Datasheet

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6 Clamping Voltage
7 Switch Settings
ON
OFF
1
3
OPEN
SW1
HG A
HG B
PD
8 Physical Description
8.1 PCB Layout
Clamping Voltage
The VCA2617 allows for a user to limit the output voltage swing to a defined level. For this configuration,
the desired clamping voltage level is applied to the V
CLMP
A and V
CLMP
B pins of the VCA2617. The EVM
includes a 3.3V reference (U3) that supplies a stable voltage. Using potentiometer RP1, the clamping
voltage can be adjusted to the desired value.
Use switch SW1 to control the post-gain and power-down functions of the VCA2617. (See Figure 1 and
Table 1 .)
Figure 1. Switch SW1 Settings
Table 1. Switch SW1 Summary
HG A / HG B PD
ON = H (5V) Low-Gain Mode (–16dB to +32dB range) Normal operation
OFF = L (0V) High-Gain Mode (–10dB to +38dB range) Power-down mode
This section describes the physical characteristics and PCB layout of the evaluation module, and lists the
components used in the VCA2617EVM.
The EVM is constructed on a four-layer, 4.5in x 3.5in PCB using FR-4 material. Figure 2 shows the
schematic of the VCA2617EVM. Figure 3 through Figure 6 give a brief description of the individual layers.
SBOU033 – November 2005 VCA2617EVM User's Guide 3