Datasheet

Evaluation Schematic
1-2
-
Power PADt heatsinking capability
EVM Channel 1:
The default configuration design for EVM channel 1 provides a voltage gain
of +2. This voltage gain is the ratio of the voltage at the output pin of the
amplifier (pin 1) to the voltage at the J3 input. R1 and R6 are equal and
therefore provide for a gain of +2.
The noninverting gain of the EVM channel 1 amplifier, when using the default
configuration, is affected by a voltage divider composed of R5 and R4. When
using a 50-Ω signal source and 50-Ω measurement device, its voltage gain
(from J3 to J1) is indicated in the following equation.
V
O
V
I
+
ǒ
1 )
R6
R1 ) R2
Ǔ
ǒ
R4 ø 50 W
R4 ø 50 W ) R5
Ǔ
+ 0.456
(1)
EVM Channel 2:
The default configuration for EVM channel 2 is designed to provide a voltage
gain of +1 with the amplifier loaded with approximately 500 Ω. This voltage
gain is the ratio of the voltage at the output pin of the amplifier (pin 9) to the
voltage input at J5.
R7 jumper makes EVM section 1 amplifier a unity gain buffer. R10 is 49.9 Ω
to match the impedance of a 50-Ω signal generator. R11 and R12 form a
voltage divider to J6, the EVM channel 2 output jack. The following equation
represents the voltage gain to J6, if a measurement device with a 50-Ω input
impedance is connected to J5.
V
O
V
I
+
ǒ
R12 ø 50 W
R12 ø 50 W ) R11
Ǔ
+ 0.473
(2)