Texas Instruments BUF634T

Overview

BUF634T 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 across ±2.25V to ±18V supplies, enabling use in valve drivers, ATE pin drivers, and video line drivers.

For engineers reviewing the BUF634T datasheet, BUF634T pinout, BUF634T application, or BUF634T equivalent, key selection criteria include its adjustable bandwidth via external resistor, thermal shutdown protection, internal current limiting, low-quiescent-current mode (1.5mA), and compatibility with SOIC-8, TO-220-5, and TO-263-5 packages.

Technical Context

The BUF634T implements an open-loop complementary follower architecture with separate input and output stages, eliminating thermal feedback between gain and output devices. Its bandwidth is controlled by a resistor between V– and the BW pin, directly setting quiescent current and thus small-signal gain-bandwidth trade-off.

It features dual operating modes: low-quiescent-current mode (1.5mA, 30MHz) and wide-bandwidth mode (up to 15mA, 180MHz), with full protection including internal current limit and thermal shutdown at 175°C junction temperature.

Key Specifications

Pinout & Package

BUF634T is available in TO-220-5 (KC) and TO-263-5 (KTT) packages. The TO-220-5 variant uses a through-hole mounting format with exposed tab for thermal dissipation; TO-263-5 is surface-mount with similar pinout and thermal performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BUF634T, BUF634A offers superior speed at higher power cost, while LMH6321 trades bandwidth adjustability for configurable current limiting-making BUF634T optimal for designs prioritizing tunable bandwidth and lowest quiescent current in the 30–180MHz range.

Availability

BUF634T is available at Aetrix Electronics and suitable for valve drivers, ATE pin drivers, video line drivers, and solenoid drivers requiring stable component supply, long-term manufacturability, and consistent electrical performance across temperature.

Supply support for BUF634T 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 as a rugged, easy-to-use unity-gain buffer for applications demanding high output current, fast transient response, and robust protection-targeting industrial automation, test equipment, and video infrastructure.

FAQ

What is the maximum continuous output current of the BUF634T?

The BUF634T delivers ±250mA continuous output current into resistive or capacitive loads. This rating holds across its full operating temperature range (–40°C to +125°C) and supply range (±2.25V to ±18V), with internal current limiting engaging above ±350mA in low-IQ mode to protect the device. The BUF634T maintains this output capability without external boost components.

How does the BW pin function on the BUF634T?

The BW pin on the BUF634T controls bandwidth by setting quiescent current: connecting a resistor between BW and V– adjusts IQ from 1.5mA (open circuit) to 15mA (0Ω), scaling bandwidth from 30MHz to 180MHz. This resistor-based tuning avoids layout changes and enables dynamic optimization for specific signal bandwidth requirements in the final system design of the BUF634T.

Does the BUF634T require external compensation capacitors?

No, the BUF634T is an open-loop unity-gain buffer and does not require external compensation capacitors. Its internal architecture is inherently stable across all specified loads and supply conditions. However, proper PCB layout-especially ground plane integrity, short traces to V+ and V–, and local bypassing-is essential to maintain stability and achieve rated slew rate and bandwidth for the BUF634T.

What thermal protection features does the BUF634T include?

The BUF634T integrates thermal shutdown that activates at 175°C junction temperature, halting output conduction until die temperature falls by ~10°C. It also includes internal current limiting to prevent excessive power dissipation. These protections operate independently of external circuitry and remain functional across all package variants (TO-220-5, TO-263-5), ensuring robust operation of the BUF634T under sustained overload or inadequate heatsinking.

Can the BUF634T be used with single-supply configurations?

Yes, the BUF634T supports single-supply operation by biasing VIN and VO around mid-rail using a reference voltage or resistor divider. Its input common-mode range extends to within 1.6V of either rail at ±15V supply, and output swing reaches within 2.5V of each rail at 150mA load. Designers must ensure V– is connected to ground (not left floating) and verify headroom margins for their specific load and supply in the BUF634T application.