SK99

The SK99 is a discrete Op-Amp that is pin compatible with the API* 2520. It is a low noise, high performance DOA that will perform extremely well in every applications.

Highlights

Pin compatible with API 2520 and “99” DOA's
100% Class A with RL ≥ 600 Ω
Low noise, high speed, high gain, low offset
Very good stability
Matched transistors
Large supply voltage range
Short circuit protected output
Rich 20mA quiescent current

More details

The SK99 is available in 2 versions corresponding to different current in the input transistor pair.

SK99A : 60uA. It will give its best noise performance with high impedance source, like high ratio input transformers (1:4 and above).
SK99B : 2.2mA. It will give its best noise performance with low impedance source, like low ratio input transformers (1:1 to 1:5) or transformerless input. It also has a wider bandwidth than the A type.

Measurements

Typical values measured with an HP8903A Audio Analyser, a Fluke 187 multimeter a Tektronix 475 oscilloscope.
Measurement	Conditions	Value
SK99A
Open loop gain	@20Hz	120dB
Bandwidth	Gain=+40dB Deviation=-3dB	DC to 200KHz
Slew rate		8V/us
Input DC offset		250uV
Input bias current		50nA
EIN	Input shorted Bandwidth=0-30KHz	552nV or -123dBu
Max output voltage	Supply ±24V RL=150Ω	25.5dBu
Peak output current		+300mA/-250mA
Supply voltage		±15V to ±24V
Supply current	Supply ±24V	25mA
SK99B
Open loop gain	@20Hz	132dB
Bandwidth	Gain=+40dB Deviation=-3dB	DC to 600KHz
Slew rate		35V/us
Input DC offset		7.5mV
Input bias current		3uA
EIN	Input shorted Bandwidth=0-30KHz	146nV or -134.5dBu
Max output voltage	Supply ±24V RL=150Ω	23dBu
Peak output current		+300mA/-250mA
Supply voltage		±15V to ±24V
Supply current	Supply ±24V	28mA

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