My Inquiry
My Account
Texas Instruments THS4121CD
- Part No.:
- THS4121CD
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
THS4121CD.pdf
- Description:
- IC OPAMP DIFF 1 CIRCUIT 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,544
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
THS4121CD from Texas Instruments is a high-speed, fully differential-input/differential-output amplifier optimized for ADC driving and antialiasing in single-supply 3.3 V 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 THS4121CD datasheet, THS4121CD pinout, THS4121CD application, or THS4121CD equivalent, key selection criteria include differential signal integrity, low distortion at high frequencies, VOCM-controlled output swing, and compatibility with 3.3 V data converters requiring balanced drive without transformers.
Technical Context
The THS4121CD implements a true fully differential signal path from input to output, enabling balanced rejection of common-mode noise and cancellation of second-harmonic distortion. Its internal architecture supports both differential-input/differential-output and single-ended-input/differential-output configurations with gain = 1 default.
It features a dedicated VOCM pin that sets the DC common-mode level of both outputs independently of input signal, with high bandwidth up to the amplifier's operating range and recommended 0.1 µF bypass capacitance. Unlike the THS4120, it lacks a power-down (PD) pin and draws 13.5 mA quiescent current at 3.3 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Bandwidth (–3 dB) | 100 MHz - supports wideband signal conditioning up to Nyquist zone 1 of high-speed ADCs |
| Slew Rate | 55 V/µs - enables clean transient response for fast-rising digital or RF-modulated signals |
| THD @ 1 MHz | –75 dB at 2 VPP - ensures minimal harmonic corruption in precision measurement front-ends |
| Input Voltage Noise | 5.4 nV/√Hz at 10 kHz - preserves SNR in low-level analog sensor interfaces |
| Supply Voltage | 3.3 V single supply - simplifies power design and matches modern ADC reference rails |
| Common-Mode Input Range | 0.35 V to VDD – 0.1 V - accommodates rail-to-rail input signals in 3.3 V systems |
| Output Current | ±100 mA peak - drives 800 Ω differential loads or 50 Ω transmission lines with series isolation resistor |
Pinout & Package
The THS4121CD is housed in an 8-pin SOIC (D) package with exposed thermal pad (PowerPAD™), requiring solder connection to PCB copper 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 input; requires local 0.1 µF ceramic + 6.8 µF tantalum decoupling |
| VOUT+ | Positive differential output | Provides inverted-phase complement to VOUT−; balanced pair rejects common-mode interference |
| VIN+ | Non-inverting input | Differential input node; symmetry with VIN− essential for distortion performance |
| NC | No connect | Unbonded pin; must remain unconnected and unstubbed on PCB layout |
| GND | Analog ground reference | Low-inductance return path; isolated ground plane recommended beneath amplifier region |
| VOUT− | Negative differential output | Provides non-inverted-phase complement to VOUT+; forms true differential pair with VOUT+ |
Key Features
| Feature | Design Value |
|---|---|
| Fully differential I/O architecture | Enables 2× dynamic range vs. single-ended amplifiers by splitting 2 VPP signal into two 1 VPP complementary outputs |
| VOCM-controlled output level shifting | Allows precise alignment of differential output common-mode voltage to ADC reference without external resistive dividers |
| High CMRR (96 dB typical) | Maintains signal fidelity in noisy industrial environments by rejecting coupled interference on both inputs simultaneously |
| Optimized for capacitive load driving | Internal compensation allows stable operation with ≥20 Ω series output isolation resistor for >10 pF loads |
| Single-supply 3.3 V operation | Eliminates need for dual supplies or charge pumps in portable and embedded data acquisition systems |
Applications
| ADC Driver for High-Speed Data Acquisition | Differential Transmitter in Industrial IO Modules |
|---|---|
Use Scenario: Driving the differential input of a 12-bit, 100 MSPS pipeline ADC in automated test equipment. IC Role / Device Role / Timing Role: Fully differential amplifier providing matched, low-distortion signal paths to both ADC input terminals while rejecting board-level noise. Use Value: Achieves –75 dB THD at 1 MHz, enabling accurate digitization of high-fidelity analog waveforms without transformer coupling or complex bias networks. | Use Scenario: Transmitting sensor data across noisy factory-floor cabling using balanced differential signaling. IC Role / Device Role / Timing Role: Differential transmitter converting single-ended sensor output to robust 2 VPP differential signal compliant with RS-485 receiver thresholds. Use Value: Leverages 100 MHz bandwidth and 55 V/µs slew rate to preserve fast transients in vibration or pressure monitoring signals over long traces. |
| Antialiasing Filter Interface | Single-Supply Signal Conditioning for Medical Sensors |
Use Scenario: Integrating active low-pass filtering directly before a SAR ADC in portable ultrasound front-end. IC Role / Device Role / Timing Role: Differential amplifier serving as unity-gain buffer and filter driver, maintaining phase matching between + and – paths. Use Value: Balanced outputs reduce even-order harmonics in filter response, improving SFDR by >6 dB compared to single-ended implementations. | Use Scenario: Amplifying low-amplitude ECG signals in battery-powered patient monitors with 3.3 V supply constraint. IC Role / Device Role / Timing Role: Precision differential amplifier configured for single-ended input to differential output with VOCM set to midrail. Use Value: 5.4 nV/√Hz input noise and 96 dB CMRR ensure clean amplification of microvolt-level biopotentials amid switching power supply noise. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar fully differential amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| THS4120CD | Includes PD pin for power-down mode (120 µA quiescent); identical AC specs but 130 µA higher max IDD in full operation | Preferred where intermittent operation or low-power sleep states are required | Select THS4120CD only if system-level power sequencing mandates active power-down capability |
| THS4131CD | Higher 150 MHz bandwidth, 51 V/µs slew rate, lower 1.3 nV/√Hz noise; requires ±2.5 V to ±15 V split supply or 5–30 V single supply | Used in wider-bandwidth instrumentation where 3.3 V supply is not constraining | Choose THS4131CD when bandwidth >100 MHz or noise <2 nV/√Hz is mandatory and supply flexibility exists |
Compared with THS4121CD, THS4120CD adds power-down functionality at minor quiescent current cost, while THS4131CD trades supply voltage flexibility for significantly higher speed and lower noise-neither is pin-compatible, and both require PCB layout changes for supply and decoupling.
