Part Number: ISO124P

Manufacturer: Texas Instruments


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Technical Specifications of ISO124P

Datasheet  ISO124P datasheet
Category Integrated Circuits (ICs)
Family Linear – Amplifiers – Instrumentation, OP Amps, Buffer Amps
Manufacturer Texas Instruments
Packaging Tube
Part Status Active
Amplifier Type Isolation
Number of Circuits 1
Output Type
Slew Rate 2 V/μs
Gain Bandwidth Product
-3db Bandwidth 50kHz
Current – Input Bias
Voltage – Input Offset 20mV
Current – Supply 5mA
Current – Output / Channel 15mA
Voltage – Supply, Single/Dual (±) ±4.5 V ~ 18 V
Operating Temperature -25°C ~ 85°C
Mounting Type Through Hole
Package / Case 16-DIP (0.300″, 7.62mm), 8 Leads
Supplier Device Package 16-PDIP

ISO124P Description

ISO124 is a unique duty cycle modulation demodulation isolation amplifier. A 2-pF differential capacitive barrier allows for the digital transmission of the signal. Due to the fact that the barrier qualities have no bearing on the signal integrity when using digital modulation, the barrier has excellent dependability and exceptional high-frequency transient immunity. Two barrier capacitors are encased within the plastic body of the package.

Utilizing ISO124 is simple. There are no additional parts needed for functioning. The main requirements are a maximum nonlinearity of 0.010%, a signal bandwidth of 50 kHz, and a VOS drift of 200 V/°C. The ISO124 device is an excellent option for a variety of applications because to its quiescent currents of 5 mA on VS1 and 5.5 mA on VS2, as well as its 4.5 V to 18 V power supply range. The ISO124 is in plastic surface-mount packaging with 16-pin PDIP and 28-lead SOIC connectors.

ISO124P Features

  • For high-voltage breakdown, 100% tested.
  • a 1500 Vrm rating.
  • IMR is high at 140 dB at 60 Hz.
  • 010% is the maximum nonlinearity.
  • Operation in bipolar mode: VO = 10 V.
  • PDIP-16 and SOIC-28 packages.
  • Fixed Unity Gain Configuration is simple to use.
  • Supply Voltage: 4.5 to 18 volts.

ISO124P Detailed Description

The input and output sections of the ISO124 isolation amplifier are galvanically isolated by matched 1-pF isolating capacitors included in the plastic package. The input is digitally transferred through the barrier while being duty-cycle modulated. The output section receives the modulated signal, which demodulates it, turns it back to an analog voltage, and removes the ripple component. The fabrication of input and output parts is followed by laser trimming for the best possible circuitry matching between the two sections. The isolating capacitors are then put between the two parts, with the sections mounted on the package’s opposing ends. There are 250 transistors in the ISO124.

● Modulator

An input amplifier integrates the input current (VIN/200 kA) and a switching 100-A current source. This current source is implemented with a switchable 200-A source and a fixed 100-A current sink. To understand the fundamental operation of the modulator, assume VIN = 0 V. Until the comparator threshold is met, the integrator ramps in a single direction. The comparator and sensing amp produce a triangle waveform with a 50% duty cycle by forcing the current source to switch. Due to the inbuilt oscillator, the current source must switch at a frequency of 500 kHz. The ensuing capacitor drive is a square wave with complementary duty-cycle modulation.

● Demodulator

A switching current source is sent into integrator A2 by the sensing amplifier, which recognizes when a signal crosses the capacitive barrier. The output stage balances the feedback current flowing via the 200-k feedback resistor and the duty-cycle modulated current, yielding an average value at the VOUT pin equal to VIN. The output feedback loop’s sample-and-hold amplifiers eliminate undesirable ripple voltages, a byproduct of the demodulation process.

ISO124P Feature Description

● Isolation Amplifier

A precise analog isolation amplifier, the ISO124. A capacitive barrier with a high voltage differential transmits the input signal digitally. The barrier properties affect signal integrity with digital modulation, leading to outstanding reliability and high-frequency transient immunity.

ISO124P Application Information

● Carrier Frequency Considerations

Using a 500-kHz duty-cycle modulation approach, the ISO124 amplifier transfers the signal over the isolation barrier. This device functions like any linear amplifier for input signals with a frequency below 250 kHz. However, the behavior is comparable to that of a sampling amplifier for frequencies greater than 250 kHz.

● High IMV dV/dt Errors

The sense amp may begin to falsely trigger as the IMV frequency rises and the dV/dt surpasses 1000 Vs., and the output will show spurious faults. The high slew rate’s ability to send common-mode current across the barrier causes the sense amplifier to trigger falsely. For usual performance, lowering the power-supply voltages below 15 V may reduce the dV/dt to 500 V/M s.

● High Voltage Testing

TI has approved the German VDE0884 Optocoupler Standards as a partial discharge test criterion. With this technique, each ISO124 isolation barrier must withstand 2400-Vrms, 60-Hz high-voltage stress while measuring tiny current pulses (less than 5 PC). This test cannot be passed by initiating any partial discharges. This criterion verifies that ISO124 is protected from transient overvoltage (1.6 1500 Vrms) without harm. The findings of the life test confirm that there is no failure at the maximum temperature and continuous rated voltage.

This innovative test technique is “state-of-the-art” in nondestructive high-voltage reliability testing. It is based on how nonuniform fields behave in heterogeneous dielectric material as barriers degrade. When void nonuniformities exist, the high-voltage barrier is partially bridged before the electric field stress ionizes the void region. An external burst of 0.01-0.1-s current pulses that repeats with each ac voltage cycle can be used to externally detect the transient conduction of charge during and after the ionization. The “inception voltage” is the lowest ac barrier voltage required to start partial discharge. Before partial discharge stops, the barrier voltage must be reduced to a lower value, known as the “extinction voltage.”

To prevent ISO124 from being harmed by transient overvoltages below this level, package insulation techniques have been devised and characterized to produce an inception voltage greater than 2400 Vrms. Since the extinction voltage exceeds 1500 Vrms, even overvoltage-induced partial discharge will stop once the barrier voltage reaches its rated level of 1500 Vrms. Older high-voltage test techniques relied on applying an overvoltage that was just enough (above rating) to damage marginal parts but not enough to harm good ones.


In conclusion, the ISO124 is a precision isolation amplifier that transmits signals across a differential capacitive barrier using digital modulation. As a result, it has unpaid dependability and immunity to high-frequency transients. It is available in 16-pin PDIP and 28-lead SOIC plastic surface-mount packages and has a power supply range of 4.5 V to 18 V. The gadget is simple to use and requires no extra parts to work. German VDE0884 Optocoupler Standards are followed during high-voltage testing to ensure protection without damage.

If you want to purchase the ISO124P or have any questions, our professional staff at ICRFQ is always here to assist you. We provide cost-effective, high-quality electrical parts and knowledgeable advice to ensure you acquire the parts you need for your project. Do not be reluctant to contact us; allow us to provide the certainty you require to begin your project.

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