Texas Instruments

BUF634FKTTT - 250mA 180MHz High-Speed Buffer | TI

MPN: BUF634FKTTT ✓ Active
In Stock Ships in 1-3 business days
+/-2.25 V to +/-18 V (4.5 V to 36 V total) Vdss 250 mA Id TO-263 (DDPAK / KTT), 5+tab pins Package
From $2.87 USD / Unit
MOQ: 1 |
Price updated: 2026-09-12
Volume Pricing
Qty Unit Price Extended
1 $4.62 $4.62
10 $4.16 $41.60
100 $3.7 $370.00
500 $3.24 $1,620.00
1,000 $2.87 $2,870.00
ℹ️ All prices are in USD

Drop-in alternatives for BUF634FKTTT — 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:

BUF634AKTTT

✅ Drop-In ⚠️ 参数待验证
📦 TO-263 (DDPAK / KTT)
same 250mA/180MHz die family with upgraded performance per TI; pin-to-pin drop-in per TI product page

📋 Reference alternative (not in catalog)

BUF634AIDDAR

✅ Drop-In
Texas Instruments
📦 SOIC-8 (D)
35 MHz to 210 MHz (pin-selected) · 250 mA · 3750 V/us · 1.5 mA (35 MHz BW setting) · +/-2.25 V to +/-18 V · 4.5 V to 36 V · Open-loop buffer, unity gain · 1

✓ In Stock

$2.15 / Unit

View Datasheet →

BUF634AIDR

✅ Drop-In
Texas Instruments
📦 SOIC-8 (D)
High-speed open-loop buffer amplifier · 36 V · 250 mA · 35 MHz to 210 MHz (adjustable via BW pin) · External resistor between V- and BW pins · 1 · Push-Pull · 8-SOIC (0.154 in, 3.90 mm width)

✓ In Stock

$1.56 / Unit

View Datasheet →

BUF634FKTTT Maximum Ratings & Electrical Characteristics

Amplifier Type Unity-Gain Open-Loop Buffer
Number of Channels 1
Output Current 250 mA
Bandwidth 180 MHz
Slew Rate 2000 V/us
Supply Voltage Range +/-2.25 V to +/-18 V (4.5 V to 36 V total)
Operating Temperature -40C to +125C
Package TO-263 (DDPAK / KTT), 5+tab pins
Mounting Type Surface Mount
Bandwidth Select Pin Yes (BW pin)
Thermal Feedback Eliminated when used inside op amp feedback loop
Capacitive Load Drive Improved vs op amp alone (buffered output)
Supplier Device Package KTT

BUF634FKTTT ktt Pin Configuration Guide

Complete pinout information for BUF634FKTTT (ktt 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.

ktt package pinout diagram for BUF634FKTTT

No detailed pinout data available for BUF634FKTTT.

Refer to the datasheet for full pin configuration.

Safe Operating Area (SOA) & Thermal Characteristics

Safe Operating Area Chart Default safe operating area chart for BUF634FKTTT Drain-to-Source Voltage (Vds) Drain Current (Id)

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

BUF634FKTTT is suitable for 6 applications: Op Amp Output Current Boosting, Test and Measurement Front Ends, Capacitive Load and Cable Driving, Industrial Control Signal Output, Video and High-Speed Signal Distribution, Audio Line Output Drivers.

🔧

Op Amp Output Current Boosting

The primary application of the BUF634FKTTT is extending the output current of precision op amps from the typical tens of milliamperes up to 250 mA. Placed inside the op amp feedback loop, the buffer carries the load current while the op amp only supplies the buffer input, so the amplifier's internal output stage stays cool and thermal feedback - the dominant cause of offset drift - is eliminated. With 180 MHz bandwidth and 2000 V/us slew rate, the buffer adds no speed penalty to the host amplifier. The +/-2.25V to +/-18V supply range matches virtually all precision op amp rails, making integration a two-pin-series change in most designs.

🔬

Test and Measurement Front Ends

Bench instruments, data acquisition systems, and automated test equipment require output stages that combine precision with drive capability. The BUF634FKTTT's 250 mA output current drives low-impedance probes, coaxial cables, and stimulus loads, while its open-loop unity-gain topology introduces no gain error of its own - closed-loop accuracy is set entirely by the surrounding op amp. The 2000 V/us slew rate preserves fast pulse edges in stimulus generation, and the BW pin lets engineers trade standby current for bandwidth in battery-powered portable instruments. The TO-263 package handles the sustained dissipation typical of continuous test cycles.

