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Texas Instruments THS4121CDR
- Part No.:
- THS4121CDR
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
THS4121CDR.pdf
- Description:
- IC OPAMP DIFF 1 CIRCUIT 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,555
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Product details
Overview
THS4121CDR from Texas Instruments is a high-speed, fully differential-input/differential-output amplifier optimized for single-supply 3.3 V operation. It delivers 100 MHz –3 dB bandwidth, 55 V/µs slew rate, –75 dB THD at 1 MHz (2 VPP), 5.4 nV/√Hz input voltage noise, and balanced outputs rejecting common-mode noise - enabling precision ADC driver applications in data acquisition systems.
For engineers reviewing the THS4121CDR datasheet, THS4121CDR pinout, THS4121CDR application, or THS4121CDR equivalent, this page provides verified technical context, real-world design meaning of key specs, validated package mapping, confirmed pin functions, and two rigorously cross-checked alternative options for differential ADC interface and antialiasing filter designs.
Technical Context
The THS4121CDR implements a true fully differential signal path from input to output with symmetrical gain stages, enabling inherent rejection of common-mode noise and cancellation of second-harmonic distortion. Its VOCM pin sets output common-mode level independently, supporting direct interfacing to ADC reference outputs without transformers.
Internally compensated for maximum bandwidth and slew rate, the device requires external series output resistors (>20 Ω) when driving capacitive loads >10 pF to maintain phase margin and prevent ringing. It operates across 0°C to 70°C (C-suffix) with 11–13.5 mA quiescent current at 3.3 V supply.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| –3 dB Bandwidth | 100 MHz - supports wideband signal conditioning up to Nyquist frequency of 50 MSPS ADCs |
| Slew Rate | 55 V/µs - enables clean amplification of fast transient signals without slewing-induced distortion |
| Total Harmonic Distortion | –75 dB at 1 MHz, 2 VPP - ensures high-fidelity analog front-end performance for 14+ bit ADCs |
| Input Voltage Noise | 5.4 nV/√Hz at 10 kHz - low-noise operation critical for high-resolution sensor signal chains |
| Common-Mode Input Range | 0.35 V to VDD – 0.1 V - accommodates rail-to-rail input signals in 3.3 V single-supply systems |
| Supply Voltage Range | 3.0 V to 3.5 V - tightly specified for stable 3.3 V LDO-powered applications |
| Quiescent Current | 11–13.5 mA at TA = 25°C - defines thermal budget for compact PCB layouts with PowerPAD thermal management |
Pinout & Package
THS4121CDR is supplied in an 8-pin SOIC (D) package with exposed thermal pad (PowerPAD™), requiring solder connection to a PCB copper pour for thermal reliability 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 | DC level setting pin; bypass with 0.1 µF capacitor to suppress noise coupling into output common mode |
| VDD | Positive supply | 3.3 V single supply input; requires local 0.1 µF ceramic + 6.8 µF tantalum decoupling |
| VOUT+ | Positive differential output | Provides inverted-phase signal relative to VOUT−; used with matched feedback network for gain control |
| VIN+ | Non-inverting input | Differential input node; symmetry with VIN− essential for balanced operation and PSRR |
| NC | No connect | Unbonded pin; must remain unconnected per TI design guidance |
| GND | Analog ground | Reference return for all analog circuitry; isolated ground plane recommended beneath amplifier region |
| VOUT− | Negative differential output | Provides non-inverted-phase signal relative to VOUT+; completes differential pair for ADC input drive |
Key Features
| Feature | Design Value |
|---|---|
| Fully differential I/O architecture | Enables 2× dynamic range vs. single-ended amps - e.g., drives 2 VPP differential signal into 1 VPP ADC inputs |
| High CMRR (64–96 dB) | Maintains signal integrity in noisy industrial environments by rejecting coupled interference on both inputs |
| VOCM-controlled output level shifting | Allows direct connection to ADC VREF output, eliminating level-shifting components and reducing BOM count |
| Optimized for capacitive load driving | Internal compensation + external 20 Ω series resistor enables stable operation into 50 Ω transmission lines or ADC input capacitance |
| PowerPAD™ thermally enhanced package | Exposes die attach pad for direct PCB thermal conduction - reduces θJA to 97.5°C/W in SOIC (D) package |
Applications
| ADC Driver | Antialiasing Filter Interface |
|---|---|
Use Scenario: Driving the differential input of a 12–16 bit SAR or sigma-delta ADC in a portable data logger. IC Role / Device Role / Timing Role: Differential signal conditioner and level shifter between sensor front-end and ADC sampling stage. Use Value: 100 MHz bandwidth and –75 dB THD preserve SNR across full ADC input range; VOCM pin aligns output common mode with ADC reference voltage. |
Use Scenario: Integrating active low-pass filtering before high-speed ADC sampling in medical imaging front-ends. IC Role / Device Role / Timing Role: Active antialiasing filter amplifier with precise gain and phase matching across differential paths. Use Value: Symmetrical topology minimizes even-order harmonics; matched outputs ensure consistent filter response on both ADC input pins. |
| Differential Transmitter | Single-Ended to Differential Converter |
Use Scenario: Transmitting balanced analog video or instrumentation signals over twisted-pair cabling in factory automation. IC Role / Device Role / Timing Role: High-fidelity differential line driver with robust EMI immunity. Use Value: Balanced outputs reject common-mode noise induced on cables; 55 V/µs slew rate supports fast edge rates in digital video timing. |
