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Texas Instruments THS4121IDGNR
- Part No.:
- THS4121IDGNR
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
THS4121IDGNR.pdf
- Description:
- IC OPAMP DIFF 1 CIRCUIT 8HVSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,633
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Product details
Overview
THS4121IDGNR from Texas Instruments is a single-channel, fully differential-input/differential-output high-speed amplifier optimized for ADC driver and antialiasing filter applications. 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 from a 3.3 V single supply. Its VOCM pin enables precise output common-mode level control in data acquisition systems.
For engineers reviewing the THS4121IDGNR datasheet, THS4121IDGNR pinout, THS4121IDGNR application, or THS4121IDGNR equivalent, key selection criteria include differential output drive capability into 800 Ω loads, VOCM-controlled DC level shifting, low distortion at 1–10 MHz, thermal performance of the MSOP PowerPAD™ package, and compatibility with 3.3 V ADC reference interfaces.
Technical Context
The THS4121IDGNR implements a true fully differential signal path with matched internal transconductance stages, enabling balanced output swing and inherent rejection of even-order harmonics. Its architecture supports both differential-input/differential-output and single-ended-input/differential-output configurations without external level-shifting circuitry.
VOCM pin functionality provides direct control over the common-mode voltage of both outputs, allowing seamless interfacing to ADCs with mid-rail reference voltages (e.g., AVDD/2). The device is internally compensated for unity-gain stability but requires external 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 - Supports high-fidelity signal conditioning up to Nyquist frequency of 50 MSPS ADCs. |
| Slew Rate | 55 V/µs - Enables clean reproduction of fast transient signals without slewing-induced distortion. |
| THD @ 1 MHz | –75 dB (2 VPP) - Meets stringent linearity requirements for 14-bit+ precision data acquisition. |
| Input Noise | 5.4 nV/√Hz @ 10 kHz - Minimizes added noise floor in low-level sensor signal chains. |
| Supply Voltage | 3.3 V single supply - Directly interfaces with modern low-voltage ADCs and digital logic rails. |
| CMRR | 64–96 dB - Rejects board-level common-mode interference in noisy industrial environments. |
| Quiescent Current | 13.5 mA @ 25°C - Balances performance and power efficiency in continuous-operation systems. |
Pinout & Package
THS4121IDGNR is housed in an 8-pin MSOP PowerPAD™ package (DGN), featuring an exposed thermal pad on the underside for enhanced heat dissipation. The package is RoHS-compliant and rated MSL-2.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VIN−) | Inverting Input | Differential input node; requires matched trace length and impedance to VIN+ for optimal CMRR. |
| 2 (VOCM) | Output Common-Mode Control | Sets DC level of both outputs; bypass with 0.1 µF capacitor to suppress noise coupling. |
| 3 (VDD) | Positive Supply | 3.3 V single supply input; requires local 6.8 µF + 0.1 µF decoupling per layout guidelines. |
| 4 (VOUT+) | Positive Differential Output | Delivers inverted-phase signal; must be terminated symmetrically with VOUT− for balanced operation. |
| 5 (VIN+) | Non-Inverting Input | Differential input node; forms fully differential pair with VIN−; sensitive to PCB parasitics. |
| 6 (NC) | No Connect | Internally unused; must remain unconnected and unstubbed to avoid resonance or coupling. |
| 7 (GND) | Analog Ground Reference | Primary ground return for signal path; isolated from digital ground per high-speed layout rules. |
| 8 (VOUT−) | Negative Differential Output | Delivers non-inverted-phase signal; complements VOUT+ to form 2 VPP differential swing. |
Key Features
| Feature | Design Value |
|---|---|
| Fully differential I/O architecture | Enables 2× dynamic range vs. single-ended amplifiers-e.g., delivers 2 VPP differential output to feed 1 VPP ADC inputs. |
| VOCM-controlled output level shifting | Allows direct interface to ADCs with internal reference (e.g., AVDD/2), eliminating external level-shift circuits. |
| High PSRR (68–85 dB) | Maintains signal integrity despite supply rail noise from switching regulators or digital cores. |
| PowerPAD™ thermal package (DGN) | Reduces θJA to 58.4°C/W-enables sustained 13.5 mA operation at 85°C ambient without derating. |
| Low 1st- and 2nd-harmonic distortion | Even-order harmonic cancellation via symmetrical output structure improves SFDR in wideband receivers. |
Applications
| High-Speed Data Acquisition | Differential Signal Transmission |
|---|---|
Use Scenario: Driving the differential input of a 14-bit, 50 MSPS SAR ADC in a portable ultrasound front-end. IC Role / Device Role / Timing Role: ADC driver providing gain = 1, 2 VPP differential output, and VOCM alignment to ADC's internal 1.65 V reference. Use Value: Eliminates transformer coupling, reduces board area by 40%, and achieves –75 dB THD at 1 MHz for accurate tissue echo digitization. | Use Scenario: Transmitting analog sensor data across noisy industrial backplanes using differential signaling. IC Role / Device Role / Timing Role: Differential transmitter converting single-ended sensor output to balanced 2 VPP signal with common-mode immunity. Use Value: Rejects >64 dB of coupled EMI from adjacent motor drives, enabling reliable 12-bit accuracy over 1 m cable runs. |
| Antialiasing Filter Interface | Single-Supply Sensor Conditioning |
Use Scenario: Active antialiasing filter stage preceding a 16-bit sigma-delta ADC in energy metering. IC Role / Device Role / Timing Role: Gain-stage amplifier in 2nd-order active low-pass topology with VOCM set to mid-supply for rail-to-rail ADC compatibility. Use Value: Maintains <0.01% gain error across 10 kHz passband while suppressing >60 dB of out-of-band switching noise. | Use Scenario: Conditioning output of a 3.3 V MEMS accelerometer in battery-powered IoT node. IC Role / Device Role / Timing Role: Single-supply differential buffer isolating sensor from ADC input capacitance while preserving DC offset. Use Value: Achieves 110 dB SNR at 1 kHz with 5.4 nV/√Hz noise floor and zero external bias components. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar fully differential amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| THS4131IDGNR | 150 MHz BW, 51 V/µs SR, 1.3 nV/√Hz noise, ±2.5 to ±15 V dual supply only | Requires split supply; superior noise performance but incompatible with 3.3 V-only systems | Select when higher bandwidth and lower noise justify dual-supply complexity and cost. |
| LMH5401IRGT | 1.2 GHz BW, 3000 V/µs SR, 2.3 nV/√Hz, fixed-gain options, no VOCM pin | Lacks VOCM control; designed for RF/IF differential signaling, not precision ADC driving | Choose for >100 MSPS sampling or RF IQ modulation where DC level control is handled externally. |
Compared with THS4121IDGNR, THS4131IDGNR offers higher bandwidth and lower noise but mandates dual supplies, while LMH5401IRGT delivers RF-grade speed at the expense of VOCM flexibility and precision low-frequency linearity-making THS4121IDGNR optimal for cost-sensitive, 3.3 V, medium-speed data acquisition.
