AD9070

–11–

REV. B

+5 V Operation

The AD9070 may be operated above ground, with a single +5 V

power supply. All power supply ground pins are connected to

must be taken in connecting signals and determining bypass rails.

The reference voltage (REF OUT) is still generated with respect

to the positive rail, which is now +5 V. It is nominally +2.5 V,

but its voltage with respect to ground will vary directly with

changes in the power supply voltage (for example, if the power

supply goes to +5.1 V, the reference becomes +2.6 V). The

reference input is likewise processed with respect to +5 V. This

dictates that these pins be bypassed to +5 V as well. However,

the COMP and REF BYPASS pins must continue to be

bypassed to the most negative supply, which is now ground. The

AIN input must still be connected or bypassed to the ground

reference of the input signal.

AD9070

0.1 F

ENCODE

ENCODE

GND

500

0.1 F

ENCODE

ENCODE

1Vp-p

AIN

AIN

VREF OUT

VREF IN

(MSB) D9

510

(OR 100

TO +3V)

D9

(LSB) D0

510

(OR 100

TO +3V)

D0

+5V

COMP

REF

BYPASS

10 H

+5V

0.1 F

0.1 F

0.1 F

Figure 22. AD9070 in +5 V (PECL) Environment

Package Options

The AD9070 is available in two packages. The BR package is a

standard 28-lead Small Outline IC (SOIC). The DIP package is

a ceramic Dual-in-Line Hybrid. The SOIC is offered in a commer-

cial grade, and specified over the industrial (–40

°C to +85°C)

temperature range. The DIP is a full MIL-PRF-38534 QML

version that operates from (–55

°C to +125°C).

The SOIC version includes the on-chip voltage reference,

whereas the DIP does not. The DIP, however, provides the

Overrange (OR) output, and includes reference and power

supply bypassing, along with an internal compensation capacitor.

Equivalent performance may be obtained with either part

though, due to the internal bypassing, the DIP is not as sensitive

to board layout and parasitics.