BUF634U-VB - 250mA High-Speed Buffer, 180MHz SOIC-8 | Texas Instruments
Référence : BUF634U-VB ✓ Actif| Qté | Prix unitaire | Total |
|---|---|---|
| 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 |
BUF634U-VB Présentation
A buffer amplifier is a unity-gain stage whose purpose is to isolate a high-impedance source from a low-impedance load while passing the signal without amplification. In the signal-chain hierarchy, the buffer sits between a precision op amp and its load, providing current gain and drive capability that the op amp alone cannot deliver. High-speed buffers like the BUF634 family are essential building blocks in analog front-end design.
Key features include a continuous output current of 250 mA, a 2000 V/us slew rate for fast large-signal edges, and a bandwidth that is pin-selectable between 30 MHz, 130 MHz, and 180 MHz, allowing designers to trade bandwidth against quiescent current - only 1.5 mA at the 30 MHz setting. Internal current limiting and thermal shutdown protection guard against fault conditions.
Architecturally, the BUF634 is an open-loop bipolar buffer with no internal feedback compensation, which means it adds essentially no phase shift when placed inside an op amp feedback loop. This lets it boost op amp output current, eliminate thermal-feedback-induced errors, and improve capacitive-load drive without degrading loop stability.
Typical applications include buffering the output of precision op amps such as the OPA-series in test and measurement instrumentation, driving ADC input or reference networks, and serving as a current booster inside audio or video line-driver loops.
Design consideration: the bandwidth pin (BW) sets quiescent current, so choose the lowest bandwidth setting that meets signal requirements to minimize power dissipation and thermal rise in the SOIC-8 package.
This page synthesizes verified distributor pricing, drop-in alternative analysis, and practical design guidance not found in the manufacturer datasheet.
Alternatives de remplacement direct pour BUF634U-VB — même boîtier, compatible broche à broche. Les références à boîtier différent nécessitant une retouche du PCB sont exclues.
Variantes de cette série
Modèles de la même série directement compatibles avec BUF634U-VB (même facteur de forme et même empreinte) — différant par Package, Mounting Type, Quiescent Current, Function, Slew Rate.
Outil de comparaison rapide — sélectionnez des références alternatives pour une comparaison côte à côte :
BUF634AIDR
✅ Remplacement direct✓ En stock
$1.56 / unité
Voir la fiche technique →BUF634AIDDAR
✅ Remplacement direct✓ En stock
$2.15 / unité
Voir la fiche technique →BUF634UE4
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
BUF634U-VB Valeurs maximales et caractéristiques électriques
| Fonction | 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 |
| Courant de repos | 1.5 mA (30 MHz BW setting) |
| Supply Voltage Range | +/-2.25 V to +/-18 V |
| Protection | Internal current limit, thermal shutdown |
| Boîtier | 8-SOIC |
| Type de montage | Surface Mount |
| Bandwidth Selection Pin | Yes (BW pin) |
| Amplifier Type | Buffer |
| Architecture | Bipolar, open-loop |
| Recommended Replacement | BUF634A (upgraded version) |
| Statut RoHS | unknown |
Guide de configuration des broches du BUF634U-VB 8-soic
Configuration des broches du BUF634U-VB (boîtier 8-soic). Ce composant analogique comporte des broches d'entrée, de sortie et d'alimentation. Consultez la fiche technique du fabricant pour les configurations des broches d'annulation d'offset, de compensation et d'activation. Idéal pour le conditionnement de signaux et les circuits amplificateurs.
Aucune donnée de brochage détaillée disponible pour BUF634U-VB.
Consultez la fiche technique pour la configuration complète des broches.
Applications typiques
BUF634U-VB convient pour 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.
Recommandé
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.
Recommandé
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.
Recommandé
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.
Recommandé
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.
Recommandé
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.
Recommandé
Récapitulatif des produits recommandés
Données de référence d'ingénierie pour BUF634U-VB — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit | 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) |
| Positioning | Original BUF634 generation | Recommended drop-in upgrade | Recommended drop-in upgrade | Same-die enhanced variant |
Principaux différenciateurs
- 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)
Notes de conception
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.
Informations de conformité
Compliance status not stated in provided verified web data; verify on TI.com product page.
