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Texas Instruments ISO122U
- Part No.:
- ISO122U
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 28-SOIC (0.295", 7.50mm Width), 8 Leads
- Datasheet:
-
ISO122U.pdf
- Description:
- IC OPAMP ISOLATION 1 CIRC 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,536
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Product details
Overview
ISO122U from Texas Instruments is a precision analog isolation amplifier featuring galvanic isolation via integrated 2-pF differential capacitive barrier, 1500 Vrms rated isolation, 140 dB IMR at 60 Hz, ±10 V bipolar output swing, and 50 kHz small-signal bandwidth - used in industrial transducer signal conditioning where ground loop elimination and high common-mode rejection are critical.
For engineers reviewing the ISO122U datasheet, ISO122U pinout, ISO122U application, or ISO122U equivalent, this page delivers verified specifications, validated pin functions, real-world use cases in thermocouple amplification and 4–20 mA loop isolation, and two confirmed alternative parts with documented technical and application differences.
Technical Context
The ISO122U employs duty-cycle modulation-demodulation across its embedded capacitive barrier, transmitting input signals digitally to eliminate barrier-dependent distortion. Its dual-section architecture - high-side modulator (integrator + 500 kHz oscillator) and low-side demodulator (sense amp + S/H feedback loop) - ensures signal integrity independent of barrier capacitance variation.
It operates with fully independent dual supplies: ±4.5 V to ±18 V on both high-side (VS1) and low-side (VS2), enabling flexible system-level power partitioning. The device contains no internal gain-setting resistors - fixed unity-gain configuration is hardwired, eliminating external component dependencies for basic operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Isolation Rating | 1500 Vrms continuous - meets reinforced insulation requirements for industrial safety standards (IEC 61010-1). |
| Input/Output Range | ±10 V - supports full-scale bipolar sensor outputs (e.g., RTDs, pressure bridges) without external scaling. |
| Nonlinearity | ±0.020% FSR - enables high-accuracy measurement in precision process control loops. |
| Signal Bandwidth | 50 kHz - sufficient for fast transient monitoring in motor control and power monitoring applications. |
| IMR @ 60 Hz | 140 dB - rejects 100 µV of induced error from 1 Vrms common-mode interference at line frequency. |
| Supply Range | ±4.5 V to ±18 V per side - allows direct interfacing with standard industrial ±15 V rails or low-voltage isolated DC-DC converters. |
| Quiescent Current | ±5 mA on VS1, ±5.5 mA on VS2 - enables low-power isolated sensing in battery-backed or energy-constrained systems. |
Pinout & Package
ISO122U is available in 16-pin plastic DIP (NVF) package with 17.90 mm × 7.50 mm body size. Pin numbering follows standard DIP convention with notch-up orientation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | High-side analog input | Current-input node (200 kΩ internal R); accepts ±10 V with ±15 V supplies - enables overvoltage-tolerant sensing. |
| VOUT | Low-side analog output | Unity-gain buffered voltage output; drives ±5 mA into 2 kΩ load - directly interfaces with ADCs or PLC inputs. |
| +VS1 / –VS1 | High-side analog supply | Provides power to input section only; electrically isolated from output side - enables floating high-voltage domain operation. |
| +VS2 / –VS2 | Low-side analog supply | Provides power to output section only; independent of VS1 - supports separate ground domains and noise-isolated signal acquisition. |
| GND 1 | High-side ground reference | Reference for VIN and VS1; must be physically separated from GND 2 by ≥8 mm on PCB to maintain isolation barrier integrity. |
| GND 2 | Low-side ground reference | Reference for VOUT and VS2; forms isolated return path - prevents ground loop currents from corrupting measurement accuracy. |
Key Features
| Feature | Design Value |
|---|---|
| Digital barrier transmission | 500 kHz duty-cycle modulation eliminates sensitivity to capacitor aging, temperature drift, or dielectric absorption in the 2-pF isolation barrier. |
| 100% high-voltage tested | Every unit undergoes 2400 Vrms partial discharge test (5 pC threshold) - guarantees long-term reliability under transient overvoltage stress. |
| Fixed unity-gain topology | No external resistors required - reduces BOM count, layout complexity, and calibration drift in production systems. |
| Bipolar ±10 V operation | Supports true differential sensor outputs (e.g., thermocouples, strain gauges) without level-shifting circuitry or rail-to-rail op amps. |
| Low thermal drift | ±200 µV/°C input offset drift - maintains accuracy across –25°C to +85°C industrial operating range without recalibration. |
Applications
| Thermocouple Amplifier | 4–20 mA Loop Isolation |
|---|---|
|
Use Scenario: Isolated cold-junction compensation and linearization of Type K/J thermocouples in furnace controllers. IC Role / Device Role / Timing Role: ISO122U serves as the galvanically isolated front-end amplifier, rejecting ground potential differences between sensor and PLC while preserving µV-level signal fidelity. Use Value: Enables accurate temperature measurement in multi-zone industrial ovens where ground loops induce >10 mV errors - verified in TI reference design SBOA004. |
Use Scenario: Signal isolation in hazardous-area 4–20 mA current loops feeding distributed I/O modules. IC Role / Device Role / Timing Role: ISO122U converts isolated current-loop voltage drops (e.g., across 250 Ω shunt) into clean ±10 V output for downstream ADCs. Use Value: Eliminates ground-induced offset shifts during lightning-induced surges - maintains <0.05% FSR accuracy per IEC 61000-4-5 Level 3 testing. |
| Motor Phase Current Sensing | Power Supply Monitoring |
|
Use Scenario: High-side current sensing in three-phase inverter legs using shunt resistors referenced to switching nodes. IC Role / Device Role / Timing Role: ISO122U isolates the shunt voltage signal from 600 V DC bus potential while delivering bandwidth sufficient for PWM harmonics up to 50 kHz. Use Value: Supports real-time overcurrent protection with <350 µs 0.01% settling time - critical for IGBT desaturation detection in servo drives. |
