THS4551IRGTR - 150MHz Fully Diff Amp | Texas Instruments
MPN: THS4551IRGTR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $5.9 | $5.90 |
| 10 | $5.45 | $54.50 |
| 100 | $4.95 | $495.00 |
| 500 | $4.42 | $2,210.00 |
| 1,000 | $3.85 | $3,850.00 |
THS4551IRGTR Overview
A fully differential amplifier is an op-amp topology that converts a single-ended or differential input signal into a balanced differential output centered around a settable common-mode voltage. FDAs sit in the signal chain between sensor/transducer signal conditioning and high-speed, high-resolution analog-to-digital converters (ADCs). They reject common-mode noise and even-order harmonics, drive differential ADCs cleanly, and enable DC-coupled paths through SAR or delta-sigma converters - placing them in the broader hierarchy of operational amplifier -> amplifier IC -> analog signal chain -> semiconductor.
Key features include 150 MHz small-signal bandwidth, 50 V/µs slew rate, 1.5 nV/√Hz voltage noise, 100 dB DC open-loop gain, and a 2.7 V to 5.4 V single-supply operating range. The integrated VOCM pin sets the output common-mode voltage independently of the input, simplifying interface to ADCs with 0.5 V to 2.5 V common-mode requirements. Internal common-mode feedback preserves output balance across frequency, eliminating the need for precision matched external resistors.
Architecturally the device combines a precision input stage with a class-AB output stage capable of driving 2 VPP into 200 Ω differential loads (typical for 16-bit ADCs). The 1.5 nV/√Hz noise floor makes it suitable for 16-bit ADC reference designs, and the wide bandwidth handles 18-bit SAR converters sampling above 1 MSPS.
Typical applications include 16-bit to 20-bit ADC drivers, precision instrumentation front-ends, transducer signal chains, and active filters. The single-ended-to-differential conversion is ideal for driving AD7768, ADS131A04, and similar precision SAR converters in measurement equipment.
When designing with this part, use a feedback resistor network that sets the desired gain and a VOCM bypass capacitor of 0.1 µF for noise decoupling. Verify output common-mode voltage tracks VOCM input over frequency to avoid ADC distortion.
This page synthesizes distributor pricing, drop-in alternatives, and application notes not found in the manufacturer datasheet alone.
Drop-in alternatives for THS4551IRGTR — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with THS4551IRGTR (same form factor and footprint) — differing in Package, Operating Temperature Range, Slew Rate, Supply Voltage Range, Output Type.
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View Datasheet →THS4551IRGTR Maximum Ratings & Electrical Characteristics
| Product Type | Fully Differential Amplifier (FDA) |
| Number of Channels | 1 |
| -3 dB Bandwidth (G = 1) | 150 MHz |
| Slew Rate | 50 V/µs |
| Input Voltage Noise Density | 1.5 nV/√Hz |
| DC Open-Loop Gain | 100 dB |
| Supply Voltage Range | 2.7 V to 5.4 V (single supply) |
| Output Type | Rail-to-Rail Differential |
| Output Common-Mode Control | Yes (VOCM pin) |
| Operating Temperature | -40 C to +125 C |
| Package | VQFN-16 (RGT) 3x3 mm with exposed pad |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| Lead-Free | Yes |
THS4551IRGTR Pin Configuration
| Pin 1 | IN+ — Non-inverting input |
| Pin 2 | IN- — Inverting input |
| Pin 3 | VS+ — Positive supply voltage |
| Pin 4 | VS- — Negative supply voltage (or GND for single supply) |
| Pin 5 | OUT+ — Non-inverting differential output |
| Pin 6 | OUT- — Inverting differential output |
| Pin 7 | VOCM — Output common-mode voltage input |
| Pin 8 | PD — Power-down control (active high) |
| Pin 9 | NC — Not connected (per datasheet) |
| Pin 10 | NC — Not connected (per datasheet) |
| Pin 11 | NC — Not connected (per datasheet) |
| Pin 12 | NC — Not connected (per datasheet) |
| Pin 13 | NC — Not connected (per datasheet) |
| Pin 14 | NC — Not connected (per datasheet) |
| Pin 15 | NC — Not connected (per datasheet) |
| Pin 16 | NC — Not connected (per datasheet) |
Typical Applications
THS4551IRGTR is suitable for 7 applications: 16-bit/18-bit SAR ADC Driver, Precision Instrumentation Front-End, Active Filter for Signal Conditioning, Transducer Signal Chain Interface, Single-Ended to Differential Conversion, Medical Imaging Front-End, Industrial Process Control Analog Input Module.
