BUF634U-VB - 250mA High-Speed Buffer, 180MHz SOIC-8 | Texas Instruments
MPN: BUF634U-VB ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $24.52 | $24.52 |
| 10 | $23.3 | $233.00 |
| 100 | $22.07 | $2,207.00 |
| 500 | $20.85 | $10,425.00 |
| 1,000 | $19.62 | $19,620.00 |
Drop-in alternatives for BUF634U-VB — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
BUF634AIDR
✅ Drop-In✓ In Stock
$1.56 / Unit
View Datasheet →BUF634AIDDAR
✅ Drop-In✓ In Stock
$2.15 / Unit
View Datasheet →BUF634UE4
✅ Drop-In📋 Reference alternative (not in catalog)
BUF634U-VB Maximum Ratings & Electrical Characteristics
| Function | Unity-gain open-loop buffer |
| Number of Channels | 1 |
| Output Current | 250 mA |
| Slew Rate | 2000 V/us |
| Bandwidth (pin-selected) | 30 MHz / 130 MHz / 180 MHz |
| Quiescent Current | 1.5 mA (30 MHz BW setting) |
| Supply Voltage Range | +/-2.25 V to +/-18 V |
| Protection | Internal current limit, thermal shutdown |
| Package | 8-SOIC |
| Mounting Type | Surface Mount |
| Bandwidth Selection Pin | Yes (BW pin) |
| Amplifier Type | Buffer |
| Architecture | Bipolar, open-loop |
| Recommended Replacement | BUF634A (upgraded version) |
| RoHS Status | unknown |
BUF634U-VB 8-soic Pin Configuration Guide
Complete pinout information for BUF634U-VB (8-soic package). This analog component features input, output, and power supply pins. Refer to the manufacturer datasheet for offset null, compensation, and enable pin configurations. Ideal for signal conditioning and amplifier circuits.
No detailed pinout data available for BUF634U-VB.
Refer to the datasheet for full pin configuration.
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
BUF634U-VB is suitable for 6 applications: Op Amp Output Current Boosting, Test and Measurement Instrumentation, Audio Line Driver and Headphone Output, Capacitive Load Drive / ADC Input Buffering, Video and Wideband Signal Distribution, Industrial Signal Conditioning and PLC I/O.
Op Amp Output Current Boosting
The BUF634U-VB is designed to be placed directly inside an op amp feedback loop to multiply available output current by more than an order of magnitude - from typical op amp limits of 20-50 mA up to the buffer's 250 mA. Because the buffer is open-loop and essentially unity-gain, it adds negligible phase shift and therefore does not destabilize the host amplifier's feedback loop. The 2000 V/us slew rate ensures the buffer never limits large-signal performance even when driving fast edges with a precision amplifier such as an OPA-series device ahead of it. Performance consideration: at high continuous output current, power dissipation in the 8-SOIC package must be budgeted, and the thermal shutdown threshold provides a fault backstop rather than a normal operating mode.
Recommended
Test and Measurement Instrumentation
Bench instruments, data-acquisition front ends, and arbitrary waveform generators require output stages that drive cables and variable loads without degrading signal fidelity. The BUF634U-VB fits this role with 250 mA drive, a 180 MHz small-signal bandwidth, and a 2000 V/us slew rate that comfortably covers fast pulse edges. Placing the buffer inside the feedback loop of the instrument's output amplifier eliminates thermal-feedback-induced errors because the high-current output stage heat no longer modulates the precision input stage of the amplifier. The pin-selectable 30 MHz mode at 1.5 mA quiescent current is useful in portable instruments where battery life matters. Design consideration: match the bandwidth setting to the instrument's specified analog bandwidth so the buffer does not contribute peaking.
Recommended
Audio Line Driver and Headphone Output
Audio line outputs and headphone jacks demand low distortion into loads ranging from 600 ohm lines down to 32 ohm headphones. The BUF634U-VB provides 250 mA of peak output current, enough to drive low-impedance headphones directly, while its bandwidth far exceeds the 20 kHz audio band so it contributes essentially no phase shift or slew-induced distortion within the audio range. When wrapped inside an audio op amp feedback loop, the buffer isolates the amplifier's input stage from load-induced thermal modulation, improving distortion figures. For battery-operated headphone amplifiers, the 30 MHz / 1.5 mA quiescent mode minimizes standby drain. Trade-off: at higher bandwidth settings, quiescent current increases, so select the mode appropriate to the application's drive and bandwidth needs.
Recommended
Capacitive Load Drive / ADC Input Buffering
Driving the switched-capacitor sampling network of a successive-approximation or delta-sigma ADC is a classic buffer application. The ADC input presents transient charge demands that many op amps cannot settle, causing conversion errors. The BUF634U-VB supplies the instantaneous 250 mA charge kick required to settle the sampling capacitor quickly, while its high 180 MHz bandwidth supports fast settling to sub-LSB accuracy. Because the buffer can sit inside the driving amplifier's feedback loop, DC accuracy is set by the precision amplifier, not the buffer. The wide +/-18 V supply range also covers high-voltage analog input conditioning. Layout consideration: keep the buffer-to-ADC trace short and provide a solid low-impedance return to minimize ringing during charge injection events.
