®

DAC707/708/709

10

signal lines need to be isolated. The data is applied to pin 11

in a serial bit stream, MSB first. The WR input is used as a

data strobe, clocking in each data bit. A RESET signal is

provided for system startup and reset. These three signals

are each optically isolated. Once the 16 bits of serial data

have been strobed into the input register pair, the data is

strobed through to the D/A register by the “carry” signal out

of a 4-bit binary synchronous counter that has counted the

16 WR pulses used to clock in the data. The circuit diagram

is given in Figure 10.

CONNECTING MULTIPLE DAC707s

TO A 16-BIT MICROPROCESSOR BUS

Figure 11 illustrates the method of connecting multiple

DAC707s to a 16-bit microprocessor bus. The circuit shown

has two DAC707s and uses only one address line to select

either the input register or the D/A register. An external

address decoder selects the desired converter.

BURN-IN SCREENING

Burn-in screening is an option available for the DAC707.

Burn-in duration is 160 hours at the temperature shown

below (or equivalent combination of time and temperature).

Product

Temp. Range

Burn-In Screening

DAC707JP-BI

0

°C to 70°C

100

°C

DAC707KP-BI

0

°C to 70°C

100

°C

DAC707KH-BI

–25

°C to +85°C

125

°C

DAC707BH-BI

–25

°C to +85°C

125

°C

DAC707SH-BI

–55

°C to +125°C

125

°C

All units are tested after burn-in to ensure that grade speci-

fications are met.

APPLICATIONS

LOADING THE DAC709 SERIALLY

ACROSS AN ISOLATION BARRIER

A very useful application of the DAC709 is in achieving

low-cost isolation that preserves high accuracy. Using the

serial input feature of the input register pair, only three