Descripción

The BUF634A device is a high-performance, high fidelity, open-loop buffer that is capable of driving 250 mA of output current. The BUF634A is a 36-V device with an adjustable bandwidth of 35 MHz to 210 MHz, which is accomplished by varying the value of an external resistor between the V– and BW pins.
The BUF634A device can be used as a standalone open-loop driver, or used inside the feedback loop of a precision op amp to provide both high-precision and large output current drive with improved capacitive load drive.
For low-power applications, the BUF634A device operates on a 1.5-mA quiescent current with a 250-mA output, 3750-V/µs slew rate, and 35-MHz bandwidth. The device consumes 8.5-mA quiescent current in wide-bandwidth mode with a 210-MHz bandwidth. The BUF634A is fully protected by an internal current limit in its output stage and by thermal shutdown, making the device rugged and easy to use.
The BUF634A device is rated to function over the extended industrial temperature range of –40°C to +125°C. The BUF634A comes in three packages: D (SOIC), DRB (VSON), and DDA (HSOIC). The DRB (VSON) and DDA (HSOIC) packages have excellent thermal performance resulting from the thermal pad on the bottom side. The DRB package comes in a very small form factor of 3.0 mm × 3.0 mm, making the device a very suitable option for portable and size constrained applications.

 

Características

• Pin-Selected Bandwidth: 35 MHz to 210 MHz
• High Output Current: 250 mA
• Slew Rate: 3750 V/µs
• Low Quiescent Current: 1.5 mA (35-MHz BW)
• Wide Supply Range: ±2.25 V to ±18 V
• Internal Output Current Limit
• Thermal Shutdown Protection
• Available in Packages with Thermal Pad
• Extended Temperature Operation:–40°C to +125°C

 

Aplicaciones

• Memory, Semiconductor Testers
• Test Equipment
• Headphone Drivers
• Flight Control Systems
• Capacitive Load Drivers
• Valve Drivers, Solenoid Drivers
• Line Drivers

 

Visión general

The BUF634A device is a high-speed, unity-gain, open-loop buffer that can be used in a wide range of applications requiring large output current drive or large slew rates. The BUF634A can operate on power supplies ranging from 4.5 V to 36 V and includes an internal output current limiting feature and thermal shutdown, thereby making the device rugged and easy to use.
The bandwidth of the BUF634A can be adjusted by connecting a resistor between the V– and BW pins. Its power scaling with bandwidth makes the device suitable for use in portable battery-powered applications.
The BUF634A can be used in a composite loop (inside the feedback loop of op amps) to increase output current, eliminate thermal feedback, and improve capacitive load drive. Decoupling the high-power output current stage from the precision amplifier gives high precision performance by eliminating thermal effects on input offset of the composite circuit. With a large slew rate of 3750 V/µs, the BUF634A can quickly reproduce its input signal at its output without adding considerable delay when used in a composite loop. When used in a composite loop, the outer amplifier controls the circuit precision and distortion performance and the buffer augments the circuit output current drive capability.

 

Apagado térmico

Power dissipated in the BUF634A causes the junction temperature to rise. A thermal protection circuit in the BUF634A disables the output when the junction temperature reaches approximately 180°C. When the thermal protection is activated, the output stage is disabled and the output current is limited, allowing the device to cool. Quiescent current is approximately 12 mA during thermal shutdown. When the junction temperature cools to approximately 160°C, the output circuitry is again enabled. This process can cause the protection circuit to cycle on and off with a period ranging from a fraction of a second to several minutes or more, depending on package type, signal, load, and thermal environment.
The thermal protection circuit is designed to prevent damage during abnormal conditions. Any tendency to activate the thermal protection circuit during normal operation is a sign of an inadequate heat sink or excessive power dissipation for the package type.