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Getting Started
2 Getting Started
This section explains the connectors and test points, and details the basic EVM functionality.
2.1 Power Supplies
The JFE150EVM is configured by default to operate from a single supply voltage of VDD = 12 V and VSS =
GND. VSS can be tied to GND by using a short BNC cable from the VSS banana jack to any GND banana jack
shown in
Figure
4-2. If dual-supply operation is required, VSS can be powered separately; adjust components
R25 and R12 to bias the JFE150 to the desired bias point. Set Vbias to midsupply, as discussed in section
Section
2.3.
2.2 Input
The input to the JFE150EVM is designed to interface high-impedance sources to the gate of the JFET. The
input is ac-coupled with capacitor C8 and the dc gate bias voltage is set with resistor R10. A single BNC
connector and Vin test point are available at the input to allow for an easy interface with signal generators or
other equipment. The midband gain of the circuit is approximately 1000 V/V or 60 dB, as shown in
For example, a 1-mVpp, 1-kHz input signal produces an approximately 1-Vpp, 1-kHz signal measured on the
output. The
Design tools and simulation
2.3 Vbias
The section labeled Vbias in
configuration is used to set the Vbias node to midsupply on a single supply voltage. Operating the EVM on
a single supply voltage of VDD = 12 V and VSS = GND results in Vbias ≅ 6 V. Vbias sets the common-mode
voltage of the OPA202 resulting in a dc voltage of approximately 6 V seen at the Vout of the EVM. Monitor Vbias
by using the test point labeled Vbias. When using the EVM in a dual-supply configuration, set the Vbias point to
midsupply by removing resistor R16 and replacing R17 with a 0-Ω resistor.
2.4 Output
Monitor the EVM output by using the BCN connector labeled Vout or the test point labeled Vout. Resistor R6
is used as an isolation resistor on OPA202 output to improve circuit stability while driving high capacitive loads
greater than 1 nF. Resistor R6 can be removed if no capacitive load drive is required.
2.5 Capacitors
When altering the JFE150EVM default configuration, consider the polarity of tantalum and electrolytic capacitors.
The JFE150EVM is populated with bipolar electrolytic capacitors for capacitors C6, C8, and C16.
4
JFE150 Evaluation Module
tab on the device web folder can assist with other configurations.
Figure 4-1
consists of a simple voltage divider. The default voltage divider
Copyright © 2022 Texas Instruments Incorporated
www.ti.com
Figure
3-2.
SLPU009 – FEBRUARY 2022
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