BUF634AIDDAR - 210MHz 250mA High-Speed Buffer | Texas Instruments
MPN: BUF634AIDDAR β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.45 | $3.45 |
| 10 | $3.1 | $31.00 |
| 100 | $2.72 | $272.00 |
| 500 | $2.42 | $1,210.00 |
| 1,000 | $2.15 | $2,150.00 |
Drop-in alternatives for BUF634AIDDAR β same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
BUF634U
β Drop-Inβ In Stock
$11.95 / Unit
View Datasheet βBUF634AIDDA
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
OPA633
β Drop-Inπ Reference alternative (not in catalog)
BUF634AIDDAR Maximum Ratings & Electrical Characteristics
| Bandwidth | 35 MHz to 210 MHz (pin-selected) |
| Output Current | 250 mA |
| Slew Rate | 3750 V/us |
| Quiescent Current | 1.5 mA (35 MHz BW setting) |
| Supply Voltage Range | +/-2.25 V to +/-18 V |
| Total Supply Voltage | 4.5 V to 36 V |
| Architecture | Open-loop buffer, unity gain |
| Number of Channels | 1 |
| Protection Features | Internal output current limit, thermal shutdown |
| Package | SOIC-8 PowerPad (DDA) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| Packaging | Tape & Reel (R suffix) |
| Configuration | Standalone open-loop driver or inside op amp feedback loop |
BUF634AIDDAR Pin Configuration
| Pin 1 | IN β Buffer input |
| Pin 2 | NC β Not connected (per datasheet) |
| Pin 3 | NC β Not connected (per datasheet) |
| Pin 4 | V- β Negative supply |
| Pin 5 | BW β Bandwidth select; external resistor to V- sets 35-210 MHz bandwidth |
| Pin 6 | OUT β Buffer output |
| Pin 7 | OUT β Buffer output (paralleled) |
| Pin 8 | V+ β Positive supply |
| Pin Pad | PowerPad β Exposed thermal pad; solder to ground plane for heat dissipation |
Safe Operating Area (SOA) & Thermal Characteristics
No official SOA curve available for this component. Always operate within absolute maximum ratings specified in the datasheet. Ensure adequate cooling and derate as needed.
Typical Applications
BUF634AIDDAR is suitable for 6 applications: High-Fidelity Audio Headphone Driver, Precision Instrumentation Signal Buffering, ADC Input and Reference Driving, Coaxial Cable and Line Driving, Industrial PLC Analog Output Stages, Portable and Size-Constrained High-Speed Buffers.
High-Fidelity Audio Headphone Driver
The BUF634AIDDAR fits headphone amplifier output stages because it combines 250 mA output current with high-fidelity open-loop buffering, easily driving low-impedance 16-32 ohm headphones while maintaining bandwidth far above the audible range. In a typical topology, an op amp provides voltage gain and the BUF634A is placed inside the feedback loop to supply load current without degrading the op amp's distortion performance. Setting the BW pin resistor to the 35 MHz mode cuts quiescent current to 1.5 mA per channel, valuable for portable headphone amplifiers running from batteries. The wide +/-18 V supply range also supports high-voltage headphone and line-driving stages. The SOIC PowerPad package dissipates heat from sustained low-impedance loads when soldered to a copper pour.
Recommended
Precision Instrumentation Signal Buffering
In precision instrumentation front ends, the BUF634AIDDAR buffers high-impedance sensor or transducer outputs before they reach cables, filters, or converters. Its unity-gain open-loop architecture adds no gain error and its wide 35-210 MHz bandwidth keeps phase shift negligible at instrumentation signal frequencies, while the 4.5 V to 36 V supply range accommodates industrial signal levels. Used after instrumentation amplifiers such as the INA series, it isolates the sensitive amplifier output from capacitive cable loading that would otherwise cause instability. The 250 mA drive capability also allows direct excitation of bridges and actuators. Because quiescent current is only 1.5 mA in the low-bandwidth setting, multi-channel instrumentation racks keep thermal budget and power consumption low even with many buffer channels populated.
Recommended
ADC Input and Reference Driving
High-speed ADCs require input drivers that settle quickly and source dynamic charge-injection currents; the BUF634AIDDAR addresses this with a 3750 V/us slew rate and 210 MHz maximum bandwidth, settling fast enough for megasample-class converters. Placed directly before the ADC input, the buffer provides low output impedance that absorbs the switching charge kickback of sample-and-hold stages, preserving signal fidelity that an ordinary op amp output stage might not sustain at 250 mA dynamic peaks. The internal current limit protects the converter input during fault conditions, and thermal shutdown adds a further safety layer in dense data-acquisition boards. Designers should verify settling time against the ADC aperture budget and reserve the BW pin resistor value accordingly in the design.
Recommended
Coaxial Cable and Line Driving
Transmission lines and backplane cables present low characteristic impedances (typically 50-100 ohm) that demand substantial drive current; the BUF634AIDDAR's 250 mA capability supports double-terminated 50-ohm lines with healthy voltage swing at supplies up to +/-18 V. Its open-loop buffer topology contributes minimal phase shift, and the 35-210 MHz bandwidth covers video, timing-reference, and instrumentation pulses with clean edges thanks to the 3750 V/us slew rate. In a line-driver configuration the buffer sits at the end of an op amp gain stage or directly after a source, with a series or back-termination resistor setting the impedance match. The PowerPad package conducts heat into the PCB during continuous line drive, so a ground pour beneath the part is recommended.