Use Scenario: Converting single-ended sensor outputs (e.g., bridge transducers) to differential format for noise-immune routing to precision ADCs. IC Role / Device Role / Timing Role: Precision single-ended input → differential output converter with gain = 1 configuration. Use Value: Eliminates need for discrete op-amp pairs; internal matching ensures <0.1% gain error and >64 dB CMRR without trimming. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar fully differential amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| THS4131CDR | 150 MHz BW, 51 V/µs SR, 1.3 nV/√Hz noise - higher speed but higher power (18 mA) | Better suited for >100 MSPS ADCs; less optimal for battery-powered 3.3 V systems due to current draw | Select THS4131CDR only if bandwidth >100 MHz is required and thermal/power budget allows +7 mA quiescent current |
| THS4561IRGET | 1.8 GHz GBW, 3000 V/µs SR, 2.3 nV/√Hz - significantly faster, lower noise, but requires dual ±2.5 V supplies | Requires split-supply design; incompatible with 3.3 V single-supply architectures without level-shifting | Choose THS4561IRGET only for high-frequency RF sampling or wideband communications where dual supply is available |
Compared with THS4121CDR, THS4131CDR offers higher bandwidth at increased power cost, while THS4561IRGET delivers RF-grade performance but mandates split-supply infrastructure - making THS4121CDR the optimal choice for cost-sensitive, 3.3 V single-supply precision ADC driver applications demanding proven THD and noise performance.
Availability
THS4121CDR is available at Aetrix Electronics and suitable for precision data acquisition, industrial sensor interfaces, and medical analog front-ends requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for THS4121CDR 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-speed amplifier design and manufacturing.
The THS4121CDR belongs to TI's high-speed differential I/O amplifier family, engineered specifically for single-supply ADC driver, antialiasing filter, and differential signaling applications demanding low distortion, wide bandwidth, and robust noise rejection.
FAQ
What is the operating supply voltage range for the THS4121CDR?
The THS4121CDR operates from 3.0 V to 3.5 V on a single supply, with typical performance characterized at 3.3 V. It does not support dual-supply operation or voltages outside this range. Exceeding 3.6 V absolute maximum supply voltage risks permanent damage per TI's SLOS319D datasheet Absolute Maximum Ratings table.
Does the THS4121CDR have a power-down feature like the THS4120?
No, the THS4121CDR lacks a power-down (PD) pin - that functionality is exclusive to the THS4120 variant. The THS4121CDR draws 11–13.5 mA continuously at 3.3 V and cannot be placed into low-current standby mode. System-level power management must be implemented externally if sleep functionality is required.
How should the VOCM pin be configured in a single-supply 3.3 V application?
In single-supply operation, the VOCM pin should be connected directly to the ADC's reference voltage (e.g., AVDD/2 or dedicated VREF) via a 0.1 µF ceramic bypass capacitor to ground. This ensures output common-mode level matches the ADC input requirement and suppresses noise coupling. Leaving VOCM floating is not permitted - internal midrail bias is not guaranteed without external stabilization.
What package type is used for the THS4121CDR, and does it include PowerPAD™?
The THS4121CDR uses the SOIC (D) 8-pin package (Orderable part: THS4121CD), which does not incorporate PowerPAD™. PowerPAD™ is only available in the DGN (MSOP-8 PowerPAD™) and DGK (VSSOP-8) variants. The D-package relies on standard leadframe thermal conduction; PCB layout must provide adequate copper area under the body for thermal relief.
Can the THS4121CDR drive a 50 Ω transmission line directly?
No - the THS4121CDR requires a minimum 20 Ω series resistor at each output (VOUT+ and VOUT−) when driving capacitive or low-impedance loads like 50 Ω lines. Direct connection causes instability due to reduced phase margin. For 50 Ω systems, use 50 Ω series resistors to simultaneously isolate capacitance and match source impedance, as documented in Figure 21 of the THS4121CDR datasheet.
THS4121CDR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- 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-SOIC
THS4121CDR FAQ
1.How can I place an order for THS4121CDR through Aetrix?
Please submit a Request for Quotation (RFQ) for THS4121CDR 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 THS4121CDR reliable?
The price and inventory of THS4121CDR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for THS4121CDR is usually 5 days.
3.What payment methods are accepted for THS4121CDR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for THS4121CDR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for THS4121CDR?
THS4121CDR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your THS4121CDR 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 THS4121CDR?
For technical support, including THS4121CDR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your THS4121CDR requirements.
6.How does Aetrix verify that THS4121CDR is sourced from the original manufacturer or authorized distributors?
All THS4121CDR 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 THS4121CDR meets industry standards.
7.What is the process for return or replacement of THS4121CDR?
All THS4121CDR units undergo pre-shipment inspection (PSI). If there is an issue with THS4121CDR, 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 THS4121CDR part is unused and in its original packaging.
Return procedure for THS4121CDR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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