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Texas Instruments THS4121CDGN
- Part No.:
- THS4121CDGN
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
THS4121CDGN.pdf
- Description:
- IC OPAMP DIFF 1 CIRCUIT 8HVSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:27,340
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Product details
Overview
THS4121CDGN from Texas Instruments is a single-channel, fully differential-input/differential-output high-speed amplifier optimized for ADC driving and antialiasing in 3.3-V single-supply systems. It delivers 100 MHz bandwidth, 55 V/µs slew rate, –75 dB THD at 1 MHz (2 VPP), 5.4 nV/√Hz input noise, and operates with VOCM pin for output common-mode level control.
For engineers reviewing the THS4121CDGN datasheet, THS4121CDGN pinout, THS4121CDGN application, or THS4121CDGN equivalent, this page provides verified specifications, MSOP PowerPAD™ package details, differential signal path architecture, and validated alternatives for precision analog front-end design in data acquisition and communication systems.
Technical Context
The THS4121CDGN implements a true fully differential signal path from input to output, enabling balanced rejection of common-mode noise and suppression of second-harmonic distortion via symmetrical output polarity. Its internal architecture supports both differential-input/differential-output and single-ended-input/differential-output configurations without external power-down logic.
It features a dedicated VOCM pin that sets the DC common-mode level of both outputs independently of gain configuration, with high bandwidth up to the amplifier's operating range and recommended 0.1-µF bypass capacitance. The device is internally compensated for maximum bandwidth and slew rate but requires series output resistors ≥20 Ω when driving capacitive loads >10 pF to maintain phase margin.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Bandwidth (–3 dB) | 100 MHz - Enables accurate amplification of signals up to Nyquist frequency in high-speed ADC interfaces. |
| Slew Rate | 55 V/µs - Supports fast transient response for 2 VPP differential step signals with 60 ns settling to 0.1%. |
| Total Harmonic Distortion | –75 dB at 1 MHz, 2 VPP - Ensures low distortion in precision data converter driver applications. |
| Input Voltage Noise | 5.4 nV/√Hz at 10 kHz - Minimizes added noise in sensitive analog signal chains before digitization. |
| Supply Voltage | 3.3 V single supply - Simplifies system power architecture and eliminates need for dual rails in portable or embedded designs. |
| Common-Mode Input Range | 0.35 V to VDD – 0.1 V - Allows direct interfacing with 3.3-V logic and reference sources while maintaining linearity. |
| Quiescent Current | 13.5 mA typical - Balances high-speed performance with moderate power consumption in continuous operation. |
Pinout & Package
THS4121CDGN is housed in an 8-pin MSOP PowerPAD™ package (DGN) with exposed thermal pad on underside for enhanced heat dissipation. The PowerPAD is electrically isolated and must be soldered to a PCB copper pour for thermal management per TI SLMA002 guidelines.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN− | Inverting input | Differential input node; matched impedance critical for CMRR and harmonic cancellation. |
| VOCM | Output common-mode control | Sets DC level of both outputs; bypass with 0.1 µF capacitor to suppress noise coupling. |
| VDD | Positive supply | 3.3-V single supply rail; requires local 0.1-µF ceramic + 6.8-µF tantalum decoupling. |
| VOUT+ | Positive differential output | Complementary output; used with VOUT− to drive differential ADC inputs or transmission lines. |
| VIN+ | Non-inverting input | Differential input node; symmetry with VIN− essential for balanced signal path performance. |
| NC | No connect | Unbonded pin; must remain unconnected per TI specification to avoid parasitic coupling. |
| GND | Analog ground reference | Low-inductance return path; separate from digital ground to preserve PSRR and noise immunity. |
| VOUT− | Negative differential output | Complementary output; equal amplitude, opposite polarity to VOUT+ for full differential swing. |
Key Features
| Feature | Design Value |
|---|---|
| Fully differential I/O architecture | Enables 2× dynamic range vs. single-ended amps by delivering ±1 V signals for 2 VPP differential output into ADCs. |
| Balanced output common-mode rejection | 96 dB CMRR over DC–100 kHz ensures robust immunity to coupled noise in mixed-signal PCB environments. |
