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Single-Ended Configuration

IOUT1

IOUT2

50

Ω

25

Ω

50

Ω

AGND

Reference Operation

Internal Reference

I

OUTFS +

32

I

REF +

32

V

REF

R

SET

(9)

External Reference

DAC5652

SLAS452A – MARCH 2005 – REVISED FEBRUARY 2006

APPLICATION INFORMATION (continued)

load resistance of 25

Ω. Node IOUT2 must be connected to AGND or terminated with a resistor of 25 Ω to

AGND. The nominal resistor load of 25

Ω gives a differential output swing of 1 V

full-scale output current.

Figure 20. Driving a Doubly-Terminated 50-

Ω Cable Using a Single-Ended Output

The DAC5652 has an on-chip reference circuit which comprises a 1.2-V bandgap reference and two control

Using the internal reference, a 2-k

Ω resistor value results in a full-scale output of approximately 20 mA. Resistors

with a tolerance of 1% or better should be considered. Selecting higher values, the output current can be

adjusted from 20 mA down to 2 mA. Operating the DAC5652 at lower than 20-mA output currents may be

desirable for reasons of reducing the total power consumption, improving the distortion performance, or

observing the output compliance voltage limitations for a given load condition.

It is recommended to bypass the EXTIO pin with a ceramic chip capacitor of 0.1 µF or more. The control

amplifier is internally compensated and its small signal bandwidth is approximately 300 kHz.

The internal reference can be disabled by simply applying an external reference voltage into the EXTIO pin,

which in this case functions as an input. The use of an external reference may be considered for applications that

require higher accuracy and drift performance or to add the ability of dynamic gain control.

While a 0.1-µF capacitor is recommended to be used with the internal reference, it is optional for the external

reference operation. The reference input, EXTIO, has a high input impedance (1 M

Ω) and can easily be driven

by various sources. Note that the voltage range of the external reference must stay within the compliance range

of the reference input.

17

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