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Texas Instruments THS3491IRGTR
- Part No.:
- THS3491IRGTR
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 16-VFQFN Exposed Pad
- Datasheet:
-
THS3491IRGTR.pdf
- Description:
- IC OPAMP CFA 1 CIRCUIT 16VQFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,244
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Product details
Overview
THS3491IRGTR from Texas Instruments is a 900-MHz current feedback amplifier (CFA) designed for high-power, low-distortion output driving in wideband analog signal chains. It delivers ±420 mA linear output current, 8000 V/µs slew rate, and 1.7 nV/√Hz input voltage noise, operating from ±7 V to ±16 V bipolar supplies. It is used in arbitrary waveform generators, LCR meter drivers, and piezo element drivers requiring fast transient response and high-voltage swing.
For engineers reviewing the THS3491IRGTR datasheet, THS3491IRGTR pinout, THS3491IRGTR application, or THS3491IRGTR equivalent, key selection criteria include small-signal bandwidth (900 MHz), large-signal bandwidth (320 MHz at 10 VPP), output headroom (1.5 V to either rail), thermal shutdown protection, and VQFN-16 package compatibility with PCB layout for high-current routing and thermal management.
Technical Context
The THS3491IRGTR employs a current feedback architecture that maintains near-constant bandwidth and harmonic distortion across gain settings (2–20 V/V), unlike voltage feedback amplifiers. Its transimpedance gain exceeds 5 MΩ, enabling stable operation with capacitive loads up to 100 pF when combined with series isolation resistors.
It integrates power-down control (PD pin), junction temperature sensing (TJ_SENSE on Pin 6), and internal current limiting. The RGT package features dual output pins (VOUT on Pins 10 & 11), exposed thermal pad, and dedicated feedback (FB) and ground (GND) terminals to minimize parasitic inductance in high-speed layouts.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Small-signal bandwidth | 900 MHz at 2 VPP output - enables clean signal reproduction through UHF frequencies in test equipment front-ends |
| Large-signal bandwidth | 320 MHz at 10 VPP output - supports full-scale fast pulses in pattern generators without amplitude droop |
| Slew rate | 8000 V/µs - ensures sub-ns rise/fall times (1.3 ns) for 10-V steps, critical for arbitrary waveform fidelity |
| Linear output current | ±420 mA - drives heavy capacitive loads (e.g., piezo actuators, LCD column lines) without clipping or thermal foldback |
| Input voltage noise | 1.7 nV/√Hz - preserves SNR in low-level signal conditioning stages preceding high-gain output stages |
| Supply range | ±7 V to ±16 V bipolar - provides 28 VPP output swing into 100 Ω with ±16-V rails, exceeding legacy THS3095 capability |
| Harmonic distortion | –76 dBc HD2 / –75 dBc HD3 at 50 MHz, 10 VPP - meets spectral purity requirements for VDSL line drivers and RF test sources |
Pinout & Package
The THS3491IRGTR is housed in a 3.00 mm × 3.00 mm VQFN-16 (RGT) package with an exposed thermal pad. This thermally enhanced, leadless package supports high-power dissipation in compact PCB footprints and requires solder paste stencil optimization for reliable thermal pad attachment.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 (FB) | Feedback input | Current feedback node - connects externally to output via resistor network; determines closed-loop gain and stability |
| 3 (VIN–) | Inverting input | Differential input terminal - accepts inverted signal path; high-impedance node (15–18 Ω) per CFA topology |
| 4 (VIN+) | Noninverting input | Reference input terminal - used for unity-gain buffer or noninverting configurations; 35–50 kΩ || 1.2 pF impedance |
| 5 (GND) | Ground reference | Logic and PD reference for VQFN package - must be low-inductance connection to PCB ground plane |
| 6 (TJ_SENSE) | Junction temperature monitor | Analog voltage output (1.06 V @ 25°C, +3.2 mV/°C) - enables real-time thermal derating in high-duty-cycle applications |
| 7, 8 (±VS) | Negative supply terminals | Dual negative supply pins - reduce IR drop and improve PSRR; connect directly to local ±VS decoupling caps |
| 10, 11 (VOUT) | Amplifier output | Dual-output configuration - splits high-current drive path to lower inductance and improve thermal distribution |
| 13, 14 (+VS) | Positive supply terminals | Dual positive supply pins - symmetric layout with ±VS pins minimizes supply loop area for EMI suppression |
