VGA001 Variable Gain Amplifier • 100Hz - 100MHz Variable Gain Amplifier • Fully differential input and output • Can be used as single-ended input to differential output • 3.3V Supply • Designed in C3N (0.35µ) process (See General Notes 1) 1.0 Description The VGA001 is a voltage controlled Variable Gain Amplifier. It was designed for a maximum input signal of 600uV over a bandwidth of 100Hz to 100MHz. A control voltage must be provided to set the gain, and the typical range is –3dB to 17dB. Additional circuitry can be used to control the common mode voltage of the differential output. The current required for the common mode adjustment circuitry varies depending on the desired voltage level. (3) 2.0 Key Performance Features Key Performance Features Value Nominal bandwidth 100Hz to 100MHz Nominal gain range -3dB to 17dB Nominal reference current 25uA Temperature range 0 – 85 ºC Nominal supply voltage, Vdd 3.3V Nominal supply current, Idd 1.2mA Maximum supply current (simulated) 2.2mA Functional Silicon (2) Status 3.0 Cell Pin Definition IREF25u INP INN LVDD + OUTP – OUTN CNTRL LVSS AMI Semiconductor www.amis.com Pin Name Description LVDD Positive voltage supply LVSS Ground IREF25u Reference current CNTRL Gain control voltage INP Positive input INN Negative input OUTP Positive output OUTN Negative output VGA001 Variable Gain Amplifier 4.0 General Notes (1) C3N is a double-poly process. The VGA could be used in a single-poly process, but some adjustment would be required because the resistivity of the poly would be slightly different. (2) Parts have only been evaluated in ceramic packages. (3) The common mode adjust circuit may require significant current to move the common mode voltage close to either supply rail. 5.0 Application Notes The VGA uses transistors to change the resistance seen by the amplifiers and changes the effective gain. However, the change in the resistance also changes the common mode voltage on the output, and thus a common mode adjust circuit may be required. The gain range is sensitive to the reference current and also to the external load; a differential buffer should be used when driving large loads. The gain vs control voltage function is not linear, but it is monotonic, and centered approximately about Vdd/2. AMI Semiconductor www.amis.com © 2002 AMI Semiconductor, Inc. AMI Semiconductor makes no warranty for the use of its products, other than those expressly contained in the company’s standard warranty contained in AMI Semiconductor’s Terms and Conditions. The company assumes no responsibility for any errors which may appear in this document, reserves the right to change devices or specifications detailed herein at any time without notice, and does not make any commitment to update the information contained herein. No licenses to patents or other intellectual property of AMI Semiconductor are granted by the company in connection with the sale of AMI Semiconductor products, expressly or by implication.