GENERAL DESCRIPTION

The AD8519 and AD8529 are rail-to-rail output bipolar amplifiers with a unity gain bandwidth of 8 MHz and a typical voltage offset of less than 1 mV. The AD8519 brings precision and bandwidth to the SC70 and SOT-23 packages. The low supply current makes the AD8519/AD8529 ideal for battery powered applications. The rail-to-rail output swing of the AD8519/AD8529 is larger than standard video op amps, making
them useful in applications that require greater dynamic range than standard video op amps. The 2.9 V/μs slew rate makes the AD8519/AD8529 a good match for driving ASIC inputs such as voice codecs.
The small SC70 package makes it possible to place the AD8519 next to sensors, reducing external noise pickup.
The AD8519/AD8529 is specified over the extended industrial (−40°C to +125°C) temperature range. The AD8519 is available in 5-lead SC70 and 5-lead SOT-23 packages, and an 8-lead SOIC surface-mount package. The AD8529 is available in 8-lead SOIC and 8-lead MSOP packages.

 

FEATURES

Space-saving SC-70 and SOT-23 packaging
Wide bandwidth: 8 MHz @ 5 V
Low offset voltage: 1.2 mV maximum
Rail-to-rail output swing
2.9 V/μs slew rate
Unity gain stable
Single-supply operation: 2.7 V to 12 V

 

APPLICATIONS

Portable communications
Microphone amplifiers
Portable phones
Sensor interface
Active filters
PCMCIA cards
ASIC input drivers
Wearable computers
Battery-powered devices
Voltage reference buffers
Personal digital assistants

 

APPLICATIONS INFORMATION

MAXIMUM POWER DISSIPATION

The maximum power that can be safely dissipated by the AD8519/AD8529 is limited by the associated rise in junction temperature. The maximum safe junction temperature is 150°C for these plastic packages. If this maximum is momentarily exceeded, proper circuit operation is restored as soon as the die temperature is reduced. Operating the product in an overheated condition for an extended period can result in permanent damage to the device.
PRECISION FULL-WAVE RECTIFIER
Slew rate is probably the most underestimated parameter when designing a precision rectifier. Yet without a good slew rate, large glitches are generated during the period when both diodes are off.
This type of rectifier can be very precise if the following electrical parameters are adhered to:
• All passive components should be of tight tolerance, 1% for resistors and 5% for capacitors.
• If the application circuit requires high impedance (that is, direct sensor interface), then an FET amplifier is a better choice than the AD8519.
• An amp such as the AD8519, which has a great slew rate specification, yields the best result because the circuit involves switching.

 

10× MICROPHONE PREAMP MEETS PC99 SPECIFICATIONS

This circuit, while lacking a unique topology, is anything but featureless when an AD8519 is used as the op amp. This preamp gives 20 dB gain over a frequency range of 20 Hz to 20 kHz and is fully PC99 compliant in all parameters including THD + N, dynamic range, frequency range, amplitude range, and crosstalk.
Not only does this preamp comply with the PC99 specifications, it far surpasses them. In fact, when the input noise is 120 dB, this preamp has a VOUT noise of around 100 dB, which is suitable for most professional 20-bit audio systems. At 120 dB THD + N in unity gain, the AD8519 is suitable for 24-bit professional audio systems. In other words, the AD8519 will not be the limiting performance factor in audio systems despite its small size and low cost.
Slew rate related distortion is not present at the lower voltages because the AD8519 is so fast at 2.1 V/μs. A general rule of thumb for determining the necessary slew rate for an audio system is to take the maximum output voltage range of the device, given the design’s power rails, and divide by two.
Many audio circuits are enhanced with the use of the AD8519. Examples include: active audio filters such as bass, treble, and equalizers; PWM filters at the output of audio DACs; buffers and summers for mixing stations; and gain stages for volume control.