Availability
THS4121CD is available at Aetrix Electronics and suitable for high-speed data acquisition, industrial communications, medical sensor interfaces, and test equipment requiring stable component supply and long-term production continuity.
Supply support for THS4121CD 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 high-performance signal chain solutions.
The THS4121CD belongs to TI's high-speed differential I/O amplifier family, designed specifically for precision, low-distortion signal conditioning in 3.3 V data converter interfaces and noise-sensitive measurement systems.
FAQ
What is the function of the VOCM pin on the THS4121CD?
The VOCM pin on the THS4121CD sets the DC common-mode voltage of both differential outputs. It accepts an external voltage or defaults to VDD/2 internally, enabling precise alignment of output swing to the reference voltage of downstream ADCs. A 0.1 µF bypass capacitor is required for stability and noise suppression, as specified in the TI SLOS319D datasheet.
Does the THS4121CD support single-supply operation?
Yes, the THS4121CD is explicitly designed for single-supply operation at 3.3 V. Its input common-mode range extends from 0.35 V to VDD – 0.1 V, and its VOCM pin allows midrail output biasing-enabling direct interface with 3.3 V ADCs without level-shifting circuitry or dual supplies.
How does the THS4121CD differ from the THS4120CD?
The THS4121CD omits the power-down (PD) pin present on the THS4120CD. Otherwise, their AC performance-100 MHz bandwidth, 55 V/µs slew rate, –75 dB THD-is identical. The THS4121CD draws 13.5 mA quiescent current continuously, while the THS4120CD reduces to 120 µA in power-down mode.
Can the THS4121CD drive a 50 Ω transmission line?
Yes-the THS4121CD can drive 50 Ω loads when used with a 20–50 Ω series isolation resistor at each output, as recommended in the TI datasheet for capacitive or mismatched loads. This configuration prevents instability while providing source termination for controlled-impedance routing.
Is a PowerPAD™ thermal pad required for THS4121CD in SOIC (D) package?
No-the THS4121CD in SOIC (D) package does not include a PowerPAD™ thermal pad; that feature is exclusive to the DGN (MSOP PowerPAD™) variant. The D package relies on standard SOIC thermal conduction through leads and PCB copper; no underside thermal pad soldering is needed or possible.
THS4121CD Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Bulk
- 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:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
THS4121CD FAQ
1.How can I place an order for THS4121CD through Aetrix?
Please submit a Request for Quotation (RFQ) for THS4121CD 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 THS4121CD reliable?
The price and inventory of THS4121CD are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for THS4121CD is usually 5 days.
3.What payment methods are accepted for THS4121CD?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for THS4121CD transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for THS4121CD?
THS4121CD orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your THS4121CD 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 THS4121CD?
For technical support, including THS4121CD datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your THS4121CD requirements.
6.How does Aetrix verify that THS4121CD is sourced from the original manufacturer or authorized distributors?
All THS4121CD 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 THS4121CD meets industry standards.
7.What is the process for return or replacement of THS4121CD?
All THS4121CD units undergo pre-shipment inspection (PSI). If there is an issue with THS4121CD, 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 THS4121CD part is unused and in its original packaging.
Return procedure for THS4121CD:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
THS4121CD Tags
-
LM358DT
STMicroelectronics
-
LM358DR
Texas Instruments
-
LM2904DR
Texas Instruments
-
LM358ADR
Texas Instruments
-
LM2904DGKR
Texas Instruments
-
LM324DR
Texas Instruments
-
MCP6006T-E/OT
Microchip Technology
-
MCP6006UT-E/OT
Microchip Technology
-
LM324PWR
Texas Instruments
-
LM2902PWR
Texas Instruments
-
LM2902DR
Texas Instruments
-
LM358P
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
