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Optional Configurations

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4.2 DAC Output to Filter Network and 4:1 Transformer

The DAC output can first go through a filter network before going to the 4:1 transformer. The network can

accommodate up to a 5th order filter network. As an example, the instructions below will provide an option

for a 5th order Butterworth low-pass filter with 75MHz cut-off frequency. To employ this option, please use

the following settings:

1. Remove 1uF at C31, C32, C33, and C34

2. Install 0-Ω at R140, R148, R150, R151, R152, R154, R158, and R159

3. Install 270nH at L12, L17, R125, R128, L14, L19, R111, and R115

4. Install 22pF at C166 and C160

5. Install 12pF at C171, R124, R105, and C161

6. Install 0-Ω at L13, L16, L15, and L18

7. Remove 100-Ω at R7, R13, R21, and R26

Please refer to the TSW4200-DAC EVM schematic in the design package for the filter example mentioned

above. Other filter component values can also be used to provide a desired frequency response.

4.3 TRF3703-33 Output

The back side of the EVM contains the TRF3703-33 quadrature modulator as an alternative to the

TRF372017 device. To employ this option, please use the following settings:

1. Remove 1uF at C31, C32, C33, and C34

2. Install 0-Ω at R142, R145, R146, and R149

3. Remove 100-Ω at R126 and R114

4. Install 100-Ω at R124 and R105

5. Install L13, L16, L15, and L18

6. Move jumper at JP17 to the TRF3703 side to power up the device.

For this option, an external LO signal must be applied at J27, and the output is monitored at J24.

4.4 External LO Option for the TRF372017

The TRF372017 can be configured for external LO. Toggle the En_EXTVCO register on the TRF372017

tab and inject the desired LO frequency at J26.

4.5 External Clock Frequency

An external clock can be provided instead of using the internal VCO of the CDCE62005. To configure the

CDC for this operation, modify the following on the CDC tab of the software.

1. Inject desired clock signal at J25 (i.e., 614.4 MHz)

2. Remove jumper at JP19

3. Move jumper at JP22 to connect pins 2 and 3

4. Change Input Level to LVPECL

5. Change Input Source to Manual_PRI-IN

6. Change Pri Ref PreDivider to Divide by 1

7. Change Sec Ref PreDivider to 3-state

8. Select Pri Term to Disabled

9. Change Output 0 through 4 from VCO to Primary

10. Toggle Wake up button

4.6 DC/DC Power Supply Bypass Mode

The primary DC/DC switching power supply (U14) can be completely bypassed to further minimize the

switching noise of the power supply. The main 6V is stepped down initially by two TPS7A4501 LDOs (U17

and U18). To bypass the DC/DC power supply, please modify the following:

1. Remove 0-Ω at R88, R96, and R165

DAC3282 SLAU304C–February 2010–Revised November 2010

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