DAC5675

SLAS352C − DECEMBER 2001 − REVISED AUGUST 2004

12

www.ti.com

analog current outputs (continued)

The DAC5675 can easily be configured to drive a doubly terminated 50-

Ω cable using a properly selected

transformer. Figure 11 and Figure 12 show the 1:1 and 4:1 impedance ratio configuration. These configurations

provide maximum rejection of common-mode noise sources and even order distortion components, thereby

doubling the DAC’s power to the output. The center tap on the primary side of the transformer is terminated to

AVDD, enabling a dc current flow for both IOUT1 and IOUT2. Note that the ac performance of the DAC5675

is optimum and specified using a 1:1 differential transformer coupled output.

IOUT1

1:1

IOUT2

DAC5675

3.3 V

(AVDD)

50

Ω

50

Ω

3.3 V

(AVDD)

3.3 V

(AVDD)

RLOAD

50

Ω

100

Ω

Figure 11. Driving a Doubly Terminated 50-

Ω Cable Using a 1:1 Impedance Ratio Transformer

4:1

DAC5675

3.3 V

(AVDD)

100

Ω

100

Ω

3.3 V

(AVDD)

3.3 V

(AVDD)

RLOAD

50

Ω

IOUT1

IOUT2

15

Ω

Figure 12. Driving a Doubly Terminated 50-

Ω Cable Using a 4:1 Impedance Ratio Transformer