16-bit/18-bit SAR ADC Driver
The THS4551IRGTR is purpose-built for driving precision SAR ADCs such as the AD7768 and ADS131A04. Its 1.5 nV/√Hz input voltage noise density preserves the ADC's signal-to-noise ratio, while the 150 MHz bandwidth supports sampling rates up to 10 MSPS. The internal VOCM pin lets the designer set the output common-mode to 0.5xAVDD for direct-coupled 1.8 V or 3.3 V ADC inputs. Compared with discrete single-ended-to-differential op-amp solutions, the THS4551IRGTR halves board area and eliminates resistor matching for common-mode balance. Designers should place 0.1 µF VOCM bypass caps close to the pin to minimize distortion at high input frequencies.
Recommended
Precision Instrumentation Front-End
The THS4551IRGTR serves as the differential input stage of precision instrumentation front-ends where common-mode noise rejection is critical. Its 100 dB DC open-loop gain and rail-to-rail differential output ensure high linearity across the full input range. In bridge sensor signal conditioning for load cells and pressure transducers, the FDA converts the small differential bridge signal to a clean differential output while rejecting common-mode interference. The 16-pin VQFN footprint fits compact multi-channel data acquisition boards. Designers should use 0.1% matched feedback networks to maintain common-mode rejection above 80 dB at the signal frequency of interest.
Recommended
Active Filter for Signal Conditioning
The THS4551IRGTR's 150 MHz bandwidth and 50 V/µs slew rate make it ideal for implementing active low-pass, high-pass, and band-pass filters in precision signal chains. Used in Sallen-Key or multiple-feedback topologies, it provides sharp roll-off without sacrificing phase linearity. In medical ultrasound or audio test equipment, it shapes anti-aliasing filters ahead of high-resolution ADCs. The internal VOCM control simplifies single-supply filter designs. Designers should evaluate stability with capacitive loads above 20 pF by adding a small series output resistor (10-50 Ω) to preserve phase margin.
Recommended
Transducer Signal Chain Interface
The THS4551IRGTR is widely used to interface differential-output transducers (such as piezoelectric sensors, MEMS microphones, and current-sense transformers) to single-ended or differential-input ADCs. Its low noise floor preserves transducer dynamic range, while the differential output rejects common-mode noise picked up on long sensor cables. The 2.7 V to 5.4 V single-supply range supports battery-powered industrial sensor nodes. Designers should AC-couple the input when transducer common-mode voltage differs from the FDA supply mid-rail, and add input protection for over-voltage transients.
Recommended
Single-Ended to Differential Conversion
The THS4551IRGTR simplifies single-ended-to-differential signal conversion required when driving modern differential-input ADCs from a single-ended source such as a sensor output or DAC. By tying one input to VOCM, designers create a true differential output from a single-ended signal, doubling the effective dynamic range into the ADC. The wideband VOCM control maintains balance across frequency, critical for preserving ADC SFDR. In test-and-measurement equipment, this FDA eliminates the need for a balun or impedance-matching network.
Recommended
Medical Imaging Front-End
In medical ultrasound and patient monitoring equipment, the THS4551IRGTR drives high-speed ADCs that digitize low-amplitude signals from piezoelectric transducers. Its 1.5 nV/√Hz noise floor preserves the dynamic range needed for diagnostic-quality imaging, while its 150 MHz bandwidth handles multi-MHz transducer frequencies. The exposed thermal pad aids heat dissipation in densely-packed multi-channel beamformer boards. Designers should use low-ESR ceramic bypass capacitors and ensure the PCB ground plane is unbroken beneath the FDA for optimal noise rejection.