| 16 (PD) | Power-down control | Active-high enable - pulls output to high-impedance state when low; logic threshold 1.5 V (VIH), 0.8 V (VIL) |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-high slew rate | 8000 V/µs enables <1.3 ns rise/fall times for 10-V steps - essential for pulse fidelity in LCR meters and ATE systems |
| Low harmonic distortion | –76 dBc HD2 / –75 dBc HD3 at 50 MHz, 10 VPP - meets spectral mask requirements for VDSL and broadband communications |
| Thermal monitoring | Integrated TJ_SENSE (Pin 6) provides calibrated 3.2 mV/°C analog output - allows closed-loop thermal management without external sensors |
| Robust protection | Current limit and thermal shutdown prevent damage during overload or poor heatsinking - improves system reliability in unattended test environments |
| Flexible power control | Power-down mode reduces quiescent current to <1 mA per rail - extends uptime in battery-backed or low-power standby modes |
Applications
| Arbitrary Waveform Generator Output Stage | LCR Meter Excitation Driver |
|---|---|
Use Scenario: Generating programmable high-voltage, high-slew-rate waveforms (sine, square, pulse) for component characterization. IC Role / Device Role / Timing Role: Final-stage wideband current feedback amplifier delivering 28 VPP into 100 Ω with <1.5% overshoot. Use Value: Enables 900-MHz small-signal bandwidth and ±420 mA linear drive - critical for accurate impedance measurement across 100 kHz–10 MHz range. |
Use Scenario: Driving precise AC excitation signals into unknown DUTs (capacitors, inductors, resistors) under test. IC Role / Device Role / Timing Role: High-fidelity output driver maintaining flat frequency response and low THD up to 10 MHz. Use Value: 320-MHz large-signal bandwidth at 10 VPP ensures minimal amplitude error and phase shift during swept-frequency measurements. |
| Piezo Element Actuator Driver | VDSL Line Driver |
Use Scenario: Controlling high-capacitance piezoelectric transducers (nF-range) in precision positioning or ultrasonic imaging systems. IC Role / Device Role / Timing Role: High-current, low-headroom output stage sourcing/sinking ±420 mA while maintaining linearity. Use Value: 1.5 V output headroom and 8000 V/µs slew rate allow fast, distortion-free step response to piezo capacitance without external boost stages. |
Use Scenario: Transmitting broadband DSL signals (up to 30 MHz) over twisted-pair copper lines with stringent spectral mask compliance. IC Role / Device Role / Timing Role: Final line driver amplifier meeting ITU-T G.993.2 (VDSL2) harmonic distortion limits. Use Value: –75 dBc HD3 at 50 MHz enables >70 dB carrier-to-interference ratio - directly supporting 100+ Mbps downstream data rates. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-speed current feedback amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| THS3095IDDA | Lower 190-MHz bandwidth, ±250 mA linear output, 1200 V/µs slew rate, HSOIC-8 package | Legacy design upgrade path only; lacks TJ_SENSE, power-down, and VQFN thermal performance | Select THS3095IDDA only for drop-in replacement in existing SOIC-8 layouts where bandwidth <200 MHz suffices |
| THS3217IRGTR | Higher 1.8-GHz bandwidth but lower ±250 mA output drive; no power-down or TJ_SENSE; same RGT package | Better for RF signal chain gain blocks; unsuitable for high-current capacitive load driving | Choose THS3217IRGTR when bandwidth >1 GHz is primary requirement and output current ≤250 mA |
Compared with THS3095IDDA and THS3217IRGTR, the THS3491IRGTR uniquely balances 900-MHz bandwidth, ±420 mA drive, integrated thermal sensing, and power-down - making it optimal for next-generation test equipment requiring both speed and robustness.
Availability
THS3491IRGTR is available at Aetrix Electronics and suitable for arbitrary waveform generators, LCR meter excitation stages, piezo actuator drivers, and VDSL line drivers requiring stable component supply, long-term production continuity, and guaranteed traceable sourcing.
Supply support for THS3491IRGTR 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, embedded processing, and connectivity technologies, with decades of expertise in high-performance amplifiers and precision signal chain solutions.
The THS3491IRGTR belongs to TI's high-speed current feedback amplifier product line, engineered specifically for applications demanding ultra-low distortion, high output current, and wide bandwidth in test and measurement, communications, and industrial automation systems.
FAQ
What is the maximum output voltage swing of the THS3491IRGTR?
