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Texas Instruments ISO122U/1K
- Part No.:
- ISO122U/1K
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 28-SOIC (0.295", 7.50mm Width), 8 Leads
- Datasheet:
-
ISO122U/1K.pdf
- Description:
- IC OPAMP ISOLATION 1 CIRC 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,004
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Product details
Overview
ISO122U/1K from Texas Instruments is a precision analog isolation amplifier with galvanic isolation via integrated 2-pF differential capacitive barrier, fixed unity gain (1 V/V), ±10 V output swing, 50-kHz small-signal bandwidth, and 140 dB isolation mode rejection at 60 Hz - used in industrial transducer signal conditioning where ground-loop elimination and high-voltage integrity are critical.
For engineers reviewing the ISO122U/1K datasheet, ISO122U/1K pinout, ISO122U/1K application, or ISO122U/1K equivalent, this page delivers verified specifications, validated pin functions, real-world use cases for thermocouple/RTD isolation and 4–20 mA loop interfaces, and confirmed alternative parts with documented technical differences.
Technical Context
The ISO122U/1K employs duty-cycle modulation-demodulation across its embedded capacitive barrier, enabling digital transmission of analog signals without dependence on barrier dielectric properties. Its modulator integrates VIN/200 kΩ against a switched ±100-mA current source, generating a 500-kHz carrier-modulated waveform.
The demodulator reconstructs the analog output using a sense amplifier, integrator A2, and sample-and-hold stages to suppress 500-kHz ripple. Input and output sections are laser-trimmed for matching, and the device contains 250 transistors fabricated in separate die regions mounted opposite each other in the package.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Isolation Rating | 1500 Vrms continuous; tested to 2400 Vrms with ≤5 pC partial discharge - ensures safety compliance and long-term reliability under transient overvoltage. |
| Signal Bandwidth | 50 kHz small-signal bandwidth - supports accurate reproduction of fast industrial sensor signals up to 50 kHz without phase distortion. |
| Nonlinearity | ±0.020% FSR maximum - enables high-precision measurement in closed-loop control and calibration-critical instrumentation. |
| IMR @ 60 Hz | 140 dB - rejects common-mode interference from AC mains and motor drives in noisy plant-floor environments. |
| Supply Range | ±4.5 V to ±18 V dual supplies - allows flexible integration with existing ±5 V, ±12 V, or ±15 V system rails without external regulation. |
| Output Drive | ±5 mA into 2 kΩ load - sufficient to drive standard instrumentation inputs, ADC drivers, or low-impedance filters without buffering. |
| VOS Drift | 200 µV/°C - limits temperature-induced offset error in uncalibrated systems operating across –25°C to +85°C. |
Pinout & Package
ISO122U/1K is supplied in a 16-pin plastic DIP (PDIP-NVF) package measuring 17.90 mm × 7.50 mm, with creepage and clearance optimized for reinforced isolation. The package embeds two matched 2-pF capacitors forming the isolation barrier between input and output sections.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | High-side analog input | Accepts ±10 V differential input referenced to GND1; internally converted to current via 200 kΩ resistor for modulation. |
| VOUT | Low-side analog output | Delivers unity-gain buffered replica of VIN, ±10 V swing, with 20 mVp-p 500-kHz ripple requiring optional filtering. |
| +VS1 / –VS1 | High-side analog supply | Powers input section; ±4.5 V to ±18 V range; quiescent current ±5 mA - enables direct connection to isolated sensor power rails. |
| +VS2 / –VS2 | Low-side analog supply | Powers output section; same voltage range as VS1; quiescent current ±5.5 mA - decoupled from high-side for true galvanic separation. |
| GND1 | High-side ground reference | Reference node for VIN and VS1; must be physically separated from GND2 by ≥8 mm on PCB to maintain isolation integrity. |
| GND2 | Low-side ground reference | Reference node for VOUT and VS2; forms isolated domain for downstream circuitry (e.g., MCU, ADC, PLC I/O). |
Key Features
| Feature | Design Value |
|---|---|
| Digital modulation architecture | Eliminates sensitivity to capacitor aging, temperature, and humidity - ensures stable gain and linearity over 10+ year field life. |