Recommended
Industrial Process Control Analog Input Module
The THS4551IRGTR is suited for industrial analog input modules that digitize 4-20 mA or 0-10 V process signals with high noise immunity. Its differential output rejects common-mode ground noise typical in factory-floor installations with long cable runs. The wide 2.7 V to 5.4 V supply range supports both 3.3 V and 5 V PLC architectures. When paired with a 24-bit delta-sigma ADC, the FDA maintains linearity needed for precise process control loops. Designers should add input TVS protection and EMC filtering for IEC 61000-4 compliance in harsh industrial environments.
Recommended
Recommended Products Summary
Engineering reference data for THS4551IRGTR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | THS4551IRGTT | THS4551IRGTRG4 | THS4513RGTR | ADA4945-1 | LTC6363 |
|---|---|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Analog Devices | Analog Devices |
| Package | VQFN-16 (RGT) 3x3 mm | VQFN-16 (RGT) - same | VQFN-16 (RGT) - same | VQFN-16 (RGT) - same | VQFN-16 (LFCSP) - equivalent footprint | VQFN-16 (LFCSP) - equivalent footprint |
| -3 dB Bandwidth | 150 MHz (G = 1) | 150 MHz | 150 MHz | ~2000 MHz | 145 MHz | 145 MHz |
| Input Voltage Noise Density | 1.5 nV/√Hz | 1.5 nV/√Hz | 1.5 nV/√Hz | 6 nV/√Hz | 4.8 nV/√Hz | 2.8 nV/√Hz |
| Slew Rate | 50 V/µs | 50 V/µs | 50 V/µs | 900 V/µs | 45 V/µs | 35 V/µs |
| Supply Voltage Range | 2.7 V to 5.4 V | 2.7 V to 5.4 V | 2.7 V to 5.4 V | 3.0 V to 5.5 V | 3.0 V to 10 V | 2.8 V to 11 V |
| Output Common-Mode Control | Yes (VOCM pin) | Yes (VOCM pin) | Yes (VOCM pin) | Yes (VOCM pin) | Yes (VOCM pin) | Yes (VOCM pin) |
Key Differentiators
- Lowest input voltage noise density in its class (vs ADA4945-1)
- Wider bandwidth than closest cross-brand competitor (vs LTC6363)
- Wider supply range than TI THS4513 (vs THS4513RGTR)
Design Notes
Place 0.1 µF ceramic bypass capacitors as close as possible to the VS+ and VS- supply pins (within 2 mm). Add a 10 µF bulk tantalum or ceramic capacitor on each supply rail to filter low-frequency noise from upstream LDOs. Keep the exposed thermal pad soldered to a continuous ground plane for both electrical performance and thermal dissipation. Avoid routing digital signals beneath the FDA to prevent digital noise coupling into the analog signal path.
Do not exceed the 5.4 V absolute maximum supply rating - even brief transients from inductive kickback can damage the device. The VOCM pin must be driven by a low-impedance source (the ADC's common-mode reference or a buffered divider) - leaving it floating causes output common-mode drift. Match feedback resistor values within 0.1% to maintain common-mode rejection above 80 dB. Capacitive loads above 20 pF may cause peaking - add a 10-50 Ω series output resistor if needed.
The VQFN-16 (RGT) package has a thermal resistance of approximately 45 C/W (theta_JA) on a standard JEDEC 4-layer board with the exposed pad soldered. At 5 V supply and 2 VPP output into 200 Ω differential load, the device dissipates roughly 130 mW, yielding a 6 C junction temperature rise above ambient - well within the 125 C limit. For multi-FDA layouts in dense beamformer boards, ensure adequate copper pour on the thermal pad to keep junction rise below 20 C.
Differential PCB trace routing should maintain constant 100 Ω differential impedance with matched trace lengths within 0.5 mm to preserve common-mode rejection at high frequencies. Use a continuous ground reference plane beneath the differential traces to control impedance and minimize crosstalk. For ADC driver applications, place the FDA within 10 mm of the ADC input pins to minimize parasitic loading. Add a 100 Ω differential termination resistor at the ADC input if the trace length exceeds 25 mm to absorb reflections.
Compliance Information
RoHS compliant per TI product page. Industrial-grade (-40C to +125C) - not AEC-Q100 qualified; consult TI for automotive-grade variants. Halogen-free status not provided in the verified web data.