Availability
THS4121IDGNR is available at Aetrix Electronics and suitable for high-speed data acquisition, industrial sensor interfaces, and precision ADC driver applications requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for THS4121IDGNR 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 interfaces.
The THS412x family was designed specifically for precision, high-speed differential signal conditioning-targeting applications including medical imaging, test equipment, and communications infrastructure where linearity, noise, and power efficiency are critical.
FAQ
What is the recommended power supply configuration for THS4121IDGNR?
The THS4121IDGNR is specified for single-supply operation at 3.3 V (range: 3.0 V to 3.5 V). It requires local decoupling with a 6.8 µF tantalum capacitor in parallel with a 0.1 µF ceramic capacitor placed within 2.54 mm of the VDD pin. The GND pin must connect to a dedicated analog ground plane, and the VOCM pin should be bypassed with a 0.1 µF capacitor to minimize noise injection into the output common-mode level. THS4121IDGNR does not support dual-supply operation.
How does the VOCM pin function in THS4121IDGNR, and what happens if left unconnected?
The VOCM pin sets the DC common-mode voltage of both differential outputs (VOUT+ and VOUT−). When left unconnected, THS4121IDGNR defaults to mid-rail (VDD/2 ≈ 1.65 V), enabling direct interface with 3.3 V ADCs that reference to AVDD/2. However, TI recommends bypassing VOCM with a 0.1 µF capacitor to suppress high-frequency noise coupling. Leaving it floating without bypass may degrade PSRR and introduce instability in noisy environments. THS4121IDGNR does not require external pull-up/down resistors on VOCM.
Can THS4121IDGNR drive a 50 Ω transmission line directly?
No, THS4121IDGNR should not drive a 50 Ω load directly. Its specified load is 800 Ω differential (400 Ω per output). To interface with 50 Ω systems, place a 20–50 Ω series resistor at each output (VOUT+ and VOUT−) to isolate capacitive loading and provide source termination. This preserves stability and prevents ringing, especially above 10 MHz. The resistor value must be selected based on trace impedance and required signal integrity-TI validates 20 Ω for general use and 50 Ω for 50 Ω transmission lines.
What is the maximum allowable capacitive load for THS4121IDGNR without external compensation?
THS4121IDGNR is internally compensated for unity-gain stability with resistive loads. Capacitive loads exceeding 10 pF directly at the output pins reduce phase margin and risk oscillation. For loads >10 pF-including PCB trace capacitance, ADC input capacitance, or cabling-TI mandates a series resistor (≥20 Ω) between each output and the load. This isolation network restores stability; typical values are 20 Ω for general use and 50 Ω for 50 Ω systems. Layout best practices also require minimizing output trace length and avoiding stubs.
Does THS4121IDGNR support single-ended input operation, and how is gain configured?
Yes, THS4121IDGNR supports single-ended input/differential output operation. In this mode, VIN+ is driven with the signal, VIN− is grounded or biased, and gain is set by external feedback resistors (Rf) and gain-setting resistors (Rg) per the equation A = Rf/Rg. TI recommends 1% tolerance or better resistors for Rf and Rg to preserve CMRR and harmonic cancellation. The device maintains full differential output swing and VOCM control regardless of input configuration. THS4121IDGNR does not require modification to its internal architecture for this mode.
THS4121IDGNR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width) Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-HVSSOP
THS4121IDGNR FAQ
1.How can I place an order for THS4121IDGNR through Aetrix?
Please submit a Request for Quotation (RFQ) for THS4121IDGNR 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 THS4121IDGNR reliable?
The price and inventory of THS4121IDGNR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for THS4121IDGNR is usually 5 days.
3.What payment methods are accepted for THS4121IDGNR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for THS4121IDGNR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for THS4121IDGNR?
THS4121IDGNR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your THS4121IDGNR 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 THS4121IDGNR?
For technical support, including THS4121IDGNR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your THS4121IDGNR requirements.
6.How does Aetrix verify that THS4121IDGNR is sourced from the original manufacturer or authorized distributors?
All THS4121IDGNR 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 THS4121IDGNR meets industry standards.
7.What is the process for return or replacement of THS4121IDGNR?
All THS4121IDGNR units undergo pre-shipment inspection (PSI). If there is an issue with THS4121IDGNR, 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 THS4121IDGNR part is unused and in its original packaging.
Return procedure for THS4121IDGNR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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