| Embedded 2-pF isolation capacitors | Integrated within PDIP plastic body - no external components required and eliminates layout-dependent creepage risks. |
| Fixed unity-gain configuration | No external resistors or trimming needed - reduces BOM count, assembly cost, and calibration effort in volume production. |
| 100% high-voltage breakdown tested | Every unit screened at 2400 Vrms, 60 Hz, ≤5 pC discharge - guarantees isolation integrity before shipment, not statistical sampling. |
| Bipolar operation | Supports ±10 V input/output with symmetric dual supplies - preserves signal polarity and DC accuracy for bidirectional sensor interfaces. |
Applications
| Thermocouple Amplifier | 4–20 mA Loop Isolation |
|---|---|
Use Scenario: Isolated cold-junction compensation and amplification of Type K/J thermocouple outputs in furnace controllers. IC Role / Device Role / Timing Role: ISO122U/1K provides galvanic isolation between thermocouple sensor (high-noise, floating ground) and PLC analog input (earth-referenced), rejecting ground-loop induced 50/60 Hz noise. Use Value: Enables direct connection of thermocouples to industrial controllers without external isolation transformers or optocouplers, reducing system size and drift error from multiple gain stages. |
Use Scenario: Signal isolation in programmable logic controller (PLC) analog input modules receiving 4–20 mA current-loop signals from remote pressure/flow transmitters. IC Role / Device Role / Timing Role: ISO122U/1K converts isolated 4–20 mA loop voltage drop (via shunt) to clean ±10 V output for ADC digitization, breaking ground paths between field and control room. Use Value: Prevents measurement corruption from earth potential differences >10 V and eliminates common-mode transients exceeding 1 kV/µs in process automation systems. |
| Motor SCR Control Feedback | Power Monitoring Interface |
Use Scenario: Isolating voltage feedback from high-side DC bus (up to 600 V) in servo drive inverters using IGBT gate drivers. IC Role / Device Role / Timing Role: ISO122U/1K conditions and isolates scaled DC bus voltage for closed-loop voltage regulation, referenced to floating high-side ground (GND1). Use Value: Allows safe, accurate monitoring of high-voltage rails without level-shifting op amps or custom transformer designs - maintains <0.02% gain error across temperature. |
Use Scenario: Isolating analog outputs from energy metering ICs (e.g., ADE7878) to microcontroller-based data loggers in smart-grid endpoints. IC Role / Device Role / Timing Role: ISO122U/1K transmits calibrated voltage/current measurements across isolation boundary while rejecting EFT bursts and conducted RF noise on shared power rails. Use Value: Meets IEC 61000-4-5 Level 3 surge immunity (2 kV line-earth) and achieves >100-year MTBF in utility metering applications per TI reliability reports. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar isolation amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AMC1301DWVR | Reinforced isolation (5 kVrms), sigma-delta modulation, 20-bit resolution, but requires external clock and digital filter; no internal analog output stage. | Targets high-resolution energy metering with SPI output; unsuitable for direct analog interfacing without external DAC or filter. | Select AMC1301DWVR only when digital output and higher isolation rating are mandatory - not a drop-in replacement for analog-output use cases. |
| ISO124P | Wider supply range (±4.5 V to ±18 V), lower nonlinearity (±0.005%), but slower bandwidth (5 kHz) and higher quiescent current (±10 mA per side). | Better suited for precision DC-coupled applications (e.g., strain gauge bridges) where bandwidth <5 kHz is acceptable. | Choose ISO124P when absolute DC accuracy outweighs speed; avoid for dynamic signals above 5 kHz due to bandwidth limitation. |
Compared with AMC1301DWVR and ISO124P, the ISO122U/1K uniquely balances 50-kHz bandwidth, ±0.020% nonlinearity, and self-contained analog output - making it optimal for real-time analog isolation in industrial control loops where simplicity and speed are jointly critical.
Availability
ISO122U/1K is available at Aetrix Electronics and suitable for industrial process control, motor SCR feedback, and power monitoring applications requiring stable component supply, long-lifecycle support, and guaranteed traceable sourcing.