Recommended
Industrial PLC Analog Output Stages
Programmable logic controller analog output modules must drive long field wiring, actuator inputs, and 4-20 mA loop interfaces from limited board space. The BUF634AIDDAR suits these outputs because its 4.5 V to 36 V total supply range spans common industrial rails, and its 250 mA output drives heavy loads or parallel channels without additional power stages. Operating the buffer inside the feedback loop of a precision op amp preserves output accuracy while the buffer contributes only current gain. The internal output current limit and thermal shutdown provide robust protection against wiring faults commonly encountered on factory floors. With 1.5 mA quiescent current in the 35 MHz setting, module thermal design remains simple even in densely populated multi-channel output cards.
Recommended
Portable and Size-Constrained High-Speed Buffers
Battery-powered and handheld instruments benefit from the BUF634AIDDAR's combination of low standby power and burst drive capability. Configured through the BW pin for 35 MHz, the buffer draws only 1.5 mA quiescent current, yet retains the ability to deliver 250 mA transient output for loads such as ultrasonic transducers, displays, and RF prescaler inputs. The wide +/-2.25 V minimum supply allows operation from low-voltage rails typical of portable designs, while the 8-pin SOIC PowerPad footprint remains hand-assemblable and reworkable, unlike chip-scale alternatives. Designers in truly space-constrained products may consider the same die in the 3.0 mm x 3.0 mm DRB (VSON) package (BUF634AIDRBR), trading footprint compatibility for board area savings in new layouts.
Recommended
Recommended Products Summary
Engineering reference data for BUF634AIDDAR β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | BUF634U | BUF634AIDDA | OPA633 |
|---|---|---|---|---|
| Package | SOIC-8 PowerPad (DDA) | SOIC-8 | SOIC-8 PowerPad (DDA) | SOIC-8 |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Bandwidth | 35-210 MHz (pin-selected) | Up to 180 MHz class (previous generation) | 35-210 MHz | [DATA_NEEDED] |
| Output Current | 250 mA | 250 mA | 250 mA | [DATA_NEEDED] |
| Slew Rate | 3750 V/us | 2000 V/us class (previous generation) | 3750 V/us | [DATA_NEEDED] |
| Supply Range (total) | 4.5 V to 36 V | 4.5 V to 36 V | 4.5 V to 36 V | [DATA_NEEDED] |
| Quiescent Current (low BW) | 1.5 mA | [DATA_NEEDED] | 1.5 mA | [DATA_NEEDED] |
| Protection | Current limit + thermal shutdown | Current limit + thermal shutdown | Current limit + thermal shutdown | [DATA_NEEDED] |
| Lifecycle | Active (recommended upgrade of BUF634) | Legacy; TI recommends BUF634A as drop-in upgrade | Active | [DATA_NEEDED] |
Key Differentiators
- Pin-selected bandwidth lets one design serve three power/speed points (vs BUF634U)
- High-fidelity open-loop buffer rated for 250 mA (vs OPA633)
- Integrated protection reduces external circuitry (vs BUF634U)
Design Notes
The SOIC-8 PowerPad (DDA) package exists specifically to handle the heat from 250 mA output drive. Solder the exposed pad to a minimum 1 square inch solid copper ground pour with thermal vias; without the pad connection, sustained high-current operation may trigger thermal shutdown. Estimated: at +/-15 V supplies driving a 50-ohm load at 5 V peak output, device dissipation is on the order of 1-2 W, so verify junction temperature against your board's actual theta_JA with the TI datasheet thermal model before committing to layout.
Place a 0.1 uF ceramic decoupling capacitor within 2-3 mm of each supply pin (V+ pin 8, V- pin 4), plus bulk 4.7-10 uF capacitance nearby. Keep the BW resistor trace from pin 5 to V- short and away from the high-current OUT traces to prevent bandwidth modulation. Route the input (pin 1) away from the output pins 6-7 to avoid parasitic feedback loops at 210 MHz operation.
Do not leave the BW pin floating; the bandwidth-setting resistor between BW (pin 5) and V- is required and its value determines both bandwidth and quiescent current. When using the buffer inside an op amp feedback loop, check loop stability with the buffer's open-loop output impedance - a small series resistor or output RC snubber often resolves ringing with capacitive loads. Never exceed the 36 V total supply rating, and observe power-up sequencing on dual rails.
At the 210 MHz bandwidth setting, treat the BUF634A as an RF component: use a solid ground plane, minimize stub lengths on the output, and source-terminate long coaxial or cable runs (typically 33-50 ohm) to absorb reflections. For high-fidelity audio, choose the 35 MHz setting, which limits open-loop output-stage gain and reduces distortion from the buffer's output transistors while cutting quiescent current to 1.5 mA.
Compliance Information
RoHS compliant and lead-free per TI ordering data; AEC-Q100 qualification not indicated in provided data for this commercial/industrial amplifier.
