Texas Instruments BUF634U/2K5

Overview

BUF634U/2K5 from Texas Instruments is a unity-gain, open-loop high-speed buffer IC designed for current boosting and capacitive load driving in precision analog signal paths. It delivers 250mA continuous output current, 2000V/µs slew rate, and pin-selectable bandwidth from 30MHz to 180MHz, enabling use as an op amp current booster in test equipment, video drivers, and solenoid/valve control circuits.

For engineers reviewing the BUF634U/2K5 datasheet, BUF634U/2K5 pinout, BUF634U/2K5 application, or BUF634U/2K5 equivalent, this page provides verified package mapping (SOIC-8), confirmed thermal shutdown and internal current limit protection, bandwidth adjustment via external resistor, and real-world design meaning for quiescent current (1.5–15mA) and output headroom (1.6–2.5V at ±100mA).

Technical Context

The BUF634U/2K5 implements an open-loop complementary follower architecture with separate bias control for bandwidth and quiescent current. Its BW pin enables resistor-based selection between low-IQ (30MHz, 1.5mA) and wide-BW (180MHz, 15mA) operating modes, directly altering internal stage currents without changing gain topology.

Thermal shutdown activates at 175°C junction temperature, and internal current limiting restricts short-circuit output to ±350–±550mA depending on mode. Input impedance ranges from 1400MΩ||5pF (low-IQ) to 180MΩ||5pF (wide-BW), supporting high-impedance source interfacing while maintaining stability into 100Ω loads.

Key Specifications

Pinout & Package

BUF634U/2K5 is supplied in an 8-pin SOIC (D) package measuring 4.9mm × 6mm, optimized for surface-mount assembly and moderate power dissipation (R_θJA = 123°C/W). Pin functions are validated per TI SBOS030C Rev. March 2024.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar unity-gain buffer applications.

Compared with BUF634U/2K5, BUF634A offers superior speed and noise but trades off power efficiency, while LMH6321 provides flexible current limiting at the cost of fixed bandwidth and higher static power - all three require distinct PCB layout and thermal design due to differing package footprints and thermal resistance.

Availability

BUF634U/2K5 is available at Aetrix Electronics and suitable for test equipment, industrial valve control, video signal distribution, and ATE pin driver applications requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for BUF634U/2K5 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor company specializing in analog and embedded processing technologies, with leadership in high-performance amplifiers and precision signal chain solutions.

The BUF634 product line was engineered for high-current, high-speed buffering in demanding analog systems - specifically targeting op amp output stage enhancement, video line driving, and industrial actuator control where unity-gain stability and ruggedness are essential.

FAQ

What is the maximum continuous output current specification for BUF634U/2K5?

The BUF634U/2K5 delivers ±250mA continuous output current into resistive or capacitive loads. This rating applies across its full operating temperature range (–40°C to +85°C ambient) and supply range (±2.25V to ±18V), with output voltage swing degrading predictably as current increases - e.g., ±13.2V at ±150mA with ±15V supplies. Current limit protection engages above ±350mA in low-IQ mode.

How does the BW pin function on BUF634U/2K5, and what resistor values set common bandwidths?

The BW pin on BUF634U/2K5 selects operating mode by connecting to V− via an external resistor. An open circuit yields 30MHz bandwidth and 1.5mA quiescent current; a 0Ω connection gives 180MHz and 15mA. Per Figure 6-9 in TI SBOS030C, 10kΩ sets ~90MHz/5mA, and 100kΩ sets ~45MHz/2.5mA. Resistor tolerance directly affects bandwidth accuracy, so 1% metal-film types are recommended.

Does BUF634U/2K5 require external compensation for driving capacitive loads?

No, BUF634U/2K5 does not require external compensation for capacitive loads. Its open-loop complementary follower architecture provides inherent stability into >1nF loads, as confirmed by Figure 6-5 and Figure 6-6 showing stable gain/phase response up to 1nF in both low-IQ and wide-BW modes. This eliminates series resistors or feedback networks needed with conventional op amps.

What thermal protection features are integrated into BUF634U/2K5?

BUF634U/2K5 integrates two independent protections: (1) internal current limiting that caps output at ±350–±550mA depending on mode and temperature, and (2) thermal shutdown that disables output above 175°C junction temperature. Both features are fully internal - no external components needed - and recovery occurs automatically once junction temperature falls below threshold by ~10°C.

Can BUF634U/2K5 operate from a single supply, and what are the implications?

BUF634U/2K5 is specified for dual-supply operation (±2.25V to ±18V) and is not characterized for true single-supply use. While it may function with V− grounded and V+ at +4.5V to +36V, input common-mode range, output swing, and thermal behavior are not guaranteed outside the symmetric supply spec. TI recommends dual supplies for full parameter compliance and reliability.