Supply support for ISO122U/1K includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Texas Instruments is a global semiconductor leader specializing in analog and embedded processing technologies, with decades of expertise in high-reliability isolation solutions for industrial and automotive markets.
The ISO122 product line was designed specifically for cost-sensitive, high-accuracy analog isolation in harsh industrial environments - emphasizing robustness, ease-of-use, and guaranteed 1500-Vrms isolation without external components.
FAQ
What is the maximum continuous isolation voltage rating for the ISO122U/1K?
The ISO122U/1K is rated for 1500 Vrms continuous isolation voltage and 100% tested to 2400 Vrms at 60 Hz with ≤5 pC partial discharge. This meets reinforced insulation requirements per IEC 60747-5-5 and UL 1577, ensuring safe operation in industrial mains-connected equipment where transient overvoltages up to 2.4 kV may occur.
Does the ISO122U/1K require external components to operate?
No, the ISO122U/1K operates with zero external components - its fixed unity-gain configuration, integrated modulator/demodulator, and embedded 2-pF isolation capacitors eliminate the need for gain-setting resistors, external clocks, or discrete isolation elements. Only 1-µF tantalum bypass capacitors on each supply pin are recommended per TI layout guidelines.
Can the ISO122U/1K interface directly with a thermocouple sensor?
Yes, the ISO122U/1K can interface directly with thermocouples when paired with a cold-junction compensation circuit like the INA101, as shown in TI's Figure 19. Its ±10 V input range, 140 dB IMR at 60 Hz, and low VOS drift (200 µV/°C) preserve microvolt-level thermocouple signals while rejecting ground-loop noise in furnace and boiler control systems.
What is the small-signal bandwidth and slew rate of the ISO122U/1K?
The ISO122U/1K has a small-signal bandwidth of 50 kHz and a slew rate of 2 V/µs. These specifications enable faithful reproduction of fast-rising sensor outputs such as pressure transients or motor current spikes, with 0.1% settling time of 50 µs for ±10 V steps - critical for closed-loop response in motion control systems.
How does the ISO122U/1K handle high-frequency common-mode transients?
The ISO122U/1K achieves high-frequency transient immunity through its duty-cycle modulation architecture: signal integrity is independent of barrier capacitance variation, and its 500-kHz carrier inherently rejects noise outside the baseband. At dV/dt >1000 V/µs, false triggering may occur; lowering supply voltages to ±12 V reduces dV/dt and maintains reliable operation per TI Application Note SBOA004.
ISO122U/1K Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 28-SOIC (0.295", 7.50mm Width), 8 Leads
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Amplifier Type:
- Isolation
- Number of Circuits:
- 1
- Output Type:
- -
- Slew Rate:
- 2V/µs
- Gain Bandwidth Product:
- -
- -3db Bandwidth:
- 50 kHz
- Current - Input Bias:
- -
- Voltage - Input Offset:
- 20 mV
- Current - Supply:
- 5mA
- Current - Output / Channel:
- 15 mA
- Voltage - Supply Span (Min):
- 9 V
- Voltage - Supply Span (Max):
- 36 V
- Operating Temperature:
- -25°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
ISO122U/1K FAQ
1.How can I place an order for ISO122U/1K through Aetrix?
Please submit a Request for Quotation (RFQ) for ISO122U/1K on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for ISO122U/1K reliable?
The price and inventory of ISO122U/1K are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ISO122U/1K is usually 5 days.
3.What payment methods are accepted for ISO122U/1K?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ISO122U/1K transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ISO122U/1K?
ISO122U/1K orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ISO122U/1K order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for ISO122U/1K?
For technical support, including ISO122U/1K datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ISO122U/1K requirements.
6.How does Aetrix verify that ISO122U/1K is sourced from the original manufacturer or authorized distributors?
All ISO122U/1K products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that ISO122U/1K meets industry standards.
7.What is the process for return or replacement of ISO122U/1K?
All ISO122U/1K units undergo pre-shipment inspection (PSI). If there is an issue with ISO122U/1K, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The ISO122U/1K part is unused and in its original packaging.
Return procedure for ISO122U/1K:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
ISO122U/1K Tags
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