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Parallel Interface

Cross-Reference

DAC7821

SBAS365A – OCTOBER 2005 – REVISED FEBRUARY 2006

APPLICATION INFORMATION (continued)

Data is loaded to the DAC7821 as a 12-bit parallel word. The bi-directional bus is controlled with CS and R/W,

allowing data to be written to or read from the DAC register. To write to the device, CS and R/W are brought low,

and data available on the data lines fills the input register. The rising edge of CS latches the data and transfers

the latched data-word to the DAC register. The DAC latches are not transparent; therefore, a write sequence

must consist of a falling and rising edge on CS in order to ensure that data is loaded to the DAC register and its

analog equivalent is reflected on the DAC output.

To read data stored in the device, R/W is held high and CS is brought low. Data is loaded from the DAC register

back to the input register and out onto the data line, where it can be read back to the controller.

The DAC7821 has an industry-standard pinout. Table 1 provides the cross-reference information.

Table 1. Cross-Reference

SPECIFIED

TEMPERATURE

PACKAGE

PACKAGE

CROSS-

PRODUCT

INL (LSB)

DNL (LSB)

RANGE

DESCRIPTION

OPTION

REFERENCE PART

DAC7821

±1

±1

–40

°C to +125°C

20-Lead TSSOP

TSSOP-20

AD5445

DAC7821

±1

±1

–40

°C to +125°C

QFN-20

AD5445

(1)

Available 2Q 2006.

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