The THS3491IRGTR delivers up to 28 VPP output swing into a 100-Ω load when operated from ±16-V supplies. Its output headroom is specified at 1.5 V to either supply rail, meaning it can swing within 1.5 V of +VS or –VS. This enables higher usable output amplitude than legacy amplifiers like the THS3095 under identical supply conditions, directly improving dynamic range in waveform generation applications. The THS3491IRGTR achieves this while maintaining <1.5% overshoot and 1.3 ns rise time.
Does the THS3491IRGTR support single-supply operation?
Yes, the THS3491IRGTR supports single-supply operation from 14 V to 32 V, as confirmed in its Recommended Operating Conditions table. In single-supply mode, the device requires proper biasing of the input common-mode voltage and output DC level - typically using resistive dividers or level-shifting networks. The THS3491IRGTR's input voltage range extends to within 4.3 V of either rail (HRIN), and output swings to within 1.5 V (HROUT), allowing flexible rail-to-rail signal handling when configured correctly. This capability is validated across all package variants including the THS3491IRGTR.
How does the power-down feature work on the THS3491IRGTR?
The THS3491IRGTR uses an active-high Power-Down (PD) pin (Pin 16) that disables the amplifier core when driven low. When PD is pulled below 0.8 V (VIL), quiescent current drops to <1 mA per supply rail (e.g., 650–880 µA on +VS), and the output enters high-impedance state. The turnoff delay is 4 µs; turnon delay is 50 ns. The PD pin requires a logic reference - on the RGT package, GND (Pin 5) serves as the reference, eliminating need for external REF pin routing. This feature is fully implemented and characterized in the THS3491IRGTR.
What is the purpose of the TJ_SENSE pin on the THS3491IRGTR?
The TJ_SENSE pin (Pin 6) on the THS3491IRGTR provides an analog voltage proportional to die junction temperature: 1.06 V at 25°C with a +3.2 mV/°C coefficient. It is exclusive to the RGT (VQFN-16) package and enables real-time thermal monitoring without external sensors. The output is buffered and has 35 kΩ input impedance, allowing direct ADC sampling. This feature supports dynamic thermal derating in high-duty-cycle applications such as continuous waveform generation - a capability not present in the DDA-package THS3095 or THS3217IRGTR.
Can the THS3491IRGTR drive capacitive loads directly?
The THS3491IRGTR can drive moderate capacitive loads (≤100 pF) directly, but larger loads require series isolation (e.g., 1–10 Ω) at the output to maintain stability, as documented in TI's "Driving a Large Capacitive Load" application section. Its low 1-Ω closed-loop output impedance (ZOUT) at 50 MHz and high slew rate make it well-suited for such configurations. Layout best practices - including short traces, ground plane beneath the RGT thermal pad, and local 100-nF + 10-µF supply decoupling - are essential. This behavior is verified and specified for the THS3491IRGTR across all operating conditions.
THS3491IRGTR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 16-VFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Amplifier Type:
- Current Feedback
- Number of Circuits:
- 1
- Output Type:
- -
- Slew Rate:
- 8000V/µs
- Gain Bandwidth Product:
- 900 MHz
- -3db Bandwidth:
- -
- Current - Input Bias:
- -
- Voltage - Input Offset:
- 1 mV
- Current - Supply:
- 16.8mA
- Current - Output / Channel:
- 620 mA
- Voltage - Supply Span (Min):
- 14 V
- Voltage - Supply Span (Max):
- 32 V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-VQFN (3x3)
THS3491IRGTR FAQ
1.How can I place an order for THS3491IRGTR through Aetrix?
Please submit a Request for Quotation (RFQ) for THS3491IRGTR 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 THS3491IRGTR reliable?
The price and inventory of THS3491IRGTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for THS3491IRGTR is usually 5 days.
3.What payment methods are accepted for THS3491IRGTR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for THS3491IRGTR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for THS3491IRGTR?
THS3491IRGTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your THS3491IRGTR 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 THS3491IRGTR?
For technical support, including THS3491IRGTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your THS3491IRGTR requirements.
6.How does Aetrix verify that THS3491IRGTR is sourced from the original manufacturer or authorized distributors?
All THS3491IRGTR 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 THS3491IRGTR meets industry standards.
7.What is the process for return or replacement of THS3491IRGTR?
All THS3491IRGTR units undergo pre-shipment inspection (PSI). If there is an issue with THS3491IRGTR, 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 THS3491IRGTR part is unused and in its original packaging.
Return procedure for THS3491IRGTR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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