📡

Capacitive Load and Cable Driving

Long coaxial cables, ADC input sampling networks, and reference bypass capacitance present capacitive loads that destabilize standalone op amps by adding a pole inside the loop. Buffering with the BUF634FKTTT isolates the op amp from the load capacitance: the op amp closes its loop around the buffer output, and the capacitive load pole is moved outside the loop-gain path. According to the TI datasheet, improved capacitive load drive is an explicitly intended function of this part. A small series output resistor is still recommended with very long cables to damp transmission-line reflections at the 180 MHz bandwidth edge.

🏭

Industrial Control Signal Output

Industrial controllers drive actuators, valve positioners, and process transmitters that often need more current than a precision op amp can supply. The BUF634FKTTT boosts controller outputs to 250 mA while the surrounding op amp maintains loop accuracy and thermal stability. Its -40C to +125C operating range meets industrial ambient requirements, and the 4.5V to 36V total supply span accommodates both 5V logic-referenced and 24V-backplane-referenced analog subsystems. The KTT DDPAK tab solders directly to a PCB copper area, providing passive cooling without a heatsink at moderate dissipation levels.

📺

Video and High-Speed Signal Distribution

With 180 MHz bandwidth and 2000 V/us slew rate, the BUF634FKTTT distributes wideband video, IF, and RF-envelope signals to multiple low-impedance loads without rate limiting. Because the buffer is open-loop, it adds no closed-loop phase shift, preserving phase margin of the surrounding amplifier. The dual-supply range of +/-2.25V to +/-18V supports AC-coupled video levels and bipolar modulation formats. For fan-out designs, one buffer per output leg prevents channel-to-channel crosstalk; the BW pin should be tied to V- for full-speed operation, accepting the higher quiescent current of the high-bandwidth mode.

🎧

Audio Line Output Drivers

In the low-bandwidth mode (BW pin open), the BUF634FKTTT reduces standby current while retaining enough bandwidth for professional audio, making it suitable for headphone and line-output stages driven by low-power precision op amps. The 250 mA capability drives low-impedance headphones and long balanced-line runs directly, while buffering inside the op amp loop keeps distortion and offset dominated by the precision amplifier, not the output stage. Wide +/-18V operation provides ample headroom for high-level balanced studio signals, and the TO-263 package dissipates output-stage heat through the PCB copper without additional thermal hardware.