| Single-supply 3.3-V operation with VOCM control | Eliminates need for transformers or level-shifting circuitry when interfacing with modern low-voltage ADCs. |
| Optimized for antialias filtering | Internal compensation allows stable integration with active RC filters (e.g., 2nd-order Butterworth) without peaking. |
| PowerPAD™ thermal enhancement | θJC = 4.7°C/W enables 1.71 W power dissipation at 25°C ambient-critical for sustained high-frequency operation. |
Applications
| High-Speed Data Acquisition | Differential Communication Transceivers |
|---|---|
|
Use Scenario: Driving SAR or pipeline ADCs sampling at ≥10 MSPS in test equipment and medical imaging front-ends. IC Role / Device Role / Timing Role: Differential ADC driver providing precise gain, offset, and noise-controlled signal conditioning prior to digitization. Use Value: 75 dB THD and 5.4 nV/√Hz noise preserve SNR integrity across 1-MHz bandwidth, directly improving effective resolution. |
Use Scenario: Transmitting baseband I/Q signals in software-defined radio and broadband modems. IC Role / Device Role / Timing Role: Differential transmitter buffer converting single-ended DAC outputs to balanced differential pairs for improved EMI immunity. Use Value: Balanced outputs reject common-mode noise on PCB traces and cables, reducing radiated emissions by >20 dB. |
| Instrumentation Signal Conditioning | Active Antialias Filtering |
|
Use Scenario: Precision sensor signal amplification in industrial process controllers with 24-bit sigma-delta ADCs. IC Role / Device Role / Timing Role: High-PSRR (85 dB), low-drift front-end amplifier rejecting supply ripple and ground bounce. Use Value: 25 µV/°C offset drift and 68 dB PSRR ensure stable DC accuracy across temperature and varying load conditions. |
Use Scenario: Implementing 2nd-order low-pass filtering immediately before ADC input to prevent aliasing. IC Role / Device Role / Timing Role: Active filter stage using THS4121CDGN as unity-gain integrator with external R/C network. Use Value: Internally compensated design avoids oscillation when cascaded with passive RC sections, enabling clean cutoff at 10–50 MHz. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar fully differential amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| THS4131CDGN | 150 MHz BW, 51 V/µs SR, 1.3 nV/√Hz noise, wider 5–30 V supply range | Higher bandwidth and lower noise suit wideband IF sampling; requires higher supply voltage | Select THS4131CDGN when >100 MHz small-signal BW or sub-2 nV/√Hz noise is required, accepting 5-V minimum supply. |
| THS4561IRGET | 1.8-GHz GBW, 3000 V/µs SR, rail-to-rail output, 3.3-V only, no VOCM pin | Ultra-high speed for RF sampling; lacks VOCM flexibility and has higher quiescent current (24 mA) | Choose THS4561IRGET for GHz-range applications where VOCM control is unnecessary and layout allows tighter thermal management. |
Compared with THS4121CDGN, THS4131CDGN offers higher bandwidth and lower noise but demands ≥5-V supply, while THS4561IRGET delivers extreme speed at the cost of VOCM configurability and increased power-making THS4121CDGN optimal for 3.3-V, precision ADC driver use cases requiring balanced flexibility and thermal efficiency.
Availability
THS4121CDGN is available at Aetrix Electronics and suitable for high-speed data acquisition, instrumentation signal conditioning, and differential communication transceiver designs requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for THS4121CDGN 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-performance amplifiers and data converter interface solutions.
The THS412x family was designed specifically for precision, high-speed differential signal conditioning in single-supply data acquisition systems-emphasizing THD, noise, and common-mode rejection over raw bandwidth alone.
FAQ
What is the function of the VOCM pin on the THS4121CDGN?
The VOCM pin on the THS4121CDGN sets the DC common-mode voltage level of both differential outputs. It accepts an externally applied voltage or defaults to VDD/2 when left open, enabling precise alignment with ADC reference voltages. A 0.1-µF bypass capacitor is required for stability, and VOCM bandwidth extends across the amplifier's operating range-critical for maintaining common-mode integrity in time-critical sampling applications. This functionality is integral to the THS4121CDGN's role as a flexible ADC driver.
