AD7538 Analog Devices, AD7538 Datasheet - Page 14

• Manufacturer Part Number: AD7538
• Description: LC2MOS Microprocessor-Compatible 14-Bit DAC
• Manufacturer: Analog Devices

Specifications of AD7538

• Resolution (bits): 14bit
• Dac Update Rate: 667kSPS
• Dac Settling Time: 1.5µs
• Max Pos Supply (v): +15.75V
• Single-supply: No
• Dac Type: Current Out
• Dac Input Format: Par

AD7538
DIGITAL FEEDTHROUGH
The digital inputs to the AD7538 are directly connected to the
microprocessor bus in the preceding interface configurations.
These inputs are constantly changing even when the device is
not selected. The high frequency logic activity on the bus can
feed through the DAC package capacitance to show up as noise
on the analog output. To minimize this digital feedthrough
isolate the DAC from the noise source. Figure 13 shows an
interface circuit, which uses this technique. All data inputs are
latched from the bus by the CS signal. One may also use other
means, such as peripheral interface devices, to reduce the digital
feedthrough.
Rev. B | Page 14 of 16
PROCESSOR
Figure 13. AD7538 Interface Circuit Using Latches to Minimize Digital
SYSTEM
MICRO-
D0 TO D15
A0 TO A15
WR
1
LINEAR CIRCUITRY OMITTED FOR CLARITY.
Feedthrough
ADDRESS
DECODE
LATCH
16-BIT
EN
CS
LDAC
WR
DB0 TO DB13
AD7538
1