REV. 0

AD9752

–13–

SLEEP MODE OPERATION

The AD9752 has a power-down function which turns off the

output current and reduces the supply current to less than

8.5 mA over the specified supply range of 2.7 V to 5.5 V and

temperature range. This mode can be activated by applying a

logic level “1” to the SLEEP pin. This digital input also con-

tains an active pull-down circuit that ensures the AD9752 re-

mains enabled if this input is left disconnected. The AD9752

takes less than 50 ns to power down and approximately 5

µs to

power back up.

POWER DISSIPATION

several factors which include: (1) AVDD and DVDD, the

input waveform. The power dissipation is directly proportional

than a factor of 2 when DVDD is reduced from 5 V to 3 V.

35

5

220

4

6

8

10

12

141618

30

25

20

15

10

18

16

0

0.01

1

0.1

8

6

4

2

12

10

14

125MSPS

100MSPS

50MSPS

25MSPS

5MSPS

8

0

0.01

1

0.1

6

4

2

125MSPS

100MSPS

50MSPS

25MSPS

5MSPS

APPLYING THE AD9752

OUTPUT CONFIGURATIONS

The following sections illustrate some typical output configura-

tions for the AD9752. Unless otherwise noted, it is assumed

ing the optimum dynamic performance, a differential output

configuration is suggested. A differential output configuration

may consist of either an RF transformer or a differential op amp

configuration. The transformer configuration provides the opti-

mum high frequency performance and is recommended for any

application allowing for ac coupling. The differential op amp

configuration is suitable for applications requiring dc coupling, a

bipolar output, signal gain and/or level shifting.

A single-ended output is suitable for applications requiring a

unipolar voltage output. A positive unipolar output voltage will

result if IOUTA and/or IOUTB is connected to an appropri-

figuration may be more suitable for a single-supply system

requiring a dc coupled, ground referred output voltage. Alterna-

tively, an amplifier could be configured as an I-V converter thus

converting IOUTA or IOUTB into a negative unipolar voltage.

This configuration provides the best dc linearity since IOUTA

or IOUTB is maintained at a virtual ground. Note, IOUTA

provides slightly better performance than IOUTB.

DIFFERENTIAL COUPLING USING A TRANSFORMER

An RF transformer can be used to perform a differential-to-

single-ended signal conversion as shown in Figure 28. A

differentially coupled transformer output provides the optimum

distortion performance for output signals whose spectral content

lies within the transformer’s passband. An RF transformer such

as the Mini-Circuits T1-1T provides excellent rejection of

common-mode distortion (i.e., even-order harmonics) and noise

over a wide frequency range. It also provides electrical isolation

and the ability to deliver twice the power to the load. Trans-

formers with different impedance ratios may also be used for

impedance matching purposes. Note that the transformer

provides ac coupling only.