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Texas Instruments THS3121IDGN
- Part No.:
- THS3121IDGN
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
THS3121IDGN.pdf
- Description:
- IC OPAMP CFA 1 CIRCUIT 8HVSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:221
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Product details
Overview
THS3121IDGN from Texas Instruments is a current-feedback operational amplifier optimized for high-speed video distribution and capacitive-load driving. It delivers 475 mA output current, 1700 V/μs slew rate (G = 2, RL = 50 Ω), 120 MHz small-signal bandwidth, and 0.007% differential gain (PAL/NTSC) at ±15 V supply - enabling multi-load broadcast-grade analog video amplification.
For engineers reviewing the THS3121IDGN datasheet, THS3121IDGN pinout, THS3121IDGN application, or THS3121IDGN equivalent, this page provides verified electrical specs, MSOP-8 PowerPAD™ package details, video-system design context, and validated alternative options for high-output-current, low-distortion signal conditioning in industrial and broadcast infrastructure.
Technical Context
The THS3121IDGN uses a current-feedback architecture with separate high-impedance noninverting input (41 MΩ, 0.4 pF) and low-impedance inverting input, enabling wide bandwidth independent of closed-loop gain. Its transimpedance gain exceeds 1.9 MΩ at ±15 V, supporting stable operation into 150 Ω video loads and up to eight parallel outputs without gain flatness degradation.
It operates across ±5 V to ±15 V dual supplies (or 10–30 V single supply), with input common-mode range extending to ±12.7 V at ±15 V and output swing reaching ±13.5 V into 50 Ω. The device exhibits 2.5 nV/√Hz voltage noise and 1 pA/√Hz noninverting current noise - critical for preserving SNR in baseband video and precision analog signal paths.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Small-signal bandwidth | 120 MHz at G = 2, RL = 50 Ω - supports full HD baseband video (up to ~100 MHz) with minimal attenuation. |
| Slew rate | 1700 V/μs (G = 2, VO = 8 VPP, RL = 50 Ω) - enables clean 10-MHz 8-VPP square waves without slewing distortion. |
| Output current | ±475 mA sourcing/sinking (RL = 25 Ω) - drives multiple 75 Ω video lines or heavy capacitive loads (e.g., LCD column drivers). |
| Differential gain error | 0.007% (PAL/NTSC, G = 2, RL = 150 Ω) - meets broadcast video fidelity requirements for color accuracy. |
| Voltage noise density | 2.5 nV/√Hz (f > 20 kHz) - preserves signal integrity in low-level analog signal chains without adding measurable noise floor. |
| Supply range | ±5 V to ±15 V - compatible with legacy ±12 V and modern ±15 V video processing rails. |
| Operating temperature | –40°C to +85°C - qualified for industrial video equipment and outdoor broadcast enclosures. |
Pinout & Package
The THS3121IDGN is housed in an 8-pin MSOP PowerPAD™ package (DGN), with the exposed thermal pad electrically isolated and intended for PCB thermal plane connection to maintain junction temperature ≤125°C under continuous load.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (NC) | No internal connection | Not bonded; must be left floating or grounded per layout best practices for noise immunity. |
| 2 (VIN–) | Inverting input | Low-impedance node; connects to feedback network (e.g., 649 Ω resistor to VOUT) for gain-setting. |
| 3 (VIN+) | Noninverting input | High-impedance node (41 MΩ); accepts source signal with minimal loading (0.4 pF capacitance). |
| 4 (VS–) | Negative supply rail | Connects to –5 V to –15 V; supports rail-to-rail input common-mode down to VS– + 2.3 V (at ±5 V). |
| 5 (NC) | No internal connection | Not bonded; no routing required; avoid stubs to minimize parasitic coupling. |
| 6 (VS+) | Positive supply rail | Connects to +5 V to +15 V; PSRR ≥75 dB ensures immunity to supply ripple in sensitive analog stages. |
| 7 (VOUT) | Amplified output | Capable of ±13.5 V swing into 50 Ω; drives 75 Ω transmission lines directly with <0.02° differential phase error. |
| 8 (NC) | No internal connection | Not bonded; leave unconnected; thermal pad (underside) must be soldered to copper pour for thermal management. |