What is the BUF634FKTTT and what are its key specifications?
The BUF634FKTTT is a Texas Instruments 250 mA high-speed unity-gain open-loop buffer in a 5-pin TO-263 (DDPAK/KTT) package. Key specifications include 180 MHz bandwidth, 2000 V/us slew rate, a supply range of +/-2.25V to +/-18V (4.5V to 36V total), and operation from -40C to +125C. According to the TI BUF634 datasheet, it is designed to operate inside op amp feedback loops to boost output current, eliminate thermal feedback, and improve capacitive load drive.
What is the difference between BUF634 and BUF634A?
The BUF634A is TI's upgraded, drop-in replacement for the original BUF634 with improved performance. According to TI's product page for the BUF634 family, TI explicitly positions BUF634A as a drop-in replacement with upgraded functionality. The original BUF634FKTTT remains in production, but TI recommends the BUF634A family for new designs; pinout and package options are compatible, so migration requires no PCB change.
Can I use BUF634FKTTT to increase the output current of an op amp?
Yes - this is the primary intended use. Place the BUF634FKTTT inside the feedback loop of an op amp: the op amp output drives the buffer input, and the loop is closed around the buffer output. This configuration boosts effective output current up to 250 mA, eliminates thermal feedback that degrades the op amp offset voltage, and improves capacitive load drive. According to the TI datasheet, this is the recommended application topology for the BUF634 family.
What is the purpose of the BW pin on the BUF634FKTTT?
The BW (bandwidth) pin selects between two operating modes of the BUF634FKTTT. Tying BW to the negative supply engages the full 180 MHz high-speed mode with higher quiescent current; leaving BW open reduces standby current for power-sensitive applications at reduced bandwidth. According to the TI datasheet, this pin lets designers trade standby power for speed on a per-channel basis, which is unique among buffer ICs of this class.
What is the best drop-in replacement for BUF634FKTTT?
The best drop-in replacement for the BUF634FKTTT is the BUF634A in the same TO-263 (KTT) package, which TI identifies as an upgraded, drop-in-compatible successor on the BUF634 product page. Because it shares the same footprint and pinout, migration requires no PCB redesign while gaining improved performance. For reduced package options, other BUF634 family members exist, but only same-package KTT variants are true drop-in replacements.
Is BUF634FKTTT suitable for driving capacitive loads?
Yes. According to the TI datasheet, a key application of the BUF634 is improving capacitive load drive when used inside an op amp feedback loop. The open-loop buffer isolates the capacitive load from the op amp's internal output stage, moving the load pole out of the loop-gain path. This makes the BUF634FKTTT well suited for driving long cables, ADC input networks, and reference bypass capacitance that would destabilize a standalone precision op amp.
BUF634FKTTT vs BUF634A - which is better for a new design?
For new designs, the BUF634A is the better choice: TI markets it as a drop-in replacement with upgraded functionality compared to the BUF634. The original BUF634FKTTT remains active and fully supported, so existing production designs do not need to change. If you are starting a fresh PCB layout, use the BUF634A in the same TO-263 (KTT) package; if you are maintaining a legacy BOM, the BUF634FKTTT stays a valid, active part.
Where can I buy BUF634FKTTT and how much does it cost?
The BUF634FKTTT is available from authorized distributors including DigiKey and Mouser, as well as secondary sources such as Ampheo and Octopart-listed suppliers; DigiKey lists the part as in stock and ships same day. Pricing on this page is provided as of 2026-09-13 with quantity breaks from 1 to 1000 units. Note that distributor pricing changes frequently, so verify current price and stock at checkout on the distributor site before ordering.
Is BUF634FKTTT in stock and what is the lead time?
Yes, per the verified distributor data, DigiKey shows BUF634FKTTT available with same-day shipping ("Buy now, ships today"). Mouser also lists inventory for the part, and Octopart aggregates 2 distributors carrying it. Lead time for in-stock units is standard distributor shipping time. As of 2026-09-13 the part is in active production at Texas Instruments, so ongoing supply should not be a concern, though checking distributor stock before scheduling production is recommended.
What package does BUF634FKTTT come in and what is the pinout?
The BUF634FKTTT comes in a TO-263 package known as DDPAK-5 or KTT, with 5 functional pins plus the thermal tab, and is a surface-mount device. The package provides a low thermal resistance path for dissipating power at 250 mA output currents. Refer to the TI BUF634 datasheet PDF for the complete pin configuration diagram, package dimensions, and land pattern recommendation for the KTT package.
Where can I download the BUF634FKTTT datasheet PDF?
The BUF634FKTTT datasheet PDF is available directly from Texas Instruments at https://www.ti.com/lit/ds/symlink/buf634.pdf (the BUF634 250mA High-Speed Buffer datasheet, 40 pages). The same document covers the entire BUF634 family including the FKTTT KTT-package variant. A mirror is also listed on alldatasheet.com, but always prefer the TI.com original for the latest revision, since TI occasionally updates electrical characteristics and application guidance.
What supply voltage does BUF634FKTTT need?
The BUF634FKTTT operates from dual supplies of +/-2.25V to +/-18V, equivalent to 4.5V to 36V total across the supply pins. This wide range covers common analog rails such as +/-5V, +/-12V, and +/-15V, and also supports wide-swing applications near the +/-18V limit. According to the TI datasheet, ensure supply decoupling of at least 0.1uF close to both supply pins, and respect absolute maximum ratings when close to the upper supply limit.
How much power can BUF634FKTTT dissipate in the TO-263 package?
Estimated: the DDPAK (TO-263/KTT) package with a solid copper pour typically achieves a junction-to-ambient thermal resistance in the tens of C/W range. For example, at +/-15V supplies delivering 250 mA into a load, internal dissipation is roughly the output voltage drop times load current; verify against the datasheet thermal table and derate above 25C ambient. Always consult the TI BUF634 datasheet package-thermal section for the exact theta-JA value for your PCB copper area before finalizing a design.
What is the best TI equivalent for BUF634FKTTT in other packages?
The BUF634 family offers the same 250 mA buffer die in multiple packages: the BUF634FKTTT (TO-263/DDPAK KTT), BUF634T (TO-220-5), and BUF634U (SOIC-8), all from Texas Instruments. The direct equivalent with upgraded performance is the BUF634A family, which TI identifies as a drop-in successor. Note that only KTT-package variants are pin-to-pin drop-in replacements for the FKTTT; SOIC-8 and TO-220 versions require different footprints.
Is BUF634FKTTT still active or is it end-of-life?
The BUF634FKTTT is an active part in TI's catalog. TI's product page notes the BUF634 is a "250-mA high-speed buffer - see BUF634A for upgraded version," which is a recommendation for new designs rather than a discontinuation notice. Distributors including DigiKey and Mouser actively stock it as of 2026-09-13. For long-term supply planning, evaluate the BUF634A as a second-source on new spins, since TI positions it as the drop-in upgraded successor.

