BUF634U - 250mA, 180MHz High-Speed Buffer | Texas Instruments
MPN: BUF634U ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $15.55 | $15.55 |
| 10 | $14.6 | $146.00 |
| 100 | $13.75 | $1,375.00 |
| 500 | $12.9 | $6,450.00 |
| 1,000 | $11.95 | $11,950.00 |
Drop-in alternatives for BUF634U — 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 Maximum Ratings & Electrical Characteristics
| Amplifier Type | Open-Loop Buffer (unity gain) |
| Number of Channels | 1 |
| Output Current | 250 mA |
| Slew Rate | 2000 V/us |
| Bandwidth | 180 MHz (full) / 30 MHz (low power, pin-selected) |
| Quiescent Current | 1.5 mA (30 MHz BW mode) |
| Supply Voltage Range | +/-2.25 V to +/-18 V (4.5 V to 36 V total) |
| Voltage Gain | Unity (buffer) |
| Protection Features | Internal current limit, thermal shutdown |
| Bandwidth Selection | Pin-selectable (BW pin) |
| Package | 8-SOIC (0.154 in, 3.90 mm width) |
| Mounting Type | Surface Mount |
| Polarity | Single / Dual Supply |
| Product Status | Not recommended for new designs (NRND); BUF634A recommended |
| Datasheet Revision | BUF634 datasheet (Rev. C) |
BUF634U 8-soic (0.154 in, 3.90 mm width) Pin Configuration Guide
Complete pinout information for BUF634U (8-soic (0.154 in, 3.90 mm width) 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.
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 is suitable for 6 applications: Op-Amp Output Current Boosting, Audio Headphone Amplifiers, Video and Communications Line Drivers, Capacitive Load Driving in Data Acquisition, Industrial Instrumentation and Control, Portable and Battery-Powered Equipment.
Op-Amp Output Current Boosting
The BUF634U's defining application is placement inside an op-amp's feedback loop to raise output current from tens of milliamps to 250 mA while preserving the op-amp's precision. According to the TI datasheet, this technique also eliminates thermal feedback to the op-amp input stage and improves capacitive load drive. Because the buffer runs open-loop inside the loop, the composite remains unity-gain stable, and the 2000 V/us slew rate ensures the buffer never limits the op-amp's transient response. The wide +/-18 V supply range covers standard +/-15 V analog rails, making it a direct fit for instrumentation and control loops that must drive cables, actuators, or low-impedance sensor loads.
Recommended
Audio Headphone Amplifiers
In headphone amplifiers, the BUF634U drives low-impedance headphones directly with its 250 mA output capability, while the pin-selected 30 MHz low-power mode draws only 1.5 mA quiescent current for portable, battery-powered designs. Community designs such as the Head-Fi Pimeta amplifier established the BUF634 as a de facto standard output stage. Placed inside the feedback loop of a low-noise op-amp, the composite stage achieves low output impedance and low distortion across the audio band, while the 180 MHz full-bandwidth mode removes any dynamic-range concern for demanding transients and wideband sources.
Recommended
Video and Communications Line Drivers
The 2000 V/us slew rate and 180 MHz bandwidth allow the BUF634U to preserve fast video edges and drive 75-ohm coaxial loads with clean transients. In communications test equipment and video distribution, the buffer isolates sensitive sources from cable capacitance; the datasheet specifically cites improved capacitive load drive when the part is looped with an op-amp. The wide supply range supports +/-5 V to +/-15 V video rails, and internal current limit protects the output against shorted cable faults, an important robustness feature in rack-mounted distribution and broadcast environments.
Recommended
Capacitive Load Driving in Data Acquisition
Sample-and-hold nodes, ADC input networks, and long shielded cables present significant capacitive loads that destabilize ordinary op-amps. The TI datasheet recommends the BUF634 explicitly to improve capacitive load drive, and its open-loop output stage remains stable where closed-loop amplifiers would oscillate. With 250 mA peak current, the buffer rapidly charges and discharges large capacitances, minimizing acquisition settling error. Designers should allocate headroom for the buffer's dropout and use the 30 MHz mode when settling time permits, halving quiescent power in multichannel acquisition systems.