Recommended
Video and Wideband Signal Distribution
Video distribution and wideband signal chains need buffers that preserve fast edges over 75 ohm coaxial loads. The BUF634U-VB's 2000 V/us slew rate and 180 MHz pin-selected bandwidth support standard- and high-definition video timing without slew limiting, while the bipolar open-loop architecture maintains consistent delay across signal swings. The wide +/-2.25 V to +/-18 V supply range accommodates conventional +/-5 V video rails and higher-swing industrial video formats. Used inside the driver amplifier's loop, the buffer eliminates cable-load-induced distortion at the amplifier's output stage. Performance consideration: for AC-coupled video, ensure the buffer's input bias path is provided, and select the 130 MHz or 180 MHz bandwidth mode to avoid group-delay variation near the band edge.
Recommended
Industrial Signal Conditioning and PLC I/O
Industrial analog output modules in PLCs and process-control systems must drive long cables, resistive loads, and sometimes capacitive filter networks with robust fault tolerance. The BUF634U-VB's 250 mA output, internal current limiting, and thermal shutdown provide the drive and protection margins expected in industrial environments, while the +/-18 V maximum supply range covers standard +/-15 V analog backplanes. Its open-loop buffer topology allows a precision control amplifier to close the loop and set accuracy, with the buffer providing muscle. In noisy industrial settings, the buffer's wide bandwidth should be paired with appropriate output filtering, using the 30 MHz mode where full bandwidth is unnecessary to reduce sensitivity to high-frequency pickup and lower power consumption.
Recommended
Recommended Products Summary
Engineering reference data for BUF634U-VB — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | BUF634AIDR | BUF634AIDDAR | BUF634UE4 |
|---|---|---|---|---|
| Package | 8-SOIC | 8-SOIC - same | 8-SOIC - same | 8-SOIC - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Output Current | 250 mA | 250 mA | 250 mA | 250 mA |
| Slew Rate | 2000 V/us | better than 2000 V/us (upgrade) | better than 2000 V/us (upgrade) | 2000 V/us |
| Bandwidth | 30/130/180 MHz (pin-selected) | higher than BUF634 (upgrade) | higher than BUF634 (upgrade) | 30/130/180 MHz (pin-selected) |
| Quiescent Current | 1.5 mA (30 MHz mode) | [DATA_NEEDED] | [DATA_NEEDED] | 1.5 mA (30 MHz mode) |
| Supply Range | +/-2.25 V to +/-18 V | [DATA_NEEDED] | [DATA_NEEDED] | +/-2.25 V to +/-18 V |
| Positioning | Original BUF634 generation | Recommended drop-in upgrade | Recommended drop-in upgrade | Same-die enhanced variant |
Key Differentiators
- Pin-selectable bandwidth trades speed vs power (vs BUF634AIDR)
- Open-loop topology for in-loop stability (vs BUF634AIDR)
- Proven incumbent with second-source socket coverage (vs BUF634AIDR)
Design Notes
Estimate power dissipation before layout: P = (VS+ - VS-) * IQ + (VO+ - VO-) * IOUT. For example, with +/-15 V supplies and 100 mA continuous into a grounded-referenced load at 5 V output, device dissipation is approximately (10 V * 0.1 A) + 30 mV-class quiescent contribution - about 1 W in the 8-SOIC, which demands attention to theta_JA. Use the 30 MHz bandwidth mode (1.5 mA quiescent) whenever the application does not need 180 MHz to cut static dissipation. The internal thermal shutdown protects against faults but is not a substitute for thermal design.
Provide a solid, low-inductance ground and decouple both supplies with 0.1 uF ceramic capacitors placed within a few millimeters of the supply pins. Because the BUF634U can deliver 250 mA transient currents, use short, wide traces from the output to the load and place any series isolation resistor (typically a few ohms for pure capacitive loads) close to the buffer output. When the buffer sits inside an op amp feedback loop, keep the loop-return trace away from the high-current output path to avoid ground-loop error injection.
The BW (bandwidth-select) pin determines quiescent current and bandwidth: tie it to V- for 180 MHz, leave open for 130 MHz, or use a resistor for the 30 MHz low-power mode. Omitting the resistor in low-power designs leaves the part in a high-bandwidth, higher-current mode. Do not treat the 180 MHz figure as usable closed-loop bandwidth for precision settling - it is the buffer's small-signal characteristic. When replacing with BUF634A, verify the bandwidth-pin behavior against the newer datasheet even though the part is pin-to-pin.
Compliance Information
Compliance status not stated in provided verified web data; verify on TI.com product page.