Does the THS4121CDGN support single-supply operation?
Yes, the THS4121CDGN is explicitly designed for single-supply operation at 3.3 V, with guaranteed performance across its full common-mode input range (0.35 V to VDD – 0.1 V) and rail-compatible output swing. Its VOCM pin simplifies interfacing with 3.3-V ADC references without level-shifting circuitry. Unlike split-supply amplifiers, the THS4121CDGN maintains full differential functionality-including 75 dB THD and 100 MHz bandwidth-under this constraint, making it ideal for portable and embedded systems where dual supplies are impractical.
How does the THS4121CDGN differ from the THS4120CDGN?
The THS4121CDGN omits the power-down (PD) pin present on the THS4120CDGN, resulting in fixed 13.5-mA quiescent current versus the THS4120's 120-µA shutdown mode. All AC and DC specifications-including bandwidth, THD, noise, and VOCM behavior-are identical between the two parts. Therefore, THS4121CDGN is selected when continuous operation is required and power gating is unnecessary, avoiding the external 10-kΩ pullup resistor and PD control logic needed for THS4120CDGN. Both share identical pinout and package.
Can the THS4121CDGN drive capacitive loads directly?
No-the THS4121CDGN is internally compensated for maximum bandwidth and slew rate, making it susceptible to instability with capacitive loads >10 pF. TI recommends placing a minimum 20-Ω series resistor between each output and the load to isolate capacitance and restore phase margin. In 50-Ω systems, a 50-Ω series resistor also provides source termination. This requirement is documented in Figure 21 of the THS4121CDGN datasheet and applies regardless of load type-PCB trace capacitance, ADC input capacitance, or cable capacitance must all be addressed via this series resistance.
What thermal considerations apply to the THS4121CDGN in the DGN package?
The THS4121CDGN in the MSOP PowerPAD™ (DGN) package requires soldering its exposed thermal pad to a PCB copper pour for reliable thermal performance. With θJC = 4.7°C/W, failure to thermally connect the pad risks exceeding the 125°C maximum junction temperature during continuous operation-even at modest power dissipation. TI technical brief SLMA002 specifies minimum pad size, thermal via count, and copper area guidelines. The pad is electrically isolated, so grounding it poses no functional risk and significantly improves long-term reliability and distortion performance under thermal stress.
THS4121CDGN 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:
- Obsolete
- Amplifier Type:
- Differential
- Number of Circuits:
- 1
- Output Type:
- Differential
- Slew Rate:
- 55V/µs
- Gain Bandwidth Product:
- -
- -3db Bandwidth:
- 100 MHz
- Current - Input Bias:
- 1.2 pA
- Voltage - Input Offset:
- 3 mV
- Current - Supply:
- 11mA
- Current - Output / Channel:
- 100 mA
- Voltage - Supply Span (Min):
- 3 V
- Voltage - Supply Span (Max):
- 3.5 V
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-HVSSOP
THS4121CDGN FAQ
1.How can I place an order for THS4121CDGN through Aetrix?
Please submit a Request for Quotation (RFQ) for THS4121CDGN 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 THS4121CDGN reliable?
The price and inventory of THS4121CDGN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for THS4121CDGN is usually 5 days.
3.What payment methods are accepted for THS4121CDGN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for THS4121CDGN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for THS4121CDGN?
THS4121CDGN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your THS4121CDGN 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 THS4121CDGN?
For technical support, including THS4121CDGN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your THS4121CDGN requirements.
6.How does Aetrix verify that THS4121CDGN is sourced from the original manufacturer or authorized distributors?
All THS4121CDGN 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 THS4121CDGN meets industry standards.
7.What is the process for return or replacement of THS4121CDGN?
All THS4121CDGN units undergo pre-shipment inspection (PSI). If there is an issue with THS4121CDGN, 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 THS4121CDGN part is unused and in its original packaging.
Return procedure for THS4121CDGN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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