Recommended
Industrial Instrumentation and Control
Industrial loops often demand driving heavy loads - solenoid drivers, long 4-20 mA wiring interfaces, and piezo actuators - from +/-15 V analog rails. The BUF634U's +/-18 V maximum supply, 250 mA current limit, and thermal shutdown protection give robust fault tolerance in electrically noisy factory environments. Buffered precision references and setpoint signals stay accurate because the buffer's open-loop topology adds no gain error beyond its small output resistance. Integrators typically pair it with precision op-amps and instrumentation amplifiers to form high-current, high-accuracy analog output channels for process control.
Recommended
Portable and Battery-Powered Equipment
In portable test instruments, battery-powered audio gear, and handheld communicators, the BUF634U's 1.5 mA quiescent current in the 30 MHz bandwidth mode extends battery life without sacrificing the 250 mA peak output needed for load transients. The +/-2.25 V minimum supply allows operation from low-voltage single-cell stacks, and thermal shutdown plus current limiting protect against accidental short circuits in field conditions. The pin-selected bandwidth lets firmware-free hardware designs trade speed for power simply by wiring the BW pin, a convenient one-component power-management lever in battery-constrained products.
Recommended
Recommended Products Summary
Engineering reference data for BUF634U — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | BUF634AIDR | BUF634AIDDAR | BUF634UE4 |
|---|---|---|---|---|
| Package | 8-SOIC (3.90 mm width) | 8-SOIC (3.90 mm width) - same | 8-SOIC (3.90 mm width) - same | 8-SOIC (3.90 mm width) - 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 | 2000 V/us | 2000 V/us | 2000 V/us |
| Bandwidth | 180 MHz / 30 MHz (pin-selectable) | 180 MHz / 30 MHz (pin-selectable) | 180 MHz / 30 MHz (pin-selectable) | 180 MHz / 30 MHz (pin-selectable) |
| Supply Voltage Range | +/-2.25 V to +/-18 V | +/-2.25 V to +/-18 V | +/-2.25 V to +/-18 V | +/-2.25 V to +/-18 V |
| Lifecycle Status | NRND (not recommended for new designs) | Active - TI recommended upgrade | Active | NRND / lead-free variant |
| Quiescent Current (30 MHz mode) | 1.5 mA | 1.5 mA | 1.5 mA | 1.5 mA |
| Price (qty 1, approx) | $15.55 (as of 2026-09-13) | [DATA_NEEDED] | [DATA_NEEDED] | [DATA_NEEDED] |
Key Differentiators
- Active lifecycle support (vs BUF634UE4)
- TI-verified functional equivalence (vs BUF634U)
- Pin-selected bandwidth/power trade (vs BUF634AIDDAR)
Design Notes
The BW (bandwidth-select) pin must be tied per the datasheet connection scheme: one configuration yields the 180 MHz full-bandwidth mode, the other the 30 MHz low-power mode (1.5 mA quiescent). Leaving it floating produces unpredictable frequency response and possible instability. Decide at schematic capture time which mode the application needs and document it on the BOM, since a miswired BW pin is the most common bring-up failure reported on BUF634 designs.
Estimated: at a 250 mA continuous output into a low-impedance load with a 12 V headroom (e.g., +/-15 V rails driving a resistive load), internal dissipation can reach several watts. The 8-SOIC package offers limited theta_JA, so verify junction temperature using the SOIC-8 thermal resistance from the datasheet. TI added thermal shutdown protection, but relying on it as a routine operating mode degrades reliability; reduce duty cycle or increase copper pour on the SOIC-8 thermal lands to manage sustained high-current loads.
Place a 0.1 uF ceramic decoupling capacitor at each supply pin, within a few millimeters of the SOIC-8 pads, plus bulk capacitance (10 uF) nearby. Because the BUF634 delivers 250 mA load steps, supply leads with high inductance cause rail bounce and ringing at the output; use short, wide traces or ground-plane vias for the ground return. When looping the buffer with an op-amp, keep the feedback path away from the buffer's high di/dt output node to prevent injected transients.
Compliance Information
Compliance status was not included in the verified web data. The BUF634UE4 variant is TI's Pb-free (lead-free) designation for RoHS-driven designs; confirm current RoHS/REACH status on TI.com product page before ordering.
