Datasheet AD834 (Analog Devices) - 10

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AD834 Data Sheet EXPLANATION OF TYPICAL PERFORMANCE
The squarer configuration shown in Figure 8 is used to determine
CHARACTERISTICS AND TEST CIRCUITS
wideband performance because it eliminates the need for (and the response uncertainties of) a wideband measurement device Figure 4 is a plot of the mean-square output vs. frequency for at the output. The wideband output of a squarer configuration the test circuit of Figure 8. Note that the rising response is due is a fluctuating current at twice the input frequency with a mean to package resonances. value proportional to the square of the input amplitude. For frequencies above 1 MHz, ac feedthrough is dominated by By placing the capacitors, C3/C5 and C4/C6, across the load static nonlinearities in the transfer function and the finite offset resistors, R1 and R2, a simple low-pass filter is formed, and the voltages. The offset voltages cause a small fraction of the funda- mean-square value is extracted. The mean-square response can mental to appear at the output, and can be nulled out (see be measured using a DVM connected across R1 and R2. Figure 5). Care should be taken when laying out the board. When using THD data represented in Figure 6 is dominated by the second the DIP package, mount the IC socket on a ground plane with a harmonic, and is generated with 0 dBm input on the ac input clear area in the rectangle formed by the pins. This is important and 1 V on the dc input. For a given amplitude on the ac input, because significant transformer action can arise if the pins pass THD is relatively insensitive to changes in the dc input ampli- through individual holes in the board; improperly constructed test tude. Varying the ac input amplitude while maintaining a jigs have caused oscil ation at 1.3 GHz. constant dc input amplitude affects THD performance. Rev. F | Page 10 of 20 Document Outline Features Applications Functional Block Diagram General Description Product Highlights Revision History Specifications Absolute Maximum Ratings Thermal Characteristics Chip Dimensions and Bonding Diagram ESD Caution Pin Configuration and Function Descriptions Typical Performance Characteristics Test Circuits Explanation of Typical Performance Characteristics and Test Circuits Theory of Operation Transfer Function Biasing the Output Transformer Coupling Wideband Multiplier Connections Power Measurement (Mean-Square and RMS) Frequency Doubler Wideband Three-Signal Multiplier/Divider Outline Dimensions Ordering Guide