Key Features
| Feature | Design Value |
|---|---|
| Current-feedback topology | Enables constant 120 MHz bandwidth across gains of 1–10 - unlike voltage-feedback op-amps whose bandwidth drops with gain. |
| PowerPAD™ thermal enhancement | θJC = 4.7°C/W allows 1.71 W power dissipation at TA = +25°C - essential for sustained 475 mA output into low-Z loads. |
| Ultra-low differential phase/gain | 0.018°/0.007% (NTSC/PAL) ensures broadcast-compliant color fidelity across 8 simultaneous 150 Ω video loads. |
| High slew rate + low distortion | 1700 V/μs slew with –50 dBc 2nd harmonic (10 MHz, 2 VPP) enables clean composite video and RGB signal distribution. |
| Wide supply flexibility | Operates from ±5 V (e.g., portable gear) to ±15 V (e.g., studio equipment) without performance trade-offs in bandwidth or drive. |
Applications
| Broadcast Video Distribution | High-Speed Pin Driver |
|---|---|
|
Use Scenario: Amplifying and splitting a single SDI-derived analog component video signal (Y/Pb/Pr) to feed eight monitor outputs in a production truck. IC Role / Device Role / Timing Role: Current-feedback video buffer with unity-gain stable configuration driving 75 Ω coaxial cables. Use Value: Maintains <0.02° differential phase across all eight loads, preventing hue shift and ensuring SMPTE compliance. |
Use Scenario: Driving 100 pF gate capacitance of six parallel MOSFETs in a high-frequency PWM motor control stage. IC Role / Device Role / Timing Role: High-current, low-impedance output driver delivering fast, monotonic gate voltage transitions. Use Value: 1700 V/μs slew rate achieves <10 ns rise/fall times, minimizing switching losses and EMI generation. |
| Capacitive Load Buffer | Test Equipment Signal Conditioning |
|
Use Scenario: Buffering a 5 VPP, 5 MHz sine wave from an arbitrary waveform generator into a 2 nF capacitive DUT (e.g., piezoelectric actuator). IC Role / Device Role / Timing Role: Unity-gain stable current-feedback amplifier with RISO-compensated output stage. Use Value: Delivers full 5 VPP amplitude without peaking or ringing, even with 2 nF load, due to 0.04 Ω closed-loop output impedance. |
Use Scenario: Amplifying low-level sensor signals (e.g., photodiode transimpedance output) before ADC sampling in automated test equipment. IC Role / Device Role / Timing Role: Low-noise, high-bandwidth gain stage with 2.5 nV/√Hz input voltage noise and 1 pA/√Hz input current noise. Use Value: Preserves dynamic range and SNR for sub-mV signals up to 10 MHz, avoiding noise floor elevation in digitized results. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-output-current, current-feedback amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| THS3121CDGN | Same silicon, commercial temperature range (0°C to +70°C) vs. industrial (–40°C to +85°C); identical electrical specs. | Restricted to indoor, climate-controlled environments (e.g., lab instruments, consumer AV receivers). | Select THS3121CDGN only when ambient operating temperature remains within 0°C–70°C and cost sensitivity outweighs long-term reliability margin. |
| LMH6723MA/NOPB | Lower output current (190 mA), higher voltage noise (4.2 nV/√Hz), but wider 1.8 GHz gain-bandwidth product and rail-to-rail output. | Better suited for RF IF amplification or low-voltage, high-GHz signal chains where drive strength is secondary to bandwidth. | Choose LMH6723MA/NOPB when system requires >500 MHz small-signal bandwidth and can accept reduced output drive and higher noise. |
Compared with THS3121CDGN, the THS3121IDGN guarantees operation over –40°C to +85°C with no derating, while LMH6723MA/NOPB trades 2.5× lower output current for 15× higher GBW - making THS3121IDGN optimal for robust, high-fidelity video and industrial analog buffering where drive and fidelity are primary.
Availability
THS3121IDGN is available at Aetrix Electronics and suitable for broadcast infrastructure, industrial motion control, automated test equipment, and medical imaging systems requiring stable component supply across extended temperature ranges and high-reliability manufacturing cycles.