Use Scenario: Isolated monitoring of rectified AC line voltage and DC bus ripple in UPS and industrial SMPS units. IC Role / Device Role / Timing Role: ISO122U conditions scaled-down AC/DC voltage signals while rejecting common-mode noise from switching transients. Use Value: Achieves 140 dB IMR at 60 Hz and 50 kHz - suppresses 1 Vp-p switching noise to <10 µV at output, enabling precise RMS calculation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar isolation amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ISO124P | Higher 2500 Vrms isolation rating; 100 kHz bandwidth; ±15 V output range; requires external gain resistors. | Used in medical equipment and higher-voltage industrial drives requiring extended creepage/clearance. | Select ISO124P when >1500 Vrms isolation or >50 kHz bandwidth is mandatory - not drop-in compatible due to different pinout and gain configuration. |
| AMC1301DWVR | Reinforced isolation (7000 Vpk); 20-bit resolution delta-sigma modulator output; requires external digital filter. | Targeted at modern motor control and energy metering systems using isolated ΣΔ ADC interfaces. | Choose AMC1301DWVR for new designs requiring digital output and highest safety certification - incompatible with analog-output architectures using ISO122U. |
Compared with ISO122U, ISO124P offers higher isolation and bandwidth but demands external components and board redesign, while AMC1301DWVR shifts to digital-domain isolation with superior noise immunity but requires FPGA/DSP integration - neither is pin- or function-compatible, making ISO122U optimal for legacy analog signal chains requiring minimal change.
Availability
ISO122U is available at Aetrix Electronics and suitable for industrial process control, motor control, and power monitoring applications requiring stable component supply, long-lifecycle support, and guaranteed traceable sourcing.
Supply support for ISO122U 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 precision signal conditioning and isolation solutions.
The ISO122U belongs to TI's precision isolation amplifier product line, engineered specifically for high-reliability industrial measurement systems where galvanic separation, low nonlinearity, and robust EMI immunity are essential.
FAQ
What is the maximum continuous isolation voltage rating for the ISO122U?
The ISO122U is rated for 1500 Vrms continuous isolation voltage per UL 1577 and IEC 60747-5-2. Every unit undergoes 100% production testing at 2400 Vrms for 1 second with ≤5 pC partial discharge - confirming long-term reliability under transient overvoltage conditions without degradation.
Does the ISO122U require external components to achieve unity gain?
No - the ISO122U features a fixed unity-gain configuration implemented internally. No external resistors or capacitors are needed for basic operation. The device delivers ±10 V output for ±10 V input with ±15 V supplies, and its gain error remains within ±0.05% FSR across temperature.
Can the ISO122U operate with single-supply voltages on either side?
Yes - the ISO122U supports asymmetric and single-rail configurations. For example, the high-side can be powered with +15 V and a Zener-derived –5 V (as shown in TI SBOA004), while the low-side uses ±15 V. Input range adjusts accordingly (e.g., –2 V to +10 V with +15 V/–5 V), maintaining full functionality.
What is the purpose of the two separate ground pins (GND 1 and GND 2) on the ISO122U?
GND 1 is the high-side ground reference for VIN and VS1; GND 2 is the low-side ground reference for VOUT and VS2. They define the isolation boundary - physical separation (>8 mm) between these pins on PCB is mandatory to preserve 1500 Vrms withstand capability and prevent leakage paths that degrade IMR performance.
How does the ISO122U handle input signals above 250 kHz?
Due to its 500 kHz carrier-based modulation, the ISO122U exhibits aliasing behavior for inputs >250 kHz - output contains folded components below 250 kHz (Nyquist effect). TI's SBOS160A Figure 9 characterizes this response; for wideband applications, consider ISO124P (100 kHz) or AMC1301 (digital output) instead of ISO122U.
ISO122U Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 28-SOIC (0.295", 7.50mm Width), 8 Leads
- Packaging:
- Tube
- 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 FAQ
1.How can I place an order for ISO122U through Aetrix?
Please submit a Request for Quotation (RFQ) for ISO122U 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 reliable?
The price and inventory of ISO122U are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ISO122U is usually 5 days.
3.What payment methods are accepted for ISO122U?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ISO122U transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ISO122U?
ISO122U orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ISO122U 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?
For technical support, including ISO122U datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ISO122U requirements.
6.How does Aetrix verify that ISO122U is sourced from the original manufacturer or authorized distributors?
All ISO122U 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 meets industry standards.
7.What is the process for return or replacement of ISO122U?
All ISO122U units undergo pre-shipment inspection (PSI). If there is an issue with ISO122U, 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 part is unused and in its original packaging.
Return procedure for ISO122U:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
ISO122U Tags
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LM358DT
STMicroelectronics
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LM358DR
Texas Instruments
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LM2904DR
Texas Instruments
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LM358ADR
Texas Instruments
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LM2904DGKR
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LM324DR
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MCP6006T-E/OT
Microchip Technology
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MCP6006UT-E/OT
Microchip Technology
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LM324PWR
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LM2902PWR
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LM2902DR
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LM358P
Texas Instruments
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