA3140 operate at supply voltage from 4V to 36V (either single or dual supply).

Voltage regulator that uses CA3130

A voltage regulator that uses CA3130 - Range 0.1 to 50V at 1 Amp.

CA3130 - 15MHz, BiMOS Operational Amplifier with MOSFET Input/CMOS Output

"15MHz, BiMOS Operational Amplifier with MOSFET Input/CMOS Output
A CMOS transistor-pair, capable of swinging the output voltage to within 10mV of either supply-voltage terminal (at very high values of load impedance), is employed as the output circuit."

Function Generator using the CA3140

Applications - Ground-Referenced Single Supply Amplifiers, Fast Sample-Hold Amplifiers, Long-Duration Timers/Monostables.

Wednesday, September 06, 2017

Offline Isolated Flyback LED Controller - LT3799-1

This chip for LED driving has a power factor correction, the critical conduction mode keeps transformer small. A opto-coupler for feedback is avoided by an innovative primary shunt monitor.

Offline Isolated Flyback LED Controller - LT3799-1

The LT3799-1 uses a micropower hysteretic start-up to efficiently operate at offline input voltages, with a third winding to provide power to the part. An internal LDO provides a well regulated supply for the part’s internal circuitry and gate driver.

LED Controller - LT3799-1

20 Watt LED Driver using LT799-1

The FAULT pin provides notification of open and short LED conditions. The LT3799-1 offers improved line regulation over the LT3799, but is not designed for use with a TRIAC dimmer.

  • Offline 4W to 100W+ LED Applications
  • High DC VIN LED Applications
  • Gate driver to drive an external high voltage MOSFET.
  • Typical power factors of 0.97.

Tuesday, September 05, 2017

LED Drive using TPS61042

This Chip from TI is simple to integrate into your designs and this solution is good for production of lighting gadgets, here a consistent quality and predictable performance is easily obtained.

TPS61042 30-V, 500-mA Switch Boost Converter  for White LED Applications
LED-driver application that drives four LEDs with 20 mA of forward current and operates from an input voltage range of 1.8 to 6.0 V.

The entire circuit consists of the control IC, two small ceramic caps, an inductor, a diode, and a current sense resistor. The primary power-supply functions and the secondary features such as load disconnect, overvoltage protection, and PWM dimming have been implemented with a control IC and five small surface-mount passive components.

LED Drive using TPS61042

LED-driver considerations - By Michael Day

Many of today’s portable electronics require backlight LED-driver solutions with the following features: direct control of current, high efficiency, PWM dimming, overvoltage protection, load disconnect, small size, and ease of use.

Monday, September 04, 2017

AD636 - True RMS to DC Converter

Working on low signals in the range of 0 mV to 200 mV rms, AD636 makes a precision AC to DC signal conditioner for Instrumentation. DMM, Data Loggers and Process Indicators can use this.

AD636 - True RMS to DC Converter

Using this chip you can make a True RMS Voltmeter for your Lab or Project.

The AD636 is easy to use. The device is factory-trimmed at the wafer level for input and output offset, positive and negative waveform symmetry (dc reversal error), and full-scale accuracy at 200 mV rms. Therefore, no external trims are required to achieve full-rated accuracy.

Some Features and Specs
  • Laser-trimmed to high accuracy
  • 0.5% maximum error (AD636K)
  • Computes rms of ac and dc signals
  • 1 MHz, −3 dB bandwidth: V rms > 100 mV
  • Signal crest factor of 6 for 0.5% error
  • Low power: 800 μA quiescent current

Friday, August 11, 2017


The MOC303XM and MOC304XM devices consist of a AlGaAs infrared emitting diode optically coupled to a monolithic silicon detector performing the function of a zero voltage crossing bilateral triac driver. MOC3041.

They are designed for use with a triac in the interface of logic systems to equipment powered from 115 VAC lines such as teletypewriters, CTRs, solid-state relays, industrial controls, printers, motors, solenoids and consumer appliances, etc

  • Simplifies logic control of 115 VAC power
  • Zero voltage crossing
  • dv/dt of 2000 V/µs typical, 1000 V/µs guaranteed
Motorola used to make these then it was Infineon Technologies now Isocom also makes it

MOC3041 Zero Crossing Triac Output, 6 Pin

See the original Motorola Application below.

MOC3041 Zero Crossing Triac Output, 6 Pin

These were used by me to make solid state relays. Look at the circuits here Power Electronics Circuits. The were used to control Heaters from DC control signal from a Proportional Temperature Controller. The Magnetic Contactors can be avoided for lower powers. At higher powers SCR banks become a bit expensive.

OC3041M: 6-Pin DIP 400V Zero Crossing Triac Driver Output Optocoupler

The SSR has no mechanical wear and tear but heat up at high currents. So if we overrate by 5 Times then it is an excellent solution for lower power controls upto 5 Kilo Watts. The cycle time of Contactors must be 20-60 Seconds to make it last long. In a SSR a one second cycle time is possible as 10-20mS is the switching speed due to zero crossing.