Supply support for THS3121IDGN 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 op-amps and signal chain solutions.
The THS3121IDGN belongs to TI's high-speed current-feedback op-amp family, engineered specifically for demanding video distribution, precision instrumentation, and high-current analog interface applications where bandwidth, drive, and fidelity cannot be compromised.
FAQ
What is the maximum safe continuous output current for THS3121IDGN at +85°C ambient?
The THS3121IDGN delivers ≥400 mA sourcing/sinking into 25 Ω loads at +85°C ambient (per Electrical Characteristics table). Sustained operation at full 475 mA requires thermal management via the PowerPAD™ to limit junction temperature to ≤125°C - achievable with ≥2 oz. copper on the PCB thermal plane.
Does THS3121IDGN support single-supply operation, and what is the minimum usable supply voltage?
Yes, THS3121IDGN supports single-supply operation from 10 V to 30 V. At 10 V (±5 V equivalent), it maintains 100 MHz small-signal bandwidth and 620 V/μs slew rate, with input common-mode range extending from 2.7 V below VS+ to 2.7 V above VS– - enabling use in low-voltage portable video gear.
How does THS3121IDGN differ from THS3120IDGN in functionality and pin compatibility?
The THS3121IDGN lacks the power-down (PD) pin present on THS3120IDGN; its pin 5 is NC instead of PD, and pin 1 is NC instead of REF. All other pins (VIN–, VIN+, VS–, VS+, VOUT) are functionally identical and physically pin-compatible in the MSOP-8 DGN package - allowing drop-in replacement where power-down is not required.
Can THS3121IDGN drive 75 Ω video loads directly without external series resistors?
Yes - THS3121IDGN is characterized for direct 75 Ω load driving with G = 2 and RF = 649 Ω. Its 0.04 Ω closed-loop output impedance and ±13.5 V swing into 50 Ω ensure minimal mismatch loss and <0.02° differential phase error, meeting SMPTE RP 168 and ITU-R BT.601 video standards without series termination.
What is the recommended layout practice for the PowerPAD™ thermal pad on THS3121IDGN?
The underside PowerPAD™ must be soldered to a dedicated, thermally robust PCB copper area (≥3″ × 3″, 2 oz. copper) connected to ground or a low-impedance thermal plane. TI recommends 9 thermal vias (0.3 mm diameter) evenly distributed under the pad to achieve θJA = 58.4°C/W - critical to sustain 475 mA output without exceeding TJ(max) = 125°C.
THS3121IDGN Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width) Exposed Pad
- Packaging:
- Bulk
- Product Status:
- Active
- Amplifier Type:
- Current Feedback
- Number of Circuits:
- 1
- Output Type:
- -
- Slew Rate:
- 1700V/µs
- Gain Bandwidth Product:
- -
- -3db Bandwidth:
- 130 MHz
- Current - Input Bias:
- 3 µA
- Voltage - Input Offset:
- 2 mV
- Current - Supply:
- 7mA
- Current - Output / Channel:
- 490 mA
- Voltage - Supply Span (Min):
- 10 V
- Voltage - Supply Span (Max):
- 30 V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-HVSSOP
THS3121IDGN FAQ
1.How can I place an order for THS3121IDGN through Aetrix?
Please submit a Request for Quotation (RFQ) for THS3121IDGN 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 THS3121IDGN reliable?
The price and inventory of THS3121IDGN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for THS3121IDGN is usually 5 days.
3.What payment methods are accepted for THS3121IDGN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for THS3121IDGN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for THS3121IDGN?
THS3121IDGN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your THS3121IDGN 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 THS3121IDGN?
For technical support, including THS3121IDGN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your THS3121IDGN requirements.
6.How does Aetrix verify that THS3121IDGN is sourced from the original manufacturer or authorized distributors?
All THS3121IDGN 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 THS3121IDGN meets industry standards.
7.What is the process for return or replacement of THS3121IDGN?
All THS3121IDGN units undergo pre-shipment inspection (PSI). If there is an issue with THS3121IDGN, 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 THS3121IDGN part is unused and in its original packaging.
Return procedure for THS3121IDGN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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