Engineering reference data for BUF634FKTTT — comparison, design guidance, and compliance information.

Selection Guide

Choose the BUF634FKTTT when you need a proven 250 mA high-speed buffer in the thermally capable TO-263 (KTT) package and your existing PCB footprint is already KTT - it remains active and in stock at major distributors as of 2026-09-13. For new designs, choose the BUF634A in the same KTT package (BUF634AKTTT), which TI positions as the upgraded drop-in successor on the same footprint. If board area is more critical than thermal performance, the BUF634AIDR/BUF634AIDDAR in SOIC-8 offer the same electrical family in a smaller footprint, but require a layout change and dissipate less heat through the PCB. For prototyping on breadboards, the BUF634P DIP-8 variant is convenient. In all cases, the BUF634 family is specifically optimized for use inside op amp feedback loops - if you need a standalone closed-loop buffer amp rather than an in-loop booster, consider general-purpose high-output-current op amps instead.

Comparison with Alternatives

Parameter This Product BUF634AKTTT BUF634AIDDAR BUF634AIDR
Package TO-263 (DDPAK / KTT), 5+tab TO-263 (DDPAK / KTT) - same SOIC-8 (D) - different footprint SOIC-8 (D) - different footprint
Brand Texas Instruments Texas Instruments Texas Instruments Texas Instruments
Output Current 250 mA 250 mA 250 mA 250 mA
Bandwidth 180 MHz 180 MHz (upgraded performance per TI) 180 MHz (upgraded performance per TI) 180 MHz (upgraded performance per TI)
Slew Rate 2000 V/us [DATA_NEEDED] [DATA_NEEDED] [DATA_NEEDED]
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
Operating Temperature -40C to +125C -40C to +125C -40C to +125C -40C to +125C
Lifecycle Active (TI recommends BUF634A for new designs) Active - TI's upgraded drop-in successor Active - upgraded family Active - upgraded family

Key Differentiators

  • In-loop buffering eliminates thermal feedback (vs BUF634AKTTT)
  • Selectable standby power via BW pin (vs BUF634AIDDAR)
  • Sustained 250 mA without heatsink hardware (vs BUF634AIDR)

Design Notes

When closing an op amp loop around the BUF634FKTTT, ensure the op amp phase margin is analyzed with the buffer inside the loop. Although the open-loop buffer adds minimal phase shift, the BW pin setting changes the buffer's small-signal behavior: BW tied to V- gives the full 180 MHz mode with higher quiescent current, while BW open reduces standby power at reduced bandwidth. Choose the mode deliberately - leaving BW floating unintentionally due to a layout error is a common source of reduced bandwidth.

Estimated: at +/-15V supplies delivering 100 mA into a mid-rail load, dissipation is roughly (V+ - VOUT) * IOUT, on the order of 1-2 W sustained. The KTT DDPAK tab must be soldered to at least 1 square inch of 2-oz copper pour to keep junction temperature within the -40C to +125C rating. Verify the exact theta-JA value in the TI BUF634 datasheet thermal section for your specific board stackup before finalizing power budget.

Place 0.1uF ceramic decoupling capacitors within 3 mm of both supply pins, with a 4.7uF-10uF bulk capacitor nearby. Keep the BW pin trace short and, in noisy environments, route it away from switching regulators. For capacitive loads beyond a few hundred pF or long cables, add a small series output resistor (10-50 ohm) to isolate transmission-line effects at the 180 MHz bandwidth edge. The exposed tab is electrically connected internally per the datasheet - verify tab net before connecting it to a copper pour.

Compliance Information

RoHS
Unknown
REACH
Unknown
AEC-Q100
Not Applicable
Lead Free
Unknown
Halogen Free
Unknown
Conflict Minerals
Unknown

Compliance data was not present in the verified web data retrieved for this part. Consult the TI product page for BUF634FKTTT environmental certification details.

Data verified on: 2026-09-13 — data verified and curated by XAIPART's component engineering team

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Related Components & Terms

Texas Instruments BUF634FKTTT BUF634 BUF634A BUF634AKTTT BUF634AIDR BUF634U buffer amplifier unity-gain open-loop buffer high-speed operational amplifier buffer PSRR TO-263 DDPAK-5 KTT surface mount RoHS thermal feedback capacitive load drive slew rate bandwidth select pin
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