Data Sheet

AD8313

EVALUATION BOARD

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Rev. F | 21 of 23

Figure 42. Layout of Signal Layer

Figure 43. Signal Layer Silkscreen

Figure 44. Evaluation Board Schematic

Table 8. Evaluation Board Configuration Options

Component

Function

Default

VPS1, VPS2,

GND, VNEG

Supply Pins. VPS1 is the positive supply pin for the AD8313. VPS2 and VNEG are the positive and negative

supply pins for the AD8009. If the AD8009 is being operated from a single supply, VNEG should be

connected to GND. VPS1 and VPS2 are independent. GND is shared by both devices.

Not Applicable

Z1

AD8313 Logarithmic Amplifier. If the AD8313 is used in measurement mode, it is not necessary to power up

the AD8009 op amp. The log output can be measured at TP1 or at the SMA connector labeled VSET.

Installed

Z1

AD8009 Operational Amplifier.

Installed

SW1

Device Enable. When in Position A, the PWDN pin is connected to ground and the AD8313 is in normal

operating mode. In Position B, the PWDN pin is connected to an SMA connector labeled ENBL. A signal can

be applied to this connector.

SW1 = A

R7, R8

Slope Adjust. The slope of the AD8313 can be increased from its nominal value of 18 mV/dB to a maximum

of 40 mV/dB by removing R11, the 0 Ω resistor, which shorts VSET to VOUT, and installing a 0 Ω resistor at

R7. The 20 kΩ potentiometer at R8 can then be used to change the slope.

R7 = 0 Ω (Size 0603)

R8 = installed

Operating in Controller Mode. To put the AD8313 into controller mode, R7 and R11 should be removed,

breaking the link between VOUT and VSET. The VSET pin can then be driven externally via the SMA

connector labeled VSET.

L/R, C1, C2, R9

Input Interface. The 52.3 Ω resistor in position L/R, along with C1 and C2, create a wideband 50 Ω input.

Alternatively, the 52.3 Ω resistor can be replaced by an inductor to form an input matching network. See

Input Coupling section for more details. Remove the 0 Ω resistor at R9 for differential drive applications.

L/R = 53.6 Ω (Size 0603)

C1 = C2 = 680 pF (Size 0603)

R9 = 0 Ω (Size 0603)

R10, R12

Op Amp Gain Adjust. The AD8009 is initially configured as a buffer; gain = 1. To increase the gain of the op

amp, modify the resistor values R10 and R12.

R10 = open (Size 0603)

R12 = 301 Ω (Size 0603)